جستجوی مقالات مرتبط با کلیدواژه "alpha- amylase" در نشریات گروه "پزشکی"

The study focused on the amylase enzyme, widely used in the industrial starch liquefaction process. We looked into the best way to immobilize the native strain Bacillus licheniformis, which is the only alpha-amylase-producing bacterium, by trapping it in calcium alginate gel. This is a promising way to increase enzyme output.

We examined the effects of alginate content, biomass age, initial cell loading (ICL), bead size, and solidification duration in calcium chloride solution on enzyme synthesis. We conducted batch fermentations using both immobilized and free cells.

Alpha-amylase production significantly increased with the alginate concentration ratio, achieving a maximum enzyme yield of 23.5 U/mL at a 30 g/l alginate concentration, utilizing an initial cell loading of 1.5 g in 150-200 beads per flask. These involved cells from a 12-hour culture with a bead size of 5.0 mm, were solidified for 24 hours in a 2.5% (w/v) calcium chloride solution. The yield of the immobilized cells was approximately 111.71% higher than that of the free cells, which produced 11.1 U/ml. The immobilized cells consistently generated alpha-amylase over five repeated cycles, attaining a peak value of 23.5 U/ml during the first cycle, which was 2.2-fold more than the control (free cells).

We used a basic mass balance analysis to understand the growth of both fractions and the dynamics of amylase production in free cells and cells immobilized in Ca-alginate beads. The production of alpha-amylase in immobilized cells results in enhanced volumetric activities during fermentation. Notable advantages of this technique encompass prolonged stability, reuse and recycling, and the potential for adaptable regeneration.

Diabetes mellitus is a persistent hyperglycemic condition. Thai cuisine and medicine incorporate spices: nutmeg, mace, clove buds, cardamom, cinnamon, and coriander. The in vitro impacts of these spices on anti-diabetic, antioxidant, anti-inflammatory, and total phenolic and flavonoid content were assessed.

Experimental approach: 

Alpha-amylase and alpha-glucosidase inhibition assays were conducted. Antioxidant potential was measured through DPPH and ABTS assays. Anti-inflammatory activity was determined by inhibiting nitric oxide generation in RAW 264.7 cells. Total phenolic content was quantified using the Folin Ciocalteu method, while total flavonoid content was estimated via the aluminum chloride colorimetric method.

Ethanolic and aqueous extracts of a blend of spices (Siam cardamom, nutmeg, mace, and clove buds), denoted as 4-GlurE and 4-GlurA, displayed concentration-dependent inhibition of alphaglucosidase, with IC50 values of 0.373 and 0.435 mg/mL, respectively. 4-GlurE and 4-GlurA exhibited antioxidant activity, by ABTS•+ radical and DPPH scavenging capabilities. 4-GlurE demonstrated antiinflammatory potential by reducing nitric oxide generation (IC50: 43.95 ± 2.47 μg/mL). 4-GlurE and 4-GlurA possessed total phenolic content (TPC) of 122.47 ± 1.12 and 148.72 ± 0.14 mg GAE/g, respectively. 4-GlurE exhibited a higher total flavonoid content (TFC) compared to the aqueous extract (340.33 ± 4.77 and 94.17 ± 3.36 mg QE/g). Cinnamon and clove aqueous extracts were more potent than acarbose in alpha-glucosidase inhibition with the highest antioxidant activity. Polyphenol levels (TPC and TFC) exhibited strong correlations with antioxidant capacity.

Conclusions and implications: 

Findings are consistent with the traditional use of 4-Glur, with cinnamon, for diabetes prevention and treatment.

This study focused on the evaluation of antioxidant and antidiabetic activities of polyherbal extract (PHE), containing Cassia absus (L.), Gymnema sylvestre (R. Br.), Nigella sativa (L.), and Piper nigrum (L.), in alloxan-induced diabetes model.

In vitro, HPLC characterization, DPPH scavenging assay, and α-amylase inhibition test were conducted. In vivo, acute oral toxicity of PHE was assessed. Alloxan-induced diabetic Wistar rats (n=6) were orally treated with PHE (200, 400, and 600 mg/kg/day) and glibenclamide (GLB; 10 mg/kg/day) for six consecutive weeks. Then, biochemical biomarkers, oxidative stress parameters, histopathological examination, and mRNA expression levels (RT-qPCR) were determined.

The presence of polyphenols in PHE was confirmed in correlation to marked DPPH scavenging (IC50: 1.60 mg/ml) and α-amylase inhibition (IC50: 0.82 mg/ml). PHE demonstrated no toxicity in rats up to a dose of 2000 mg/kg. In diabetic rats, PHE dose-dependently ameliorated the serum levels of glucose, insulin, glycated hemoglobin A1c (HbA1c), leptin, and glucokinase (GCK). Also, PHE substantially alleviated serum inflammatory markers (TNF-α and CRP) and oxidative stress indicators (MDA, SOD, and CAT) in pancreatic tissues. PHE, particularly at 600 mg/kg, attenuated cellular oxidative stress via modulating the mRNA expression levels of genes regulating MAPK/JNK (Mapk-8, Traf-4, and Traf-6) and Nrf-2/Keap-1 pathways and promoted insulin signaling through up-regulating insulin signaling cascade (Pdx-1, Ins-1, and Ins-2), as compared to GLB. Furthermore, histopathological findings supported the aforementioned results.

