Scholarly article on topic 'Caffeoylquinic acids in leaves of selected Apocynaceae species: Their isolation and content'

Caffeoylquinic acids in leaves of selected Apocynaceae species: Their isolation and content Academic research paper on "Biological sciences"

0
0
Share paper
Academic journal
Pharmacognosy Research
OECD Field of science
Keywords
{""}

Academic research paper on topic "Caffeoylquinic acids in leaves of selected Apocynaceae species: Their isolation and content"

PHCOG RES

ORIGINAL ARTICLE

Caffeoylquinic acids in leaves of selected Apocynaceae species: Their isolation and content

Siu Kuin Wong, Yau Yan Lim, Sui Kiong Ling1, Eric Wei Chiang Chan2

School of Science, Monash University Sunway Campus, Bandar Sunway, 46150 Petaling Jaya, Selangor, Malaysia, 1Natural Products Division, Forest Research Institute Malaysia, Kepong, 52109 Selangor, Malaysia, 2Faculty of Applied Sciences, UCSI University, 56000 Cheras, Kuala Lumpur, Malaysia

Submitted: 07-03-2013 Revised: 15-03-2013 Published: 12-12-2013

ABSTRACT

Background: Three compounds isolated from the methanol (MeOH) leaf extract of Vallaris glabra (Apocynaceae) were those of caffeoylquinic acids (CQAs). This prompted a quantitative analysis of their contents in leaves of V. glabra in comparison with those of five other Apocynaceae species (Alstonia angustiloba, Dyera costulata, Kopsia fruticosa, Nerium oleander, and Plumeria obtusa), including flowers of Lonicerajaponica (Japanese honeysuckle), the commercial source of chlorogenic acid (CGA). Materials and Methods: Compound were isolated by column chromatography, and identified by NMR and MS analyses. CQA content of leaf extracts was determined using reversed-phase HPLC. Results: From the MeOH leaf extract of V glabra, 3-CQA, 4-CQA, and 5-CQA or CGA were isolated. Content of 5-CQA of V. glabra was two times higher than flowers of L. japonica, while 3-CQA and 4-CQA content was 16 times higher. Conclusion: With much higher CQA content than the commercial source, leaves of V glabra can serve as a promising alternative source.

Key words: Apocynaceae, caffeoylquinic acids, chlorogenic acid, Vallaris glabra

Access this article online

Website:

www.phcogres.com DOI: 10.4103/0974-8490.122921 Quick Response Code:

INTRODUCTION

The family of Apocynaceae consists of about 250 genera and 2000 species of tropical trees, shrubs, and vines.[1,2] Almost all species of the family produce milky sap. Other characteristic features are simple, opposite or whorled leaves; large, colorful, and slightly fragrant flowers with five contorted lobes; and fruits are in pairs. The family has now been enlarged from two to five subfamilies with the inclusion of species of Asclepiadaceae.[3]

In traditional medicine, Apocynaceae species are used to treat gastrointestinal ailments, fever, malaria, pain, and diabetes.[1] Apocynaceae species have also been reported to demonstrate anticancer and antiplasmodial properties.

Our earlier study on the antiproliferative (APF) activity of sequential leaf extracts of ten Apocynaceae species showed that Alstonia angustiloba, Calotropis gigantea, Catharanthus roseus, Nerium oleander, Plumeria obtusa,

and Vallaris glabra displayed positive inhibition.[4,5] Allamanda cathartica, Cerbera odollam, Dyera costulata, and Kopsia fruticosa did not display any APF activity. Leaves were sequentially extracted with hexane (Hex), dichloromethane (DCM), and methanol (MeOH). DCM and DCM: MeOH (1:1) leaf extracts of V. glabra inhibited all six cancer cell lines of MCF-7, MDA-MB-231, HeLa, HT-29, SKOV-3, and HepG2, while the MeOH extract inhibited MCF-7 and HepG2 cells. Against MCF-7 cells, growth inhibition of DCM and DCM: MeOH extracts of Vglabra was stronger than standard drugs of xanthorrhizol and comparable to tamoxifen. Results showed that leaves of V glabra possessed strong and broad-spectrum APF properties.

