The Dioscorea genus:: a review of bioactive steroid saponins

This review will summarize some of the important reports on the chemistry and the biological activities of Dioscorea steroid saponins from the literature data of recent years (2000-2006) and from the authors' studies. These discoveries became possible as a result of the scientific development of isolation, structure elucidation, and the development of in vitro bioassays. Over 50 steroid saponins of furostane-, spirostane-, and pregnane-type skeleton have been discovered and characterized from 13 Dioscorea species, namely, D. bidbifera L., D. cayenensis Lam.-Holl, D. colletii Hook. F. var. hypoglatica (Palib.) Pei et Ting, D. deltoidea Wall var. orbiculata, D. futschauensis R. Kunth, D. nipponica Mak., D. panthaica Prain et Burkill, D. parviflora Ting, D. polygonoides Humb. et Bonpl., D. pseudojaponica Yamamoto, D. spongiosa Xi, Mizuno et Zhao, D. villosa L., D. zingiberensis Wright. The main biological and pharmacological properties of Dioscorea saponins concern cytotoxic and antifungal activity, which are highlighted.