Protein isolate from the herb Phyllanthus niruri modulates carbon tetrachloride-induced cytotoxicity in hepatocytes

Phyllanthus niruri is a well-known hepatoprotective herbal plant. In the present study, hepatoprotective potential of the protein isolate of P. niruri was investigated against carbon tetrachloride (CCl4)-induced hepatoxicity in vitro. Isolated hepatocytes were treated with CCl4 and also separately with various concentrations of the protein isolate of P. niruri along with CCl4. Levels of different marker enzymes related to hepatic integrity and different antioxidant enzymes as well as lipid peroxidation products in hepatocytes were measured in normal, control (toxicity induced), and protein isolate-treated cells. Administration of CCl4 increased the leakage of glutamate pyruvate transaminase (GPT) by four fold and lactate dehydrogenase (LDH) by 84% in cell suspension, along with increased lipid peroxidation (114%), and reduced the levels of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) to almost 30% and 37% of the normal values, respectively. Treatment with the protein isolate of P. niruri significantly altered these changes. GPT value almost came down to normal levels and LDH value was reduced to 32% of normal values. Depletion of SOD and CAT activities were restored significantly to 75% and 87% of normal values, respectively. Lipid peroxidation was also reduced significantly. In the DPPH free radical scavenging activity, the protein isolate was also able to quench the free radical. Results suggest that the protein isolate of P. niruri protects hepatocytes against CCl4-induced oxidative damage and may be used as an effective cytoprotector against CCl4-induced hepatotoxicity.