Scholarly article on topic 'Molecular signaling of ginsenosides Rb1, Rg1, and Rg3 and their mode of actions'

Molecular signaling of ginsenosides Rb1, Rg1, and Rg3 and their mode of actions Academic research paper on "Clinical medicine"

Share paper
Academic journal
Journal of Ginseng Research
OECD Field of science
{ginsenoside / signaling / review / PPD / Rg3}

Abstract of research paper on Clinical medicine, author of scientific article — Padmanaban Mohanan, Sathiyamoorthy Subramaniyam, Ramya Mathiyalagan, Deok-Chun Yang

Abstract Ginseng has gained its popularity as an adaptogen since ancient days because of its triterpenoid saponins, known as ginsenosides. These triterpenoid saponins are unique and classified as protopanaxatriol and protopanaxadiol saponins based on their glycosylation patterns. They play many protective roles in humans and are under intense research as various groups continue to study their efficacy at the molecular level in various disorders. Ginsenosides Rb1 and Rg1 are the most abundant ginsenosides present in ginseng roots, and they confer the pharmacological properties of the plant, whereas ginsenoside Rg3 is abundantly present in Korean Red Ginseng preparation, which is highly known for its anticancer effects. These ginsenosides have a unique mode of action in modulating various signaling cascades and networks in different tissues. Their effect depends on the bioavailability and the physiological status of the cell. Mostly they amplify the response by stimulating phosphotidylinositol-4,5-bisphosphate 3-kinase/protein kinase B pathway, caspase-3/caspase-9-mediated apoptotic pathway, adenosine monophosphate-activated protein kinase, and nuclear factor kappa-light-chain-enhancer of activated B cells signaling. Furthermore, they trigger receptors such as estrogen receptor, glucocorticoid receptor, and N-methyl-d-aspartate receptor. This review critically evaluates the signaling pathways attenuated by ginsenosides Rb1, Rg1, and Rg3 in various tissues with emphasis on cancer, diabetes, cardiovascular diseases, and neurodegenerative disorders.

Academic research paper on topic "Molecular signaling of ginsenosides Rb1, Rg1, and Rg3 and their mode of actions"

J Ginseng Res xxx (2017) 1-10

10 11 12

20 21 22

Contents lists available at ScienceDirect

Journal of Ginseng Research

journal homepage:

Review article

Molecular signaling of ginsenosides Rb1, Rg1, and Rg3 and their mode of actions

q4 Padmanaban Mohanan1, Sathiyamoorthy Subramaniyam 2, Ramya Mathiyalagan1,

Deok-Chun Yang

1,2, *

1 Graduate School of Biotechnology and Ginseng Bank, College of Life Sciences, Kyung Hee University, Suwon, South Korea

2 Department of Oriental Medicinal Biotechnology, College of Life Science, Kyung Hee University, Suwon, South Korea


Article history: Received 9 August 2016 Accepted 16 January 2017 Available online xxx

Keywords: ginsenosides Korean Red Ginseng Rb1 Rg1 Rg3 Q1 signaling


Ginseng has gained its popularity as an adaptogen since ancient days because of its triterpenoid saponins, known as ginsenosides. These triterpenoid saponins are unique and classified as protopanaxatriol and protopanaxadiol saponins based on their glycosylation patterns. They play many protective roles in humans and are under intense research as various groups continue to study their efficacy at the molecular level in various disorders. Ginsenosides Rb1 and Rg1 are the most abundant ginsenosides present in ginseng roots, and they confer the pharmacological properties of the plant, whereas ginsenoside Rg3 is abundantly present in Korean Red Ginseng preparation, which is highly known for its anticancer effects. These ginsenosides have a unique mode of action in modulating various signaling cascades and networks in different tissues. Their effect depends on the bioavailability and the physiological status of the cell. Mostly they amplify the response by stimulating phosphotidylinositol-4,5-bisphosphate 3-kinase/pro-tein kinase B pathway, caspase-3/caspase-9-mediated apoptotic pathway, adenosine monophosphate-activated protein kinase, and nuclear factor kappa-light-chain-enhancer of activated B cells signaling. Furthermore, they trigger receptors such as estrogen receptor, glucocorticoid receptor, and N-methyl-D-aspartate receptor. This review critically evaluates the signaling pathways attenuated by ginsenosides Rb1, Rg1, and Rg3 in various tissues with emphasis on cancer, diabetes, cardiovascular diseases, and neurodegenerative disorders.

Copyright © 2017, The Korean Society of Ginseng, Published by Elsevier. This is an open access article under the CC BY-NC-ND license (

1. Introduction

Ginseng, a traditional herbal adaptogen, is widely used in Southeast Asian countries, and continues to gain worldwide popularity because of its medicinal properties. The root of the ginseng plant is used as medicine. Ginseng belongs to the genus Panax in the family Araliaceae. Of the 17 different species assigned to this genus, Panax ginseng, Panax notoginseng, and Panax quin-quefolius are used as medicine. Among them, P. ginseng is widely popular. It has several secondary metabolites, among which sapo-nins are the major contributing factor for its pharmacological efficacy [1]. Among the 150 different types of ginsenoside saponins, Rb1, Rb2, Rc, Rd, Re, and Rg1 constitute more than 90% of the total ginsenosides in P. ginseng. However, Rb1, Rg1, Rg3, Rd, Re, Rh1, and Rh2 are the most frequently studied [2]. Ginsenosides have diverse

pharmacological activities mainly because of their steroidal structure, which enables them to interact with cell membranes, membrane-bound ion channels, as well as extra- and intracellular receptors to produce changes at the transcriptomic level. Based on several in vitro and in vivo studies, Rb1, Rg1, and Rg3 have multiple pharmacological efficacies to neuronal, cardiovascular, and immune systems, and have neuroprotective, anticancer, and antidia-betic activities.

Ginsenoside Rb1 is abundant in roots, rhizomes, and root hairs of ginseng, compared wtih the stem and leaves. Rb1 appears to be responsible for most of the plant's pharmacological activity especially in cardiovascular, endocrine, and immune systems, and is the chief component for neuroprotection [3]. A recent investigation has suggested that Rb1 exhibits greater neuroprotection activity when administrated intranasally than orally [4]. Ginsenoside Rg1 is one of

* Corresponding author. Department of Oriental Medicinal Biotechnology, College of Life Science, Kyung Hee University, 1 Seocheon, Giheung-gu Yongin-si, Gyeonggi-do 449-701, South Korea.

E-mail address: (D.-C. Yang).

p1226-8453 e2093-4947/$ — see front matter Copyright © 2017, The Korean Society of Ginseng, Published by Elsevier. This is an open access article under the CC BY-NC-ND license (

60 61 62

80 81 82

99 100 101 102

110 111 112

118 119

J Ginseng Res 2017;rn:1-10

10 11 12

20 21 22

60 61 62

the active compounds found in ginseng. It stimulates glucose uptake, relieves oxidative stress, and suppresses adipocyte development and possible neuroprotective role as well [5]. It is reported to have phytoestrogen-like properties and resembles that of steroid hormone-like structure. It has been widely used to treat Alzheimer's disease (AD) in clinics [6] and believed to be the principal compound for the antiaging property of ginseng.

Ginsenoside Rg3 is a steroidal saponin that is highly enriched in Korean Red Ginseng. It exhibits a broad range of pharmacological activities—notably, it has an enhanced anticancer role compared with other ginsenosides [7]. It has the best proapoptosis effect [8] compared with other ginsenosides and is clinically approved for use in cancer treatment [9]. Rg3 displays stereospecificity, wherein 20(R) isomer exhibits higher antioxidant activity [11] and more potent immune response [12] but dissolves poorly, whereas 20(S) shows antidiabetic and anticancer activity and readily dissolves, making it easier to use in pharmaceutics. Rb1, Rg1, and Rg3 respectively represent the protopanaxadiol (PPD), protopanaxatriol (PPT), and Korean Red Ginseng enriched fractions, which are used as parameters to evaluate the quality of ginseng and ginseng-based products. Hence, it is important to understand the molecular mechanism and signal transduction attenuated by Rb1, Rg1, and Rg3 in various pathophysiological conditions. Therefore, this review summarizes the pathways and the receptors they modulate in neuronal disorders, cardiovascular diseases (CVDs), cancer, and diabetes mellitus (DM). We strongly believe that the information shared in this review will be helpful in generating an efficient treatment strategy with ginsenoside-based medications.

1.1. Ginsenosides are triterpenoid saponins

Ginsenosides are glycosylated triterpenoid saponins with diverse chemical structures based on the sugar moieties and linkage position on the skeleton of aglycones. Triterpenoid ginsenosides are further classified into dammarane type and oleanane type (a natural triterpene found in the flowering plants), and ocotillol type [10]. Glycosylation of hydroxylated C3, C12, and C20 hydroxylated groups at the triterpenoid skeleton contributes to the diversity of PPT and PPD. Ginsenosides Rb1 and Rg3 belongs to the PPD class whereas Rg1 belongs to the PPT class (Fig. 1) [11]. Moreover, the aglycone structure and the position of sugar moieties attached to them determine the pharmacological activity of ginsenosides.

