title: 7-Oxodioscin, a new spirostan steroid glycoside from the rhizomes of Dioscorea nipponica.
abstract: Nine glycosides of spirostan (1-7) and furostan (8 and 9) type steroids including a new compound, 7-oxodioscin (1), were isolated from the rhizomes of Dioscorea nipponica. The structure of 1 was established as (25R)-3beta-O-[(alpha-L-rhamnopyranosyl-(1 --> 4)-O-[alpha-L-rhamnopyranosyl-(1 --> 2)]-beta-D-glucopyranosyl)oxy]spirost-5-en-7-one by extensive spectroscopic techniques including HRESI-TOFMS, 1D and 2D NMR, and chemical methods. Known compounds were elucidated as dioseptemloside G (2), (25R)-dracaenoside G (3), orbiculatoside B (4), dioscin (5), progenin III (6), gracillin (7), (3beta3,22alpha,25R)-26-(beta-D-glucopyranosyloxy)-22-methoxyfurost-5-en-3-yl O-[alpha-L-rhamnopyranosyl-(1 --4)]-beta-D-glucopyranoside (8), and methylprotodioscin (9).
authors.affiliation: National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
authors.forename: Zulfiqar
authors.initials: Z
authors.lastname: Ali
authors.forename: Troy J
authors.initials: TJ
authors.lastname: Smillie
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khana
mesh_terms: D027742:Dioscorea / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry*; D015394:Molecular Structure; D013150:Spirostans / Q000737:chemistry*; D013256:Steroids / Q000737:chemistry
chemical_list: D006027:Glycosides; D013150:Spirostans; D013256:Steroids