Our study suggests that polyherbal extract has promising antioxidant and antidiabetic activities by modulating the MAPK/JNK, Nrf-2/Keap-1, and insulin signaling pathways.

Anxiety is a significant health issue in mothers who give birth to unhealthy neonates. Different studies have investigated the  relationship between anxiety and alpha-amylase. According to the necessity for psychological care of mothers whose infants are hospitalized in intensive care units and consequently the anxiety that is imposed on mothers due to the condition, this study aims to assess anxiety in these mothers and the relationship between this anxiety and salivary alpha-amylase.

This study was a cross-sectional study conducted at Besat Hospital in Hamadan in 2021. Thirty mothers were enrolled in the study through a census method sampling. The Hamilton questionnaire measured maternal anxiety during the children’s hospitalization period. Salivary alpha-amylase samples were taken from all mothers according to the scientific method, and mothers’ salivary alphaamylase levels were measured. All the gathered data were analyzed using SPSS 21 software. The significant level was considered 0.05 in all comparisons.

The mean age of the 30 mothers was 29.27+6.24 years. The mean score of maternal anxiety was 16.27 + 6.78, and the mean salivary amylase level was 33.02 ± 16.22 U / ml. Fourteen mothers obtained low anxiety scores, 14 had moderate anxiety, and two had severe anxiety. No significant relationship was found between the mean of salivary alpha-amylase at the three levels and anxiety. There was no significant relationship between anxiety level with parent location, age, mother’s level of education, infant gender, and child rank.

According to the results of the present study, there was no significant relationship between the level of alpha-amylase and the level of anxiety in mothers of neonates admitted to the neonatal intensive care unit (NICU), so further researches in similar groups that are in anxious conditions seem necessary.

Alpha-amylase is one of the most widely used enzymes in the starch industry. However, industrial application of soluble alpha-amylase is hampered by changes in pH and temperature (adverse effects on enzyme stability) and activity loss, leading to higher costs. Immobilization of alpha-amylase is an efficient strategy to reduce the enzyme losing and subsequently reduces costs in this regard. Alpha-amylases are immobilized by adsorption, entrapment, covalent attachment, and cross-linking. A barrier in alpha-amylase immobilization is the large size of its substrate, namely amylose and amylopectin. Most of these immobilization methods decrease the affinity of the enzyme for its substrate as well as the maximum rate of reaction (Vmax). This review aims to study different aspects of alpha-amylase including enzyme activity, applications, structure, starch, immobilization methods, and immobilization’s obstacles to improve alpha-amylase efficiency in the industry and also lowering the costs related to providing this enzyme.

Context: 

The growth and production of enzymes by microorganisms depend highly on the compounds and factors entering the system.

The present systematic review aimed to assess the optimized medium content to enhance alpha-amylase production from the microorganisms.

The PubMed, EmbaseWeb of Science, Scopus, and Google Scholar databases were searched from inception to April 2022, restricted to the English language. The reference list of the included studies was cross-checked, and a partial gray literature search was undertaken. Alpha-amylase production from the microorganisms and optimized medium content by statistical design were the key evaluated outcomes.

Among 995 initially gathered litterateurs, 12 studies were included in this review, which involved bacteria (seven studies), yeasts (two studies), fungi (two studies), and protists (one study). The results indicated that the optimized medium composition by statistical design might increase alpha-amylase production.

Growth conditions, including pH, temperature, and starch concentration, are essential to be optimized to improve alpha-amylase yield.

Stress and fear caused by computer games have been shown to have various effects on the cognitive system. This work was aimed to investigate the effects of short-time horror computer games on cognitive indicators.

A total of twenty female subjects were recruited and divided into experimental and control groups. All required tests were performed before and after the intervention (playing or watching horror game) on the control and experimental groups. The saliva samples were collected before and after the intervention to measure levels of cortisol and alpha-amylase. Also, blood was taken before and during the game from each subject to evaluate plasma levels of oxytocin and brain-derived neurotrophic factor. The Brain waveforms were acquired by Emotive brain signal recording device before and after the intervention. Data analysis was conducted using R and MATLAB software.

The cortisol and alpha-amylase levels were shown to significantly increase after the horror game playing. Also, the levels of oxytocin were significantly higher after the experimentation. The levels of brain-derived neurotrophic factor were displayed to reduce after the experimentation. The results of the brainwave analysis revealed that the average stress index was significantly higher, while the average attention index was lower after playing the game. No significant difference in the study variables was observed in the control group.

Horror computer games may have adverse effects on the activity of the stress system in the central nervous system. Fear-induced stress was shown to relatively undermine some cognitive elements.