1.2. Bioavailability and safety of ginsenosides

Most ginsenosides are poorly absorbed in the gastrointestinal tract of humans because of their poor absorption in the intestine and distribution by blood circulation. However, they are modified/transformed by gastric juices and intestinal microflora, producing ginsenosides with increased in vivo physiological activity than their parent compound. Various processing methods of ginseng and biotransformation of ginsenosides yield much simpler variants with improved

bioavailability molecules such as the conversion of Rb2 to Rg3 during red ginseng processing and metabolism of Rb1 to F2 and compound K by intestinal microflora [12]. These transformed ginsenosides further contribute to the chemical diversity of ginsenosides.

It has been believed from ancient days that ginseng is a reliable drug for longevity, and to fight fatigue and stress. Results from the effects of ginsenosides on cell culture practices and animal efficacy studies have provided promising effects in various disease conditions. The role of ginsenoside Rb1 as a neuroprotective agent, Rg3 as an anticancer and antidiabetic agent, and Rg1 as an antidiabetic agent has been established by many studies. It is important to note that ginsenosides were supplemented with other drugs to reduce or nullify the side effects produced by those drugs. The effect of ginseng consumption on cancer prevention was evaluated by a meta-analysis, which proved that ginseng use confers 16% lower risk of developing cancer regardless of tissue type [13].

2. Action of ginsenosides in CVD

CVDs, a group of disorders affecting the heart and blood vessels, account for 31% of all global deaths according to World Health Organization 2012 estimates. CVDs are often called as "the causes of causes" as any dysfunction of cardiovascular system might lead to the abnormalities of other bodily functions. Various signaling mechanisms have been attributed to involve the cardiovascular system at many different levels [14]. In recent years, the effects of ginsenosides on CVD has been researched extensively because of their intrinsic property of controlling reactive oxygen species (ROS), nitric oxide (NO) production, and the ability to activate various receptors in endothelial cells.

2.1. Ginsenosides target endothelial NO synthase, phosphatidylinositol 3-kinase/Akt pathway in endothelial cells

NO is one of the most important compounds produced in endothelial cells by nitric oxide synthase (NOS) from L-arginine. NO has various biological activities and plays a crucial role in vascular endothelium homeostasis, prevention of injury, regulation of local cell growth, etc. [15]. Endothelial NOS (eNOS) in human aortic endothelial cells are regulated by the activation of androgen receptor and phosphotidylinositol-4,5-bisphosphate 3-kinase/pro-tein kinase B (PI3K/Akt) and MEK/extracellular signal-regulated kinase (ERK) pathways. Most ginsenosides have the ability to activate NO production, but Rb1 possesses proven elucidation by triggering signaling pathways mentioned above (Fig. 2). Rb1 prevents homocysteine (Hcy)-induced oxidative damage to endothe-lial cells by activating the PI3K/Akt pathway and mitigating the protein kinase C (PKC) pathway to maintain the phosphorylation state of eNOS, thus enabling NO production [3]. Oxidized low-density lipoprotein is a most common risk factor for endothelial dysfunction in coronary atherosclerosis. It prevents NO production in endothelial cells by downregulating the expression of eNOS

Fig. 1. Structure of ginsenosides Rg1, Rb1, and Rg3.

80 81 82

99 100 101 102

110 111 112

120 121 122

P. Mohanan et al / Molecular action ofRb1, Rg1, Rg3

10 11 12

20 21 22

60 61 62

Fig. 2. Effect of ginsenosides Rb1, Rg1, and Rg3 on endothelial cells. Bax, Bcl-2-associated X protein; Bcl2, B-cell lymphoma 2; ERK1/2, extracellular signal-regulated protein kinases 1 and 2; GR, glucocorticoid receptor; HIF1-a, hypoxia-inducible factor 1-alpha; MAPK, mitogen-activated protein kinase; PI3K/AKT, phosphatidylinositol 3-kinase/AKT; VEGF, vascular endothelial growth factor.

messenger RNA (mRNA) [16]. However, Rbl could reverse this effect by upregulating the expression of eNOS in vascular endothelial cells, thereby sustaining the production of NO. Besides Rbl, Rg3-mediated eNOS activation is dependent on glucocorticoid receptor (GR) and estrogen receptor (ER) signaling cascade involving P13K and c-Jun N-terminal kinase [17].

2.2. Attenuating homocysteinemia

Hcy is an intermediate product in the biosynthesis of amino acids methionine and cysteine. The elevated level of Hcy is related to increased risk for CVD. In endothelial dysfunction, the effect of Hcy is linked to the generation of oxidative stress, nuclear factor kappa B (NF-kB) activation, inflammation, and inhibition of eNOS, which are collectively recognized as independent risk factors for atherosclerosis [18]. During Hcy-induced oxidative damage to endothelial cells, ginsenoside Rbl prevents damage by inducing NO production and eNOS expression, and also by promoting the secretion of ghrelin, which suggests an important treatment strategy during homocysteinemic conditions [19].

Many patients with coronary heart disease or cerebrovascular atherosclerosis have hyperhomocysteinemia, which causes endo-thelial cell dysfunction and induces apoptosis. Recent studies target the secretion of ghrelin during Hcy-induced vascular endothelial dysfunction and structural damage. Rbl excites NO production in human aortic endothelial cells 15 min after the treatment and reaches a maximum by 30 min. It was found that it induces phosphorylation of eNOS protein at Ser1177 in less than 10 min by phosphorylating Akt at Ser473 (via P13K signaling) and ERK1/2 at Thr202/Thr204 (via MEK signaling). Androgen receptor-mediated function is implicated in the phosphorylation of eNOS by Rb1 [20]. Apart from promoting eNOS phosphorylation, Rb1 could prevent the oxidative damage induced by hydrogen peroxide.

2.3. Antiangiogenesis in CVDs

Angiogenesis is the development of new blood vessels from preexisting endothelium or vasculature. 1t is a dynamic multistep developmental process that happens during wound healing and

fetal development [21]. Furthermore, abnormal angiogenesis is contributed to the pathogenesis of diabetic retinopathy, rheumatoid arthritis, and tumor development [22]. Multiple molecular mediators and signaling mechanisms have been implicated in this process such as growth factors, intracellular signaling pathways, and cell—cell interactions. The production of NO is vital for proper vasodilatory function, as well as antiproliferative and antiapoptotic states of endothelial cells. However, a recent investigation suggests an involvement of a few microRNA (miRNAs) in promoting or suppressing angiogenesis. By using human umbilical cord endo-thelial cells (HUVECs), it was shown that Rg1 has a direct relationship in downregulating five miRNAs, including that of miRNA-214, which is closely associated with eNOS expression and angio-genesis [23]. MiR-214 overexpression downregulates XBP1 transcription factor, by which it suppresses angiogenesis; moreover, in chronic cardiac failure patients, miR214 is found to be upregulated [24]. Certainly, 20(S)-Rg3 is more active than 20(R)-Rg3; in addition, their mode of signaling is also different in promoting angio-genesis. 20(S)-Rg3 enhances eNOS production by rapidly inducing the ERK/Akt signaling pathway via the activation of peroxisome proliferator-activated receptor-g (PPAR-g) and induces HUVECs proliferation. However, the stereoisomer 20(R)-Rg3 reduces angiogenic activity in HUVECs at low concentration (mM), whereas at higher concentration (mM) it promotes angiogenesis by activating PPAR-g. The activity of Rg3 depends on the state at which the endothelial cells are in; it promotes angiogenesis when they are activated, and it suppresses angiogenesis when they are not [22]. Rg1 induces angiogenesis by a nongenomic crosstalk with GR and fibroblast growth factor [25].

2.4. Preventive effect in cardiac injury

Cardiac hypertrophy is characterized by the adaptive increase in heart size by the enlargement of individual cardiomyocytes. Prolonged cardiac hypertrophy leads to cardiomyopathy, heart failure, or even sudden death [26]. Drugs such as angiotensin-converting enzymes and calcium channel blockers can decrease cardiac hypertrophy, and NOs have shown strong antihypertrophy effects. Among various ginsenosides, Rb1, in particular, has shown an

80 81 82

99 100 101 102

110 111 112

120 121 122

J Ginseng Res 2017;m:1-10

10 11 12

20 21 22

60 61 62

antihypertrophic effect by NO release and reducing intracellular Ca2+ concentration in myocytes. Moreover, it attenuates the expression of NFAT3 and GATA4 transcription factors in cardiomyocytes to exhibit its antihypertrophic activity by reducing calcineurin signal trans-duction pathway [27]. Interestingly, Rg1 shows a protective effect on left ventricular hypertrophic condition by activating p38 and mitogen-activated protein kinase (MAPK) signaling, and promotes angiogenesis by increasing the expression of hypoxia-inducible fac-tor-1 and vascular endothelial growth factor (Fig. 2) [28].

