Structural Characterization and Biological Activity of Acidic Polysaccharide Fractions Isolated from Bacillus polymyxa NRC-A

The heteropolysaccharides coded as A P-I, AP-II and AP -III were obtained from t he crude extracellular p olysaccharide of Bacillus polymyxa NRC-A by eluting f rom DEAE-cellulose col umn and Sephadex G-150 c olumn. Their chemical structure and m olecular weights were characterized b y IR, GC- MS, periodate oxidation-Smith's degradation and gel permeation chromatography (GPC). These polysaccharides comprised mainly glucose, mannose, rhamnose and glucouronic acid in the ratio of (3.00: 2.10: 1.40: 1.00), (3.40: 2.52:1.00: 2.11) and (4.11: 2.68: 1.00: 3.00) in AP -I, AP-II and AP-III, respectively. The antioxidant activities of the AP-I, AP-II and A P-III were evaluated by DPPH radical scavenging. The order effectiveness of polysaccharide f ractions in i nhibiting free radicals was as follows: AP-III>AP-II> AP -I. The effects of the molecular weight and uro nic acid content of the polysaccharide fractions on t he i mprovement of the b ioactivities app eared to be significant. In addition, these native and modified fractions st ill determined as in-vitro anticoagulant activity. The m odified fractions showed high anticoagulant ac tivity than the native fractions. Keyword: Exocellular p olysaccharide (EPS), Bacillus polymyxa NRC-A, GC-MS, peri odate oxidati on, Smith-degradation, an tioxidant, anticoagulant.