Four new natural Diels-Alder type adducts, mulberrofuran E, kuwanon Q,R, and V from callus culture of Morus alba L.

Abstract

From callus tissues of Morus alba L. the four new Diels-Alder type adducts mulberrofuran E (3), kuwanon Q (4), R (5), and V (6) have been isolated. Their structures were established by chemical and spectroscopic means. Mulberrofuran E (3) was found to be an adduct of a chalcone and a dehydroprenyl-2-arylbenzofuran, whereas kuwanon Q (4), R (5), and V (6) were identified as adducts of two prenylchalcone derivatives.