ANTIBACTERIAL ACTIVITY OF BUAS-BUAS (Premna pubescens Blume) LEAF EXTRACTS AGAINST Bacillus cereus AND Escherichia coli

Premna pubescens blume popularly known as buasbuas belonging to the family Lamiaceae, wide-spread in the forests of Sumatra and Malaya peninsula. The preliminary screening of the ethanol extract of P. pubescens revealed the presence of alkaloids, steroids, flavonoids and phenolic. Previous studies revealed that there is no systematic study regarding the antimicrobial activity of leaf extracts of P. pubescens. The aim of this study was to assess the in vitro effect of leaf extracts of P. pubescens against Bacillus cereus and Escherichia coli causative agent of diarrheal diseases. Materials and Methods: Fresh leaves were procured from personal P. pubescens plant collections aged 5-7 years. Crude ethanol extract of leaves from P. pubescens were tested in vitro against B. cereus and E. coli at concentrations 10, 20, 30, 40 and 50 μg μL–1. Results: The B. cereus and E. coli showed concentration-dependent susceptibility towards the ethanol leaf extracts from P. pubescens. The degree of susceptibility varied depends on the concentrations, 50% concentration of P. pubescens leaf extracts showed the highest inhibition zone (12.5 and 13.6 mm diameter). Conclusion: Based on the current findings, it can be concluded that P. pubescens has antimicrobial activity which is as potent as standard antimicrobial drugs against B. cereus and E. coli. The antibacterial properties of P. pubescens leaves were not as effective as the commercial antibiotics chloramphenicol, enrofloxacin and penicillin. Nevertheless, future studies with higher extract concentrations, different method of extraction, properties from flowers, fruits, barks and roots extracts may be useful to evaluate the actual antibacterial performed to other pathogenic bacteria.