Sequential leaf extracts of all five Apocynaceae species (A. angustiloba, C. gigantea, D. costulata, K. fruticosa, and Vglabra were effective against K1 strain of Plasmodium falciparum.[5] Three species (C. gigantea, D. costulata, and K. fruticosa were effective against 3D7 strain. Against K1 strain, all four extracts of V glabra displayed effective APM activity.

In this study, three compounds isolated from the MeOH leaf extract of Vglabra were those of caffeoylquinic acids. This

Address for correspondence:

Dr. Eric W.C. Chan, Faculty of Applied Sciences, UCSI University, 56000 Cheras, Kuala Lumpur, Malaysia. E-mail: chanwc@ucsiuniversity.edu.my

prompted a quantitative analysis of their contents in leaves of V. gglabra in comparison with those of five other Apocynaceae species and flowers of Lonicera japonica (Japanese honeysuckle), the commercial source of chlorogenic acid.

MATERIALS AND METHODS

Plant materials

The six Apocynaceae species studied were A. angustiloba, D. costulata, K. fruticosa, N. oleander, P. obtusa, and V glabra [Figure 1]. Their common or vernacular names and brief descriptions are given in Table 1. Leaves of the species studied were collected in June 2012 from Sunway, Puchong, or Kepong, all in the state of Selangor, Malaysia. Identification of species was verified by Dr. H.T. Chan (Forest Research Institute Malaysia), and based on

documented descriptions and illustrations.[1,2] Voucher specimens of these species were deposited in the herbarium of Monash University Sunway Campus.

Extraction of leaves

For isolation of compounds from MeOH extracts, leaves (40 g) of Vglabra were freeze-dried overnight, ground, and extracted successively with Hex, DCM, DCM: MeOH (1:1), and MeOH. For each solvent (50 ml/g of sample), the suspension of ground samples was shaken for 1 h on the orbital shaker. After filtering, the samples were extracted two more times for each solvent. Solvents were removed with a rotary evaporator to obtain the dried extracts, which were stored at -20°C for further analysis.

For quantitative analysis of caffeoylquinic acid (CQA) content, fresh leaves (1 g) were powdered with liquid nitrogen in a mortar and extracted with 50 ml of 70% methanol. Extracts were filtered under suction, prepared in triplicate, and stored at 4°C for analysis, which were conducted within a week of extraction.

Table 1: Common or vernacular names and brief description of Apocynaceae species

Species (common Brief description

vernacular name)

Alstonia angustiloba Miq. (Pulai)

Dyera costulata Hook (Jelutong)

Kopsia fruticosa (Ker.) A. DC. (Pink kopsia)

Nerium oleander L. (Oleander)

Plumeria obtusa L. (Frangipanni)

Vallaris glabra Kuntze (Bread flower)

A medium-sized tree with leaves in whorls and having fine secondary veins

A tall timber tree with straight columnar bole, leaves in whorls and latex which was an important source of chewing gum A shrub with large glossy leaves and clusters of light pink flowers resembling those of Ixora An ornamental shrub with thick narrow leaves in pairs or whorls and bearing clusters of pink, red, or purple flowers

A tree producing dark green, glossy and oval leaves and white fragrant flowers with a yellow center A woody climber producing clusters of white flowers with a scent characteristic of leaves of pandan (Pandanus amaryllifolius) or fragrant rice

Figure 1: The six Apocynaceae species studied

Isolation of compounds

MeOH leaf extract of V. glabra (40 g) was chromatographed on a MCI CHP-20P gel column with gradient H2O-MeOH (0^100% MeOH) to obtain eight fractions (M1 to M8). Fraction M4 (0.69 g) was then subjected to Chromatorex C18 with gradient H2O-MeOH (0^100% MeOH) to give two sub-fractions (M4-1 and M4-2). Sub-fraction M4-1 (0.60 g) was passed through Silica gel 60 with gradient CHCl3:MeOH:H2O (10:0:0^6:4:1) to give eight sub-fractions (M4-1-1 to M4-1-8). Sub-fraction M4-1-6 (0.51 g) was then subjected to MCI CHP-20P gel with gradient H2O-MeOH (0^100% MeOH) to yield Compound 1 (38 mg), Compound 2 (9 mg), and Compound 3 (24 mg).

