Antimethicillin-resistant Staphylococcus aureus and Biological Activities of Metabolites from Digitaria Sanguinalis L.

Abstract

The present research was aimed to evaluate the antimicrobial, antimethicillin-resistant Staphylococcus aureus, antiviral and cytotoxic activities of active fractions of the alcohol extract and seven isolated compounds from the aerial parts of Digitaria sanguinalis. Bioassay-guided fractionation of the ethanol extract of the aerial parts of Digitaria sanguinalis L. (Poaceae) followed by several chromatographic purification steps resulted in the isolation of seven compounds. Structural elucidation of isolated compounds was achieved on the basis of spectroscopic analysis (ultraviolet, infrared, 1H and 13C nuclear magnetic resonance and mass spectra). Antimicrobial, antimethicillin-resistant Staphylococcus aureus, antiviral and cytotoxic activities were determined for the n-hexane, ethyl acetate, n-butanol fractions of the ethanol extract, in addition to the isolated compounds. Seven compounds were isolated, p-coumaric acid (1) tricin (2), p-hydroxybenzoic acid (3), stigmasterol (4), β-sitosterol-3-O-β-D-glucoside (5), tricin-7-O-β-D-glucopyranoside (6) and isoorientin (7). The results revealed that most of the isolated compounds exhibited marked antimicrobial, antiviral and cytotoxic activities, while compounds 1, 2, 5 and 6 showed a significant activity against methicillinresistant Staphylococcus aureus. This study revealed that several fractions and isolated compounds from Digitaria sanguinalis appear to be potential new therapeutic agents, due to their significant antimicrobial, antimethicillin-resistant Staphylococcus aureus, antiviral and cytotoxic activities.