Optimisation of alpha-amylase inhibitor production in solid state fermentation

Though not a known producer of alpha-amylase inhibitor, the potential of Streptomyces xinghaiensis AAI-2 to produce this important metabolite was assessed and the process optimised in solid substrate using response surface methodology. The isolate was grown in an inoculum medium, inoculated into wheat bran and supplemented with a basal medium for production of alpha amylase inhibitor. Optimum conditions were determined by Response Surface Methodology. The extract was recovered using sodium phosphate buffer at refrigerated temperature and assay for the presence of alpha-amylase inhibitor was carried out by Dinitrosalicylic acid method. Based on the results of the experimental trials and iteration with those values, it was predicted that optimal pH for alpha-amylase inhibitor production using S. xinghaiensis in solid culture of wheat bran was pH 6.4-6.9 while optimal moisture content and incubation time were predicted as 71%-73% and 9-12 days respectively.

An Insight of Alpha-amylase Inhibitors as a Valuable Tool in the Management of Type 2 Diabetes Mellitus

BACKGROUND

Among the millions of people around the world, the most prevalent metabolic disorder is diabetes mellitus. Due to the drawbacks which are associated with commercially available antidiabetic agents, new therapeutic approaches are needed to be considered. Alpha-amylase is a membrane- bound enzyme which is responsible for the breakdown of polysaccharides such as starch to monosaccharides which can be absorbed.

METHODS

We searched the scientific database using alpha-amylase, diabetes, antidiabetic agents as the keywords. Here in, only peer-reviewed research articles were collected which were useful to our current work.

RESULTS

To overcome the research gap, the alpha-amylase enzyme is regarded as a good target for antidiabetic agents to design the drug and provide an alternate approach for the treatment of type 2 diabetes mellitus. Basically, alpha-amylase inhibitors are classified into two groups: proteinaceous inhibitors, and non-proteinaceous inhibitors. Recently, non-proteinaceous inhibitors are being explored which includes chalcones, flavones, benzothiazoles, etc. as the potential antidiabetic agents.

CONCLUSION

Herein, we discuss various potential antidiabetic agents which are strategically targeted alpha-amylase enzyme. These are having lesser side effects as compared to other antidiabetic agents, and are proposed to prevent the digestion and absorption of glucose leading to a decrease in the blood glucose level.

Development of a Novel Series of Anticancer and Antidiabetic: Spirothiazolidines Analogs

4-(4-Aminophenyl)-1-thia-4-azaspiro[4.5]decan-3-one 1 was prepared and allowed to react with nitrogen nucleophiles to give the corresponding hydrazones 2–4. Further, compound 1 underwent diazotization and afforded the parallel hydrazono derivative 5; moreover, compound 1 refluxed with active methylene derivatives yielded the corresponding aminospirothiazolo pyridine–carbonitrile derivative 6 and spirothiazolopyridinone–carbonitrile derivative 7. Condensation of spirothiazolidine 1 with 4-chlorobenzaldehyde gave the corresponding spiro arylidiene derivative 8, which was utilized as a component of Micheal addition to react with excess of nitrogen nucleophiles to yield novel ring frameworks 4-(3′-(4-chlorophenyl)–spiro [cyclohexane-1,5′-pyrazolo[3,4-d]thiazol]-6′(1′H)-yl)aniline (9) and 4-(3′-(4-chlorophenyl)-6′H- spiro[cyclohexane-1,5′-thiazolo[5,4-d]isoxazol]-6′-yl)aniline (10). Finally, when spirothiazolo pyridinone–carbonitrile derivative 7 sodium salt generated in situ was reacted with different alkyl halides, it produced the corresponding N-derivatives 12–16. Three compounds, 6, 14, and 16, showed high significantly anticancer activities compared with Doxorubicin® (positive control) against human breast carcinoma (MCF-7) and human liver carcinoma (HepG-2) cell lines. On the other hand, compounds 6 and 9 showed higher therapeutic indices for both of alpha-amylase inhibitor and alpha-glucosidase inhibitor than the other tested compounds compared with the antidiabetic Acarbose (positive control).

