Marine organisms, particularly algae, have garnered significant attention due to their rich biodiversity and potential as sources of novel bioactive compounds. Among them, Caulerpa racemosa, a green alga commonly found in tropical marine environments has been recognized for its therapeutic potential, but its biological activities remain underexplored. The current study investigates the antibacterial, antioxidant, and anti-inflammatory potential of Caulerpa racemosa methanolic extract. The antibacterial activity was evaluated against four bacterial strains (Staphylococcus aureus, Streptococcus mutans, Shigella sonnei, and Micrococcus luteus) using the well diffusion method. The extract exhibited dose-dependent antibacterial activity, with the highest inhibition zone of 15.6 ± 0.2 mm against M. luteus at 100 µg/mL. The biofilm inhibition assay also revealed a significant reduction in biofilm formation, with M. luteus showing the highest inhibition (15.6 ± 0.2%) at 100 µg/mL. The antioxidant activity was assessed using the DPPH assay, where the extract demonstrated a concentration-dependent increase in radical scavenging activity, with a maximum of 69.14% RSA at 100 µg/mL and an IC50 value of 8.40 µg/mL, indicating potent antioxidant potential. In the anti-inflammatory assay, the extract was tested using the BSA denaturation method. A concentration-dependent inhibition of protein denaturation was observed, with the highest inhibition of 88.50% at 50 µg/mL. The results suggest that Caulerpa racemosa methanolic extract possesses significant antibacterial, antioxidant, and anti-inflammatory properties, making it a promising candidate for further studies in the development of natural therapeutic agents.
