Minor desacylsaponins from the corms of Crocosmia masoniorum.

Two novel triterpene saponins, named desacylmasonosides 4 and 5, and a new oxygenated fatty acid have been isolated, together with a known saponin, desacylcrocosmioside A, from the weak alkaline hydrolysate of the crude saponin obtained from the corms of Crocosmia masoniorum. On the basis of spectral and chemical evidence, the structures of desacylmasonosides 4 and 5 were elucidated as 3-O-[beta-D-fucopyranosyl-(1-->6)-beta-D-glucopyranosyl]-28-O-(2-O-[beta - D-apiofuranosyl-(1-->4)-beta-D-xylopyranosyl-(1-->4)-alpha-L- rhamnopyranosyl]-3-O-(beta-D-glucopyranosyl)-beta-D-fucopyranosyl)-po lygalaci c acid and 3-O-[alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranosyl]-28-O- [2-O-(alpha-L-rhamnopyranosyl)-3-O-(beta-D-glucopyranosyl)-beta-D- fucopyranosyl]-polygalacic acid, respectively. An oxygenated fatty acid derived from the acyl moiety of the esterified saponins was identified as 2,16-dihydroxy-9-oxohexadecanoic acid.