engleski

Olive Leaf Extract Polyphenols and Diabetes Mellitus

Objective: Diabetes (lat. Diabetes mellitus DM) is now one of the most common diseases worldwide, affecting 415 million people. Abnormal glutamate homeostasis may contribute to the pathogenesis of diabetes with its direct and indirect effects on the integrity of the β-cells of pancreatic islets of Langerhans. The increased concentration of glutamate is present in all tissues with DM type 1 and type 2 DM. Polyphenols are associated with antioxidant, antihypertensive, anti-inflammatory, hypoglycemic and hypocholesterolemic effects on the human body. This study is based on the experimental therapeutic effect of olive leaves polyphenols in DM type 1. Oleuropein is a majority polyphenol in olive leaf extract (lat. Olea europaea L.). Material and methods: Type 1 DM was chemically induced in male Wistar rats by intraperitoneal injection of streptozotocin. The purpose of this study was to determine the level of glutamate in the liver of diabetic rats and to compare it to the level of glutamate in the liver of diabetic rats post-treated with different concentrations of polyphenols olive leaf extract (512 mg/kg, 768 mg/kg and 1024 mg/kg). The concentration of glutamate was determined spectrophotometrically in 20% liver homogenate while polyacrylamide gel, sodium dodecyl sulphate (SDS-PAGE) was used to separate the proteins and to determine the difference in the expression of the same in the experimental groups. Results: The increased levels of glutamate were established in the liver of diabetic rats. In groups of animals with short diabetes (8 days), glutamate concentration was proved to be lower compared to a group of animals with long-term diabetes (30 days). Furthermore, the results showed a significantly lower concentration of glutamate in the liver of post-treated animals with olive leaf extract in a dose-dependent manner.

type 1 diabetes mellitus ; olive leaf polyphenols ; oleuropein ; liver ; glutamate

This work was supported by the University of Rijeka under the project number 13.11.1.2.02.