Methylated A-type proanthocyanidins and related metabolites from Cassipourea gummiflua.
The range of natural dimeric A-type proanthocyanidins is extended by identification of two new dimeric afzelechins in the form of 7-OMe-epiafzelechin-(4 beta-->8,2 beta-->0-->7)- epiafzelechin and 7-OMe-epiafzelechin-(4 beta-->8, 2 beta-->0-->7)-ent-afzelechin. These are accompanied in the stem bark of Cassipourea gummiflua by the related metabolites afzelechin, kaempferol-3-0-alpha-L-rhamnopyranoside, afzelechin-3-0- alpha-L-rhamnopyranoside, epiafzelechin (4 beta-->8,2 beta-->0-->7)-epiafzelechin and epiafzelechin-(4 beta-->8, 2 beta-->0-->7)-ent-afzelechin, the latter three compounds being reported from a natural source for the second time.