Tannins and related compounds. LXXVII. Novel chalcan-flavan dimers, assamicains A, B and C, and a new flavan-3-ol and proanthocyanidins from the fresh leaves of Camellia sinensis L. var. assamica Kitamura.

Abstract

Three novel chalcan-flavan dimers, assamicains A (1), B (2) and C (3), and a new flavan-3-ol (14) and proanthocyanidins (19, 20) have been isolated, together with the known flavan-3-ols (4-13), proanthocyanidins(15-18, 21), theasinensins (22-24) and hydrolyzable tannins (25, 26), from the fresh leaves of Camellia sinensis var. assamica (Camelliaceae), and their structures have been established on the basis of spectroscopic evidence in conjunction with thiolytic degradation and enzymatic hydrolysis.