Ameliorating Effect of Standardized Extract From Textured Soy Protein (Glycine max L.) on Memory Deficit and Learning Insufficiency in Scopolamine-induced Amnesia

INTRODUCTION: Textured soy protein (TSP) and nuts are two processed forms of soybean (Glycine max L.) that are widely consumed for nutritional purposes in Iran. Recently, we have reported the antioxidant and anticholinesterase effects of raw soybean (RS) attributed to isoflavones, such as genistein. In this work, we aimed to compare in vitro antioxidant and anticholinesterase effects of TSP, nuts, and RS to select the most effective one for learning capacity and spatial memory studies. METHODS: Genistein content was determined using high-performance thin layer chromatography (HPTLC), while diphenylpicrylhydrazil (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) were used to study antioxidant evaluation and Ellman’s colorimetric method was used to measure anticholinesterase. TSP extract (TSPE) was administered to male rats (100 mg/kg, 200 mg/kg and 400 mg/kg, intraperitoneally [i.p] for 7 days) before scopolamine injection (1 mg/kg). Learning capacity and spatial memory were evaluated using 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 the MWM test at 200 mg/kg. CONCLUSION: The memory-improving effect of TSPE may be due to its antioxidant and anticholinesterase effect as well as neuroprotective effects of its isoflavones. HIGHLIGHTS: Different samples (nuts-raw soybeans-TSP) prepared from soybeans. All samples exhibited antioxidant and anti-cholinesterase effects in vitro studies. TSP showed the most biological activity and the greatest genistein content. TSP significantly improved memory and learning indicators at 200 mg/kg. These effects are attributed to its antioxidant and anticholinesterase activity. Plant isoflavones have neuroprotective effects. PLAIN LANGUAGE SUMMARY: Alzheimer's disease (AD), is one of the problems of the elderly society, which has a lot of emotional and financial costs. AD is a type of progressive brain disease in which neurons are destroyed and memory is lost. This disease currently has no definitive treatment and the only way is to prevent the disease from spreading. Much research has been devoted to finding suitable and effective treatments for AD. Many food and herbal medicines have shown to be effective in controlling this disease. Soybean is a plant that is widely used as food and snacks in Iran in different ways. In this study, we prepared three preparation from soya beans which have been widely used by Iranian people including raw soya, nut (roasted form) and textured soy protein (TSP). The effect of these preparations have been studied on memory and learning in amnestic rats through different pharmacological studies. The results indicated that TSP due to antioxidant and anticholinesterase activity significantly can augment memory enhancing and learning ability Alzheimer's disease (AD), is one of the problems of the elderly society, which has a lot of emotional and financial costs. AD is a type of progressive brain disease in which neurons are destroyed and memory is lost. This disease currently has no definitive treatment and the only way is to prevent the disease from spreading. Much research has been devoted to finding suitable and effective treatments for AD. Many food and herbal medicines have shown to be effective in controlling this disease. Soybean is a plant that is widely used as food and snacks in Iran in different ways. In this study, we prepared three preparation from soya beans which have been widely used by Iranian people including raw soya, nut (roasted form) and textured soy protein (TSP). The effect of these preparations have been studied on memory and learning in amnestic rats through different pharmacological studies. The results indicated that TSP due to antioxidant and anticholinesterase activity significantly can augment memory enhancing and learning ability. TSP also contains some phytochemicals such as phytoestrogens which have shown neuroprotective activity in different studies.