Alisolide, alisols O and P from the rhizome of Alisma orientale

Abstract A nor- protostane, alisolide ( 1 ), a rearranged protostane, alisol O ( 2 ), and a 2,3- seco- protostane triterpene, alisol P ( 3 ), were isolated from the rhizomes of Alisma orientale , along with eight known protostane triterpenes. The structures were elucidated to be (17 S )-3,11-dioxo-23- nor- protost-12-en-23(17)-olide, 3-oxo-11β,23-dihydroxy-24,24-dimethyl-26,27-dinorprotost-13(17)-en-25-oic acid, and (20 R ,23 S ,24 R )-23,24,25-trihydroxy-2,3- seco- protost-13(17)-en-3-oic acid 2,11β-lactone, respectively, by interpretation of spectroscopic data.