The Antibacterial Activity against Methicillin-Resistant Staphylococcus Aureus from the Ethyl Acetate Extract in Clinacanthusnutans
Clinacanthusnutans (CN) plants have been received much interest from phytochemical researchers because of their plentiful bioactive compounds of total phenolic compound (TPC) and total flavonoid compound (TFC). Many of report study exhibit wide varieties of biological activities. In this study, herbal ethyl acetate extracts was isolated from C. nutans (CN) leaf, identified by Thin layer Chromatography. Phytochemical screening illustrated to the tannins compound. Crude extracted was freshly prepared by solubilizing in DMSO and immediately diluted in Müller-Hinton broth for antibacterial testing. The data showed that Staphylococcus aureus and Methicillin resistant Staphylococcus aureus (MRSA) of three strains such as ATCC 29213, MRSA 4738 and MRSA 20649 were susceptible to crude extracts in disc diffusion method. Using the two-fold microdilution method, it was found that the extracts possessed antimicrobial activity against MRSA with minimum inhibitory concentration (MIC) of CN extract is 3.125 mg/ml. Minimum bactericidal concentration (MBC) is 6.25 mg/ml. To investigate the mechanism of action of the extracts, transmission electron microscopy (TEM) was performed to observe the ultrastructure of MRSA. The TEM images showed that ruptured the bacterial cell membrane and cell wall. It is suggested that the action of the crude extracts is likely to be the direct disruption of the cell membrane.