Identification of compounds

Compounds were dissolved in a deuterated solvent and subjected to JH and 13C NMR analysis using a Bruker DRX 300 MHz spectrometer (300 MHz for JH and 75 MHz for 13C). Chemical shifts were recorded in ppm (8) using tetramethylsilane (TMS) as internal standard.

Compounds were subjected to electrospray ionization mass spectrometry (ESI-MS) using a Perkin Elmer Flexar SQ 300 mass spectrometer. Mass spectra were acquired in negative ion mode [M-H]-. Analytes were introduced into the mass spectrometer by direct infusion. Mass up to 3000 m/z was measured.

Analysis of CQA content

Fresh leaf extract of V glabra was analyzed for its CQA content using reversed-phase HPLC with comparison

made to leaf extracts of five other Apocynaceae species. 3-O-caffeoylquinic acid (3-CQA), 4-O-caffeoylquinic acid (4-CQA), and 5-O-caffeoylquinic acid (5-CQA) isolated from the MeOH leaf extract of V glabra by column chromatography were used to identify and quantify the CQA content in the six species in the HPLC chromatogram. Leaves of L. japonica, known to have high CQA content, were used as positive control.

HPLC (Agilent Technologies 1200 Series) instrument with Agilent Zorbax SBC-18 column (4.6 x 250 mm) were used in the HPLC analysis. A 15-min linear gradient from 5^-100% MeOH was used to elute samples at 1.2 ml/min. Mobile phases were acidified with 0.1% trifluoroacetic acid (TFA) for better resolution. A 20-|l loop was used for injection and elution was monitored at 280 nm. Commercially purchased HPLC standard of 5-CQA (chlorogenic acid) was used to construct the calibration curve. CQA content was determined using peak areas. The calibration equation of peak area (mAU*s) against concentration of CGA (mg/l) was y = 24.262x (R2 = 0.9998). CQA content was expressed as mg CGAE/100 g.

As 3-CQA, 4-CQA, and 5-CQA all shared similar UV absorption pattern as the HPLC standard of 5-CQA, the amount of 3-CQA and 4-CQA present in the extracts can be inferred from the calibration curve of the HPLC standard of 5-CQA.

RESULTS AND DISCUSSION

Three compounds isolated from the MeOH leaf extract of V glabra were 3-O-caffeoylquinic acid (3-CQA) or neochlorogenic acid, 4-O-caffeoylquinic acid (4-CQA) or cryptochlorogenic acid, and 5-O-caffeoylquinic acid (5-CQA) or chlorogenic acid (CGA). Their appearance, ESI-MS, and JH and 13C NMR spectral data are as follows:

Compound 1: 3-ö-caffeoylquinic acid (3-CQA)

Brownish amorphous powder; ESI-MS m/z 353.08 [M-H]-; JH NMR (CD3OD, 300 MHz) quinic moiety 8: 5.28 (1H, H-3), 3.89 (1H, m, H-5), 3.66 (1H, m, H-4), 1.94 (1H, m, H-6), 1.83 (1H, m, H-2); caffeoyl moiety 8: 7.49 (1H, d, J = 15.9, H-8'), 6.92 (1H, m, H-2'), 6.83 (1H, dd, J = 1.5, 8.1, H-6'), 6.66 (1H, d, J = 8.1, H-5'), 6.22 (1H, d, J = 15.9, H-7'); 13C NMR (CD3OD, 75 MHz) quinic moiety 8: 73.5 (C-4), 72.5 (C-3), 69.8 (C-5), 40.0 (C-6), 37.3 (C-2); caffeoyl moiety 8: 168.8 (C-9'), 149.4 (C-4'), 146.8 (C-7'), 146.7 (C-3'), 127.9 (C-1'), 122.9 (C-6'), 116.4 (C-5'), 115.7 (C-8'), 115.1 (C-2').

