الفهرس 
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Abstract
Present study included the chemical composition of two species of grape (Vitis vinifera) (thompson seedless and flame seedless), zizyphus (Zizyphus spina-christi), pomegranate (Punica granatum) and fig (Ficus carica) leaves belong to families Viticeae, Rhamnaceae, Punicaceae and Moraceae, respectively. Moisture content of air dried investigated leaves were 9.50, 10.83, 9.67, 8.16 and 9.50% for thompson seedless, flame seedless, zizyphus, pomegranate and fig leaves, respectively. Ash, crude fiber, crude protein, crude lipids, total sugars, soluble sugars and insoluble sugars were determined in thompson seedless, flame seedless, zizyphus, pomegranate and fig leaves. All results were calculated as (g/100g dry weight). Zizyphus and pomegranate leaves have the lowest percentage values for both ash (14.43 and 13.41%) and crude protein (11.17 and 10.03%) contents, respectively. On the other hand, the same leaves have the highest values of crude fiber contents which were 39.43 and 39.11% for zizyphus and pomegranate leaves, respectively. Thompson seedless leaves have lower values of ash, crude fiber and crude lipids contents which were 17.55, 26.42 and 2.52%, respectively, than flame seedless leaves which were 18.93, 29.76 and 3.15%, respectively. On the other hand, thompson seedless leaves have higher values of crude protein (17.07%), total sugars (36.44%), soluble sugars (25.30%) and insoluble sugars (11.14%) contents than flame seedless leaves which were 15.45, 32.71, 23.20 and 9.51% for crude protein, total sugars, soluble sugars and insoluble sugars contents, respectively. Potassium was the main element in all samples which ranged from 227.00 to 311.00 mg/100g on dry weight basis in flame seedless and pomegranate leaves, respectively. Contents for total chlorophyll of thompson seedless, flame seedless, zizyphus, pomegranate and fig leaves were 2.029, 2.150, 3.199, 3.793 and 3.037 mg/g on fresh weight basis, respectively. While, chlorophyll (a) was the predominant type of chlorophylls because the values of chlorophyll (a) were higher than chlorophyll (b) for all leaves samples. The phytochemical constituents of crude methanolic extract of thompson seedless, flame seedless, zizyphus, pomegranate and fig leaves proved that the crude methanolic extract of investigated leaves were rich in terpenes, tannins, flavonoids, alkaloids, carbohydrate or glycosides, phenolic glycosides and resins within the acceptable limits. On the other hand, all extracts were poor in saponins, except zizyphus leaves extract was so rich in saponins, also saponins were found in fig leaves extract in acceptable limits. Total polyphenols (mgGAE/g) content of thompson seedless, flame seedless, zizyphus, pomegranate and fig leaves were 119.82, 117.51, 147.47, 122.52, and 123.51 mgGAE/g dry weight for total polyphenols, respectively. Total flavonoids were ranged from 13.25, 15.93, 16.35, 10.95 and 9.57 mgQE/g on dry weight basis for thompson seedless, flame seedless, zizyphus, pomegranate and fig leaves, respectively. HPLC analysis proved that thompson seedless, flame seedless, zizyphus, pomegranate and fig leaves contained Protocatechuic, Catechin, P-hydroxy benzoic acid, P-coumaric acid, O-coumaric acid and Coumarin with different concentrations comparing with standard compounds. Pure isolated compound from ethyl acetate fraction of zizyphus leaves was identified using assignment of 1H-13C-NMR signals which indicated that the isolated compound is Quercetin-3-O-β-D-galactopyranoside-7-O-β-D-glucopyranoside. The reducing ability increased with increasing the methanolic extracts concentrations for all samples. Zizyphus leaves extract have the most effective reducing ability which was ranged from 0.485 and 1.433 nm at concentrations of 20 and 100 mg/ml, respectively. The capacity of investigated leaves extracts to scavenge the ABTS radical proved that crude methanolic extract of zizyphus leaves have the lowest absorbance value (0.062) with the highest inhibition percentage (88.17%) followed by pomegranate leaves which have 86.83% as inhibition capacity. Crude methanolic extracts of investigated leaves was used as natural antioxidant, for keeping quality of soybean oil, led to retard the deterioration of the oil compared BHT as a synthetic antioxidant. The effect of various concentrations (1, 2 and 4 mg/ml) of thompson seedless, flame seedless, zizyphus, pomegranate and fig crude methanolic leaves extracts on the growth inhibition of Alternaria solani, Botrytis cinerea, Botrytis fabae, Fusarium oxysporum and Fusarium solani showed that zizyphus leaves extract produced the highest growth inhibition (95.56%) against Botrytis fabae at 4mg/ml. While, the percentages of growth inhibition for thompson seedless, flame seedless, pomegranate and fig leaves extracts were 78.89, 84.44, 94.44 and 91.11% against the same fungi strain. On contrary, Fusarium oxysporum and Fusarium solani showed the highest resistance effect for the methanolic extracts of all investigated leaves. Antidiabetic effect of crude methanolic extracts of investigated leaves on streptozocin-diabetic rats leads to the following points: The injection of streptozocin at a dose of 4.5 mg/100g body weight caused a highly significant (P<0.05) increase in the levels of blood glucose, ALT, AST, creatinine, urea, triglycerides, total cholesterol, LDL and vLDL. whereas, HDL level was decreased as a result of injection with streptozocin. All investigated leaves extracts showed a significant decrease in serum glucose, ALT, AST, creatinine, urea, triglycerides, total cholesterol, LDL and vLDL levels with different values. While, crude methanolic extracts of investigated leaves increased HDL levels. The most effective treatment for decreasing serum glucose level was the methanolic extract of zizyphus leaves.