Myocardial ischemia/reperfusion (MI/R) injury is another serious cardiac arrest caused by thrombosis that results from a sudden impairment in coronary blood supply. It is partly mediated by ROS generation and exacerbated by ischemic reperfusion (IR) injury. Under hypoxic conditions, this may lead to cellular damage and acute signaling pathway, which leads to cell death. Ca2+ influx into vascular myocytes has been considered deleterious during IR injury. It was proven that Rg1 treatment directly suppresses the Ca2+ channel to inhibit Ca2+ overload in cardiomyocytes and improves the production of antioxidant enzymes such as T-SOD, CAT, and GSH, in cardiac myocytes during myocardial ischemia [29]. Meanwhile, Rg3 inhibits apoptosis caused by MI/R injury by inhibiting the activation of caspase-3 and caspase-9 and altering the ratio of Bcl-2/Bax while increasing the expression of p-Akt, eNOS in rat neonatal cardiomyocytes [30]. The preconditioning of ginsenosides Rb1 shows a novel therapeutic potential with better results in MI/R injury. In streptozotocin-induced Mi/R injury in diabetic rats, preconditioning with Rb1 reduces cardiomyocyte apoptosis and alleviates cardiac dysfunction despite impaired PI3K/ Akt signaling [31]. Rb1 preconditioning of diabetic rats at a dose of 40 mg/kg reduces the severity of MI/R injury associated with NOS expression and NO release [32]. Rg1 suppresses human arterial vascular smooth muscle cell proliferation by blocking tumor necrosis factor-a signaling and cell cycle arrest at G1 phase.

This inhibition is achieved by diminishing the activation of Akt, ERK1/2, and protein kinase B signaling cascades [33]. Inflammatory cells such as leukocytes adhere to intracellular adhesion molecule-1 (ICAM1) and promote inflammatory reactions. IR injury upregulates ICAM1 expression because of the generation of ROS. Rb1 treatment controls ROS production by preventing ICAM1 expression [34], thereby attenuating inflammatory reactions too in IR injury. Ventricular remodeling is a phenomenon associated with lesion repair and ventricular composition during MI/R injury. This may lead to decline in left ventricular systolic function followed by heart failure and death. Apart from the lethal effects of MI/R injury, injection with ginsenoside Rb1 (2 mg/kg) for 4 wk reduces the left ventricular remodeling, presumably by the renin—angiotensin system. Likewise, continuous application of Rg1 (5 mg/kg) to rats with acute myocar-dial infarction increased the number of peripheral blood stem cells and stimulated their homing to the infarcted myocardium [32].

3. Impact of ginsenosides in ROS, cancer, and apoptosis

Cancer is rated as a dreadful disease with increasing mortality rate worldwide. Although various treatment methods are available for cancer, complementary and alternative medicines have been rapidly gaining popularity in recent years because they increased chances of patient survival with little side effects [35]. Ginsenoside saponins are considered an excellent option for their anticancer property, and their effect is directly proportional to the number of sugar moieties, the position of a hydroxyl group, and stereoselectivity [9].

3.1. Rg3 dominates cancer prevention by ginsenosides

The anticancer evaluation of ginsenoside relies heavily on its parental compound. Orally administered ginsenosides are poorly

absorbed, whereas some of them are broken down into simpler compounds by intestinal bacterial flora, which allows them to be absorbed readily in the body. Compared with bulkier ginsenosides, ginsenoside Rg3 is less polar—hence it has a pronounced effect in different cancer tissues. It has been broadly researched and prescribed clinically against cancer in China [36]. Radiation therapy combined with surgery or chemotherapy is applied to eradicate cancerous cells and its growth. However, cancer cells continuously evade the treatment because of the continuous activation of NF-kB transcription factor. However, Rg3 treatment in g-ray sensitized lung cancer cells suppresses NF-kB activity significantly, leading to the inhibition of tumor progression (Fig. 3) [37]. Histone acetylation by histone acetyltransferases is characterized by increased gene transcription whereas histone deacetylation by histone deacetylase is typically correlated with gene silencing. Rg3 treatment in skin melanoma cell reduces the expression of histone deacetylase-3, which promotes the acetylation of p53 protein. The acetylated p53 protein could arrest the proliferation of cell cycle in the G0/G1 phase [38].

Matrix metalloproteinases (MMPs) are endopeptidases that specifically degrade collagens and noncollagenous proteins. The damaged liver protects itself from MMP activity by overexpressing tissue inhibitors of metalloproteinase and suppresses MMPs. The administration of Rb1 exhibits antiproliferative effect by inhibiting transforming growth factor $1 (TGF-31), MMP-2, and tissue inhibitors of metalloproteinase-1 activation and by preventing the activation of the a-SMA gene [39]. In hepatocellular carcinoma, Rg3 exhibits its protective role through caspase-mediated apoptosis [40] by altering Bax and Bcl-2 expression to enable the release of pro-apoptotic factor such as cytochrome c [41]. Moreover, by suppressing NF-kB activation, Rg3 reduces the expression of Ki67, a nuclear protein expressed during cell cycle stages—namely, S, G1, G2, M phases, vascular endothelial growth factor, and CD34—to induce apoptosis in cancer cells. Gallbladder cancer (GBC) is another life-threatening disease with poor prognosis and treatment method. 20(S)-Rg3 reduces GBC progression remarkably by activating the p53-mediated apoptotic pathway [42]. In another study, when Rg3 was orally administered to mice with GBC, it induced cytotoxic effect by inducing endoplasmic stress mediated by C/EBP homology protein (CHOP) upregulation [43]. These studies reveal the potential therapeutic cure for GBC by ginsenoside Rg3.

Fig. 3. Ginsenoside Rg3 and its stereoisomer 20(S)-Rg3 differentially attenuate cancer cell growth. IAP, inhibitors of apoptosis proteins; IKK, IkB kinase; NF-kB, nuclear factor kB.

80 81 82

99 100 101 102

110 111 112

120 121 122

P. Mohanan et al / Molecular action ofRb1, Rg1, Rg3

10 11 12

20 21 22

60 61 62

When administered together with cisplatin, Rg3 improves the efficacy by inhibiting heme oxygenase-1 and NAD(P)H-quinone oxidoreductase-1 enzyme, and protects the kidney and liver by scavenging cisplatin-induced ROS generation [44]. The stereoisomer 20(S)-Rg3 prevents proliferation of ovarian cancer cells by triggering the caspase-3- and caspase-9-mediated apoptotic pathway. Rg3 downregulates PI3K/Akt and inhibitor of apoptosis family of proteins, thereby allowing caspase 3 and caspase 9 to function [45]. The role of Rg3 in colon/colorectal cancer is also well documented. It induces apoptosis and suppresses the migration of colon cancer by repressing the activation of NF-kB transcription factor [46]. The proliferation of tumor growth is inhibited by blocking nuclear translocation of b-catenin, thereby preventing Tcf transcriptional activity [47].

3.2. Rb1 and anticancer mechanism

Beyond its ability to suppress tumor growth and inflammation, Rb1 specifically activates estrogen receptor subunit b (ER-b) to specifically enhance the production of pigment epithelium-derived factor (PEDF) by recruiting transcriptional activators to the promoter of PEDF. The secretion of PEDF inhibits tube formation in endothelial cells (Fig. 4) [48]. The selective binding of Rb1 to ERb could be a potential pharmaceutical target for specific tissue types because it reduces the potential side effects. Rg1 exerts anti-metastatic effect in liver cancer cells by inhibiting TGF-b1. This inhibition prevents the transition of epithelial cells to mesen-chymal transition and increases the expression of E-cadherin, thus preventing metastasis [49]. Chemoprevention in cancer treatment or from chemical carcinogen might involve preventing the interaction of carcinogen or endogenous free radicals to DNA, thereby preventing disease progression [50].

Cytochrome P450 1A1 (CYP1A1) plays a significant role in the oxidation of endogenous and exogenous chemical compounds, and

also most of the clinically prescribed drugs [51]. The transcriptional activation of CYP1A1 is mediated by aryl hydrocarbon receptor (AhR) binding to the promoter of CYP1A1. Ginsenosides Rg1 and Rb1 have shown a greater affinity for these receptors and enhance the activity of AhR to bind to the xenobiotic responsive element loci including CYP1A1 promoters (Fig. 4). Treatment with ginsenosides improved the expression of CYP1A1 via AhR, which might be useful for chemoprevention in chemical carcinogen [52]. Although gin-senosides are known for their proliferative effect on cells, they are an antagonist to cancer cells. 1t was demonstrated effectively in hepatocellular carcinoma that ginsenosides differentially activates the expression of c-Myc and hepatocyte nuclear factor-4a and drug metabolizing enzyme such as Cyp3a4 in a concentration-dependent manner. At 40 mg/L concentration, ginsenoside treatment enhances the expression of c-Myc and suppresses the proliferation of HepG2 cells, whereas at 200 mg/L it activates both c-Myc and hepatocyte nuclear factor-4 with a notable increase in Cyp3a4 [53]. These results are of high clinical significance and provide relevant information on the dosage of ginsenoside crude fractions or pure fractions used as an anticancer agent.

