Cytoprotective effects of fruit pulp of Eugenia jambolana on H 2 O 2 -induced oxidative stress and apoptosis in rat Leydig cells in vitro.

This study was undertaken to investigate the cytoprotective effect of the fruit pulp of Eugenia jambolana (50-250 μg ml(-1) ) against the damage induced by H 2 O 2 (100 μm) exposure to Leydig cells in vitro. Cell survival with extract was found comparable to similar effects by N-acetyl-l-cysteine. H 2 O 2 -induced rise in thiobarbituric acid reactive substance formation and decline in the activity and expression of antioxidant enzymes like superoxide dismutase, catalase and glutathione-s-transferase were effectively checked. Cellular glutathione and total antioxidant capacity demonstrated significant improvement. The increase in expression of inducible nitric oxide (NO) synthase leading to NO production was successfully countered. Co-treatment of the extract helped in the down-regulation of caspase-3 and poly-ADP-ribose polymerase resulting in a significant reduction in Leydig cell apoptosis induced by H 2 O 2 . Upstream marker proteins of extrinsic (caspase-8, Fas, FasL) and intrinsic (caspase-9) pathway of metazoan apoptosis were identically down-regulated. The Bcl-2 family of proteins, though, remained unaffected. The extract also positively modulated the other marker proteins like c-Jun NH 2 -terminal kinase, p38, Akt, nuclear factor-κB, c-Fos, cellular FLICE-inhibitory protein, cyclooxygenase-2 and p53. Taken together, the above-mentioned findings establish the anti-oxidative and anti-apoptotic potency of the extract that ameliorates the H 2 O 2 -induced adverse effects on rat Leydig cells in vitro.