This study is conducted to evaluate the antidiabetic and immunological effect Olea europaea L. leaves and callus extracts on experimental alloxan-induced diabetic mice. To study the effect of Olea europaea extract, callus was induced from newly leaves in apical meristem, and it was maintained on Murashige and Skoog, MS culture medium supplemented with 1.5 mg/L benzyl adenine (BA) and 0.5 mg/L 2, 4-Diclorophenoxyacetic acid (2, 4-D). Aqueous and ethanol extracts were prepared and detection of chemical compounds was carried out. Results revealed that both aqueous and ethanolic extracts contain, phenols, flavonoids, tannins, terpenes, steroids, glucosides and saponins while no alkaloid appeared in both extracts. Diabetes was induced in experimental mice by intraperitoneal injection of single dose 100mg/kg of freshly prepared alloxan. Non-treated alloxaninduced diabetic mice exhibited all diabetes symptoms including hyperglycemia, polydipsia,polyphagia,
polyuria with significant increases in level of cholesterol, TG, LDL and VLDL and a significant decrease in HDL level.A significant change was recorded in total and absolute count of leucocytes with
a significant increase in gamma-globulin percentage.Insulin treatment (10U/kg body weight) was capable of reversing these changes. Olea europaea extracts treated diabetic mice showed a significant decrease in blood glucose level compared to non – treated diabetic mice. This hypoglycemic effect was comparable to that induced by insulin in diabetic mice. Olea europaea extracts (water and ethanolic extracts of leaves and callus) treated diabetic mice showed variable responses. in general there was a significant decrease in cholesterol, TG, LDL, VLDL and increased of HDL
level at the ends of experiments as compared to non- treated diabetic mice(74, 51, 13, 10) respectively as compared with untreated diabetic mice ( 116, 181,55, 37 respectively).
However, the callus extract was more potent than the leaves extracts.Furthermore, only the ethanolic callus extract showed the most potent effect than other extracts and even most potent than insulin in causing a significant decrease in LDL, VLDL, cholesterol and TG.A significant increase was recorded in total, absolute count of leucocytes and gamma- globulin percentage of serum protein in mice treated with both types of extract as compared to non- treated diabetic group.Furthermore, similar to its peculiar effects on lipid profile, the ethanolic extract of callus was the most potent extract in correcting the diabetes- associated changes in leucocytes and gamma-globulin percentage. In conclusion, this study demonstrated that, under the present experimental conditions, olive leaves and its callus extract exhibited variable antidiabetic effects. Furthermore, the callus extracts, especially the ethanolic one exerted pronounced antidiabetic effects that, in most instances, were more
potent than the effect of insulin. In addition, the immunomodulatory effect of the callus extract, together with its effect on leucocytes count is an interesting finding. Further studies are needed to investigate the mechanism(s) responsible for this finding, and to determine whether or not its has any potential clinical importance.
