POTENTIAL OF MACROALGAE FROM TIDUNG ISLAND WATERS AS ACTIVE INGREDIENTS FOR FUNCTIONAL FOODS

Abstract

Macroalgae are valuable for functional foods due to their rich secondary metabolites which are greatly influenced by their environmental condition. This study evaluated the potential of Tidung Island’s macroalgae as a source of bioactive compounds for functional food ingredients. Seventeen macroalgae samples were collected from Tidung Besar (TB) and Tidung Kecil (TK), Kepulauan Seribu, representing Chlorophyceae, Phaeophyceae, and Rhodophyceae. The macroalgae were extracted using ethanol and analysed for their total phenol using Folin-Ciocalteu method, antioxidant using Ferric Reducing Antioxidant Power (FRAP) assay, antibacterial using Resazurin-based Microtiter Dilution Assay, and anticancer activity using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Result showed that total phenolic content varied among species (39.85–122.26 mg GAE g⁻¹).  Antioxidant activity ranged from 16.43–96.58 mg mL⁻¹, with Turbinaria ornata exhibiting the strongest effect, while Gracilaria debilis showed the lowest. Species of Phaeophyceae generally displayed higher antioxidant capacity compared to the other groups. Antibacterial assays revealed minimum inhibitory concentrations (MIC) between 2.5 and 10 mg mL⁻¹, with Halimeda gracilis showing the strongest inhibition. Anticancer evaluation against MCF-7 breast cancer cells demonstrated inhibition ranging from 7.68–90.22%, with H. gracilis and H. macroloba being the most active. Phenolics correlated moderately with anticancer activity (r = 0.56) and weakly with antioxidant activity (r = 0.36), while antioxidant–anticancer correlation was strong (r = 0.76). In conclusion, H. gracilis, C. sertularioides, P. australis, and A. muscoides emerged as promising candidates for further development as natural sources of antioxidant, antibacterial, and anticancer compounds.