An Standardized Extract from Textured Soy Protein (Glycine Max L.) Has Ameliorating Effect on Memory Deficit and Learning Insufficiency in Scopolamine-Induced Amnesia

Purpose of the study: Textured soy protein (TSP) and Ajil are two processed forms of soybean (Glycine max L.) which are widely consumed by Iranian for nutritional purpose. Recently, we have reported antioxidant and anticholinesterse effect of raw soybean (RS) which has been attributed to isoflavones such as genistein. In this work, we aimed to compare in vitro antioxidant and antichoinesterase effects of TSP, Ajil and RS to select the most effective one for learning capacity and spatial memory studies. Method: Genistein content was determined using high performance thin layer chromatography (HPTLC) while diphenylpicrylhydrazil (DPPH) radiacal scavenging and ferric reducing antioxidant power (FRAP) were used for antioxidant evaluation study and Ellman's colorimetry method was used for anticholinesterase assay. TSP extract (TSPE) was administered to male rats (100, 200 and 400mg/kg, i.p for 7 days) before scopolamine (1mg/kg) injection. Learning capacity and spatial memory was evaluated by passive avoidance test (PAT) and Morris water maze (MWM) methods compared to physostigmine and piracetam. Results: The greatest antioxidant and anticholinesterase effect was observed for TSPE which significantly prolonged initially latency in PTA (p<0.05) and improved all indicators in MWM test at 200mg/kg. Conclusion: The memory improving effect of TSPE might be due to its antioxidant and anticholinesterase effect as well as neuroprotective effects of its isoflavones.