Concentration dependency of antioxidant activity was investigated as a function of reducing power as shown in Figure 4. The reducing capacity of various concentrations of C. marina extracts behaved in a dose dependent manner (0.2 to1.0 mg/mL). Similar to the total antioxidant activity (TAA), diethyl ether extract showed better reducing power than methanol and hexane. Among the three extracts, methanolic extract exhibited higher radical scavenging activity when compared to diethyl ether and hexane. Thus, the phenolic compounds were major source to the antioxidative capacities of C. marina.