Antioxidant activity and Antibacterial potential of Single and Combined extracts from the Leaves of Clinacanthus nutans, Justica gendarussa, and Blumea balsamifera

Abstract

This study aimed to evaluate the total phenolic and flavonoid contents, antioxidant activity using the DPPH radical scavenging method, and the antibacterial activity against Staphylococcus aureus and Escherichia coli from single, the mixtures contained two and three types of leaves extracts. The herbs included Clinacanthus nutans, Justica gendarussa, and Blumea balsamifera. Total phenolic content was assessed using the Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE). Total flavonoid content was determined using the aluminum chloride colorimetric method and expressed as quercetin equivalents (QE). Antioxidant activity was evaluated using the DPPH method with Trolox as a standard, and antibacterial activity was tested using the broth dilution method to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The results showed that B. balsamifera had the highest total phenolic content (194.82 mg GAE/g of extract), total flavonoid content (191.23 mg QE/g of extract), and DPPH radical scavenging activity (% inhibition at 56.99). Antioxidant activity of the binary mixtures of C. nutans with B. balsamifera and J. gendarussa with B. balsamifera did not show significant statistical differences. Antibacterial activity against S. aureus and E. coli revealed that B. balsamifera and the binary mixture of C. nutans with J. gendarussa exhibited an MIC of 0.625 mg/mL. These findings demonstrate the potential of these herbs as significant sources of bioactive compounds. Furthermore, The results of this study highlight the potential of herbs as a significant source of bioactive compounds and support the use of herbal combinations in traditional Thai and folk medicine for further development.