Dinklagins A, B and C: three prenylated flavonoids and other constituents from the twigs of Dorstenia dinklagei.

Three prenylated flavonoids, dinklagins A, B and C identified, respectively, as (-)-6-(3,3-dimethylallyl)-7-hydroxy-6''', 6'''-dimethylchromeno-(4',3',2''',3''')-flavanone, (+)-5,4',5"xi-trihydroxy-6'',6''-dimethylchromano-(7,6,2'',3'')-flavone and (+)6-(2xi-hydroxy-3-methyl-3-butenyl)-5,7,4'-trihydroxyflavone were isolated from the twigs of Dorstenia dinklagei together with the known 6-prenylapigenin, 4-hydroxylonchocarpin, stipulin and 5,4'-dihydroxy-6'',6''-dimethylchromano-(7,6,2'',3'')-flavone. Their structures were determined on the basis of spectral data and by comparison with data reported in the literature and with authentic specimens for known compounds. Copyright 2002 Elsevier Science Ltd.