ABSTRACT
Phytochemical analysis, antimicrobial and antioxidant properties of the leaf extract and fractions of Sabicea brevipes were studied. Theleaveswere defatted and the marc extracted with methanol. The extractwas further purified by solvent-solvent partitioning using n-hexane, ethyl acetate and n-butanol to obtain the three solvent fractions. They were screened for phenolics, flavonoids, tannins, saponins, terpenoids, glycosides, and steroids. Total phenolics, flavonoids and tannins were determined quantitatively. The antimicrobial test was screened in vitroby agar diffusion method. Analysis of variance (ANOVA) was used to test for significant difference at p ≤ 0.05 in all study groups. The methanol extract exhibited the most significant amount of phenolics (110.78 ± 1.06 mg GAE/g) while ethyl acetate fraction had the least total phenolics content (50.55 ± 2.91 mg GAE/g). The same trend was observed for the total flavonoids content whereas the methanol extractmeasured (418.40 ± 14.03 mg QE/g) while ethyl acetate fraction had 192.40 ± 3.06 mg QE/g. Total tannins contents were: methanol extract (102.22 ± 7.58 mg GAE/g) and ethyl acetate (27.33 ± 0.77 mg GAE/g). The antioxidant results showed that the methanol extract had the highest DPPH free radical scavenging ability (93.69%) with half maximal inhibitory concentration (IC50) of 0.601± 0.02 and also highest ferric ion reducing power (50.381 ± 1.56 μmol Fe2+/g). Also, the methanol extract showed high total antioxidant capacity (96.79 ± 0.31 mg AAE) and IC50of 0.798± 0.01. The antimicrobial results revealed that the methanol extract showed better activity against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, andCandida albicans than the solvent fractions at concentrations of 200, 100, 50, 25, 12.5, mg/mL having various inhibition zone diameters (IZDs). The methanol extract and fractions of S. brevipescompared favourably in terms of zone of inhibition and minimum inhibition concentration (MIC) with the standard drug disc (Gentamycin and Ketoconazole) against the tested microorganisms. The MIC of the extract and solvent fractions ranged from 6.31 mg/mL to 50.12 mg/mL. The continual use of the extract of Sabicea brevipesin preventing oxidative stress and in the treatment of common infection is justified by these results.