THE STRUCTURES OF YEMUOSIDE YM₁₀ AND YM₁₂ FROM STAUNTONIA CHINENSIS

Two new nortriterpenoid saponins, named yemuoside YM₁₀ (Ⅰ) and YM₁₂ (Ⅱ) , were isolated from Stauntonia chinensis Decne. A new prosaponin (Ⅵ) was isolated from the cleavage of ester-glycoside linkage. Their chemicaI structures were elucidated by means of chemical and spectrometric analysis.Yemuoside YM₁₀ (Ⅰ): C₅₈H₉₂O₂₅, a white powder, mp 215～8219℃ (dec), α_D²⁰-4.41° ( c 0.272, CH₃OH). Its structure was found to be 28-O-α-L-rhamnopyanosyl- (1→-4) -β-D-glucopyranosyl- (1→-6) -β D-glucopyranosyl ester of 3-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl-30-norolean -12, 20 (29) -dien-28-oic acid.Yemuoside YM₁₂ (Ⅱ)- C₅₂H₈₂O₂₁, a white powder, rap 200～204℃ ( dec. ), α_D²⁰+10.12° ( c 0.346, CH₃OH). Its structure was found to be 28-O-β-D-glucopyranosyl- (1→6) -β-D-glucopyranosyl ester of 3-O-α-L-rhamnopyranosyl- (1→-2) -α-L-arabinopyranosyl-30-norolean - 12, 20 (29) -dien - 28 - oic acid.Prosaponin (Ⅳ) :C₄₀H₆₂O₁₁, a white powder, mp 243～246℃ (dec.), α_D²² +12.13° ( c 0.128, CH₃OH). Its strvcture was found to be 3-O-α-L-rhamnopyranosyl- (1→2) -α-L-arabinopyranosyl-30-norolcan 12, 20 (29)-dien-28-oic acid.