Antioxidant activity of methanolic extract of Eucheuma spinosum extracted using a microwave

Eucheuma spinosum is a widely cultivated red seaweed. The phenolic compounds contained in E. spinosum, especially flavonoids, can be used as a source of natural antioxidants. This study aimed to determine the antioxidant activity of E. spinosum extracted using a microwave with different extraction times (6, 8 and 10 minutes). The parameters measured included yield, phytochemical test, total phenolic content, total flavonoid content and antioxidant activityt, namely 2,2 diphenyl-1-picrihydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The results showed that the E. spinosum extract with an extraction time of 10 minutes had the highest yield with a total phenolic content of 59.42 ± 27.36 mg GAE/g and a total flavonoid content of 65.48 ± 25.34 mg QE/g. The results of phytochemical screening showed that the extract contain triterpenoid compounds. The antioxidant activity of the E. spinosum extract showed the highest IC50 value of 46.52 ± 5.53 ppm using the DPPH method and the FRAP method was 58.92 ± 1.76 μM/g.