Tannins and Related Compounds. LXXXVIII. : Isolation and Characterization of Hydrolyzable Tannins from Mallotus japonicus (THUNB.) MUELLER-ARG. and M. philippinensis (LAM.) MUELLER-ARG.

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Further chemical examination of the bark and the leaves of Mallotus japonicus (THUNB.) MUELLER-ARG. (Euphorbiaceae) has led to the isolation of two new tannins [named mallotannins A (16) and B (18)]. Based on chemical and spectroscopic evidence, the structures of 16 and 18 were established to be dimeric hydrolyzable tannins in which the free carboxylic acid in mallotinic acid is connected to the C-6 position of bergenin and D-glucose, respectively. On the other hand, fifteen known tannins and related compounds have been isolated from the leaves of M. philippinensis (LAM.) MUELLER-ARG. and identified by comparisons of their physical and spectral data with those of authentic samples. In addition, a survey of tannin patterns in Mallotus species is presented.