Furanoid Norditerpenes from Dioscoreaceae Plants. I. Diosbulbins A, B and C from Dioscorea bulbifera L. forma spontanea MAKINO et NEMOTO

Abstract

Three nonsteroidal compounds, named diosbulbins A, B and C, were isolated from the root tubers of Dioscorea bulbifera L. forma spontanea MAKINO et NEMOTO (a wild type of D. bulbifera L.) in which scarcely steroid sapogenin was found. Diosbulbin A, C₂₀H₂₄O₇, mp 265°(decomp.), [α]²⁰_D+26.7°, B, C₁₉H₂₀O₆, mp 285°(decomp.), [α]²⁰_D+92.0°and C, C₁₉H₂₂O₇, mp 247-250°(decomp.), [α]²⁰_D+64.7°, all having bitter taste, were assigned the partial structural formulae III, I, II, respectively, and regarded as a series of novel type of furanoid norditerpenes. These are first terpenoids reported in Dioscoreaceae and first furanoid diterpenoids in Monocotyledoneae.