HEPATOPROTECTIVE ACTIVITY OF THYMOQUINONE IN ISOLATED RAT HEPATOCYTES

Thymoquinone, the active constituent of Nigella sativa, was tested in isolated rat hepatocytes as a hepatoprotective agent against tert-buty l hydroperoxide (TBHP) toxicity. TBHP (2 mM) was used to produce oxida tive injury in isolated rat hepatocytes and caused progressive depleti on of intracellular glutathione (GSH), loss of cell viability as evide nced by trypan blue uptake and leakage of cytosolic enzymes, alanine t ransaminase (ALT) and aspartic transaminase (AST). Preincubation of he patocytes with 1 mM of either thymoquinone or silybin, which is a know n hepatoprotective agent, resulted in the protection of isolated hepat ocytes against TBHP induced toxicity evidenced by decreased leakage of ALT and AST, and by decreased trypan blue uptake in comparison to TBH P treated hepatocytes. Both thymoquinone and silybin prevented TBHP in duced depletion of GSH to the same extent. Although thymoquinone prote cted the liver enzymes leakage, the degree of protection was less than that caused by silybin. (C) 1998 Elsevier Science Ireland Ltd. All ri ghts reserved.