4. Diabetes and insulin metabolism

DM is the eighth leading cause of death among both men and women worldwide and the fifth leading cause of death in women in 2012. It is acute, and chronic disease occurs owing to the impairment in insulin production by the pancreas and uptake by the body. Diabetes leads to serious complications that affect all the important organs during hyperglycemic conditions [54]. The hypoglycemic activity of ginseng and its extract has been known for a very long time. Different ginseng preparations were demonstrated to have efficacy in people with diabetes, and active research with cell lines and animal studies are exploring the possible mechanism by which the hypoglycemic action of ginsenosides could be achieved [55].

Fig. 4. Mechanism of cancer prevention by ginsenosides Rb1 and Rg1. AhR, aryl hydrocarbon receptor; ER, estrogen receptor; PEDF, pigment epithelium derived factor; TGF-ß1, transforming growth factor ß1; XRE, xenobiotic responsive elements.

80 81 82

99 100 101 102

110 111 112

120 121 122

J Ginseng Res 20Í7;—:Í-Í0

10 11 12

16 1l 1B

20 21 22

26 2l 2B

36 3l 3B

46 4l 4B

56 Sl SB

60 б1 б2

4.1. Enhancing glucose uptake and insulin sensitivity

Ginsenoside Rbl has a significant antihyperglycemic effect and increases insulin sensitivity; thus, it has been used clinically to treat DM and its complications [56]. Furthermore, R1 has been shown to be useful in treating obesity and diabetes; notably, those effects are partially mediated by a reduction in food intake and body weight besides lowering glucose [57]. Acute intraperitoneal injection of Rbl (10 mg/kg) significantly suppresses food intake in rats, although chronic treatment with Rbl possesses no deleterious side effects in obese rats [58]. Uptake of glucose in tissues is a critical step in maintaining glucose homeostasis, and PI3K/Akt pathway is one of the key pathways involved in the translocation of glucose transporter 4 (GLUT4) in muscles [59]. It enables GLUT4 transporter-mediated intracellular uptake of glucose to the cells. Hyperglycemic condition and enhanced unfolded protein response evoke ER stress by nicotinamide adenine dinucleotide phosphate-oxidase induced ROS generation. The stressed ER upregulates the secretion of interleukin-lb, leading to inflammation, which is a critical factor for insulin resistance. Rbl suppresses insulin resistance due to inflammation by preventing interleukin-lb maturation and secretion in ER. It attenuates the activation of ER stress associated NLRP3 inflammasome while phosphorylating insulin receptor substrate-1 (IRS-1), thereby restoring the PI3K/Akt signaling pathway in adipose tissue [60].

Adenosine monophosphate kinase (AMPK) mediates the regulation of energy balance at the whole body level by responding to the hormones and nutrient signals. Ginsenoside Rgl significantly enhanced the glucose uptake in myocytes by AMPK-mediated GLUT4 translocation (Fig. 5) [6l]. In contrast, glucose homeostasis in hepatic cells is maintained by AMPK by inhibiting the expression of gluconeogenesis genes such as Glu-6-phosphate and phospho-enolpyruvate carboxylase. Rgl suppresses hepatic gluconeogenesis by inducing the phosphorylation of liver kinase Bl, AMPK, and forkhead box class Ol transcription factor [62]. By phosphorylating these kinases and transcription factors, Rgl inhibits the expression of gluconeogenic genes in hepatic cells [62]. Similarly, Rbl promotes insulin uptake in insulin-sensitive cells by GLUTl, GLUT4 translocation mediated by IRS-l and protein kinase B [63]. Recent

findings suggest that Rbl-mediated AMPK activation is amplified by the phosphorylation of downstream effector TBCl domain family member 4, thereby enhancing glucose uptake in skeletal muscle cells. Moreover, it reduces hepatic glucose production by suppressing the expression of glucose-6-phosphate and phospho-enolpyruvate carboxykinase [57]. These actions of Rgl and Rbl provide a possible therapeutic target for type 2 diabetes.

The antihyperglycemic effect of ginsenoside Rg3 has been well established in recent years. Unlike Rbl and Rgl, Rg3 stimulates the expression of IRS-l and GLUT4 at the transcriptional level (Fig. 5). Rg3 treatment increases the phosphorylation of IRS-l in myotubes than Akt; however, the classical AMPK pathway is unaltered. Strikingly, recent findings suggested a new role for Rg3. It improved the expression of the primary genes involved in mitochondrial biogenesis such as peroxisome proliferator-activated receptor gamma coactivator l-a and its downstream targets. The Rg3-mediated mitochondrial biogenesis improves the energy status of skeletal muscle cells leading to enhanced insulin resistance [64]. Meanwhile, in adipocytes, Rg3 treatment stimulates glucose uptake by enhancing PI3K signaling mediated by IRS-l signaling cascade [65]. These findings strengthen the antihyperglycemic effect of Rg3 and a possible type 2 DM drug.

4.2. Stereoselectivity and glucose metabolism

Based on the aglyone skeleton of ginsenosides, Rg3 efficiently stimulated the secretion of glucagon-like-peptide-l in endocrine cells through the sweet taste receptor-mediated signaling cascade in type 2 DM mouse model [66]. Rg3 induces the secretion of insulin in pancreatic cell lines, and the stereoisomers of Rg3 have shown differential activities in causing insulin secretion. 20(S)-Rg3 is superior to 20(R)-Rg3 in phosphorylating AMPK and acetyl-coA carboxylase in myotubes and inducing insulin secretion in b-cells [67]. 20(R)-Rg3 specifically phosphorylates AMPK and Ca2+/ calmodulin-dependent protein kinase kinase, and facilitates GLUT4 translocation in myotubes [68]. Rgl treatment reduces oxidative stress and attenuates myocardial apoptosis in diabetic rats. Rgl treatment also significantly reduces CHOP, caspase-l2 expression to ameliorate endoplasmic reticulum-induced apoptosis in diabetic

Fig. 5. Enhancing glucose uptake in muscle cells and insulin sensitive cells by ginsenosides Rbl, Rgl, and Rg3. AMPK, 5' AMP-activated protein kinase; Bcl2, B-cell lymphoma 2; CHOP, CCAATenhancer-binding protein homologous protein; eIF2a, eukaryotic initiation factor 2; ER, estrogen receptor; GLUTl, glucose transporter 1 ; GLUT4, glucose transporter 4; IRS-1, insulin receptor substrate 1; PERK, protein kinase R (PKR)-like endoplasmic reticulum kinase; PI3K, phosphatidylinositol 3 kinase; PKB, protein kinase B.

бб 6l 6B б9 l0 l1 l2

16 ll lB l9 B0 B1 B2 B3 B4 BS B6 Bl BB B9

96 9l 9B 99

100 101 102

106 10l 10B

110 111 112

116 11l 11B

120 121 122

126 12l 12B

P. Mohanan et al / Molecular action ofRb1, Rg1, Rg3 7

1 rats [69]. Besides enhancing glucose uptake and insulin meta- crucial enzyme that phosphorylates tau, which is regulated by 66

2 bolism, ginsenosides also protect the body cells from the aftermath cyclin-related activator molecules such as p35, p39, p25, and p29. 67

3 of diabetics. p25 is a product of calpain-mediated proteolysis of p35, which 68

4 forms a stable complex with cdk5 and hyperphosphorylates tau 69

5 5. Ginsenoside signaling targets in nervous system protein. The abnormal regulation of calcium level in neuronal cells 70

6 is implicated in the activation of calpain, which increases AD pa- 71

7 Numerous reports are proclaiming the neuroprotective effects thology. Rb1 pretreatment stabilizes the intracellular calcium ho- 72

8 of ginsenosides and ginsenoside derivatives in neurological disor- meostasis and microtubule integrity by suppressing the 73

9 ders, stroke, and neuroinflammation. Ginsenosides are known to transcription of cdk5 and p25 in cortical neurons [80]. The forma- 74

10 affect voltage-gated channels such as the Ca2+, Na+, K+, ligand- tion of Ab-peptide involves the proteolytic cleavage of amyloid 75

11 gated channels 5-HT3, the a-7 nicotinic acetylcholine, and N- protein precursor (APP) by a, g, and b-secretase. a-Secretase is a 76

12 methyl-D-aspartate (NMDA) receptors [70]. The magnitude of their metalloprotease that cleaves APP within the Ab domain, thus 77

13 action depends on the receptors they bind to and the extent at generating amyloid-b peptide. Upon cleavage, APP gets released 78

14 which they get absorbed in the brain. Rb1 and Rg1 increase syn- into the extracellular environment. The ER-mediated signaling 79

15 aptosomal choline uptake and acetylcholine release in rat brain by pathway involving PKC and MAPK serves as a hub for the regulation 80

16 enhancing acetylcholine mRNA expression [71], but Rb1 is more of a-secretase. It has been shown previously that activation of PKC 81

17 useful than Rg1 in triggering acetylcholine esterase in the hippo- decreases Ab production. 82

18 campus of mice. Rg3 pretreatment attenuates Hcy-induced Rg1 has antiaging and antineurodegenerative effects; it takes 83

19 neurotoxicity by reducing the intracellular Ca2+ elevation by two routes in attenuating Ab aggregation: (1) by enhancing the 84

20 acting on NMDA receptor (NMDAR) [70]. activity of a-secretase; (2) by ER-b-dependent P13K/Akt signaling 85

