EVALUATION OF ANTI-METHICILLIN RESISTANT Staphylococcus aureus PROPERTY OF Clausena excavata LEAVES BY USING ATOMIC FORCE MICROSCOPY AND FLOWCYTOMETRY TECHNIQUES.

Clausena excavata is a famous folklore medicinal plant in tropical and subtropical Asian region that is being used for the treatment of different disorders. This study was conducted to investigate the antibacterial activity of leaves extract of C. excavata against methicillin-resistance Staphylococcus aureus (MRSA), using atomic force microscopy (AFM) and flowcytometry techniques. Cell viability assay was performed by using microplate AlamarBlue assay. Among different extracts, ethyl acetate (EA) extract was found to have the lowest minimum inhibitory concentration (MIC) of 375 µg/mL followed by chloroform (CH) and methanol (MOH) extracts with MIC values of 750 and 1500 µg/mL, respectively. EA and CH extracts were selected for further mechanistic study by using AFM, and propidium iodide (PI) flowcytometry techniques. AFM results of treated cells showed highly damaged cells scattered all over due to loss of the potential to form clusters of cocci. Flowcytometry results showed that there were increases in PI fluorescence due to increase in the number of dead cells. This is the first report that highlights the antimicrobial activity of C. excavata against MRSA by the using above mentioned techniques. Further investigations are required to identify the pure compounds responsible for anti-MRSA activity, and its mechanistic study. [ABSTRACT FROM AUTHOR]