Production of polysaccharides by submerged mycelial culture of entomopathogenic fungus Cordyceps takaomontana and their apoptotic effects on human neuroblastoma cells

The effect of medium components and environmental factors on the production of mycelial biomass for the preparation of intracellular polysaccharides (IPS) and exopolysaccharides (EPS) by Cordyceps takaomontan was investigated in submerged cultures. The optimal culture condition was as follows (g/l): glucose 30, yeast extract 4, KH2PO4 0.46, K2HPO4 1, and MgSO4 0.5, and 28 °C and pH 8. When the fungus was cultivated under various agitation and aeration conditions in a 5-l stirred-tank fermenter, the maximum mycelial biomass (10.7 g/l) and EPS production (1.9 g/l) was obtained at 300 rpm and 2 vvm, respectively. The inhibitory effect of both IPS and EPS on the growth of SK-N-SH cells was studied by treating the cells with crude IPS and EPS at concentrations of 0.5, 1, and 2 mg/ml for 24, 48, 72 h, respectively. The maximum inhibitory effect on apoptosis of SK-N-SH cells (64.6%) was observed when IPS was treated at a concentration of 2 mg/ml, for 72 h. The apoptosis of SK-N-SH cells induced by IPS was evidenced by comet assay, where the number of the comet cells increased by the IPS treated. These findings suggest that IPS may therefore have therapeutic potential against neuroblastoma cells.