Extraction and characterization of alpha-amylase inhibitor from some cereals and legumes

Alpha-amylase inhibitor extracted from different sources, i.e., wheat grains [Sohag 2 and Giza 164], legume seeds such as cow pea [Carim 7 and Giza 3], and kidney bean [Giza 6 and Giza 133] was purified and tested for activity using human salivary and pancreatic alpha-amylase. Results showed that the alpha-amylase inhibitor activity from samples studied were 120 to 285 unit / mg protein. The inhibitor was found to be stable at pH range from 2 to 4. It was also stable to digestion by proteolytic enzymes [pepsin and trypsin]. The inhibition was faster at 37°C than at 25°C, The results showed that the degree of thermal stability of alpha-amylase inhibitor extracted from kidney bean [Giza 133] was at 35-37°C, activity was decreased on 50°C for 5 hr. Increased of pre-incubation time between inhibitor and both alpha-amylase enzymes at 37°C increased the rate of inhibition of these enzymes and the complex formation between them from 60 - 80% in 30 min, while addition of these enzymes to the mixture containing inhibitor and substrate [without pre-incubation] decrease the percent inhibition. Therefore, an evidence of specific interference of the alpha-amylase inhibitor with starch availability was established. Such possibilities will have valuable interest in the field of special dietary food preparations for diabetes and over weight reduction purposes

Chemical composition and characteristics of alpha-amylase inhibitor

In this study chemical constituents and characteristics of alpha amylase inhibitor extracted from kidney bean Giza 133 and wheat Giza 164 were studied. Results indicated that the purified alpha amylase inhibitors of kidney bean Giza 133 contained more total carbohydrate content [14.4%] than wheat Giza 164 [1.2%], in addition to the differences in amino acid content for both samples. The alpha amylase inhibitor characteristics indicated that the molecular weight of kidney bean Giza 133 [47.000 Da] was higher than both wheat Giza 164 [24.000 Da] and human salivary alpha-amylase [32.000 Da] and lower than enzyme-inhibitor complex [61.000 Da]. The low activity of both human and pancreatic alpha amylase was achieved using low concentration of kidney bean inhibitor [1.56 and 1.95 UI] compared with higher concentration [4.69 and 5.47 UI] of wheat Giza 164. The addition of salt [NaCl and bromide] in the purification step increased the inhibitor activity up to 80, 91%, and the inhibitor reaction rate reached maximum at ratio 1:1 [Inhibitor [I]: Enzyme [E]]. Results also indicated that the low dissociation constant of kidney bean inhibitor gave stability to the I-E complex at pH 6.9. Increasing the pH values prevent further inhibition and the reaction is irreversible, while raising the temperature up to 37°C reverse the inhibition reaction to its primary rate

Biological evaluation of the purified alpha amylase inhibitor from kidney bean [Giza 133]

The biological evaluation of the purified alpha amylase inhibitor of kidney bean [Giza 133] by using rats was carried out. Results showed that all rats gained weight at different levels. Rats in control groups gained more weight [64g] and faster than those with inhibitor. The results indicated that using 200 Ul/100g: diet was economically recommended. Diets supplemented with .200:Ul increased BV, NPU by [16%], and reduced starch hydrolysis. Glucose absorption in blood and serum insulin in all digestion hours, with little starch hydrolysis after 4 hr digestion noticed. The results also proved that using alpha amylase inhibitor in diet caused higher level of NEFA, reduction in the rate of forming fatty substances in subcutaneous layers in rats and consequently growing rate was reduced

Synthesis and fungicidal activity of some new imidazoles from 2-[chloromethyl]-1H-benzimidazole

A series of substituted 2-thiomethylbenzimidazoles 2-4, 2-phenoxy-methylbenzimidazoles 5 and 2-aminomethylbenzimidazoles 6 and 7 were synthesized by reactions of 2-chloromethylbenzimidazole 1 with dithiocarbamate, pyrirnidine-2-thiols, phenol derivatives as well as primay aromatic and heterocyclic amines, respectively. Most of the synthesized compounds were screened for their antifungal activity against Botrytis sinerea, Fusarium, solani and Rhizocionia solani fungi. Some of the tested compounds showed 100% inhibition for the fungal growth at concentration ranges from 200-1000 ppm

Synthesis and chemoprophylactic effect of novel coumarin derivatives

A series of coumarin derivatives carrying different biologically active side chains and heterocyclic substituents were synthesized from 8-acetyl-4-methyl-7-hydroxycoumarin. Among these side chains are alkylamino, semicarbazono- and N[4]-substituted thiosemicarbazonoethyl, I-hydrazonoethyl and substituted I-hydroximinoethyl groups, while heterocyclic substituents were derived from pyran, oxadiazole, thiadiazole and thiazolidinone rings. Also, some derivatives of pyrano [2,3-h]chromen-9-carbaldehyde were synthesized. Some of these new products were studied for their chemoprophylactic effect in Schistosoma mansoni infected mice