Evaluation of Antibacterial Activity against Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus of Extracts from Seven Thai Herbal Plants

Abstract

This research aims to study the antibacterial activity (Staphylococcus aureus (SA) and Methicillin-resistant Staphylococcus aureus (MRSA) of extracts from seven Thai herbal plants (Citrus aurantifolia, Cymbopogon citratus, Citrus hystrix, Curcuma longa, Centella asiatica, Senna siamea and Carissa carandas). Each plant was extracted with methanol and hexane. All crude extracts were evaluated for their antibacterial activity by using a colorimetric broth microdilution test. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated. The results showed that extract from Curcuma longa was the most active against S. aureus ATCC25923 with MIC 0.025 mg/ml and MBC 0.2 mg/ml and MRSA with MIC 0.5 mg/ml and MBC 1.6 mg/ml. On the other hand, hexane extracts from Citrus aurantifolia, Cymbopogon citratus and Citrus hystrix gave the moderate antibacterial activity with MIC 0.1 0.5 and MBC 0.8 mg/ml, respectively. whereas, the remaining extract showed the lowest antibacterial efficiency with MIC concentration range of 3.2-12.8 mg/ml and MBC concentration range of 12.8 – 20 mg/ml. These results show that crude extracts from some Thai herbal plants are interesting source of active metabolites for future application.