Prenylated and Benzylated Flavonoids from the Fruits of Cudrania tricuspidata

Three new prenylated isoflavones, 5,7-dihydroxy-6-(2 ''-hydroxy-3 ''-methylbut-3 ''-enyl)-4'-methoxylisoflavone (1), 5,4'-dihydroxy-6-(3 ''-methylbut-2 ''-enyl)-2'-(4'-hydroxy-4'-methylethyl)-3'-methoxydihydrofurano [4',5''';7,8]isoflavone (2), and 5,4'-dihydroxy-8-(3 ''-methylbut-2 ''-enyl)-2'-(4'-hydroxy-4'-methylethyl)furano[4',5''';6,7]isoflavone (3), a benzylated dihydroflavonol, 5,7,4'-trihydroxy-8-p-hydroxybenzyldihydroflavonol (4), and eight known flavonoids (5-12) were isolated from the fruits of Cudrania tricuspidata. The structures of these compounds were determined on the basis of MS and H-1 and C-13 NMR spectroscopic data, including 2D NMR experiments. Compounds 2, 3, 6, 7, 8, 10, 11, and 12 inhibited LPS-induced nitric oxide production, with IC50 values of 11.8-41.8 mu M.