Further Studies on the Structure of Polysaccharides from the Bark of Melia azadirachta

Water-soluble polysaccharides, designated as GIIa and GIIIa, were isolated together with GIa and GIb from the bark of Melia azadirachta (Meliaceae), and their anti-inflammatory effect on carrageenan-induced edema was tested. GIIa and GIIIa each gave a single peak on high-performance liquid chromatography and gel filtration. Methylation, periodate oxidation and carbon-13 nuclear magnetic resonance spectroscopic studies suggested that GIIa is composed of the following repeating unit : α-D-G1c1→4α-D-G1c1→3α-D-G1c1→3α-D-G1c6←1α-L-ArafGIIIa is [numbrical formula] a branched arabinofucoglucan containing a main chain of 1→4-linked α-D-glucopyranosyl units substituted in the 6 position with side chains of α-L-arabinofuranose and β-L-fucopyranose.