Antioxidant Activities of Eucheuma sp. (Rhodophyceae) and Laminaria sp. (Phaeophyceae)

Abstract

In this study, antioxidant activities of two macroalgae, Eucheuma sp. J.Agardh and Laminaria sp., J.V.Lamouroux used as food supplements were investigated. The antioxidant activity, free radical scavenging activity, the total content of phenolics, flavonoids and condensed tannins in extracts were determined. The IC50 values of the extracts of Eucheuma sp. and Laminaria sp. on DPPH scavenging activity was 2.26±0.03 mg/g and 2.63±0.03 mg/g of extract, respectively. The maximum total phenolic (5.31±0.04 mg GAE/g Ext.) were determined. According to our results, all extracts exhibited low radical scavenging activity when compared to the standards used, i.e. -tocopherol and butylated hydroxytoluene (BHT) with the inhibition percentage in the range of 48.45±0.06% (Eucheuma sp.) – 58.49±0.03% (Laminaria sp.). The highest flavonoid content was measured as 18.78±0.10 mg rutin/g of extract in Laminaria sp. The condensed tannins were not detected in Eucheuma sp. However, this value was measured as 6.24±0.60 mg CE/g of extract for Laminaria sp. According to our results, Eucheuma sp. and Laminaria sp., which are commercially sold in medicinal herb stores, are good sources of antioxidant components because of their phenolic and flavonoid contents.