Anthraquinones and Anthraquinone Glycosides from the Roots of Cassia multijuga*

From the ethanolic extract of the roots of Cassia multijuga two anthraquinones C15H10O4 (Qi) and C16H12O6 (Q2) and two anthraquinone glycosides C28H32O15 (Si) and C27H30O14 (S2) have been isolated. Homogeneity and purity of these compounds were established by chromatography. Anthraquinone (Qi) has been identified to be 1:3-dihydroxy-2-methyl anthraquinone (rubiadin) by standard colour reactions [2, 3], spectral data, mass fragmentation pattern, m.p. and m.m.p. Compound (Q2) had one -OMe (4.00 ppm) one C-Me (2.10 ppm) and three phenolic hydroxyl groups (triacetate). The UV absorption maxima (Amax 240, 290 and 430 nm) and mass fragments at m/z 272 (M-CO) and m/z 244 (M-2CO) are typical of anthraquinone skeleton. Isolation of 2-methyl anthracene by zinc dust distillation of Q2 showed it to be a 2-methyl anthraquinone derivative. XNMR spectrum of Q2 showed three aromatic protons, two as meta coupled doublet at 7.67 ppm (C-5, J = 2.5cps) and 6.85 ppm (C-7, J = 2.5cps) and the third as singlet at 7.89 ppm (C-4); the compound is thus a 1:2 :3 :6 :8-penta substituted anthraquinone having methyl group at position-2.