Compound 2: 4-0-caffeoylquinic acid (4-CQA)

Light brownish amorphous powder; ESI-MS m/z

353.03 [M-H]-; !H NMR (CD3OD, 300 MHz) quinic moiety 8: 4.70 (lH, m, H-4), 4.15 (1H, m, H-3), 4.09 (1H, m, H-5), 2.02 (1H, m, H-6), 1.91 (1H, m, H-2); caffeoyl moiety 8: 7.52 (1H, d, J = 15.9, H-8'), 6.92 (1H, m, H-2'), 6.83 (1H, dd, J = 1.5, 8.1, H-6'), 6.65 (1H, d, J = 8.1, H-5'), 6.22 (1H, d, J = 15.9, H-7'); 13C NMR (CD3OD, 75 MHz) quinic moiety 8: 79.1 (C-4), 76.6 (C-1), (59.5 (C-3), 65.7 (C-5), 42.5 (C-6), 38.6 (C-2); caffeoyl moiety 8: 178.0 (COO-),

169.0 (C-9'), 149.6 (C-4'), 147.1 (C-3'), 146.8 (C-7'),

127.8 (C-1'), 122.9 (C-6'), 116.4 (C-5'), 115.3 (C-8'),

115.1 (C-2').

Compound 3: 5-0-caffeoylquinic acid (5-CQA)

Cream colored amorphous powder; ESI-MS m/z 353.03 [M-H]-; 1H NMR (CD3OD, 300 MHz) quinic moiety 8: 5.19 (1H, m, H-5), 3.97 (1H, m, H-3), 3.51 (1H, m, H-4), 1.99 (1H, m, H-6), 1.75-1.83 (1H, m, H-2); caffeoyl moiety 8: 7.44 (1H, d, J = 15.6, H-8'), 6.88 (1H, d, J = 1.7, H-2'), 6.78 (1H, dd, J = 1.7, 7.8, H-6'), 6.62 (1H, d,J = 8.1, H-5'), 6.17 (1H, d, J = 15.9, H-7'); 13C NMR (CD3OD, 75 MHz) quinic moiety 8: 75.5 (C-1), 74.5 (C-5), 72.9 (C-4), 68.4 (C-3), 41.2 (C-6), 36.7 (C-2); caffeoyl moiety 8:

178.9 (COO-), 169.0 (C-9'), 149.4 (C-4'), 146.8 (C-3'), 146.7 (C-7'), 127.9 (C-1'), 123.0 (C-6'), 116.4 (C-5'), 115.7 (C-2'), 115.1 (C-8').

Previous reports on 3-CQA,[6'7] 4-CQA,[6>8] and 5-CQA[9'10] presented 1H and 13C NMR spectral data that matched those of the present study.

The molecular structures of 3-CQA, 4-CQA, and 5-CQA are shown in Figure 2. They are esters of caffeic and quinic acids with 3-CQA having the caffeoyl group attached to carbon 3, and the OH groups at carbons 1, 4, and 5. 4-CQA has the caffeoyl group at carbon 4, and the OH groups at carbons 1, 3, and 5, while 5-CQA has the caffeoyl group at carbon 5, and the OH groups at carbons 1, 3, and 4.

3-CQA, 4-CQA, and 5-CQA have a similar molecular formula of C16H18O9 and molecular weight of 354. Their IUPAC names are (1R,3R,4S,5R)-3-[(E)-3-(3,4-dihydroxyphenyl) prop-2-enoyl] oxy-1,4,5-trihydroxycyclohexane -1 -carboxylic acid; (3R,4S,5R)-4-{[(2E)-3-(3,4-dihydroxyphenyl) prop-2-enoyl] oxy} -1,3,5-trihydroxycyclohexane-1-carboxylic acid; and (1S,3R,4R,5R)-3-[(E)-3-(3,4-dihydroxyphenyl) prop-2-enoyl] oxy-1,4,5-trihydroxycyclohexane -1-carboxylic acid, respectively.

