title: Withanolides from the rhizomes of Dioscorea japonica and their cytotoxicity.
abstract: Edible yams are tropical crops that serve as important staple foods in many parts of the world. The rhizome of Dioscorea japonica , well-known as "Japanese yam", is a food and medicinal source known as "San Yak" in Korea. Bioassay-guided fractionation and chemical investigation of the extract of this yam resulted in the identification of two new withanolides, named dioscorolide A (1) and dioscorolide B (2). The structures of these new compounds were determined by spectroscopic methods, including 1D and 2D nuclear magnetic resonance (NMR) techniques, high-resolution mass spectrometry (HRMS), and chemical methods. The cytotoxic activities of the isolates (1 and 2) were evaluated by determining their inhibitory effects on four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) and a human normal cell line (HUVEC) using a sulforhodamine B (SRB) bioassay. Compounds 1 and 2 showed cytotoxicity against tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) with IC(50) values ranging from 6.3 to 26.9 μM and exhibited lower activity against the normal cell line (HUVEC) with IC(50) values ranging from 27.1 to 28.8 μM, suggesting selective toxicity among tumor and normal cells.
authors.affiliation: School of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea.
authors.forename: Ki Hyun
authors.initials: KH
authors.lastname: Kim
authors.forename: Sang Un
authors.initials: SU
authors.lastname: Choi
authors.forename: Sang Zin
authors.initials: SZ
authors.lastname: Choi
authors.forename: Mi Won
authors.initials: MW
authors.lastname: Son
authors.forename: Kang Ro
authors.initials: KR
authors.lastname: Lee
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D027742:Dioscorea / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D027343:Rhizome / Q000737:chemistry*; D054358:Withanolides / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D054358:Withanolides; C562009:dioscorolide A; C562010:dioscorolide B