English abstract
Abstract
Alzheimer's disease (AD) is the most common type of dementia characterized by loss of memory and factors such as cardiovascular disease, cancer, diabetes and traumatic brain injury, etc., may lead AD, Brain cells damage may be due to the accumulation of the protein Amyloid beta protein (AB) outside nerves cells, which leads to neuronal cell death. The mechanism of aggregation and fibrillization of AB is still unclear. The identification of compounds that can inhibit AB fibrillization is expected to be the possible therapeutic and preventive value in AD. Studies suggest that natural products may delay the risk of AD. Dates palm fruit (Phoenix dactylifera, DPF) have been used in Middle Eastern countries for nutritional/ medicinal purposes and effect of some Omani date palm fruit varieties were showing inhibition for in vitro fibrillization of AB was reported. Up to now no such studies were conducted by using four different growth stages (Khalal, Biser, Rutab and Tamr) of Omani DPF. To fill the information gab, the current study was performed to find out the effect of two DPF varieties for Oman namely Naghal and A'Seedi at their four stages of growth on the inhibition of AB fibrillization under in vitro conditions. AB fibrillization was assessed by using Thioflavin T fluorescence method and the levels of total phenolics content (TPC), total flavonoids content (TFC) and total antioxidant capacity (TAC) of the methanolic extracts of DPF were also analysed for all four stages of both varieties. Our results showed that 20ug of GAE methanolic extract of both DPF varieties offer a variable rate of inhibition of AB fibrillization and displayed the levels of TPC, TFC and TAC in varying levels (P < 0.05). The highest inhibition rate of AB fibrillization was shown in the Khalal stage for Naghal, in the Biser stage for A'Seedi. Our data indicate that Omani dates palm fruit offer anti-amyloidogenic activity, which may be due to their polyphenolic compounds. However, the exact mechanism is still unknown and further preclinical and clinical studies are warranted.
