10 ISOPRENYLATED AND C-METHYLATED FLAVONOIDS FROM THE LEAVES OF 3 VELLOZIA SPECIES

Eight new and two known lipophilic flavonoids were isolated from the l eaf surface of Vellozia coronata, V. glabra and V. nanuzae. Four are f lavanones: velloeriodictyol [2''-isopropenyldihydrofurano(4'',5'': 6,7 )-eriodictyol], 6,8-diprenyleriodictyol, 6-(3-hydroxyisopentanyl) erio dictyol and 6-C-methyleriodictyol 7,3',4'-trimethyl ether. Two are fla vonols, the 6-prenyl derivatives of quercetin 3-monomethyl ether and o f quercetin 3,7-dimethyl ether. Two new C-methyl ethers, namely 8-C-me thylquercetagetin 3,6,3'-trimethyl ether and 8-C-methyl-6-hydroxykaemp ferol 3,6,7-trimethyl ether, were accompanied by the known 3,6,7-trime thyl ether and 3,6,7,3'-tetramethyl ether of 8-C-methylquercetagetin. Also present in the lipophilic fraction is a resveratrol dimethyl ethe r mixture, which has considerable antifungal activity. The vacuolar fl avonoids of the same three Vellozia species were variously identified as tricin 5-glucosisde, five orientin-based C-glycosides, the 7-glucos ide and 7-rhamnosylglucoside of 6-hydroxyluteolin, the 7-glucoside of pleurostimin and the 6-glucoside of its 7-methyl ether. The chemosyste matic significance of these findings is briefly discussed.