Effect of exogenous selenium at a dose of 10 mug/kg body weight on the testicular toxicity induced by nicotine in rats was investigated. Male albino rats were maintained for 60 days as follows: (1) control group (normal diet), (2) nicotine group (0.6 mg /kg body weight), (3) selenium (10 microg/kg body weight), and (4) nicotine (0.6 mg/kg body weight) + selenium (10 microg/ kg body weight). Administration of nicotine caused reduction in sperm count and sperm motility. Activity of HMG CoA reductase and concentration of cholesterol were increased in the testes of the nicotine administered group. Activities of testicular enzymes 3beta hydroxysteroid dehyrogenase (3 betaHSD), 17beta hydroxysteroid dehyrogenase (17 betaHSD) were decreased. Levels of testosterone in the serum were also reduced. However, the extent of these alterations was lesser in the group administered with nicotine along with selenium. Analysis of plasma revealed reduced quantity of cotinine in the group co-administered with nicotine along with selenium in comparison with the nicotine group. Nondetectable levels of nicotine were present in the co-administered group. This indicates altered metabolism of nicotine when administered along with selenium.

Hyperglycemia causes increased protein glycation and the formation of early glycation products and advanced glycation end products (AGEs) which are major factors responsible for the complications associated with diabetes. The aim of the present study was to investigate the antioxidant as well as antiglycative potential of ethyl acetate fraction of guava leaves. Oral administration of the extract at different doses showed a significant decrease in blood glucose level. It also showed an improved antioxidant potential as evidenced by decreased lipid peroxidation and a significant increase in the activity of various antioxidant enzymes such as catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase. Glycated hemoglobin as well as fructosamine which are indicators of glycation was also reduced significantly in treated groups when compared to diabetic control. In vitro studies also support the antioxidant as well as antiglycative potential of guava leaves.

The antifertility effects of 50% ethanol extracts of Ricinus communis have been studied in male rats. There was a drastic reduction in the epididymal sperm counts. Alteration in the motility, mode of movement and morphology of the sperms were observed. Reductions in the fructose and testosterone levels were suggestive of reduced reproductive performance. Reversibility tests showed that the antifertility effect of Ricinus communis was completely reversible on withdrawal of the drug. The ethanol extracts of Ricinus communis did not cause any hepatotoxicity since the hepatic GOT and GPT levels were unaltered.

Diabetes is one of the leading causes of death in developed and developing countries. Oxidative stress has been proposed to play a crucial role in the pathogenesis of diabetic vascular complications. In recent years, selenium has been shown to mediate a number of insulinlike actions in a dose-dependent fashion both in vitro and in vivo. In this study, the effect of selenium as sodium selenite was investigated in streptozotocin-induced diabetic rats at the dose of 1 μg sodium selenite/kg body weight. Selenium supplementation restored the streptozotocin-induced alterations in the activities of antioxidant enzymes, decreased the serum glucose level, glycated hemoglobin content as well as the levels of lipid peroxidation products, and downregulated the expressions of both NFkB and RAGE. The histopathological studies also reinforce our findings. Hence, selenium has a protective role in streptozotocin-induced diabetes mellitus.

Both oxidative stress and endotoxins mediated immunological reactions play a major role in the progression of alcoholic hepatic fibrosis. Ascorbic acid has been reported to reduce alcohol-induced toxicity and ascorbic acid levels are reduced in alcoholics. Hence, we investigated the hepatoprotective action of ascorbic acid in the reversal of alcohol-induced hepatic fibrosis in male guinea pigs (n = 36), and it was compared with the animals abstenting from alcohol treatment. In comparison with the alcohol abstention group, there was a reduction in the activities of toxicity markers and levels of lipid and protein peroxidation products, expression of α-SMA, caspase-3 activity and mRNA levels of CYP2E1, TGF-β(1), TNF-α and α(1)(I) collagen in liver of the ascorbic acid-supplemented group. The ascorbic acid content in liver was significantly reduced in the alcohol-treated guinea pigs. But it was reversed to normal level in the ascorbic acid-supplemented group. The anti-fibrotic action of ascorbic acid in the rapid regression of alcoholic liver fibrosis may be attributed to decrease in the oxidative stress, hepatic stellate cells activation, cytotoxicity and mRNA expression of fibrotic genes CYP2E1, TGF-β(1), TNF-α and α(1) (I) collagen in hepatic tissues.