Evaluation of Antibacterial Activity of Methanolic Extract of Avicennia marina Leaf Extract against Staphylococcus aureus

Introduction: Mangrove are widespread in the tropical and subtropical regions of Indo-West-Pacific area. Avicennia marina possesses vast medicinal values. The pharmacological activity of the plant is attributed to the presence of several phytochemicals.

Aim: To evaluate the antibacterial activity of Avicennia marina leaf extract against Staphylococcus aureus.

Methods and Materials: Plant extract prepared by adding 20g of dried powdered mangrove leaf sample to 100 ml of methanol. MDRSA, MRSA & VRSA were cultured in Muller –Hinton Broth for 24 hr at room temperature. From this prepared bacterial suspension, 1ml of was spread over Muller Hinton agar plate and incubated for 24hrs at ambient temperature. Antibacterial activity carried out through the disc diffusion method. Whatman filter paper discs (5mm) were impregnated with various concentrations (50, 100, 150, 200, 250 & 300 µg/ml) of leaf extract. After incubating the plates for 24hr at room temperature the zone of inhibition was measured. Minimum Inhibitory Concentration was determined in 5 concentrations (50 -300 µg/ml) with blank (extract in Muller Hinton broth). The inoculated bacteria in test tubes are incubated for 24hr in ambient temperature. The results are noted as well growth (+) and inhibited (-). Tetracycline (1µg/ml) was used as standard and DMSO as negative control.

Results: The zone of inhibition was greater at 300µg/ml of the extract for MDRSA ( 13±1.2) , MRSA ( ( 13±1.4) )& VRSA ( 9±1.2). MIC for MDRSA, MRSA and VRSA was 250µg/ml, 200µg/ml 150µg/ml respectively.

Conclusion: The present study showed effective antibacterial activity of Avicennia marina against MDRSA, MRSA, VRSA. Hence, this extract may be used for infections against resistant Staphylococcus aureus.