A New Spirostanol, 19-Hydroxyyonogenin, from the Aerial Parts of Dioscorea tokoro MAKINO

Abstract

A new spirostanol (I), mp 249-250°, [α] D-15.5°, was isolated from a crude sapogenin mixture obtained by acid hydrolysis of the methanol extracts of the aerial parts of Dioscorea tokoro MAKINO. The structure of I was established as (25R)-5β-spirostane-2β, 3α, 19-triol, that is 19-hydroxy-yonogenin. This is the first spirostane derivative having an oxygen function at C₁₉, and an additional example of the unusual spirostanol carrying the α-hydroxyl group at C₃.