An in vitro and ex vivo Study on Antioxidant Activity of Coriander Seeds

The antioxidant activity of extracts of different polarity from seeds of Local variety of Coriandrum sativum was assessed via both in vitro and ex vivo models. Results indicate that hexane extract of coriander exhibited no appreciable affects at either of the concentrations in all the three in vitro free radical scavenging models i.e. hydroxyl radical, super oxide radical and nitric oxide radical. Instead, it showed prooxidant activity at higher concentrations. Whereas methanol: hexane extracts of coriander were found to be ineffective in quenching hydroxyl radical but revealed only moderate activity in quenching super oxide radical (EC₅₀=711.81 μg/ml) and nitric oxide radical (EC₅₀=569.02 μg/ml). Only methanolic extract of Local variety offered strong antioxidant activity in a concentration dependent manner for the same three free radicals with EC₅₀ of 18.33 μg/ml, 553.50 μg/ml and 179.53 μg/ml respectively. Even in vitro linoleic acid peroxidation model proved methanolic extract of coriander (80% inhibition till 48 h) to be far better than standard antioxidant ascorbic acid (70% inhibition till 12 h). EC₅₀ and SC₅₀ for ex vivo linoleic acid peroxidation of rat liver homogenate and erythrocytes were recorded as 383.10 μg/ml and 166.78 μg/ml respectively. The methanolic extract of Local variety was further evaluated for its protective effect on osmotic fragility and antioxidant enzymes of erythrocytes at various time intervals (24–96 h). The decrease in% hemolysis and protection of activities of antioxidant enzymes even for 96 h of incubation in test groups supplemented with coriander proved indubitably, the effectiveness of methanolic coriander extract in alleviating protective mechanisms.