Resveratrol and other phenolics from the bark of Yucca schidigera Roezl.

Five phenolic constituents have been identified in Yucca schidigera bark, a nd their structures were established by spectral (FABMS and NMR) experiment s. These included two known stilbenes, trans-3,4',5-trihydroxystilbene (res veratrol) and trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, as well as t hree novel compounds, yuccaols A, B, and C, with spiro-structures rarely oc curring in the plant kingdom. It is suggested that yuccaols A-C are biosynt hethized via attachment of a stilbenic derivative to the carbocationic inte rmediate of the oxidative flavanone-flavonol conversion.