A New Methylene Bisflavan-3-ol from the Branches and Leaves of

L. (Rosaceae), also known as L. (syn.), is a hardy deciduous shrub widely distributed in the north temperate regions of the world. Three methylene bisflavan-3-ols (-), together with a procyanidin dimer, (-)-afzelechin-(4α→8)-(-)-afzelechin () were isolated for the first time from the branches and leaves of the titled plant, in addition to 11 known compounds (-). Their structures were elucidated by means of extensive spectroscopic analysis and by comparison with data reported in the literatures. Methylene 6,8-bis(7--glucosyl) catechin () was determined to be a new dimeric flavan-3-ol glycoside through a methylene linkage between C-8 and C-8 of two units. At a concentration of 128 μg/mL, the known compounds - exhibited antibacterial activities on , subsp. , subsp. , and . Compound also showed certain glucose uptake stimulating activity.