Total Phenols, Flavonoids, Antioxidant Activity of Methanolic and Ethyl Acetate Extracts of Caulerpa racemosa Plants Grown in Usaha Jaya Village, Raja Ampat Regency, Southwest Papua Province

Caulerpa racemosa is a species of green seaweed that is widely distributed in almost all tropical seas in the world. Those green seaweed contain active compounds that have potential as antioxidants. Differences in phenolic and flavonoids content as antioxidants can be influenced by post-take handling and solvent polarity. The research aims to study the phenolic and flavonoid content in methanol (polar) and ethyl acetate (semi polar) solvents as well as the antioxidant activity using ABTS (2,2-azinobis-3-Ethylbenzoathiazoline-6-sulfonic acid), DPPH (1,1-diphenyl-2-picrylhydrazyl), and H2O2 (Hydrogen peroxide) methods. The highest extract yield was found in the methanol extract which amounted to 6.12%, while the ethyl acetate amounted to 1.80%. The phenolic content of the methanol extract was 40.18 ± 3.06 mgGAE/g, while the ethyl acetate extract had the lowest total phenol content of 17.22 ± 1.37 mgGAE/g. The total flavonoids content of the methanol extract was 84.42 ± 10.20 mgQE/g higher than the ethyl acetate extract which was 78.61 ± 5.31 mgQE/g. Antioxidant activity of ABTS method of methanol extract obtained IC50 value of 134.64 ± 19.90 µg/mL with the moderate category lower than that of ethyl acetate extract which was 113.50 ± 19.69 µg/mL also with moderate category. Antioxidant activity of DPPH method in methanol extract obtained IC50 reached 96.08 ± 0.45 µg/mL with strong antioxidant category, while IC50 in ethyl acetate extract reached 167.72 ± 1.08 µg/mL with weak category. The antioxidant activity of H2O2 method is classified as moderate activity in both solvents as in methanol extract it was 110.79 ± 2.52 µg/mL and in ethyl acetate extract was 123.67 ± 2.08 µg/mL.