Researches on isolation, purification and anti-complementary activity of acidic polysaccharide from the stems of Avicennia marina (Forsk.) Vierh

Crude polysaccharides were isolated from the stems of Avicennia marina (Forsk.) Vierh. by hot water extraction and ethanol precipitation. The polysaccharides were further fractioned by ultra-filtration, deproteinated by trichloroacetic acid, decolorized by DEAE-cellulose and then isolated by anion-exchange chromatography of DEAE-Sepharose fast-flow and size-exclusion chromatography of Sephacryl S-400. The purified polysaccharide HAM-3-1I b-II was proved to be homogeneous by HPGFC and polarimetry. Its molecular weight (Mw) and specific rotation were 105200 and +27.54° respectively. Analysis of monosaccharide composition indicated that HAM-3-II b-II contained high proportions of galacturonic acid, arabinose, galactose and rhamnose, characterizing an acidic heteropolysaccharide. UV spectra of HAM-3-II b-II showed absence of nucleic acid and protein. The characteristic absorptions of IR confirmed the presence of pectic polysaccharide. The measurement of activity was performed by complement fixing test, HAM-3-II b-II expressed potent anti-complementary activity via classical and alternative pathways with the increase proportional to dosage.