GC-MS Profiling, Cytotoxicity and Antiviral Activity of Caulerpa lentillifera and C. macrodisca from Northern Coastal Waters of Borneo Island, Eastern Malaysia

Bioactive compounds derived from marine sources have gained global attention in aquaculture disease control due to their novelty and promising medicinal value. However, marine algae as an alternative source remain underexplored particularly along the Borneo coast. In this study, marine algae specifically Caulerpa lentillifera and C. macrodisca were investigated on their toxicity and antiviral activity as well as bioactive profiling. The cytotoxicity was evaluated using five fish cell lines. The antiviral activity was assessed against infectious hematopoietic necrosis virus (IHNV). Results showed that both Caulerpa species exhibited moderate cytotoxicity on E-11 and EPC cells after six and 14 days, respectively. The antiviral assay revealed higher viral titer reduction by C. macrodisca (1.80 log₁₀ TCID₅₀ mL⁻¹; 98.38%) compared to C. lentillifera (0.46 log₁₀ TCID₅₀ mL⁻¹; 65.19%) after 10 days. GC-MS identified multiple potential bioactive metabolites, including two potential antiviral compounds from C. lentillifera and five potential antiviral compounds from C. macrodisca. These findings highlight the potential of Bornean Caulerpa species as a novel source of marine-derived antiviral metabolites for sustainable fish health management in aquaculture.