Tannins and related polyphenols of euphorbiaceous plants. XI. Three new hydrolyzable tannins and a polyphenol glucoside from Euphorbia humifusa.

Three new hydrolyzable tannins, euphormisins M1, M2, and M3, were isolated from Euphorbia humifusa WILLD., and respectively characterized as 1,3,6-tri-O-galloyl-4-O- brevifolincarboxyl-beta-D-glucose (19), an oxidative metabolite (23) of geraniin, and 1,3,6-tri-O-galloyl-alpha-D-glucose (18), by spectroscopic and chemical methods. A new ellagic acid glucoside (16) and fifteen known tannins, including geraniin (8) and four dimers [euphorbins A (13), B (14), excoecarianin (15) and eumaculin A (12)], were also isolated.