Systematic Review and Meta-Analysis of a Proprietary Alpha-Amylase Inhibitor from White Bean (Phaseolus vulgaris L.) on Weight and Fat Loss in Humans

The aim of this meta-analysis was to examine the evidence for the effectiveness of a proprietary alpha-amylase inhibitor from white bean (Phaseolus vulgaris L.) supplementation interventions in humans on modification of body weight and fat mass. A systematic literature search was performed using three databases: PubMed, the Cochrane collaboration, and Google Scholar. In addition, the manufacturer was contacted for internal unpublished data, and finally, the reference section of relevant original research and review papers were mined for additional studies. Eleven studies were selected for the meta-analysis of weight loss (a total of 573 subjects), and three studies for the meta-analysis of body fat reduction (a total of 110 subjects), as they fulfilled the inclusion criteria. Phaseolus vulgaris supplementation showed an average effect on weight loss difference of −1.08 kg (95% CI (confidence interval), −0.42 kg to −1.16 kg, p < 0.00001), and the average effect on body fat reduction was 3.26 kg (95% CI, −2.35 kg to −4.163 kg, p = 0.02). This meta-analysis found statistically significant effects of Phaseolus vulgaris supplementation on body weight and body fat.

Wheat allergy in children - new tools for diagnostics

BACKGROUND

The detection of wheat-specific IgE in children often leads to a suspicion of wheat allergy, but little information is available on the most reliable wheat allergens for predicting clinical reactivity.

OBJECTIVE

To evaluate the role of allergenic components of wheat in wheat allergy diagnostics.

METHODS

One hundred and eight children (median age 1.5 years; range 0.6-17.3 years) with suspected wheat allergy underwent open or double-blinded, placebo-controlled oral wheat challenges. Responsiveness to different allergenic components of wheat was studied by skin prick tests and by determination of serum IgE antibodies using a semi-quantitative microarray assay.

RESULTS

Thirty (28%) children reacted with immediate symptoms, and 27 (25%) with delayed symptoms to ingested wheat, whereas 51 (47%) children exhibited no reactions in oral wheat challenges. Positive IgE responses to any of the 12 allergenic components of wheat was seen in 93%, 41%, and 43% of those with immediate, delayed or no reactions to ingested wheat, respectively (P < 0.001 to P < 0.05 in every comparisons between those with immediate reactions and those with no reactions). Positive IgE responses to ≥5 different allergenic components improved significantly the diagnostic accuracy (with a positive likelihood ratio (LR+) of 5.10). Alpha-amylase inhibitors (AAI), in particular dimeric AAI 0.19 (LR+ 6.12), alpha-, beta-, and gamma-gliadins (LR+ from 3.57 to 4.53), and high-molecular-weight (HMW) glutenin subunits (LR+ 4.37) were the single allergenic components of wheat differentiating most effectively those with immediate symptoms from those who did not exhibit any reactions.

CONCLUSIONS AND CLINICAL RELEVANCE

Wheat allergy diagnostics is difficult, even using sophisticated component methods. Our results confirm earlier findings about gliadins and identify the dimeric AAI 0.19, as a relevant allergen in clinically reactive patients when compared to non-reactive subjects. The accuracy of wheat allergy diagnosis may be improved by measuring IgE responses to several components of wheat.

Component-resolved diagnosis of baker's allergy based on specific IgE to recombinant wheat flour proteins

BACKGROUND

Sensitization to wheat flour plays an important role in the development and diagnosis of baker's asthma.

OBJECTIVES

We evaluated wheat allergen components as sensitizers for bakers with work-related complaints, with consideration of cross-reactivity to grass pollen.

METHODS

Nineteen recombinant wheat flour proteins and 2 cross-reactive carbohydrate determinants were tested by using CAP-FEIA in sera of 101 bakers with wheat flour allergy (40 German, 37 Dutch, and 24 Spanish) and 29 pollen-sensitized control subjects with wheat-specific IgE but without occupational exposure. IgE binding to the single components was inhibited with wheat flour, rye flour, and grass pollen. The diagnostic efficiencies of IgE tests with single allergens and combinations were evaluated by assessing their ability to discriminate between patients with baker's allergy and control subjects based on receiver operating characteristic analyses.

