Antidiabetic, neuroprotective and antioxidant potentials of different parts of Pistacia terebinthus fruits
Mehmet Akyüz, Lawali Yabo-Dambagi, Tuğba Kılıç, Ahmet Çakır
Abstract
The antioxidant and enzyme inhibitory effects of hexane, acetone and ethanol extracts of different parts (shells, nuts and whole fruits) of Pistacia terebinthus (terebinth) were determined against α-glucosidase, α-amylase, acetylcholineesterase (AChE) and butyrylcholineesterase (BChE). All extracts exhibited strong inhibitory effect against α-glucosidase with the IC50 values (0.19-2.13 mg/mL) and their inhibition effects were stronger than the acarbose (IC50=10.30 mg/mL). However, all applications of the terebinth fruits acted as much weaker inhibitors against α-amylase with IC50=23.49-243.99 mg/mL in comparision to the acarbose (IC50=0.07 mg/mL). Hexane extracts rich in the vegetable oils exhibited very weak or no inhibition effect against α-amylase however, they were more effective against α-glucosidase. The acetone extract of the fruits shell was found to be most effective against α-glucosidase and α-amylase with IC50=0.19 mg/mL and IC50=23.49 mg/mL, respectively. A major compound was isolated from the acetone extract by silica gel column chromatography and its structure was elucidated as luteolin with 1H-NMR, 13C-NMR, 1D and 2D NMR. Luteolin showed stronger antidiabetic properties than the extracts with lower IC50 values (0.17 mg/mL for α-glucosidase and 9.49 mg/mL for α-amylase). In addition, terebinth extracts and luteolin were found to be very weak neuroprotective agents in comparison to neostigmine and galantamine. The acetone and ethanol extracts, and luteolin exhibited very strong DPPH and ABTS radical scavenging activities. Our results concluded that there is a powerful relationship between luteolin content and biological activities of the terebinth fruits.