Tannins and related compounds. LXXI. Isolation and characterization of mongolicins A and B, novel flavono-ellagitannins from Quercus mongolica var. grosseserrata.

Two novel flavono-ellagitannins, mongolicins A (1) and B (4), in which hydrolysable tannin and flavonoid moieties are connected through a carbon-carbon linkage, were isolated from the bark of Quercus mongolica var. grosseserrata, together with a large quantity of (+)-taxifolin 3-O-β-D-glucopyranoside (3).