Objective. To evaluate thein vitroantibacterial activities of five plant extracts which have been used as traditional medicines by local healers against three multidrug resistant bacteria, namely,Staphylococcus aureus,Escherichia coli, andPseudomonas aeruginosa.Results. The highest mean zone of inhibition (4.66 mm) was recorded from methanol extract ofCalpurnia aurea(Ait.) Benth. at a concentration of 200 mg/ml againstS. aureus, followed byCroton macrostachyusDel. (4.43 mm) at the same dose and solvent for the same bacterial species, while methanol and chloroform extracts ofE. bruceiSchwein. did not inhibit growth of any bacterial species. The lowest value (100 μg/ml) of minimum inhibitory concentration (MIC) was observed from both methanol and chloroform extracts ofC. aurea(Ait.) Benth. against all the three bacteria. The results of the positive control had no statistically significant difference (P>0.05) when compared with crude extracts ofC. aurea(Ait.) Benth. at concentration of 200 mg/ml againstS. aureus.Conclusion. The results of the present study support the traditional uses of these medicinal plants by the local healers. ExceptErythrina bruceiSchwein., all the plants investigated in this study exhibited antibacterial activities against the test bacterial species. Further researches are needed to be conducted to evaluate efficacy of these medicinal plant species on other microbes in different agroecological settings and their safety levels as well as their phytochemical compositions.
Antibacterial activities of ethanol extracts of Philippine medicinal plants against multidrug-resistant bacteria