RESULTS

Eighty percent of bakers had specific IgE levels of 0.35 kUA/L or greater and 91% had specific IgE levels of 0.1 kUA/L or greater to at least one of the 21 allergens. The highest frequencies of IgE binding were found for thiol reductase (Tri a 27) and the wheat dimeric α-amylase inhibitor 0.19 (Tri a 28). Cross-reactivity to grass pollen was proved for 9 components, and cross-reactivity to rye flour was proved for 18 components. A combination of IgE tests to 5 components, Tri a 27, Tri a 28, tetrameric α-amylase inhibitor CM2 (Tri a 29.02), serine protease inhibitor-like allergen (Tri a 39), and 1-cys-peroxiredoxin (Tri a 32), produced the maximal area under the curve (AUC = 0.84) in receiver operating characteristic analyses, but this was still lower than the AUC for wheat- or rye flour-specific IgE (AUC = 0.89 or 0.88, respectively).

CONCLUSIONS

Component-resolved diagnostics help to distinguish between sensitization caused by occupational flour exposure and wheat seropositivity based on cross-reactivity to grass pollen. For routine diagnosis of baker's allergy, however, allergen-specific IgE tests with whole wheat and rye flour extracts remain mandatory because of superior diagnostic sensitivity.

Acute effect of Ceylon cinnamon extract on postprandial glycemia: alpha-amylase inhibition, starch tolerance test in rats, and randomized crossover clinical trial in healthy volunteers

BACKGROUND

Postprandial hyperglycemia is a known risk factor for the development of several health disorders including type 2 diabetes, obesity, oxidative stress, and cardiovascular diseases. One encouraging approach for a better control of postprandial glycemia is to reduce carbohydrate digestion. Cinnamon extracts have been known for managing blood glucose. However, their effects on inhibiting digestion of carbohydrate have been poorly analyzed to date. The aim of this study was to investigate the acute effect of a specific Ceylon cinnamon hydro-alcoholic extract (CCE) on carbohydrate digestion and post-meal blood glucose reduction.

METHODS

In vitro enzymatic assays and in vivo starch tolerance tests in rats were designed as preclinical assays. Then, a randomized, double-blind, placebo-controlled, cross-over clinical trial was conducted in 18 healthy female and male volunteers. Following the intake of 1 g of CCE, the subjects ate a standardized meal. Blood samples were collected during the 2 hours following the meal to measure glucose and insulin concentrations. Areas under the curves were calculated and statistical differences between the CCE and placebo groups were analyzed using the Mann Whitney-Wilcoxon test.

RESULTS

CCE has demonstrated in the in vitro study that it inhibited pancreatic alpha-amylase activity with an IC50 of 25 μg/mL. In the in vivo study, CCE was shown to acutely reduce the glycemic response to starch in a dose-dependent manner in rats. This effect was significant from the dose of 12.5 mg/kg of body weight. In both, the in vitro and in vivo studies, the hydro-alcoholic extract has shown to be more efficacious than the aqueous extract. In the human clinical trial, 1 g of CCE lowered the area under the curve of glycemia between 0 and 120 min by 14.8% (P = 0.15) and between 0 and 60 min by 21.2% (P < 0.05) compared to the placebo. This effect occurred without stimulating insulin secretion. No adverse effects were reported.

CONCLUSION

These results suggest that Ceylon cinnamon hydro-alcoholic extract (CCE) may provide a natural and safe solution for the reduction of postprandial hyperglycemia and therefore help to reduce the risks of developing metabolic disorders.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02074423 (26/02/2014).

Phaseolamin treatment prevents oxidative stress and collagen deposition in the hearts of streptozotocin-induced diabetic rats

The development of cardiovascular complications in patients with diabetes is often associated with an imbalance between reactive oxygen species and antioxidant systems. This imbalance can contribute to high cardiac collagen content, which increases cross-linking and the stiffness of the myocardium. In this study, the protective effect of phaseolamin against damage under oxidative stress and collagen deposition in the cardiac tissue in association with diabetes was evaluated. Non-diabetic and diabetic animals were distributed into groups and treated for 20 days with commercial phaseolamin. The phaseolamin treatment increased total antioxidant activity but reduced the following in diabetic rats: (a) hyperglycaemic state, (b) catalase and superoxide dismutase activity and (c) tissue damage caused by lipid peroxidation. Additionally, the phaseolamin treatment attenuated the collagen levels compared to non-treated diabetic rats. Thus, the short-term anti-hyperglycaemic effect of the phaseolamin treatment may prevent the initial changes caused by oxidative stress and the deposition of collagen, as well as reduce the incidence of heart complications.