The isolation of CQAs from leaves of Vglabra represents the first report of CQAs in the genus Vallaris. Earlier studies have documented the occurrence of CQAs in Apocynaceae species. 5-CQA had been reported in leaves of Catharanthus roseus.[11] In the same species, 3-CQA

Figure 2: Molecular structures of 3-O-caffeoylquinic acid (3-CQA), 4-O-caffeoylquinic acid (4-CQA), and 5-O-caffeoylquinic acid (5-CQA)

and 5-CQA have been isolated from stems and leaves, and

4-CQA from petals.[12] CGA was reported in leaves of Vinca major,'131 and in stems and leaves of Trachelospermum jasminoides.[14] The content of 4-CQA and 5-CQA identified from leaves of Apocynum venetum had been reported to be 0.0-0.7% and 2.1-3.9%, respectively.'151

The occurrence and contents of CQAs in fruits and vegetables have been compiled.'161 Plants rich in CQAs include flowers of L. japonica (Japanese honeysuckle), the commercial source of CGA,[17] leaves of Ipomoea batatas (sweet potato),'181 and heads of Cynara scolymus (artichoke).'191

In prunes, the contents of 3-CQA, 4-CQA, and 5-CQA were of the ratio 79:18:4.'61 In plums, their contents were 541, 9, and 73 mg/kg, respectively.'201 The contents of CQA in three Chinese traditional herbs were investigated.'211

5-CQA was dominant in leaves of Eucommia ulmoides and flowers of L. japonica. 3-CQA and 4-CQA dominated the CQAs in leaves of Houttuynia cordata.

The antioxidant properties of CQAs are widely recognized, with those of CGA most studied. They have the ability to inhibit human low-density lipoprotein (LDL) oxidation,'22,231 scavenge free radicals such as reactive oxygen and nitrogen species,'24,251 to inhibit to lipid peroxidation,'261 to chelate iron in iron-induced lipid peroxidation,'251 and to protect against DNA breakage caused by monochloramine.'271 In terms of in vitro peroxidation of human LDL, both CGA and caffeic acid are equally effective antioxidants, with stronger activity than sinapic acid, ferulic acid, and p-coumaric acid.'281

The antioxidant activity of CQA is higher than those of vitamin C and vitamin E, based on Trolox equivalent antioxidant activity.'291 The high antioxidant activity of prunes has been attributed to CQA.'6,301 3-CQA, 4-CQA, and 5-CQA had strong scavenging activity on superoxide anion radicals and inhibitory effect against oxidation of methyl linoleate.'61 The oxygen radical absorbance capacity values of 3-CQA (5.3 units/mg) and 4-CQA (5.4 units/mg) were slightly higher than 5-CQA (4.6 units/mg).'301

It was reported that the number of caffeoyl groups contributes to the scavenging activity of DPPH and superoxide radicals rather than the linkage positions of caffeoyl groups to the quinic moiety.'311 This implies that diCQA would have stronger antioxidant activity than CQA.

Besides antioxidant properties, studies have shown that CQA display diverse bioactivities. CGA is known to have strong antimicrobial properties,'321 and is an effective anti-inflammatory, analgesic, and antipyretic agent.'33,341 Other bioactivities included anti-skin aging, anti-hypercholesterolemia, and anti-hyperglycaemia activities.'351 CGA has been reported to be cytotoxic to oral tumor cell lines of human oral squamous cell carcinoma (HSC-2) and salivary gland tumor (HSG) cell lines.'361 CGA isolated from stems of Euonymus alatus has been reported to inhibit metallo-proteinase-9, suggesting its chemopreventive properties against cancer.'371

The CQA content of fresh leaf extracts of V glabra and five other Apocynaceae species was analyzed using reversed-phase HPLC and results are shown in Table 2. HPLC standard 5-CQA (chlorogenic acid) was used to construct the calibration curve. CQA content was determined using peak areas. The calibration equation of peak area (mAU*s) against concentration of CGA (mg/l) was y = 24.262x (R2 = 1.000). 5-CQA was eluted at 7.1 min on the HPLC. As 3-CQA and 4-CQA had similar retention times (RT) of 5.9 min when eluted, they were estimated as a single aggregate.

