Aliyeh Daryanavard, - Department of Marine Biology, Faculty of Marine Science, University of Tarbiat Modares, Iran
Saber Khodabandeh - Department of Marine Biology, Faculty of Marine Science, University of Tarbiat Modares, Iran

Free radicals are destructive compounds that affect the health of the cell and body.Antioxidants are useful compounds that can react with free radicals and convert them into harmless molecules. The human body normally has an antioxidant defense system that is able to balance between the body s antioxidants and free radicals by the enzymatic antioxidants and non-enzymatic antioxidants; the occurrence of any imbalance in this balance causes the appearance of diseases such as cancer and early aging. Previously, plants were the only known sources of antioxidants, but in recent years, extensive research has shown that many marine species are rich in beneficial compounds, including antioxidants and anti-tumor.In the present study, crab (Portunus pelagicus) hemolymph isolatedwith Ethanol was used to evaluate the antioxidant properties.The free radical inhibitory ability of crab hemolymph was compared with two plant carotenoids Panax ginseng and Opuntia ficus as natural antioxidants and BHT and vitamin C as synthetic antioxidants by DPPH method. In 1 mg/ml concentration, the free radical inhibitory ability for vitamin C 88%, BHT 67%, crab hemolymph 62%, ginseng 57%, and Opuntia ficus 41% were obtained and in 0.5 mg/ml concentration, for Vitamin C 71%, BHT 50%, crab hemolymph 44%, ginseng 42% and Opuntia ficus 14% were obtained. The hemolymph isolated from crab showed a relatively good free radical inhibitory ability compared to herbal and synthetic antioxidants, which can be considered in studies of marine antioxidants.

antioxidant activity, DPPH, hemolymph, Portunus pelagicus