EVALUATION OF ANTIOXIDANT AND ANTI-STRESS ACTIVITIES OF METHANOLIC LEAF EXTRACT OF ELEPHANT EAR FERN (PLATYCERIUM ANGOLENSE) IN RATS.

Abstract

Lower plants are regarded as unstudied portion of plant kingdom that is not traditionally employed for healing, treatment and management of ailments in folklore medicine. In this study methanolic extract of Platycerium angolense, Welwex Hook (elephant ear fern) was evaluated for its phytochemical constituents and antioxidant properties as typified by the OH- radical scavenging activity, reducing power, iron chelating property, lipid peroxidation, total phenolic content, and total antioxidant activity were evaluated at various concentration. In addition the anti-stress property of the extract was assessed using two models; the swimming endurance model and the cold and immobilization induced stress. The effect of stress was evaluated using some biochemical indices such as blood glucose, lipid profile, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level in the plasma of white albino rats which were administered 70 mg/kg/bwt, 120 mg/kg/bwt of extract, and 3 mg/kg/bwt of standard drug (diazepam). The results revealed that phytoconstituents of P. angolense include: flavonoids, glycosides, saponins, steroids, tannins and deoxysugars. The extract was found to exhibit hydroxyl radical scavenging activity, iron reducing power, metals chelating activity, and inhibition of lipid peroxidation. The total phenolic content and total antioxidant activity of the extract was estimated to be 82.21±0.021 mg/g TAE and 176.34±0.0134 mg/gAAE. The present results suggested that administration of p. angolense is capable of increasingthe capacity to tolerate non-specific stress in experimental animals as evident from the prolonged swimming time of wistar rats when compared to the control thus acting as anti-stress and adaptogenic agent. P. angolense extract also restored significantly (p<0.5) a number of these restraint stress-induced changes in measured biochemical parameters such as blood glucose, plasma total cholesterol (T.C), plasma total triglycerides (T.G), ALT, and AST in the treated animal groups when compared with the untreated control groups. The plant extract has no significant (p<0.5) effect on the level of plasma high density lipoprotein(HDL), but was found to lower the level of circulating low density lipoprotein (LDL) in the plasma of experimental animals, thereby increasing the HDL:LDL ratio in the blood suggesting that the extract can serve as an important therapeutic agent in oxidative and stress related diseases, or management of adverse changes associated with the stressors that alter and impair the normal functioning of the organism.