Structures of kuwanons Y and Z, two new stilbene derivatives from the cultivated mulberry tree (Morus alba L.)

Abstract

Two novel stilbene derivatives named kuwanons Y and Z were isolated from the acetone extract of the reddish violet powder (lenticel) from the surface of the root bark of cultivated mulberry tree (Ichinose, a cultivated variety of Morus alba L.). The structures of kuwanons Y and Z were shown to be 1̃ and 2̃, respectively, on the basis of spectral and chemical evidence. Kuwanon Y is regarded biogenetically as a Diels-Alder type adduct of a chalcone derivative and a dehydroprenylstilbene derivative, while kuwanon Z as a variation of a Diels-Alder type adduct. © 1986.