Biochemical Effects of Aqueous Stem Bark Extract of Dialium guineense on Oxidative Status of Normal Wistar Rats

Dialium guineense (velvet tamarind) belongs to the Leguminosae family (1). Various parts of the plant have medicinal properties and are used to treat a variety of diseases. The pathogenesis of a number of diseases is linked to free radical-induced oxidative damage.

This study was undertaken to determine the effects of aqueous stem bark extract of Dialium guineense on antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and G6PDH), malondialdehyde and total protein concentrations in normal Wistar rats. Ten male rats were divided into two groups of five rats each. One group served as normal control while the other group received 1000 mg/kg body weight of aqueous extract. The experiment lasted twenty-eight days and assays were performed on weekly basis. Results of phytochemical analysis of the plant revealed the presence of tannins (3.76 ± 0.31%), alkaloids (1.22 ± 0.06%), phenols (1.40 ± 0.03%), flavonoids (0.92 ± 0.03%), saponins (0.18 ± 0.02%), glycosides (0.04 ± 0.01%) and steroids (0.04 ± 0.01%). There was no significant change (p > 0.05) in the concentrations of total proteins compared with control. The malondialdehyde concentrations were significantly reduced (p < 0.05) compared with control while G6PDH, superoxide dismutase, catalase and glutathione peroxidase activities were significantly increased (p < 0.05) compared with control. The extract seems to potentiate the activities of all the measured anti-oxidant enzymes. Measurement of G6PDH activity provides an indirect assessment of glutathione reductase activity as the reaction catalysed by it in the pentose phosphate pathway in the erythrocyte membrane and in cells of other sensitive tissues generates the coenzyme NADPH which furnishes the hydride ion (or hydrogen) needed to keep or maintain glutathione in the reduced state where it is active as a free radical scavenger.

Arogba, S.S, Ajiboro, A. and Odukwe, I. Journal of the Science of Food and Agriculture 2006; 66:533 – 534.