Cytotoxic phenanthrenes and phenolic constituents from the tubers of Dioscorea persimilis

Abstract

Abstract The tubers of Dioscorea persimilis have been widely consumed as a food and for the treatment of sonasthenia, intestinal disease, diarrhea, long-term dysentery, spermatorrhea, metritis, kidney failure, back pain, dizziness, and night sweats. The present study describes the isolation of 11 secondary metabolites, including three new phenanthrenes namely diospersimilosides A (1) and B (2) and diosbiphenanthrene (3), and eight known phenolic compounds: 2,4,6,7-tetrahydroxy-9,10-dihydrophenanthrene (4), aerosin (5), gastrodin (6), 2-phenylethyl-β- d -glucopyranoside (7), afzelechin (8), catechin (9), eucomic acid (10), and vanillic acid-4-O-β- d -glucopyranoside (11) from the tubers of D. persimilis. Their chemical structures were elucidated based on comprehensive analyses of the NMR and mass spectra. Evaluation of their cytotoxicity against three human cancer cell lines, including liver (HepG2), breast (MCF7), and melanoma (SK-Mel-2) revealed that the phenanthrene metabolites (3-5) possess cytotoxicity toward all the cell lines, with IC50 values ranging from 8.2–68.4 μM. Our results revealed that the free of the hydroxy groups plays an important role in cytotoxicity of the phenanthrenes and suggests that pohydroxylated dihydrophenanthrene and biphenanthrene metabolites could be considered as promising cytotoxic agents against human cancer cells.