Antioxidant Potential of Crude Methanol Leaf extract and Fraction of Mallotus oppositifolius

Abstract

Mallotus oppositifolius (Geiseler) Mull. Arg.  (Euphorbiaceae) is a predominant edible shrub in Nigeria. It is locally used for treatment of common infections and wounds. This study evaluated the toxicity and antioxidant potential of the crude extract and fractions of M. oppositifolius using invitro 1,1-diphenyl-2-picrylhydrazine (DPPH) radical scavenging assay. The result showed abundance of flavonoids (28.21), tannins (17.72), alkaloids (7.79) and Saponins (0.23) in the crude extract of M. oppositifolius leaf extract. Also, the result showed that the LD50 is above 5000 mg/kg, therefore the crude extract is safe for consumption. The result further showed that the ethyl-acetate and butanol had significant (p<0.05) antioxidant activity when compared with the control at 125, 62.5 and 31.125 µg/ml respectively while at 250 and 500 µg/ml there was no significant different in the level of reduction of oxidation between the butanol and ethyl acetate when compared with the control. The result further showed that the butanol and ethyl-acetate fraction of M. oppositifolius had the best antioxidant potential among the fractions studied. The result of GCMS studies of ethyl-acetate fraction showed the presence of 7,10,13-eicosatrienoic acid methyl ester, korormicin, agosterol, phyllanthin, ricinoic acid, 2,4,6-decatrienoic acid 1a,2,5,5a,6,9,10,10a-octahydro-5,5a-dihydroxy-4-(hydroxymethyl)-1,1,7,9, limonin, com-pounds that have shown to possess strong antioxidant activities. Also, the GCMS result of butanol fraction showed the presence of seven compounds which include: ferulylhistamine, hippeastrine, 10,13-eicosadienoic acid methyl ester, ethyl 5,8,11,14-eicosatetraenoate, 6-hydroxy-powelline-N-nitroso-7-demethoxy-aldehyde, 6,7-epoxypregn-4-ene-9,11,18-triol-3,20-dione 11,18-diacetate and 5Alpha-androstane-3,17-dione 17-monooxime,  compounds which may serve as a new lead for the treatment of diseases associated with the oxidative stress.