[P005] Poster

12:10 PM - 1:00 PM JST(3:10 AM - 4:00 AM UTC)

[P03-343] Phytochemical Characterization and Antioxidant Activity of Extracts from Red Seaweeds (Kappaphycus alvarezii and Gracilaria changii) from South Sulawesi

○Hakiki Melanie¹, Albi Darlian Santosa², Nina Artanti¹, Yulia Anita¹, Bahrun Bahrun¹, Endar Marraskuranto³, Megawati Megawati⁴, Ambo Tuwo⁵, Yusaku Miyamae⁶ (1. Research Center for Molecular Chemistry, National Research and Innovation Agency (BRIN) (Indonesia), 2. Food Science and Biotechnology Department, University of Brawijaya (Indonesia), 3. Research Center for Biomass and Bioproducts, National Research and Innovation Agency (BRIN) (Indonesia), 4. Research Center for Pharmaceutical Ingredients and Traditional Medicine, National Research and Innovation Agency (BRIN) (Indonesia), 5. Faculty of Marine Sciences and Fisheries, Hasanuddin University (Indonesia), 6. Institute of Life and Environmental Sciences, University of Tsukuba (Japan))

Keywords:

Red seaweed,Extracting solvent,Phytochemical,Antioxidant activity,GC-MS profiling

Seaweeds are increasingly recognized as sustainable sources of bioactive substances used in functional foods and nutraceuticals. Kappaphycus alvarezii and Gracilaria changii, commercially cultivated red seaweeds from South Sulawesi, Indonesia, are rich in secondary metabolites with antioxidant potential; however, their utilization in high-value-added products is still limited. The purpose of this study was to assess the antioxidant properties and phytochemical characteristics of these seaweeds by utilizing various extracting solvents (ethanol, ethyl acetate, and n-hexane). Total phenolic content (TPC) and total flavonoid content (TFC) were determined to assess phytochemical composition, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2, 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assays were employed to assess the antioxidant activity of crude extracts. Extracts with the highest antioxidant activity were subsequently characterized using Gas Chromatography–Mass Spectrometry (GC–MS) and Fourier Transform infrared (FTIR) spectroscopy for metabolite profiling and identification of functional groups. The ethyl acetate extract of K. alvarezii had the highest TPC (7.16 mg GAE/g), TFC (4.31 mg QE/g), and DPPH inhibition (63.8%), while the ethanolic extract showed the highest ABTS inhibition (55.9%). In contrast, the ethanolic extract of G. changii exhibited the highest TPC (9.11 mg GAE/g), TFC (7.89 mg QE/g), and DPPH inhibition (58.1%), whereas the ethyl acetate extract showed the highest ABTS inhibition (66.1%). GC–MS analysis identified a variety of bioactive substances, including fatty acids (myristic acid, oleic acid, hexadecanoic acid), terpenoids (phytol, neophytadiene), and ketones (2-pentadecanone), which are known to contribute to antioxidant activity. Additionally, FTIR analysis showed the presence of functional groups, including O–H, C=O, and C–O, which are associated with phenolic compounds, alcohols, and esters. These findings highlight the influence of the solvent on phytochemical extraction and indicate the potential of these seaweeds as sources of natural antioxidants for functional ingredients.
Acknowledgements: This research was supported by JST-JICA SATREPS, Japan (JPMJSA2307).