A novel polysaccharide with antioxidant, HIV protease inhibiting and HIV integrase inhibiting activities from Fomitiporia punctata (P. karst.) murrill (Basidiomycota, hymenochaetales)

A novel polysaccharide fraction (G1) was obtained from the fungus Fomitiporia punctata (P. Karst.) Murrill. G1 exhibited a molecular weight of approximately 151 kDa. The FT-IR results suggested that the monosaccharide components of G1 possessed furanoid rings and there were β-glycosidic bonds between the sugar units. The 1H NMR results showed that G1 was composed of arabinose, fructose, galactose and glucose in the molar ratio of 1.6:3.8:19.7:19.7, as determined by gas chromatography-mass spectrometry (GC–MS) and high performance liquid chromatography (HPLC). G1 produced significant antioxidant effects as evidenced by its potency in inhibiting erythrocyte hemolysis, and in scavenging hydroxyl radicals and superoxide radicals. The highest rates of inhibition achieved were 73.58%, 36.55% and 50.98% respectively. In addition, G1 brought about 19.6% inhibition of HIV-1 protease activity at the concentration of 50 μg/mL. G1 displayed inhibitory activity toward HIV-1 integrase in the concentration range of 100–1000 μg/mL. The present study indicates that G1 from Fomitiporia punctate (P. Karst.) Murrill is a novel natural antioxidant.