Estimation of Phenolic Components and in vitro Antioxidant Activity of Fennel (Foeniculum vulgare) and Ajwain (Trachyspermum ammi) seeds

摘要

Antioxidants are substances that protect cells from the cellular damage caused by unstable molecules known as free radicals induced oxidative stress. Antioxidants neutralize free radicals as a natural by-product of normal cell processes. Phenolic compounds , which are widely distributed in many fruits, vegetables, and tea are believed to account mainly for the antioxidant capacity of many plants. In the present study methanolic and aqueous seed extracts of fennel (Foeniculum Vulgare) and ajwain (Trachyspermum ammi) were studied for the quantification of the total antioxidant capacity and determination of total phenolic compounds. The total antioxidant capacity was measured using DPPH, H2O2 and FRAP methods and the total phenolic compounds were measured using the Folin- Ciocalteu reagent in an effort to validate the medicinal potential of the herb. Ascorbic acid was used as standard. The antioxidant activity expressed as IC50 displayed the similar DPPH? scavenging effect in methanol and aqueous seed extract of fennel and ajwain , less than ascorbic acid at 30μg/ml. The methanolic extract of fennel seeds showed the highest OH- scavenging potential of 71.61% at 240μg/ml concentration. The reducing ability (FRAP activity) of the extracts were in the range of 7 – 48 μm Fe (II)/g. Polyphenolic compounds are known to have antioxidant activity and it is likely that the antioxidant activity of the extracts is due to these compounds. The level of the phenolic compounds in the methanolic and aqueous seed extracts of fennel and ajwain were considerable. The study showed that the extracts have the proton-donating ability and could serve as free radical inhibitors or scavengers, acting possibly as primary antioxidants.