21 and PPAR-g-mediated suppression of b-secretase1 (BACE1), also in 86

22 5.1. Attenuation of neurodegeneration age-dependent dementia [81]. BACE1 is a membrane-bound pro- 87

23 tease that cleaves APP in the b site; its activity becomes increased in 88

24 Neurodegeneration accounts for the majority of neurological the frontal and temporal cortices of AD patients, and the tran- 89

25 disorders that result in gradual loss of neurons in the brain and scription of BACE1 increases with the downregulation of PPAR-g 90

26 spinal cord leading to ataxia or dementia. Excitotoxicity, mito- (Fig. 6) [82]. Molecular docking studies with major ginsenosides 91

27 chondrial disorders, and finally apoptosis have been the leading have suggested that ginsenosides Rb1, Rg1, and Rg3 showed sig- 92

28 cause of neurodegeneration in AD, Parkinson's disease (PD), Hun- nificant inhibitory action on acetylcholine esterase, and BACE1. 93

29 tington's disease, amyotrophic lateral sclerosis, stroke, and other These results might provide a strong validation for the treatment of 94

30 dementias [72]. Neurotrophic factors support the growth, survival, AD by ginsenosides [83]. It was demonstrated that treatment with 95

31 and differentiation of neurons by the activation of the Rg1 significantly upregulated the PPAR-g protein level in AD con- 96

32 tropomyosin-related kinase family of receptor kinases [73]. Neu- dition, which represses the transcription of BACE1 [84]. Another 97

33 rotrophic factor transcription is highly regulated; for example, study has reported that Rg1 ameliorates Ab-induced neuronal 98

34 brain-derived neurotrophic factor (BDNF) has eight different pro- apoptosis by ERa and GR-mediated signal transduction. This acti- 99

35 moters, each of which leads to different transcripts among them. vation upregulates the phosphorylation of ERK1/2 and inhibits 100

36 The transcription of the IVth exon is mediated by calcium and nuclear translocation of NF-kB. Furthermore, it facilitates the dif- 101

37 cAMP-response element through a protein signaling cascade ferentiation of mouse embryonic stem cells to neuronal lineage in 102

38 involving MAPK-ERK, P13K, PLC, and NMDAR activation [74]. When cell culture by the activation of GR-dependent downstream phos- 103

39 Schwann cells were incubated with ginsenosides Rb1 and Rg1, they phorylation of ERK1/2 and Akt signaling [85]. 104

40 induced the secretion of NGF and BDNF by an intracellular increase Treatment with Rb1 could increase p-Akt levels and p-ERK1/2 105

41 of cyclic AMP via protein kinase A signaling [75]. Likewise, long- mediated signaling to prevent the apoptosis induced by Ab [86]. 106

42 term administration of Rg1 enhances the transcription of BDNF Exposure to Ab leads to the accumulation of ROS and lipid perox- 107

43 by attenuating phospho-CREB level [76] and increases BDNF idation, which cause caspase-3-mediated neuronal apoptosis. Rb1 108

44 signaling in hippocampal neurogenesis in mice brain. It helps to treatment prevents apoptosis by modulating the Bcl2/Bax ratio and 109

45 promote neuronal survival in cerebral ischemia by facilitating the by inhibiting caspase-3 activation [56]. Rb1 enhances neural sero- 110

46 production of BDNF and enhances the translation of glial-derived tonin receptor (5-hydroxytryptamine) synthesis by upregulating 111

47 neurotrophic factor while downregulating the expression of the activities of tryptophan hydroxylases and by decreasing 112

48 caspase-3 (Fig. 6). Moreover, it reduces the expression of anti- monoamine oxidases genes mainly by ER [87]. This action of Rb1 113

49 apoptotic proteins Bcl-2 and Bax during cerebral ischemia and DEX- enables an increase in serotonin production and prevents its 114

50 induced cytotoxicity [77]. assimilation. 1nterestingly, ginsenosides have a preferential affinity 115

51 Accumulation of a-synuclein plays a significant role in the to ER; Rg1 activates ER-a subunit and phosphorylates AF-1 domain 116

52 pathogenesis of the genetic form of PD and other synucleino- in less than 5 min [88]. 117

53 pathies. Hence, inhibition of on a-syn fibrillation is considered an 118

54 effective strategy in PD. Ginsenoside Rb1 exhibits a significant 5.3. Cerebral ischemic injury 119

55 inhibitory effect on a-syn fibrillation by disaggregated fibrils, and 120

56 blocks a-syn polymerization. Rb1 outclasses Rg1 and Rg3 in neu- The increased level of extracellular glutamate concentration 121

57 roprotection and its ability to inhibit the formation of mature am- during cerebral ischemia amplifies the effect of stroke and trau- 122

58 yloid fibrils containing b-sheet structures [78]. matic injury. NMDARs are ligand-gated ion channel receptors that 123

59 get activated by glutamate in nerve cells. They participate in several 124

60 5.2. Attenuation of amyloid-b formation in AD neurological disorders including ischemia, schizophrenia, and ag- 125

61 ing. Antagonist against NMDARs has shown to improve 1R injury 126

62 AD is characterized by the accumulation of amyloid-b (Ab) and other neuropathological symptoms [89]. Rg1 displays a unique 127

63 plaque, neurofibrillary tangles in the brain, along with hyper- expression pattern for NMDAR subunits in the brain. The intra- 128

64 phosphorylated microtubule-associated protein tau [79], which cerebroventricular infusion increases the level of NMDAR subunit 129

65 promotes neurodegeneration. Cyclin-dependent kinase-5 is a NR1 expression in the temporal cortex, caudate putamen, 130

J Ginseng Res 2017;я:1-10

10 11 12

20 21 22

60 61 62

Fig. 6. Action of ginsenosides in neurodegeneration, ischemic injury, and neurotrophic factor production. BDNF, brain-derived neurotrophic factor; cAMP, adenosine monophosphate; CREB, cAMP response element binding; ERKl/2, extracellular signal-regulated protein kinases l and 2; GDNF, glial cell-derived neurotrophic factor; NGF, nerve growth factor; PKA, protein kinase A; PPAR-g, peroxisome proliferator-activated receptor gamma; ROS, reactive oxygen species; Trk, tropomyosin-related kinase.

hippocampus, and granule layer of the cerebellum. NR2B mRNA is elevated in the cortex, thalamus, and caudate putamen, but NR2C mRNA is increased only in the granule layer of the cerebellum. Apart from exhibiting the differential expression pattern for NMDARs, Rgl has also been shown to suppress their activity in pathological conditions such as hypoxic—ischemic injury by inhibiting Ca2+ influx through NMDARs and other voltage-dependent ion channels [90]. It promotes hippocampal neuro-genesis by modulating the production of intracellular NOS and NMDARs in posttransient ischemia [9l]. Long-term administration of Rgl promotes synaptic plasticity in age-related cognitive decline by enhancing the expression of plasticity-related proteins such as NMDAR subunit l, synaptophysin, and calcium/calmodulin-dependent protein kinase II alpha [92].

Rbl helps to regulate homeostasis in the brain by regulating the expression of neuropeptide Y (NPY). NPY is associated with the infundibular nucleus of the hypothalamus, as part of a reciprocal circuit controlling reproduction and energy balance; it responds to hormones such as insulin, leptin, ghrelin, as well as glucose. It has a great impact on physiological functions such as food intake, energy expenditure, reproduction, and thermoregulation [93]; hence, during obesity, NPY levels become altered in the hypothalamus [94]. By triggering the classical PI3K/Akt signaling, Rbl significantly reduces NPY gene expression in the hypothalamus of obese rats and c-Fos expression in the hindbrain. Chronic Rbl treatment significantly reduced the NPY gene expression in rat brain and also in serum [58,95], by which Rbl helps to maintain homeostasis in the body.

Among the other ginsenosides, only Rbl protects neurons against oxidative injury by enhancing the Nrf2/Ho-l pathway. The activation of Nrf2 upregulates the transcription of multiple anti-oxidant response element controlled genes, leading to the expression of drug metabolizing enzymes [96,97]. Interestingly, Rbl could prevent endoplasmic reticulum stress caused by the accumulation of misfolded protein. If it is uncontrolled, it will result in apoptosis mediated by CHOP, caspase-l2, and c-Jun N-terminal kinase pathways [98]. It has been reported that hyperglycemic condition evokes CHOP-mediated apoptosis in neurons. Ginsenoside Rbl prevents neurotoxicity in high glucose-induced neuronal death by

attenuating CHOP signaling mediated ER stress-mediated apoptotic signaling pathway. In neurons, glycogen synthase kinase-3b (GSK-3b) serves as an upstream activator of CHOP signaling. Rbl treatment inhibits GSK-3b-mediated CHOP signaling, thereby preventing neuronal apoptosis due to ER stress [99]. Moreover, Rbl treatment attenuates intracellular ROS production as well as disruption of mitochondrial dysfunction [l00].

