Evaluation of Antioxidant Activity of Three Varieties of Date Fruit Extracts (Phoenix Dactylifera L. Aarecaceae)

The aim of this study is to evaluate the antioxidant activity of three different Egyptian varieties of date palm fruit extracts. The results showed that extracts contain a large amount of phenolic compounds (113.48±0.48, 68.18±0.25 and 56.16±0.29 mg/100g respectively) of Siwi, Zaghlool and Samany date palm varieties. The antioxidants activity of the date extracts have been evaluated. The results indicated that lower EC50 value reflects better protection action against oxidation. The amount of Samany, Zaghlool and Siwi extract required scavenging 50% of DPPH (2.2 diphenyl-1- picrylhydrazyle) radical (EC_50 ) were 7.28±0.05, 4.89±0.09 and 2.17±0.04 respectively. Also, the date extracts were added at different concentrations to soybean oil (200, 500 and 1000ppm) and 200ppm BHT as synthetic antioxidant. The rate of peroxide formation of control group without the addition of date extracts was rapid and reached 46.39 meq/kg after 5 hours. The results indicated that addition of three varieties of date extracts at 1000ppm to soybean oil showed a higher inhibitory effect in the peroxide value of the oil than synthetic antioxidant (200ppm BHT). Among the three date extracts, Siwi was more effective than Zaghlool and Samany in all concentration used. Forty-eight albino rats were divided to eight groups used to study the effect of date extracts on body weight gain, food intake, weight organs, serum glucose, lipid profiles and antioxidant enzymes activity. There are significant decreases of body weight gain for all groups compared to control group, but there are no significant different of food intake between control group and other groups. The addition of date extracts to rats diet decrease the weight of kidney, heart and spleen at concentration 1.5% of Zaghlool, land 1.5% Siwi extract. There are significant decreases in serum total cholesterol, triacylglycerol (TG), low-density lipoprotein (LDL), very low density lipoprotein (VLDL). Comparing Samany, Zaghlool, and Siwi extract, it was found that Siwi extract at 1% and 1.5% concentration showed the highest effect on lowering total cholesterol and LDL cholesterol more than synthetic antioxidant and other date extracts. The results showed that different types of date extracts were effective in increase HDL cholesterol more than synthetic antioxidant. There are signif-icant increase of serum glucose for the eight group compared to the control group. The results of antioxidant enzymes activities showed that there are significant increase of catalase, superoxide dismutase (SOD) and hydrogen peroxide activity (H2O2) of rats serum treated with types of date extracts compared to control group. The rates of increase vary with the different types and concentration of date extracts. The highest increase of antioxidant enzyme activities was for rats fed on 1.5% Siwi extract. The range increase of catalase activity of rats fed on synthetic antioxidant (group2) was lower than other groups. SOD activity was equal to control group, H2O2 activity of rats fed on synthetic antioxidant shows lower decrease than that for control group. Data obtained in the present study suggested that the date extracts have potential natural antioxidant activity against free radicals DPPH more than the synthetic antioxidant and have lowering effect on lipid profile and increases the antioxidant enzymes activities. The Siwi extract have the stronger antioxidant activity followed by Zaghlool extract followed by Samany extract.