In vitro evaluation of neuroprotective effects of different sesquiterpenes against alzheimer model

Alzheimer's disease (AD) generally covers 60% of mental disorders and is one of the most important neurodegenerative diseases. In our study, the human neuroblastoma cell line (SH-SY5Y) was transformed into neuron-like cells by applying retinoic acid. In the transformed cells, β-amyloid 1-42 protein (0-200 μM) was applied for 24/48 hours at wide dose intervals to establish the Alzheimer's environment and IC50 values were determined. Next, neuroprotective effect against toxicity generated by administration of four different sesquiterpenes (guaiazulene, eustricine, farnesene, leucomicine) in large doses (0-100 μg/ml) to β-amyloid administered cell medium was examined for 24 and 48 hours. 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) release tests were performed to determine cell viability rates in the in vitro Alzheimer model. Subsequently, the Annexin-V/PI study flow cytometry method was used to determine the type of death caused by toxicity in the cells. Apoptosis and nucleus integritis in the cells were examined under the microscope using the Hoechst 33258 fluorescence staining method. Furthermore, sesquiterpenes effect on acetylcholinesterase (AChE) activity, Total antioxidant capacity (TAC) and Toplam oxidative status (TOS) levels were determined. According to the results, the protective effect of different sesquiterpenes concentrations against β-amyloid for 24 hours and 48 hours was shown by cell viability tests and the result of flow cytometry revealed that sesquiterpenes cause significant decrease in necrosis deaths in cells. It was further analyzed that the AchE activity, the TOS level and the TAC level decreased after sesquiterpene application. Our findings show that the sesquiterpenoid activities tested against anti-alzheimer potentials are ranked as guaiazulene>eustricine>farnesene>leucomicine for adminstred doses.