6. Conclusion and future recommendations

It is apparent that ginsenosides have many beneficial effects by interacting with various signaling pathways and effecting changes at the transcription level. The interaction of ginsenosides with signaling networks and receptors exhibits different benefits such as improving brain cognitive functions, attenuating inflammatory reactions, providing cytotoxicity to various cancerous cells, as well as improving glucose uptake and insulin metabolism in diabetic condition. Even though major ginsenosides are poorly absorbed in the intestinal tract, few attempts have been undertaken to increase their bioavailability using various methods such as conjugating them with polymers, fatty acids, and utilization of nanodelivery systems. However, these investigations are still at the preliminary level to guarantee their use for human consumption. In the future, the ginseng research must be directed toward (l) developing suitable drug delivery system for these ginsenosides; (2) extending the bioavailability of ginsenosides in blood circulation; (3) assessing the safety of PPD- and PPT-type ginsenosides and transformed metabolites of them in humans. For this, researchers must be encouraged to conduct improved animal testing and clinical trials to exhibit the beneficiary role of ginsenosides. Most of the available studies focused mainly on cell culture practices, but the animal studies and clinical trials are limited to describe the potential role of ginsenosides. The pharmacokinetics of crude ginseng preparations and purified ginsenosides in healthy humans must be undertaken to understand their comprehensive effect, and this has to be done sooner rather than later. As a final point, to ensure ginsenosides and ginseng-based preparations are the best alternative, medicine for various disease and disorders translational research has to be increased.

80 81 82

99 100 101 102

110 111 112

120 121 122

P. Mohanan et al / Molecular action ofRb1, Rg1, Rg3

10 11 12

20 21 22

60 61 62

Conflicts of interest

The authors have no conflict of interest.


Kim YJ, Zhang D, Yang DC. Biosynthesis and biotechnological production of ginsenosides. Biotechnol Adv 2015;33:717-35.

Lee CH, Kim JH. A review on the medicinal potentials of ginseng and ginsenosides on cardiovascular diseases. J Ginseng Res 2014;38:161-6. Lan TH, Xu ZW, Wang Z, Wu YL, Wu WK, Tan HM. Ginsenoside Rbl prevents homocysteine-induced endothelial dysfunction via PI3K/Akt activation and PKC inhibition. Biochem Pharmacol 2011;82:148-55. Ahmed T, Raza SH, Maryam A, Setzer WN, Braidy N, Nabavi SF, de Oliveira MR, Nabavi SM. Ginsenoside Rb1 as a neuroprotective agent: a review. Brain Res Bull 2016;125:30-43.

Koh EJ, Kim KJ, Choi J, Jeon HJ, Seo MJ, Lee BY. Ginsenoside Rg1 suppresses early stage of adipocyte development via activation of C/EBP homologous protein-10 in 3T3-L1 and attenuates fat accumulation in high fat diet-induced obese zebrafish. J Ginseng Res 2017;41:23-30. Zhao BS, Liu Y, Gao XY, Zhai HQ, Guo JY, Wang XY. Effects of ginsenoside Rg1 on the expression of toll-like receptor 3, 4 and their signaling transduction factors in the NG108-15 murine neuroglial cell line. Molecules 2014;19: 16925-36.

Chen XJ, Zhang XJ, Shui YM, Wan JB, Gao JL. Anticancer activities of proto-panaxadiol- and protopanaxatriol-type ginsenosides and their metabolites. Evid Based Complement Alternat Med 2016;2016.

Xu FY, Shang WQ, Yu JJ, Sun Q, Li MQ, Sun JS. The antitumor activity study of ginsenosides and metabolites in lung cancer cell. Am J Transl Res 2016;8: 1708-18.

Nag SA, Qin JJ, Wang W, Wang MH, Wang H, Zhang R. Ginsenosides as anticancer agents: in vitro and in vivo activities, structure-activity relationships, and molecular mechanisms of action. Front Pharmacol 2012;3: 1-18.

Choi JS, Chun KS, Kundu J, Kundu JK. Biochemical basis of cancer chemo-prevenion and or chemotherapy with ginsenosides. Int J Mol Med 2013;32: 1227-38.

Nabavi SF, Sureda A, Habtemariam S, Nabavi SM. Ginsenoside Rd and ischemic stroke; a short review of literatures. J Ginseng Res 2015;39:299-303.

Yang XD, Yang YY, Ouyang DS, Yang GP. A review of biotransformation and

pharmacology of ginsenoside compound K. Fitoterapia 2015;100:208-20.

Jin X, Che DB, Zhang ZH, Yan HM, Jia ZY, Jia XB. Ginseng consumption and

risk of cancer: a meta-analysis. J Ginseng Res 2015;40:269-77.

WHO fact sheet. Cardiovascular diseases (CVDs) [Internet]. 2016 September

[cited 2016 Dec 29]. Available from:


Tousoulis D, Kampoli AM, Tentolouris C, Papageorgiou N, Stefanadis C. The role of nitric oxide on endothelial function. Curr Vasc Pharmacol 2012;10: 4-18.

Pirillo A, Norata GD, Catapano AL. LOX-1, OxLDL, and atherosclerosis. Mediators Inflamm 2013;2013:152786.

Hien TT, Kim ND, Pokharel YR, Oh SJ, Lee MY, KW K. Ginsenoside Rg3 increases nitric oxide production via increases in phosphorylation and expression of endothelial nitric oxide synthase: essential roles of estrogen receptor-dependent PI3-kinase and AMP-activated protein kinase. Toxicol Appl Pharmacol 2010;246:171-83.

Ganguly P, Alam SF. Role of homocysteine in the development of cardiovascular disease. Nutr J 2015;14:6.

Xu Z, Lan T, Wu W, Wu Y. The effects of ginsenoside Rb1 on endothelial damage and ghrelin expression induced by hyperhomocysteine. J Vasc Surg 2011;53:156-64.

Yu J, Eto M, Akishita M, Kaneko A, Ouchi Y, Okabe T. Signaling pathway of nitric oxide production induced by ginsenoside Rb1 in human aortic endo-thelial cells: a possible involvement of androgen receptor. Biochem Biophys Res Commun 2007;353:764-9.

Ucuzian AA, Gassman AA, East AT, Greisler HP. Molecular mediators of angiogenesis. J Burn Care Res 2010;31:158-75.

Kwok HH, Guo GL, Lau JK, Cheng YK, Wang JR, Jiang ZH, Keung MH, Mak NK, Yue PY, Wong RN. Stereoisomers ginsenosides-20(S)-Rg(3) and -20(R)-Rg(3) differentially induce angiogenesis through peroxisome proliferator-activated receptor-gamma. Biochem Pharmacol 2012;83:893-902. Chan LS, Yue PY, Mak NK, Wong RN. Role of MicroRNA-214 in ginsenoside-Rg1-induced angiogenesis. Eur J Pharm Sci 2009;38:370-7. Duan Q, Yang L, Gong W, Chaugai S, Wang F, Chen C, Wang P, Zou MH, Wang DW. MicroRNA-214 is upregulated in heart failure patients and suppresses XBP1-mediated endothelial cells angiogenesis. J Cell Physiol 2015;230:1964-73.

Kim JH. Cardiovascular aiseases and Panax ginseng: a review on molecular mechanisms and medical applications. J Ginseng Res 2012;36:16-26. Heineke J, Molkentin JD. Regulation of cardiac hypertrophy by intracellular signaling pathways. Nat Rev Mol Cell Biol 2006;7:589-600.

[27 [28

[29 [30

[32 [33

[35 [36

[41 [42

[45 [46 [47 [48

[50 [51

Jiang QS, Hunag XN, Dai ZK, Yang GZ, Zhou QX, Shi JS, Wu Q. Inhibitory effect of ginsenoside Rb1 on cardiac hypertrophy induced by monocrotaline in rat. J Ethnopharmacol 2007;111:567-72.

Zhang YJ, Zhang XL, Li MH, Iqbal J, Bourantas CV, Li JJ, Su XY, Muramatsu T, Tian nL, Chen SL The ginsenoside Rg1 prevents transverse aortic constriction-induced left ventricular hypertrophy and cardiac dysfunction by inhibiting fibrosis and enhancing angiogenesis. J Cardiovasc Pharmacol 2013;62:50-7.

Zhu D, Wu L, Li CR, Wang XW, Ma YJ, Zhong ZY, Zhao HB, Cui J, Xun SF, Huang XL, et al. Ginsenoside Rg1 protects rat cardiomyocyte from hypoxia/ reoxygenation oxidative injury via antioxidant and intracellular calcium homeostasis. J Cell Biochem 2009;108:117-24.

Wang Y, Hu Z, Sun B, Xu J, Jiang J, Luo M. Ginsenoside Rg3 attenuates myocardial ischemia/reperfusion injury via Akt/endothelial nitric oxide synthase signaling and the B-cell lymphoma/B-cell lymphoma-associated X protein pathway. Mol Med 2015;11:4518-24.

