Structural elucidation and bioactivity of a novel exopolysaccharide from endophytic Fusarium solani SD5

A bioactive exopolysaccharide [EPS (PS-I)], having Mw ∼ 1.87 × 105 Da was produced by submerged culture of an endophytic fungus Fusarium solani SD5. Structural elucidation of the EPS (PS-I) was carried out by a series of experiments. Result indicates the presence of terminal α-l-rhamnopyranosyl, (1→2)-α-l-rhamnopyranosyl, (1→4)-β-d-galactopyranosyl, (1→4,6)-β-d-galactopyranosyl moieties in a molar ratio of nearly 1:1:3:1. TEM image showed fibril structure of the EPS with a diameter of approximately 1 nm. Melting point range of the EPS was found 172–178 °C. The isolated PS-I exhibit in vitro anti inflammatory and anti allergic activity. EPS (1000 μg/ml) protects 55% erythrocytes from hypotonic solution induced membrane lysis. Compound 48/80 induced mast cell degranulation was also protected by 56% with 100 μg/ml EPS.