Antioxidant and antibacterial properties of selected Thai weed extracts

ABSTRACT

Objective: To analyze antioxidant and antibacterial properties of selected weeds commonly found in Northeast Thailand including Ageratum conyzoides L., Alysicarpus vaginalis L., Commelina bengalensis L., Euphorbia hirta L., Hyptis suaveolens L., Parthenocissus quinquefolia L., and Trianthema portulacastrum L. Methods: Ferric reducing antioxidant power and radical scavenging activity of the aqueous and ethanol weed extracts were determined. Phytochemical screening, total phenolic and flavonoid contents were done. Antibacterial activity against Aeromonas hydrophila, Aeromonas caviae, Edwardsiella tarda, Plesiomonas shigelloides, Ralstonia spp., Xanthomonas campestris pv. Vesicatoria, Salmonella spp. and Shigella spp. was performed by disc diffusion assay. Results: The results showed that Euphorbia hirta extract had the highest total phenolic contents and was the most effective against most of the test organisms compared to the other weed extracts. Hyptis suaveolens ethanol extract weakly inhibited Ralstonia spp. and Salmonella spp. (10.42% and 9.84% inhibition, respectively). Trianthema portulacastrum ethanol extract had 20.10% inhibition against Shigella spp. Parthenocissus quinquefolia aqueous extract strongly inhibited Aeromonas caviae and Aeromonas hydrophila with 55.90% and 59.68% inhibition, respectively. Conclusions: These weeds may be serving as a potential source of antibacterial agents.