Study and comparison of inhibitory and antioxidant activity of water-methanol extracts of black cumin, coriander and dill seeds Soleimanifar, M. 1, Niazmand, R. 2 , Shahidi Noghabi, M. 3

Medicinal plants are valuable natural resources that because of large amount of active compounds have been concerned in modern societies. Black Cumin, Coriander and Dill are such resources which they have many therapeutic and medicinal properties. Our purpose of this research is To evaluate the antioxidant activity of water- methanol extract of Black Cumin, Coriander and Dill seeds in comparison with BHT. For the preparation of water- methanol extract, the mentioned seeds powders were mixed with methanol - water (80:20 v/v) solvent at ratio 1:4 w/v. The total phenolic compounds (TPC) was measured by Folin- Ciocalteau’s method. Antiradical and inhibitory activity of the extracts were evaluated by DPPH method and compared with synthetic antioxidant BHT. The antioxidant activity of above extracts was studied in soybean oil (oven test at 60 ⁰C) by measuring peroxide value (PV) and thiobarbituric acid value (TBA) and compared with BHT (at level 100 mg/ml). There water- methanol extracts of Black Cumin, Coriander and Dill seeds contained 955.77, 890.62 and 923.16 mg/kg phenolic compounds. The highest IC₅₀ related to water- methanol extract of Black Cumin (104.76 mg/ml) which demonstrated higher antiradical activity compared to the Coriander and Dill seeds extracts. In oven test, the water- methanol extract of Black Cumin showed the greatest antioxidant activity and at level 100 mg/ml acted as BHT at level 100 mg/ml. water-methanol extracts of Black Cumin, Coriander and Dill as natural antioxidants are capable of scavenging radicals derived from lipid oxidation and reduction of auto-oxidation rate.