_____________________________________________________________________________________________________ ≡ Professor; ⱷ Assistant Professor; *Corresponding author: E-mail: anitharoy@saveetha.com; Journal of Pharmaceutical Research International 33(61A): 279-286, 2021; Article no.JPRI.77720 ISSN: 2456-9119 (Past name: British Journal of Pharmaceutical Research, Past ISSN: 2231-2919, NLM ID: 101631759) Evaluation of Antibacterial Activity of Methanolic Extract of Avicennia marina Leaf Extract against Staphylococcus aureus Swetha Ramasubramanian a≡ , Anitha Roy b*ⱷ , Pitchiah Sivaperumal bⱷ and T. Lakshmi b≡ a Saveetha Dental College and Hospitals, Saveetha institute of Medical sciences and Technical Sciences (SIMATS), Chennai - 600077, Tamil Nadu, India. b Department of Pharmacology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai - 600077, Tamil Nadu, India. Authors’ contributions This work was carried out in collaboration among all authors. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JPRI/2021/v33i61A35587 Open Peer Review History: This journal follows the Advanced Open Peer Review policy. Identity of the Reviewers, Editor(s) and additional Reviewers, peer review comments, different versions of the manuscript, comments of the editors, etc are available here: https://www.sdiarticle5.com/review-history/77720 Received 20 October 2021 Accepted 26 December 2021 Published 28 December 2021 ABSTRACT 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 Original Research Article