A 43 kDa protein from the herb Cajanus indicus L. protects thioacetamide induced cytotoxicity in hepatocytes

The aim of this study was to investigate the role of a hepatoprotective protein isolated from the herb Cajanus indicus L. on thioacetamide (TAA) induced toxicity in isolated mouse hepatocytes. In vitro cell viability, lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and total protein leakage were measured as the indicator of cell damage. The amount of glutathione (GSH) and lipid peroxidation were also measured to determine the oxidative status of the cells. The reduced cell viability in TAA treated hepatocytes was almost completely recovered upon protein treatment. LDH, ALT and total protein secretion outside the cells after TAA treatment confirmed the cell membrane damage. Incubation of hepatocytes with the protein prior to TAA administration significantly prevented the cell membrane damage as revealed from less LDH, ALT and total protein leakage. TAA depleted endogenous antioxidant GSH and increased membrane lipid peroxidation in hepatocytes. The protein had very prominent effect in altering the GSH level and lipid peroxidation. The protein exhibited all these cytoprotective effects in a dose-dependent manner. Besides, measurement of DPPH radical scavenging activity showed that the protein could scavenge free radicals. In addition, the protein resisted TAA induced alterations of various effects when applied in combination with TAA. The cytoprotective activity of the protein was found to be comparable with alpha-tocopherol, a well-known antioxidant. Results suggest that the protein from C indicus can act as a hepatoprotector and primary antioxidant against TAA-induced cytotoxicity in mouse hepatocytes. (c) 2005 Elsevier Ltd. All rights reserved.