The aim of this study was to investigate the hepatoprotective action of the protein fraction of Phyllanthus niruri against acetaminophen (APAP) hepatotoxicity. The partially purified protein fraction of P. niruri was injected intraperitoneally in mice either prior to (preventive) or after the induction of toxicity (curative). Levels of different liver marker enzymes in serum and different antioxidant enzymes, as well as lipid peroxidation in total liver homogenates were measured in normal, control (toxicity induced) and P. niruri protein fraction-treated mice. P. niruri significantly reduced the elevated glutamate pyruvate transaminase (GPT) and alkaline phosphatase (ALP) levels in the sera of toxicity induced mice, compared with the control group. Lipid peroxidation levels were also reduced in mice treated with P. niruri protein fraction compared with the APAP treated control group. Among the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) levels were restored to almost normal levels compared with the control group. P. niruri treatment also enhanced reduced hepatic glutathione (GSH) levels caused by APAP administration. The results demonstrated that the protein fraction of P. niruri protected liver tissues against oxidative stress in mice, probably acting by increasing antioxidative defense.

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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 (CCl(4))-induced hepatoxicity in vitro. Isolated hepatocytes were treated with CCl(4) and also separately with various concentrations of the protein isolate of P. niruri along with CCl(4). 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 CCl(4) 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 CCl(4)-induced oxidative damage and may be used as an effective cytoprotector against CCl(4)-induced hepatotoxicity.