Role of Moringa oleifera leaf extract in the regulation of thyroid hormone status in adult male and female rats

The role of Moringa oleifera aqueous leaf extract in the regulation of thyroid hormone status, was studied in adult Swiss rats. Other than the thyroid hormone concentrations, hepatic lipid peroxidation (LPO) and the activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) were evaluated. In the first experiment, effects of the leaf extract (175 mg kg(-1) body wt. day(-1) for 10 days) were studied both in male and female animals. Following the administration of the extract, serum triiodothyronine (T-3) concentration and hepatic LPO decreased with a concomitant increase in the serum thyroxine (T-4) concentration: in female rats, while in males no significant changes were observed, suggesting that Moringa oleifera leaf extract is more effective in females than in the males. To evaluate the impact of a higher dose, in the second experiment, the study was repeated in female rats, with 350 mg kg(-1) body wt. day(-1) for the same duration. Almost similar reduction in the serum T-3 concentration (approx. 30%) and an increase in the T-4 concentration were observed suggesting the inhibiting nature of Moringa oleifera leaf extract in the peripheral conversion of T-4 to T-3, the principal source of the generation of latter hormone. As the antiperoxidative effects were exhibited only by the lower dose and percent decrease in T-3 concentration was nearly the same by both the doses, it is suggested that the lower concentration of this plant extract may be used for the regulation of hyperthyriodism. (C) 2000 Academic Press.