Phytochemical investigation of Gynura bicolor leaves and cytotoxicity evaluation of the chemical constituents against HCT 116 cells

Abstract

Gynura bicolor (Compositae) is a popular vegetable in Asia and believed to confer a wide range of benefits including anti-cancer. Our previous findings showed that the ethyl acetate extract of G. bicolor possessed cytotoxicity and induced apoptotic and necrotic cell death in human colon carcinoma cells (HCT 116). A combination of column chromatography had been used to purify chemical constituents from the ethyl acetate and water extract of G. bicolor leaves. Eight chemical constituents 5-p-trans-coumaroylquinic acid (I), 4-hydroxybenzoic acid (II), rutin (III), kampferol-3-O-rutinoside (IV), 3,5-dicaffeoylquinic acid (V), kampferol-3-O-glucoside (VI), guanosine (VII) and chlorogenic acid (VIII) were isolated from G. bicolor grown in Malaysia. To our best knowledge, all chemical constituents were isolated for the first time from G. bicolor leaves except rutin (III). 3,5-dicaffeoylquinic acid (V), guanosine (VII) and chlorogenic acid (VIII) demonstrated selective cytotoxicity (selective index>3) against HCT 116 cancer cells compared to CCD-18Co human normal colon cells.

Keywords:

• Gynura bicolor
• 3,5-dicaffeoylquinic acid
• chlorogenic acid
• guanosine
• cytotoxicity
• HCT 116 cells

Acknowledgement

The authors are grateful to Dr Yong Kien Thai from the Institute of Biological Sciences, Faculty of Science, University of Malaya, Malaysia for plant identification.

Additional information

Funding

The authors wish to thank the Ministry of Higher Education of Malaysia (MOHE) and the University of Malaya for financial assistance [grant number FRGS FP013/2012A], [grant number PPP PV042/2012A].