It is interesting to note that leaves of all the six Apocynaceae species contained significant amounts of chlorogenic acid. Highest content of 5-CQA was observed in N. oleander (537 ± 103 mg CGA/100 g) followed by Vglabra (353 ± 25 mg CGA/100 g), which were respectively three and two times higher than the amount of 5-CQA in flowers of L. japonica (173 ± 13 mg CGA/100 g), the commercial source of CGA (Table 2, Figure 31. The 5-CQA content of N. oleander and V. glabra leaves also surpasses Etlingera elatior (294 ± 53 mg CGA/100 g) and I. batatas reported to be 294 ± 53 and 115 ± 16 mg CGA/100 g,

Table 2: Caffeoylquinic acid content of MeOH leaf extract of Vallaris glabra with comparison to five other Apocynaceae species (fresh weight)

Species CQA content

3-CQA and 4-CQA 5-CQA

Vallaris glabra 370 ± 15 353 ± 25

Alstonia angustiloba 19 ± 2.8 155 ± 24

Dyera costulata ND 253 ± 32

Kopsia fruticosa 40 ± 9.9 270 ± 63

Nerium oleander 47 ± 4.4 537 ±103

Plumeria obtusa 14 ± 4.7 245 ± 60

Lonicera japonica 23 ± 2.2 173 ± 13

Caffeoylquinic acid (CQA) content in mg CGA/100 g of samples (fresh weight) was determined using reversed-phase HPLC. Values are means±SD (n=3). Flowers of Lonicera japonica were included as positive control. ND=not detected

D. costulata. The presence of other isomeric forms of CQA could account for the high amounts of CQA content in the methanol leaf extract of D. costulata.

CONCLUSION

3-CQA, 4-CQA, and 5-CQA or CGA were isolated from leaves of Vglabra. Compared to flowers of L. japonica (the commercial source of CGA), 5-CQA content was two times higher, and 3-CQA and 4-CQA content was about 16 times higher. With much higher CQA content than the commercial source, leaves of V. glabra can serve as a promising alternative source.

Figure 3: HPLC chromatograms of 3-CQA, 4-CQA, and 5-CQA in leaves of Vallaris glabra and flowers of Lonicera japonica monitored at 280 nm

respectively.1381 Although, D. costulata had the highest CQA content, the 5-CQA content of D. costulata (253 ± 32 mg CGA/100 g) was comparable to that of V glabra and K. fruticosa (270 ± 63 mg CGA/100 g). 5-CQA content of D. costulata, K. fruticosa, and P. obtusa (245 ± 60 mg CGA/100 g) were significantly higher than that of L. japonica. Leaves of A. angustiloba (155 ± 24 mg CGA/100 g) had comparable amounts of 5-CQA as L. japonica.

3-CQA and 4-CQA content of V glabra (370 ± 15 mg CGA/100 g) was the highest among the species screened and about 16 times higher than that of the flowers of L. japonica (23 ± 2.2 mg CGA/100 g) [Table 2; Figure 3]. Leaves of N. oleander (47 ± 4.4 mg CGA/100 g), K. fruticosa (40 ± 9.9 mg CGA/100 g), and A. angustiloba (19 ± 2.8 mg CGA/100 g) had significantly higher 3-CQA and 4-CQA content than that of L. japonica. 3-CQA and 4-CQA content was not detected in leaves of

ACKNOWLEDGMENTS

The authors are thankful to the Ministry of Higher Learning of Malaysia for providing the research grant. The support of Monash University Sunway Campus, Forest Research Institute Malaysia and UCSI University for their contribution of research assistants and interns (Yuen Ping, Lea Ngar, and Chee Wai) is gratefully acknowledged.

REFERENCES

1. Wiart C. Medicinal Plants of Asia and the Pacific. Boca Raton: CRC Press/Taylor and Francis; 2006.

2. Ng FS. Tropical Horticulture and Gardening. Kuala Lumpur. Malaysia: Clearwater Publications; 2006.

3. Endress ME, Bruyns PV. A revised classification of the Apocynaceae. Bot Rev 2000;66:1-56.

4. Wong SK, Lim YY, Abdullah NR, Nordin FJ. Antiproliferative and phytochemical analyses of leaf extracts of ten Apocynaceae species. Pharmacog Res 2011;3:100-6.

5. Wong SK, Lim YY, Abdullah NR, Nordin FJ. Assessment of antiproliferative and antiplasmodial activities of five selected Apocynaceae species. BMC Complement Altern Med 2011;11:3.