Wu Y, Xia ZY, Dou J, Zhang L, Xu JJ, Zhao B, Lei S, Liu HM. Protective effect of ginsenoside Rb1 against myocardial ischemia/reperfusion injury in streptozotocin-induced diabetic rats. Mol Biol Rep 2011;38:4327-35. Sun Y, Liu Y, Chen K. Roles and mechanisms ofginsenoside on cardiovascular diseases: progress and perspectives. Sci China Life 2016;59:292-8. Huang J, Li LS, Yang DL, Gong QH, Deng J, Huang XN. Inhibitory effect of ginsenoside Rg1 on vascular smooth muscle cell proliferation induced by PDGF-BB is involved in nitric oxide formation. Evid Based Complement Alternat Med 2012;2012:314395.

Guo Y, Yang T, Lu J, Li S, Wan L, Long D, Li Q, Feng L, Li Y. Rb1 post-conditioning attenuates liver warm ischemia-reperfusion injury through ROS-NO-HIF pathway. Life Sci 2011;88:598-605.

Wong AS, Che CM, Leung KW. Recent advances in ginseng as cancer therapeutics: a functional and mechanistic overview. Nat Prod Rep 2015;32:256-72. Lu P, Su W, Miao ZH, Niu HR, Liu J, Hua QL. Effect and mechanism of gin-senoside Rg3 on postoperative life span of patients with non-small cell lung cancer. Chin J Integr Med 2008;14:33-6.

Wang L, Li X, Song YM, Wang B, Zhang FR, Yang R, Wang HQ, Zhang GJ. Ginsenoside Rg3 sensitizes human non-small cell lung cancer cells to g-ra-diation by targeting the nuclear factor-KB pathway. Mol Med Rep 2015;12: 609-14.

Shan X, Fu YS, Aziz F, Wang XQ, Yan Q, Liu JW. Ginsenoside Rg3 inhibits melanoma cell proliferation through down-regulation of histone deacetylase 3 (HDAC3) and increase of p53 acetylation. PLoS One 2014;9:e115401. Lo YT, Tsai YH, Wu SJ, Chen JR, Chao JC. Ginsenoside Rb1 inhibits cell activation and liver fibrosis in rat hepatic stellate cells. J Med Food 2011;14: 1135-43.

Jiang JW, Chen XM, Chen XH, Zheng SS. Ginsenoside Rg3 inhibit hepatocel-lular carcinoma growth via intrinsic apoptotic pathway. World J Gastro-enterol 2011;17:3605-13.

Zhang C, Liu L, Yu Y, Chen B, Tang C, Li X. Antitumor effects of ginsenoside Rg3 on human hepatocellular carcinoma cells. Mol Med Rep 2012;5:1295-8. Zhang F, Li M, Wu X, Hu Y, Cao Y, Wang X, Xiang S, Li H, Jiang L, Tan Z, et al. 20(S)-Ginsenoside Rg3 promotes senescence and apoptosis in gallbladder cancer cells via the p53 pathway. Drug Des Devel Ther 2015;9:3969-87. Wu K, Li N, Sun H, Xu T, Jin F, Nie J. Endoplasmic reticulum stress activation mediates Ginseng Rg3-induced anti-gallbladder cancer cell activity. Biochem Biophys Res Commun 2015;466:369-75.

Lee CK, Park KK, Chung AS, Chung WY. Ginsenoside Rg3 enhances the che-mosensitivity of tumors to cisplatin by reducing the basal level of nuclear factor erythroid 2-related factor 2-mediated heme oxygenase-1/NAD(P)H quinone oxidoreductase-1 and prevents normal tissue damage by scavenging cisplatin-induced intracellular reactive oxygen species. Food Chem Toxicol 2012;50:2565-74.

Wang JH, Nao JF, Zhang M, He P. 20(S)-Ginsenoside Rg3 promotes apoptosis in human ovarian cancer HO-8910 cells through PI3K/Akt and XIAP pathways. Tumour Biol 2014;35:11985-94.

Junmin S, Hongxiang L, Zhen L, Chao Y, Chaojie W. Ginsenoside Rg3 inhibits colon cancer cell migration by suppressing nuclear factor kappa B activity. J Tradit Chin Med 2015;35:440-4.

He BC, Gao JL, Luo X, Luo J, Shen J, Wang L, Zhou Q, Wang YT, Luu HH, Haydon RC, et al. Ginsenoside Rg3 inhibits colorectal tumor growth through the down-regulation ofWnt/ss-catenin signaling. Int J Oncol 2011;38:437-45. Leung KW, Cheung LW, Pon YL, Wong RN, Mak NK, Fan TP, Au SC, Tombran-Tink J, Wong AS. Ginsenoside Rb1 inhibits tube-like structure formation of endothelial cells by regulating pigment epithelium-derived factor through the oestrogen beta receptor. Br J Pharmacol 2007;152:207-15. Yu M, Yu X, Guo D, Yu B, Li L, Liao Q, Xing R. Ginsenoside Rg1 attenuates invasion and migration by inhibiting transforming growth factor-ß1-induced epithelial to mesenchymal transition in HepG2 cells. Mol Med Rep 2015;11: 3167-73.

Steward W, Brown K. Cancer chemoprevention: a rapidly evolving field. Br J Cancer 2013;109:1-7.

Stejskalova L, Pavek P. The function of cytochrome P450 1A1 enzyme (CYP1A1) and aryl hydrocarbon receptor (AhR) in the placenta. Curr Pharm Biotechnol 2011;12:715-30.

Wang Y, Ye X, Ma Z, Liang Q, Lu B, Tan H, Xiao C, Zhang B, Gao Y. Induction of cytochrome P450 1A1 expression by ginsenoside Rg1 and Rb1 in HepG2 cells. Eur J Pharmacol 2008;601:73-8.

80 81 82

99 100 101 102

110 111 112

120 121 122

J Ginseng Res 20Í7'M:Í-Í0

1 [S3]

З [54]

4 [SS]

б [56]

9 [Sl]

11 [SB]

1З [59]

1б [60]

19 [61]

22 [62]

24 [63]

2б [64]

29 [65]

З1 [66]

З4 [б!]

Зб [6B]

3B [69]

41 [TO]

44 [ll]

4l [l2]

50 [73]

S1 [l4]

S4 [7s]

56 [l6]

Li Y, Xiao Z, Li B, Liu K, Wang H, Qi J, Wang Y. Ginsenoside exhibits concentration-dependent dual effects on HepG2 cell proliferation via regulation of c-Myc and HNF-4a. Eur J Pharmacol 2016;792:26-32. [77 WHO. Global report on diabetes. Geneva: WHO; 2016. Yuan HD, Kim JT, Kim SH, Chung SH. Ginseng and diabetes: the evidences from in vitro, animal and human studies. J Ginseng Res 2012;36:27-39. Hwang YP, Jeong HG. Ginsenoside Rbl protects against 6-hydroxydopamine- [78 induced oxidative stress by increasing heme oxygenase-1 expression through an estrogen receptor-related P13K/Akt/Nrf2-dependent pathway in human dopaminergic cells. Toxicol Appl Pharmacol 2010;242:18-28. Shen L, Haas M, Wang DQ, May A, Lo CC, Obici S, Tso P, Woods SC, Liu M. [79 Ginsenoside Rb1 increases insulin sensitivity by activating AMP-activated protein kinase in male rats. Physiol Rep 2015;3:e12453. [80 Xiong Y, Shen L, Liu KJ, Tso P, Xiong Y, Wang G, Woods SC, Liu M. Antiobesity and antihyperglycemic effects of ginsenoside Rb1 in rats. Diabetes 2010;59: 2505-12.

Kong HL, Wang JP, Li ZQ, Zhao SM, Dong J, Zhang WW. Anti-hypoxic effect of [81 ginsenoside Rb1 on neonatal rat cardiomyocytes is mediated through the specific activation of glucose transporter-4 ex vivo. Acta Pharmacol Sin 2009;30:396-403. [82

Chen W, Wang J, Luo Y, Wang T, Li X, Li A, Li J, Liu K, Liu B. Ginsenoside Rb1 and compound K improve insulin signaling and inhibit ER stress-associated [83 NLRP3 inflammasome activation in adipose tissue. J Ginseng Res 2016;40: 351-8.

Lee HM, Lee OH, Kim KJ, Lee BY. Ginsenoside Rg1 promotes glucose uptake [84 through activated AMPK pathway in insulin-resistant muscle cells. Phytother Res 2012;26:1017-22.

Kim SJ, Yuan HD, Chung SH. Ginsenoside Rg1 suppresses hepatic glucose [85 production via AMP-activated protein kinase in HepG2 cells. Biol Pharm Bull 2010;33:325-8.

Shang W, Yang Y, Zhou L, Jiang B, Jin H, Chen M. Ginsenoside Rb1 stimulates [86 glucose uptake through insulin-like signaling pathway in 3T3-L1 adipocytes. J Endocrinol 2008;198:561-9.

Kim MJ, Koo YD, Kim M, Lim S, Park YJ, Chung SS, Jang HC, Park KS. Rg3 [87 improves mitochondrial function and the expression of key genes involved in mitochondrial biogenesis in C2C12 myotubes. Diabetes Metab J 2016;40: 406-13.

