Antibacterial properties of alcohol and water extracts of Waltheria indica (L.) plants collected from Binh Thuan province, Vietnam

This study aimed to investigate the antibacterial ability of Waltheria indica species collected from two communes of Phan Thiet city, Binh Thuan province. Research methods included making ethanol extracts and decoction and investigating their ability to inhibit bacteria through agar well diffusion method and determining the minimum inhibitory concentration (MIC). The results showed that the ethanol extract was resistant to 5 tested strains of bacteria (Bacillus cereus, Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, Escherichia coli) with diameters of bacterial inhibition zones ranging from 6.76 to 14.50 mm, in which the resistance to Gram-positive strains was better than Gram-negative strains. The decoction inhibited only 3/5 of the tested bacterial strains (S. aureus, E. faecium, E. coli) with MICs from 125 to 750 mg/mL (dry weight of plant per volume of decoction). The antibacterial activities of extracts from the stems, leaves, and roots of the plants were different. Samples obtained from the 2 sites also showed different antibacterial capacities.