Inhibitory effect of Portulaca ‎oleracea L. Extract against the ‎Lysozyme fibrillation and its ‎possible role in ameliorate of ‎neurodegenerative diseases

One of the main features of neurodegenerative disorders such as Alzheimer's disease (AD) is the amyloid aggregation of specific proteins in the brain tissue. Inhibition of protein misfolding and aggregation is results of utmost importance in the prevention and treatment of such diseases. In the experimental present study the possible effects of Portulaca oleracea extract on amyloid fibrillation of hen egg white lysozyme (HEWL) as a protein model and possible its role in treatment of amyloidosis diseases were explored. Lysozymal amyloid was prepared in the harsh condition such as acidic pH and high temperature and confirmed by various techniques including Congo red (CR), Thioflavin T (ThT) binding assays and atomic force microscopy. Data were analyzed through SPSS 16 using descriptive statistics as well as independent t-test. The collected and dried Portulaca oleracea was first dechlorophyllized and then its hydroalcoholic extract was obtained. The extract was concentrated and  dried for 48 h, then stored at -20º. This studies by ThT showed that, amyloid formation in the presence of Portulaca oleracea extract significantly (p˂0.05) in a concentration-dependent manner was inhibited. The Amyloid formation inhibition in presence of the extract also were confirmed by Congo red assay and AFM images. Both Intrinsic and ANS fluorescence showed that inhibition effect of the extract is not due to stabilization of native structure of the protein. The results suggested that aromatic compounds in the extract may directly insert into amyloidogenic core of aggregates and disrupt pi-pi stacking interactions and thus inhibit amyloid fibril formation. These results may ultimately find applications in the development of potential inhibitors against amyloid fibril formation and its biologically adverse effects.