Polysaccharides from Phormidium versicolor (NCC466) protecting HepG2 human hepatocellular carcinoma cells and rat liver tissues from cadmium toxicity: Evidence from in vitro and in vivo tests

The in vitro antioxidant, cytotoxic and cytoprotective properties and in vivo hepatoprotective activities of crude polysaccharides extracted from cyanobacteria Phormidim versicolor NCC466 (CFv-PS) were investigated. The CFv-PS, identified as heteropolysaccharides with molecular weight of 63.79 kDa, exhibited relatively strong antioxidant activity, in a concentration-depended manner, in vitro assays. Additionally, CFv-PS did not induce cytotoxic effect on HepG2 human hepatocellular carcinoma cells within the range of tested concentrations (25-150 μg·mL−1) while preventing them against Cd. Moreover, in rats subjected to Cd-induced hepatotoxicity, CFv-PS pretreatment significantly (P < 0.05) reduced the level of ALAT, ASAT, biliburin, MDA, protein carbonyl and DNA damage, and markedly increased enzyme activities in liver tissues. These findings suggest that the cyanobacteria Phormidium versicolor is a potential source of natural products possessing antioxidant, cytoprotective and hepatoprotective properties.