Study of the characteristics and effects of amylase inhibitors present in the seeds of the red bean Phaseolus vulgaris

Cereal and legume kernels contain many α-amylase inhibitors which have the potential to inhibit the α-amylase activity from various sources. The subject of this study was the partial purification of α-amylase inhibitors of red bean seeds. To this end, extractions were carried out in three parts with different saturation percentages of ammonium sulfate. Iin order to remove ammonium sulfate and monitor the inhibitory activity of the extracts on Aspergillus oryzae α-amylase, dialysis was carried out. By assaying the rate of inhibitory activity of each sample on the basis of their absorbance in 540 nm and comparison to absorbance of negative control, it was observed that only (30-60)% fraction of each extract had inhibitory activity on the α-amylase. Inhibitory effect of these fractions for red bean extract were calculated to be 89.32 %. For further characterization of these inhibitors, HPLC and SDS-PAGE analyses were carried out. By assaying the activity of these inhibitors on other α-amylases such as salivary and pancreatic α- amylases, it may be feasible to use these- amylase inhibitors similar to other inhibitors such as Acarbose and Miglitol, for the treatment of type II diabetes. The results may also be applicable in agriculture in the design of transgenic plants that express α-amylase inhibitors against α-amylases of pests.