Antioxidant, Antimicrobial and Cytotoxicity Activities of Acacia farnesiana (L.) Willd. Leaves Ethanolic Extract

The antioxidant activity was evaluated from the ability to chelate iron, reducing property, scavenging DPPH radical and nitric oxide. The A. farnesiana ethanolic extract responded to all the antioxidant assays in concentrations dependent manner. Evaluated by broth microdilution assay, the extract exhibited MIC value at 0.8 mg/ml against Bacillus subtilis and MIC value at 2.5 mg/ml against Saccharomyces cerevisiae. The absence of cytoxicity was observed from the brine shrimp lethality test. The quantification of total phenolic content by Folin-Ciocalteu reagent resulting 209.78 ± 3.21 mg gallic acid/g ethanolic extract of A. farnesiana leaves. Analysis of the extract by both HPLC-PDA and LC/MS have tentatively identified flavonoid galloylglycoside and flavonoid glycosides from the extract. It was plausible that the preparation method of the extract influenced the consituents of the extract, and that later contributed to the exhibited antioxidant and antibacterial activities. Quercetin deoxyhexoside was tentatively identified as the major consituent of the extract. Bioassay guided isolation is suggested as future research to study the biological activities and elucidate the chemical structure of flavonoids involved.