| Popis: |
In ethnomedicine, olive leaf is used as antidiabetic agent. It is well known that hyperglycemia produces oxidative stress in organism. Oxidative stress has deleterious effects on many organs and tissues, hepatic cells being one of the main targets. Therefore, we have investigated the effects of the olive leaf extracts on the levels of extracellular lactate dehydrogenase (LDH) as well as intracellular glutathione (GSH) and glutathione S-transferase (GST) in Hep G2 cells in hyperglycemic conditions. Moreover, antioxidant activity, content of phenolic compounds and -amylase inhibitory activity of the extracts was investigated. The extract were prepared using 70% ethanol at 25 C (E1) and 100% ethanol at 20 C and 60 C (E2 and E3, respectively). The prepared extracts were rich in phenolic acids, flavonoids and other polyphenols as determined spectrophotometrically. In addition, all the extracts demonstrated notable antioxidant activities. However, neither of the extracts has shown any -amylase inhibitory activity. The activity of the extracts in HepG2 cells was dependant on the method used for its preparation. E1 has shown membrane protective properties as seen in lower amount of extracellular LDH, even in comparison to non-hyperglycemic conditions. Moreover E1 and E3 were able to restore GSH concentration to the levels of non-hyperglycemic conditions. Finally, all the investigated extracts were capable of increasing the GST activity in Hep G2 cells. It can be concluded that olive leaf and its extracts can offer benefits as adjuvant therapy in diabetes. |
