Phytochemical studies and antioxidant properties of methanolic and aqueous extracts of the leaves of mallotus oppositifolius

Abstract

Mallotus oppositifolius is a tropical plant used to treat many medical conditions in Africa. Preliminary phytochemical screening conducted on the crude methanol and aqueous extracts of the plant revealed the presence of alkaloids, flavonoids, saponins, tannins, steroids, cardiac glycosides and terpenoids in both extracts of the plant. However, only the aqueous extract showed the absence of anthraquinones. The research also used DPPH (1, 1-diphenyl-2-picrylhydrazyl) free radical as a substrate to determine the scavenging ability (antioxidant property) of the extracts. Antioxidant activity was further investigated quantitatively for flavonoid and total phenolic contents in the two extracts, using spectrophotometry. Both the methanol and aqueous extracts of the plant were observed to have exhibited antioxidant activity, with the aqueous extract having the higher scavenging ability (% inhibition) of 49.02± 0.16 than the methanol extract of 9.04± 0.07. Similarly, the aqueous extract had a higher flavonoid content of 206.8 ± 31.06 µg/g than the methanol extract 84.00 ± 33.96 µg/g. Also, the aqueous extract had its total phenolic content to be 1066.97±26.42 µg/g while the methanol extract had 672.0±20.07µg/g as its total phenolic content. The percentage alkaloid content in methanol and aqueous extracts were measured to be 8.6 % and 4.3% respectively