Abstract
Investigation of the phytoconstituents of Bombax ceiba L. flowers resulted in the isolation and identification of 7 phenolic compounds; namely: isovanillic acid (4-methoxy-3-hydroxy-benzoic acid) (I), mangiferin (2-β-D-glucosyl-1,3,6,7-tetrahydroxyxanthone) (II), protocatechuic acid (3,4-dihydroxy-benzoic acid) (III), rutin (IV), quercetin 3-O-β-D-glucopyranoside (V), apigenin 7-O-β-D-glucopyranoside (VI) and quercetin 3-O-β-D-galactouronopyranoside (VII). This is the first report on the isolation of all these compounds from Bombax ceiba flowers, while compounds (II) and (V) were previously reported from the leaves of the plant. The 70% methanolic extract (up to 5 g/kg body weight) did not induce any obvious toxic effects in mice. The extract exhibited central and peripheral analgesic activity. In addition, the acute paw oedema response was significantly reduced, indicating anti-inflammatory activity. The protective effect of the extract against paracetamol-induced liver damage was indicated by reduction of the elevation of liver enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) induced by paracetamol. Using a short-term in vitro assay of the Epstein-Barr virus (early antigen) (EBV-EA) activation induced by 12-O-tetradecanoylphorobol-13-acetate (TPA) in Raji cells, Bombax ceiba flowers extracts inhibited the activation of the early antigen (% EBV-EA positive cells). At different concentrations (1, 10 and 100 μg/ml), the ethyl acetate extract showed the most significant inhibitory effects.