Lee OH, Lee HH, Kim JH, Lee BY. Effect of ginsenosides Rg3 and Re on glucose [88 transport in mature 3T3-L1 adipocytes. Phytother Res 2011;25:768-73. Kim KS, Jung Yang H, Lee IS, Kim KH, Park J, Jeong HS, Kim Y, Ahn KS, Na YC, Jang HJ. The aglycone of ginsenoside Rg3 enables glucagon-like peptide-1 [89 secretion in enteroendocrine cells and alleviates hyperglycemia in type 2 diabetic mice. Sci Rep 2015;5:18325. [90

Park MW, Ha J, Chung SH. 20(S)-Ginsenoside Rg3 enhances glucose-stimulated insulin secretion and activates AMPK. Biol Pharm Bull 2008;31: 748-51.

Kim DY, Yuan HD, Huang B, Quan HY, Chung SH. Ginsenoside 20(R)-Rg3 [91 stimulates glucose uptake in C2C12 myotubes via CaMKK-AMPK pathways. Food Sci Biotechnol 2010;19:1277-82.

Yu H, Zhen J, Yang Y, Gu J, Wu S, Liu Q. Ginsenoside Rg1 ameliorates diabetic [92 cardiomyopathy by inhibiting endoplasmic reticulum stress-induced apoptosis in a streptozotocin-induced diabetes rat model. J Cell Mol Med 2016;20:623-31.

Kim JH, Cho SY, Lee JH, Jeong SM, Yoon IS, Lee BH, Lee JH, Pyo MK, Lee SM, [93 Chung JM, et al. Neuroprotective effects of ginsenoside Rg3 against homocysteine-induced excitotoxicity in rat hippocampus. Brain Res 2007;1136:190-9. [94

Scholey A, Ossoukhova A, Owen L, Ibarra A, Pipingas A, He K, Roller M, Stough C. Effects of American ginseng (Panax quinquefolius) on neuro- [95 cognitive function: an acute, randomised, double-blind, placebo-controlled, crossover study. Psychopharmacology (Berl) 2010;212:345-56. [96

Uttara B, Singh AV, Zamboni P, Mahajan RT. Oxidative stress and neurode-generative diseases: a review of upstream and downstream antioxidant therapeutic options. Curr Neuropharmacol 2009;7:65-74. [97

Skaper SD. The neurotrophin family of neurotrophic factors: an overview. Methods Mol Biol 2012;846:1-12.

Zheng F, Wang H. NMDA-mediated and self-induced bdnf exon IV tran- [98 scriptions are differentially regulated in cultured cortical neurons. Neuro-chem Int 2009;54:385-92. [99

Liang W, Ge S, Yang L, Yang M, Ye Z, Yan M, Du J, Luo Z. Ginsenosides Rb1 and Rg1 promote proliferation and expression of neurotrophic factors in primary Schwann cell cultures. Brain Res 2010;1357:19-25. [100

Shi YQ, Huang TW, Chen LM, Pan XD, Zhang J, Zhu YG, Chen XC. Ginsenoside Rg1 attenuates amyloid-beta content, regulates PKA/CREB activity, and

improves cognitive performance in SAMP8 mice. J Alzheimers Dis 2010;19: 977—89.

Jiang B, Xiong Z, Yang J, Wang W, Wang Y, Hu ZL, Wang F, Chen JG. Anti-depressant-like effects of ginsenoside Rg1 are due to activation of the BDNF signalling pathway and neurogenesis in the hippocampus. Br J Pharmacol 2012;166:1872—87.

Ardah MT, Paleologou KE, Lv G, Menon SA, Abul Khair SB, Lu JH, Safieh-Garabedian B, Al-Hayani AA, Eliezer D, Li M, et al. Ginsenoside Rb1 inhibits fibrillation and toxicity of alpha-synuclein and disaggregates preformed fibrils. Neurobiol Dis 2015;74:89—101.

O'Brien RJ, Wong PC. Amyloid precursor protein processing and Alzheimer's disease. Annu Rev Neurosci 2011;34:185—204.

Chen X, Huang T, Zhang J, Song J, Chen L, Zhu Y. Involvement of calpain and p25 of CDK5 pathway in ginsenoside Rb1's attenuation of beta-amyloid peptide25-35-induced tau hyperphosphorylation in cortical neurons. Brain Res 2008;1200:99—106.

Shi C, Zheng DD, Fang L, Wu F, Kwong WH, Xu J. Ginsenoside Rg1 promotes nonamyloidgenic cleavage of APP via estrogen receptor signaling to MAPK/ ERK and PI3K/Akt. Biochim Biophys Acta 2012;1820:453—60. Araki W. Post-translational regulation of the b-secretase BACE1. Brain Res Bull 2016;126:170—7.

Choi RJ, Roy A, Jung HJ, Ali MY, Min BS, Park CH, Yokozawa T, Fan TP, Choi JS, Jung HA. BACE1 molecular docking and anti-Alzheimer's disease activities of ginsenosides. J Ethnopharmacol 2016;190:219—30.

Chen LM, Lin ZY, Zhu YG, Lin N, Zhang J, Pan XD, Chen XC. Ginsenoside Rg1 attenuates beta-amyloid generation via suppressing PPARgamma-regulated BACE1 activity in N2a-APP695 cells. Eur J Pharmacol 2012;675:15—21. Wu J, Pan Z, Cheng M, Shen Y, Yu H, Wang Q, Lou Y. Ginsenoside Rg1 facilitates neural differentiation of mouse embryonic stem cells via GR-dependent signaling pathway. Neurochem Int 2013;62:92—102. Liu J, He J, Huang L, Dou L, Wu S, Yuan Q. Neuroprotective effects of ginse-noside Rb1 on hippocampal neuronal injury and neurite outgrowth. Neural Regen Res 2014;9:943—50.

Hao K, Gong P, Sun SQ, Hao HP, Wang GJ, Dai Y, Liang Y, Xie L, Li FY. Beneficial estrogen-like effects of ginsenoside Rb1, an active component of Panax ginseng, on neural 5-HT disposition and behavioral tasks in ovariec-tomized mice. Eur J Pharmacol 2011;659:15—25.

Lau WS, Chan RY, Guo DA, Wong MS. Ginsenoside Rg1 exerts estrogen-like activities via ligand-independent activation of ERalpha pathway. J Steroid Biochem Mol Biol 2008;108:6-4—71.

Shohami E, Biegon A. Novel approach to the role of NMDA receptors in traumatic brain injury. CNS Neurol Disord Drug Targets 2014;13:567—73. Zhang YF, Fan XJ, Li X, Peng LL, Wang GH, Ke KF, Jiang ZL. Ginsenoside Rg1 protects neurons from hypoxic-ischemic injury possibly by inhibiting Ca2+ influx through NMDA receptors and L-type voltage-dependent Ca2+ channels. Eur J Pharmacol 2008;586:90—9.

Shen L, Zhang J. NMDA receptor and iNOS are involved in the effects of ginsenoside Rg1 on hippocampal neurogenesis in ischemic gerbils. Neurol Res 2007;29:270—3.

Yang L, Zhang J, Zheng K, Shen H, Chen X. Long-term ginsenoside Rg1 supplementation improves age-related cognitive decline by promoting synaptic plasticity associated protein expression in C57BL/6J mice. J Gerontol A Biol Sci Med Sci 2014;69:282—94.

Escobar CM, Krajewski, Sandoval-Guzman T, Voytko ML, Rance NE. Neuropeptide Y gene expression is increased in the hypothalamus of older women. J Clin Endocrinol Metab 2004;89:2338—43. Q3

Gumbs MC, van den Heuvel JK, la Fleur SE. The effect of obesogenic diets on brain Neuropeptide Y. Physiol Behav 2016;162:161—73. Lin N, Cai DL, Jin D, Chen Y, Shi JJ. Ginseng panaxoside Rb1 reduces body weight in diet-induced obese mice. Cell Biochem Biophys 2014;68:189—94. Ye J, Yao JP, Wang X, Zheng M, Li P, He C, Wan JB, Yao X, Su H. Neuro-protective effects of ginsenosides on neural progenitor cells against oxidative injury. Mol Med Rep 2016;13:3083—91.

Ni N, Liu Q, Ren H, Wu D, Luo C, Li P, Wan JB, Su H. Ginsenoside Rb1 protects rat neural progenitor cells against oxidative injury. Molecules 2014;19: 3012—24.

Tabas I, Ron D. Integrating the mechanisms of apoptosis induced by endo-plasmic reticulum stress. Nat Cell Biol 2011;13:184—90. Liu D, Zhang H, Gu W, Liu Y, Zhang M. Ginsenoside Rb1 protects hippocampal neurons from high glucose-induced neurotoxicity by inhibiting GSK3beta-mediated CHOP induction. Mol Med Rep 2014;9:1434—8. Liu D, Zhang H, Gu W, Liu Y, Zhang M. Neuroprotective effects of ginsenoside Rb1 on high glucose-induced neurotoxicity in primary cultured rat hippocampal neurons. PLoS One 2013;8:e79399.

б1 б2

66 6l 6B б9 l0 l1 l2

16 ll lB l9 B0 B1 B2 B3 B4 BS B6 Bl BB B9

96 9l 9B 99

100 101 102

106 l0l 10B

110 111 112

116 11l 11B