INDUCTION OF MITOCHONDRIAL-MEDIATED APOPTOSIS BY SOLVENT FRACTIONS OF METHANOL EXTRACT OF Heliotropium indicum IN RAT LIVER CELLS

Mitochondrial Membrane Permeability Transition (MMPT) pore is a major player in cell death and it is considered to contribute substantially to the regulation of normal mitochondria metabolism. It has therefore emerged as a promising target for drug development because the release of cytochrome c upon the opening of the pore is a point of no return for mitochondrial-mediated apoptosis to occur. Heliotropium indicum (HI) is as an anti-tumor and wound healing agent frequently used in traditional medicine. It is not known whether its mode of action involves the induction of apoptosis. Mitochondria, isolated from male albino rats (about 100g), were exposed to varying concentrations (10, 30, 50, 70, and 90µg/ml) of Chloroform (CFHI), Ethlyacetate (EFHI), Methanol (MFHI) Fractions and Crude Methanol Extract (MEHI) of HI. In the absence of Ca 2+ , CFHI, EFHI, MFHI and MEHI induced the opening of the pore in a concentration-dependent manner with CFHI having the highest induction fold of 26 and MFHI as the lowest having 6.6. All the fractions inhibited lipid peroxidation in a concentration-dependent manner. Also these fractions induced the release of cytochrome c with CFHI having the highest effect and the least by MFHI. Mitochondrial ATPase activity was enhanced by all the fractions with CFHI having the highest stimulatory effect. Interestingly, intra-peritoneal administration of CFHI and EFHI at 2, 5, 10 and 20mg/kg body weight for 21 days resulted in opening of the pore, the release of cytochrome c and activation of caspases 3 and 9. All these effects were highest with 20mg/kg body weight. These findings therefore suggest that CFHI is the most potent fraction and therefore possibly contains the bioactive agent(s) that induces mitochondrial-mediated apoptosis. The fraction will therefore be useful for further studies for drug development in diseases requiring up-regulation of apoptosis.