Study of ?-Amylase Inhibitors among Different Bean Cultivars and Evaluation of their Effectiveness Compared with a Commercial Product using In Vitro/In Vivo Experimental Systems
Author(s): Fatemeh Ghorbani, Masoud Sadeghi, Abbas Aghaie, Arezou Ghahghaei, Cyrus Jalili, Reza Khodarahmi
Plant alpha-amylase inhibitors (αAIs) are great potential tools to manipulate resistance of crop plants against pests. They can be also considered as drug-design aims for remedy of diabetes and digestion disorder. In this study, extract of Phaseolusvulgaris L. (Red, Pinto, White and Cowpea Beans) was investigated. The rich part of αAI was almost purified by ethanol fractionation, and then studied in reaction with pancreatic α-amylase in vitro. The study of thermal stability, hemagglutination and measurement of the inhibitory activity of extracts of Red, Pinto, white and Cowpea beans were investigated. Also, an in vivo assay (acute and chronic) over 21 days performed (acute and chronic). Among the αAIs extracted from the beans that were loaded at the same concentration, the α-amylase extracted from White beans (lane C) had the highest match with peptide fractions 14 and 18 kDa and two fractions around 27 to 32 kDa. All fractions of common bean extract showed inhibitory activity. The White beans, Red beans, and Pinto beans extract revealed high inhibitory activity, similar to each other against pancreatic α-amylase. After 21 days of treatment, group 3 showed significant decreases in blood glucose level, compared to positive control. Length of the small intestine in group 1, over 21 days, significantly reduced relative to the negative control, but in group 4, the reduction was lower relative to negative control. The high inhibitory activity of fraction 3 from the beans showed that the ethanol fractionation is the proper techniques to (partially) purify the αAI from Pharsalus vulgarised. The results of this study have reported that the fraction 3, extracted from White beans, can be considered as raw material for pharmaceutical preparation of αAI to control the levels of glycemia, after successful optimizing formulation conditions to increase the half-life of the product.