6. Nakatani N, Kayano S, Kikuzaki H, Sumino K, Katagiri K, Mitani T. Identification, quantitative determination, and antioxidative activities of chlorogenic acid isomers in prune (Prunus domestica L.). J Agric Food Chem 2000;48:5512-6.

7. Chan EW. Bioactivities and chemical constituents of leaves of some Etlingera species (Zingiberaceae) in Peninsular Malaysia. PhD thesis. Malaysia: Monash University Sunway Campus Malaysia; 2009.

8. Rechner AR. Absorption and metabolism of hydroxycinnamates. In: Rice-Evans CA, Packer L, editors. Flavonoids in Health and Disease. New York: Marcel Dekker Inc. and CRC Press LLC; 2003.

9. Lin LC, Yang LL, Chou CJ. Constituents from stems of Ecdysanthera rosea. J Chin Med 2002;13:191-5.

10. Naidu MM, Sulochanamma G, Sampathu SR, Srinivas P. Studies on extraction and antioxidant potential of green coffee. Food Chem 2008;107:377-84.

11. Choi YH, Tapias EC, Kim HK, Lefeber AW, Erkelens C, Verhoeven JT, et al. Metabolic discrimination of Catharanthus roseus leaves infected by phytoplasma using 1H-NMR spectroscopy and multivariate data analysis. Plant Physiol 2004;135:2398-410.

12. Ferreres F, Pereira DM, Valentao P, Andrade PB, Seabra RM, Sottomayor M. New phenolic compounds and antioxidant potential of Catharanthus roseus. J Agric Food Chem 2008;56:9967-74.

13. Sakushima A, Nishibe S. Mass spectrometry in the structural determination of flavonol triglycosides from Vinca major. Phytochemistry 1988;27:915-9.

14. Sheu MJ, Chou PY, Cheng HC, Wu CH, Huang GJ, Wang BS, et al. Analgesic and anti-inflammatory activities of a water extract of Trachelospermum jasminoides (Apocynaceae). J Ethnopharmacol 2009;126:332-8.

15. Yin XY, Fu JJ, Yang HS, Liu HN, Luo YM. Analysis of flavonoids and phenolic acids of aqueous extracts in leaves of Apocynum venetum L. Inform Technol Agric Eng 2012;134:925-33.

16. Kuhnert N, Karaköse H, Jaiswal R. Analysis of chlorogenic acids and other hydroxycinnamates in food, plants, and pharmacokinetic studies. In: Nollet LML, Toldra F, editors. Handbook of Analysis of Active Compounds in Functional Foods. United States: CRC Press; 2012.

17. Xiang Z, Ning Z. Scavenging and antioxidant properties of compound derived from chlorogenic acid in South-China honeysuckle. LWT-Food Sci Technol 2008;41:1189-203.

18. Zheng W, Clifford MN. Profiling the chlorogenic acids of sweet potato (Ipomoea batatas) from China. Food Chem 2008;106:147-52.

19. Schutz K, Kammerer D, Carle R, Schieber A. Identification and quantification of caffeoylquinic acids and flavonoids from artichoke (Cynara scolymus l.) heads, juice, and pomace by HPLC-DAD-ESI/MS. J Agric Food Chem 2004;52:4090-6.

20. Herrmann K. Occurrence and content of hydroxycinnamic and hydroxylbenzoic acid compounds in foods. Crit Rev Food Sci Nutr 1989;28:315-47.

21. Wang Z, Clifford MN. Comparison of the profiles of chlorogenic acids and their derivatives from three Chinese traditional herbs by LC-MSn. Yao Xue Xue Bao 2008;43:185-90.

22. Nardini M, D'Aquino M, Tomassi G, Gentili V, Di Felice M, Scaccini C. Inhibition of human low-density lipoprotein oxidation by caffeic acid and other hydroxycinnamic acid derivative. Free Rad Biol Med 1995;19:541-52.

23. Rice-Evans CA, Miller NJ, Paganga G. Structure-antioxidant activity relationships of flavonoids and phenolic acids. Free Rad Biol Med 1996;20:933-56.

