Isolation and structure of eucosterol and 16beta-hydroxyeucosterol, two novel spirocyclic nortriterpenes, and of a new 24-nor-5alpha-chola-8, 16-diene-23-oic acid from bulbs of several Eucomis species.

Abstract

AbstractEucosterol and 16 β‐hydroxy‐eucosterol which have been isolated from several Eucomis species have been shown to be (23S)‐17,23‐epoxy‐3β,31‐dihydroxy‐27‐nor‐5α‐lanost‐8‐ene‐15,24‐dione (1) and (23 S)‐17,23‐epoxy‐3β,16β,31‐trihydroxy‐27‐nor‐5α‐lanost‐8‐ene‐15,24‐dione (2) by chemical transformations and spectral data. The spiro‐fused furanoic ether linkage of both metabolites represents a novel structural element for natural nortriterpenes. The structure of another metabolite (16), 3β‐hydroxy‐4β‐hydroxymethyl‐4,14α‐dimethyl‐15‐oxo‐24‐nor‐5α‐chola‐8,16‐diene‐23‐oic acid, from Eucomis autumnalis (Mill.) Chitt. was elucidated by chemical correlation of its methyl ester 17 with a degradation product of eucosterol (1).