COMPARATIVE BIOACTIVE CONSTITUENTS AND ANTIOXIDANT CAPACITY OF Tetrapleura tetraptera AQUEOUS, ETHANOLIC AND METHANOLIC FRUIT EXTRACTS

Abstract

This study aimed at comparative analysis of bioactive constituents and in vitro antioxidant Tetrapleura tetraptera's aqueous, ethanolic and methanolic friut extracts. Coarse ground dried matured fruits were extracted with distilled water and absolute ethanol and methanol followed by filtration and complete evaporation of the solvents at 50 °C. Analysis of the extracts revealed extraction yields of 14.75, 13.26 and 19.09 % dry weight respectively. Flavonoids, tannins, alkaloids and reducing sugars were confirmed present in all extracts at varying degrees whereas terpenes and steroids were not detected in all extracts. Saponins, phlobatannin and proteins were detected only in the aqueous extract, cardiac glycosides were found only in the ethanolic extract, while phenols and thiols were present in both the aqueous and methanolic extracts. The antioxidant assays conducted revealed moderate activities of the extracts relative to the standard compound (ascorbic acid). The calculated IC50 of nitric oxide radical scavenging activity is such that Ascorbic acid > Ethanolic > Aqueous > Methanolic extracts, with values of 0.44, 0.47, 0.91 and 1.94 mg/ml, while that of EC50 from total antioxidant capacity assessment revealed Ascorbic acid > Aqueous > Methanolic > Ethanolic extracts, with values of 0.33, 1.71, 4.20 and 5.35 mg/ml respectively. Although, there was variation in the order of antioxidant activity in the different assays, this study suggests the overall capacity of the aqueous > ethanolic > methanolic fruit extract. Thus, corroboration from this indagation is important in choice of solvent during the utilization of this fruit.