Phytochemical Screening and GC-MS Analysis of Bioactive Constituents in the Methanolic Extract of Caulerpa Racemosa (Forssk.) J. Agardh and Padina Boergesenii Allender & Kraft

Marine macroalgae (seaweeds) are the potential renewable energy and promising resources of many biologically active compounds. The potential sources of commercial and therapeutic impact of seaweeds are still unaware. In this study, we aim to identify and evaluate the biological activity of Caulerpa racemosa (Forssk.) J. Agardh and Padina boergesenii Allender & Kraft. The seaweed samples were shade dried and ground. The coarse powdered material was subjected to Soxhlet apparatus and successively extracted with methanol. The phyto-constituents of the seaweeds were analyzed by standard methods and GC-MS. The GC-MS results of C. racemosa (Forssk.) J. Agardh and P. boergesenii Allender & Kraft revealed the presence of hexadecenoic acid, butanoic acid, arachidonic acid, octadecadienoic acid, cis-vaccenic acid, phytol and eicosatetraenoic acid. The seaweed extracts were subjected to antimicrobial assay by agar-well diffusion. Padina boergesenii Allender & Kraft showed the highest inhibition zones (23.6 ± 0.3mm and 22.7 ± 0.5mm) against Gram-positive bacteria Pseudomonas aeruginosa and Staphylococcus aureus, respectively. Caulerpa racemosa (Forssk.) J. Agardh showed the highest inhibition zone (22.0 ± 0.8) against Gram-positive bacteria Staphylococcus aureus. Extracts of both seaweeds, C. racemosa (Forssk.) J. Agardh and P. boergesenii Allender & Kraft, contain potential bioactive compounds with high antibacterial activity and could be deployed in the pharmaceutical applications.

Keywords: seaweeds; phytocompounds;  antimicrobial activity

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