24. Kono Y, Kobayashi K, Tagawa S, Adachi K, Ueda A, Sawa Y, et al. Antioxidant activity of polyphenolics in diets. Rate constants of reactions of chlorogenic acid and caffeic acid with reactive species of oxygen and nitrogen. Biochim Biophy Acta 1997;1335:335-42.

25. Kono Y, Kashine S, Yoneyama T, Sakamoto Y, Matsui Y, Shibata H. Iron chelation by chlorogenic acid as a natural antioxidant. Biosci Biotechnol Biochem 1998;62:22-7.

26. Marinova EM, Toneva A, Yanishlieva N. Comparison of the antioxidative properties of caffeic and chlorogenic acids. Food Chem 2009;114:1498-502.

27. Shibata H, Sakamoto Y, Oka M, Kono Y. Natural antioxidant, chlorogenic acid, protects against DNA breakage caused by monochloramine. Biosci Biotechnol Biochem 1999;63:1295-7.

28. Cheng JC, Dai F, Zhou B, Yang L, Liu ZL. Antioxidant activity of hydroxycinnamic acid derivative in human low density lipoprotein: Mechanism and structure-activity relationship. Food Chem 2007;104:132-9.

29. Rice-Evans CA, Miller NJ, Paganga G. Antioxidant properties of phenolic compounds. Trend Plant Sci 1997;2:152-9.

30. Kayano S, Kikuzaki H, Fukutsuka N, Mitani T, Nakatani N. Antioxidant activity of prune (Prunus domestica L.) constituents and a new synergist. J Agric Food Chem 2002;50:3708-12.

31. Iwai K, Kishimoto N, Kakino Y, Mochida K, Fujita T. In vitro antioxidative effects and tyrosinase inhibitory activities of seven hydroxycinnamoyl derivatives in green coffee beans. J Agric Food Chem 2004;52:4893-8.

32. Almeida AA, Farah A, Silva DA, Nunan EA, Gloria MB. Antibacterial activity of coffee extracts and selected coffee chemical compounds against enterobacteria. J Agric Food Chem 2006;54:8738-43.

33. Jin XH, Ohgami K, Shiratori K, Suzuki Y, Koyama Y, Yoshida K, et al. Effects of blue honeysuckle (Lonicera caerulea L.) extract on lipopolysaccharide induced inflammation in vitro and in vivo. Exp Eye Res 2006;82:860-7.

34. dos Santos MD, Almeida MC, Lopes NP, de Souza GE. Evaluation of the anti-inflammatory, analgesic and antipyretic activities of the natural polyphenol chlorogenic acid. Biol Pharm Bull 2006;29:2236-40.

35. Harrison HF, Mitchell TR, Peterson JK, Wechter WP, Majetich, GF, Snook ME. Contents of caffeoylquinic acid compounds in the storage roots of sixteen sweet potato genotypes and their potential biological activity. J Am Soc Hort Sci 2008;133:492-500.

36. Jiang Y, Kusama K, Satoh K, Takayama F, Watanabe S, Sakagami H. Induction of cytotoxicity by chlorogenic acid in human oral tumor cell lines. Phytomedicine 2000;7:483-91.

37. Jin UH, Lee JY, Kang SK, Kim JK, Park WH, Kim JG, et al. A phenolic compound, 5-caffeoylquinic acid (chlorogenic acid), is a new type and strong matrix metalloproteinase-9 inhibitor: Isolation and identification from methanol extract of Euonymus alatus. Life Sci 2005;77:2760-9.

38. Chan EW, LimYY, Ling SK,TanSP, Lim KK, Khoo MG. Caffeoylquinic acids from leaves of Etlingera species (Zingiberaceae). LWT-Food Sci Technol 2009;42:1026-30.

Cite this article as: Wong SK, Lim YY, Ling SK, Chan EW. Caffeoylquinic acids in leaves of selected Apocynaceae species: Their isolation and content. Phcog Res 2014;6:67-72.

Source of Support: This study was partly funded by the Fundamental Research Grant Scheme of the Ministry of Higher Learning of Malaysia, Conflict of Interest: None declared.

Copyright of Pharmacognosy Research is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.