Abstract
The present study was designed to evaluate the antibacterial property of crude extracts of the leaves of Begonia goegoensis N.E.Br. prepared in different solvent systems against Pseudomonas aeruginosa (ATCC 27583) and β-lactamases producing Pseudomonas aeruginosa (MBL-positive Pseudomonas aeruginosa) strains. Therefore, five kinds of solvents were used to extract the active ingredients from the leaves of Begonia goegoensis: ethanol, methanol, ethyl acetate, hexane, and dichloromethane. The testing of antibacterial activity of the plant extracts was carried out in vitro by Kirby-Bauer disc diffusion technique. Subsequently, the present study has shown that ethanolic extract from the leaves of Begonia goegoensis exhibited strong activity against Pseudomonas aeruginosa (inhibition zone diameter ranged from 12 mm to 13 mm), while methanolic leaf extract screened revealed less profound activity (within 11–12.5 mm). Moreover, it has been observed that ethyl acetate, hexane and dichloromethane extracts obtained from leaves of Begonia goegoensis revealed no antibacterial activity against P. aeruginosa and MBL-positive Pseudomonas aeruginosa strains. MBL-positive Pseudomonas aeruginosa was also susceptible to ethanolic and methanolic extracts (inhibition zone diameter ranged from 12.5 mm to 15.5 mm). Thus, the spectrum of activity observed in the present study indicate that the alcoholic leaf extract of Begonia goegoensis could be a possible source to obtain new and effective herbal medicines to treat various infectious diseases, including infections, caused by drug resistant microorganisms.