Studies on the constituents of Aloe saponaria Haw. IV. The structures of bianthraquinoid pigments.

The phenolic components of the fresh subterranean part and rhizome of Aloe saponaria HAW. were examined to give new four bianthraquinoid pigments A (I), B (II), C (III) and D (IV). On the basis of the spectral and chemical evidences the structures of these compounds were established to be (+)-asphodelin (I), 1, 1', 8, 8', 10-pentahydroxy-3, 3'-dimethyl-10, 7'-bianthracene-9, 9', 10'-trione (II), 1, 1', 8, 8'-tetrahydroxy-3, 3'-dimethyl-4, 7'-bianthracene (10'H, 10'H)-9, 9', 10-trione (III) and 1, 1', 8, 8', 10-pentahydroxy-3, 3'-dimethyl-10, 7'-bianthracene (10'H, 10'H)-9, 9'-dione (IV).