SECONDARY METABOLITE PROFILE AND BIOACTIVE POTENTIAL OF A NATIVE Synechococcus elongatus STRAIN FROM SOUTHEAST SULAWESI AS A NUTRACEUTICAL CANDIDATE

Abstract

ARTICLE HIGLIGHTS- A native Synechococcus elongatus strain was isolated from coastal waters of Southeast Sulawesi, Indonesia.- Molecular identification confirmed 99.70% sequence identity with S. elongatus.- High total phenolic (249.81 mg GAE/g) and flavonoid (78.43 mg QE/g) contents were recorded- LC-MS analysis identified 30 bioactive compounds, including palmitic and juniperic acids.- The methanolic extract showed moderate antioxidant activity (IC50 114.34 mg/L) and anticancer potential (LC50 170.07 mg/L).- Toxicity testing yielded an LC50 of 254.06 mg/L, supporting further investigation of its potential for sustainable nutraceutical and pharmaceutical applications.ABSTRACTMicroalgae represent a potential biological resource for the development of functional raw materials due to their ability to produce a diverse range of bioactive compounds. This study aimed to identify, characterize the secondary metabolite content, and evaluate the bioactive potential of the microalga Synechococcus elongatus isolated from the coastal waters of Tambo Watu Beach, Konawe, Southeast Sulawesi. Sample identification was performed using morphological and molecular methods. Molecular analysis using BLASTn revealed that the WW1 isolate shared a 99.70% identity with the species S. elongatus. The methanolic extract from the microalgal biomass yielded 13.5%. Qualitative phytochemical screening indicated the presence of phenolic compounds, flavonoids, alkaloids, and terpenoids/steroids, but was negative for saponins. Quantitative analysis revealed a total phenolic content of 249.81 mg GAE/g extract and a total flavonoid content of 78.43 mg QE/g extract. Compound identification via LC-MS successfully detected 30 compounds, including fatty acids such as palmitic acid and juniperic acid, as well as other compounds like xanthine and deoxycholic acid, which have potential applications in the cosmetic and pharmaceutical fields. Bioactivity testing demonstrated that the S. elongatus extract possessed moderate antioxidant activity with an IC₅₀ value of 114.34 mg/L. Toxicity assessment using the Brine Shrimp Lethality Test (BSLT) showed weak toxicity with an LC₅₀ value of 254.06 mg/L, indicating its safety profile. Furthermore, the extract exhibited moderate anticancer potential with an LC₅₀ value of 170.07 mg/L. However, the extract showed no antibacterial activity against E. coli and S. aureus, nor antifungal activity against C. albicans, at concentrations up to 100 mg/disk. In conclusion, the S. elongatus isolate from Konawe waters is a rich source of phenolic and flavonoid compounds, exhibiting moderate antioxidant and anticancer bioactivities with low toxicity. These results affirm its potential for further development as a candidate for functional raw materials in the nutraceutical, pharmaceutical, and cosmetic industries.

Keywords

• Antioxidant
• Anticancer
• Bioactive Compounds
• Phytochemistry
• Synechococcus elongatus
• Southeast Sulawesi
• microalgae
• bioactive compound
• secondary metabolite