Statement of the Problem: 

Since children in adulthood are at risk of obesity and caries due to various factors such as diet and poor health habits, these can affect a child's various body systems, including body mass index (BMI) and salivary components, therefore, it is necessary to assess these factors and their relationship in this age group

The aim was to evaluate the association between decayed missing filled teeth index (DMFT), salivary alpha amylase (sAA) level and age-specific BMI in adolescent girls.

A cross-sectional study was conducted on 81 females aged 13-15 years in 3 groups of BMI percentiles; “normal”, “at risk for overweight” and “overweight” (n=27). DMFT was calculated and unstimulated saliva samples were collected. sAA level was measured with a spectrophotometer. Data were analyzed using Kolmogorov-Smirnov test, Kruskal- Wallis and Spearman correlation tests in the software of Statistical Package for the Social Sciences (version 23) at p < 0.05.

The concentration of sAA and Mean DMFT were estimated 1326.56±4.73 U/L and 2.77±2.36, respectively. There was no significant difference in sAA level and Mean DMFT among BMI groups. A positive and significant correlation was found between sAA and DMFT in overweight group (r: 0.46, p = 0.014).

Within the limitation of this study, higher level of sAA may be considered as an indicator for dental caries in overweight adolescent girls.

In Nigeria, the leaves of Manihot esculenta (Crantz) are eaten as vegetables. The leaves are rich in phytochemicals, valuable and natural sources of antioxidants, and are highly useful for human health and disease prevention. This study was aimed to evaluate the in vitro inhibitory effects of two extracts derived from the plant leaves on α-glucosidase and α-amylase. The total flavonoid and phenolic contents of the extracts were also assessed. 

 The leaves of M. esculenta were processed and extracted with ethanol and acetone. The extracts were evaluated for their α-glucosidase and α-amylase inhibitory activities. Also, their total flavonoid and phenolic contents were determined, using standard in vitro assays. 

The ethanol extract exhibited a higher α-glucosidase and α-amylase inhibitory activity than the acetone extract, which positively correlated with their total flavonoid and phenolic contents. In addition, the ethanol extract strongly inhibited the α-glucosidase activity (IC50: 0.77±0.03 mg/mL) than Acarbose (IC50: 1.52±0.14 mg/mL). However, both extracts of ethanol (IC50: 1.29±0.02 mg/mL) and acetone (IC50 1.66±0.05 mg/mL) were less effective in inhibiting  α-amylase compared with that of Acarbose (IC50 0.99±0.02 mg/mL). Comparatively, the percent inhibition of the extracts and Acarbose were in this order: ethanol extract > Acarbose > acetone extract.

The results suggest that the extract of M. esculenta leaves have anti-hyperglycemic effects. They are potential alternative antioxidants that could be used to reduce oxidative stress in the body and in the management of diabetes.

Alpha-amylase reputes for starch modification by breaking of 1-4 glycosidic bands and is widely applied in different industrial sectors. Microorganisms express unique alpha-amylases with thermostable and halotolerant characteristics dependent on the microorganism’s intrinsic features. Likewise, genetic engineering methods are applied to produce enzymes with higher stability in contrast to wild types. As there are widespread application of α-amylase in industry, optimization methods like RSM are used to improve the production of the enzyme ex vivo. This study aimed to review the latest researches on the production improvement and stability of α-amylase.

Physiological stress due to physical activity associated with mental stress can affect the responses of the sympathoadrenal axis and the hypothalamic-pituitary axis.

The present study aimed to investigate the effect of exercise with mental stress on cortisol and alpha-amylase changes in young men.

In a quasi-experimental study, 20 inactive healthy men were randomly selected and divided into two groups of exercise and exercise with mental stress. The exercise group pedaled on a fixed bike at an intensity of 60% of maximal aerobic power for 37 minutes and the exercise group with mental stress received 20 minutes of mental stress (from 12th minutes to 32nd minutes) during the 37 minutes of pedaling. Salivary samples were collected before and immediately after the end of the exercise.

The exercise had a significant effect on increasing salivary cortisol (P = 0.007) and alpha-amylase (P = 0.01). Exercise with mental stress had a significant effect on salivary cortisol (P = 0.004) and alpha-amylase (P = 0.04). The exercise and exercise with mental stress had the same effects on increasing salivary cortisol (P = 0.42) and alpha-amylase (P = 0.83).

It seems that exercise and exercise with mental stress have the same effects on increasing salivary cortisol and alpha-amylase levels.

 Diabetes mellitus is a metabolic disease characterized by hyperglycemia resulting from either defect in insulin secretion, insulin action, or both. Postprandial hyperglycemia is a prime characteristic of diabetes mellitus and has been a focus in the therapy for diabetes. One of the therapeutic approaches which involve decreasing hyperglycemia aims at lowering blood glucose by decreasing insulin resistance, raising insulin sensitivity at the tissues and inhibiting the carbohydrate absorbance in the intestine. Plants contain different chemical constituents with potential for insulin mimetic action, decrease in insulin resistance and of α-amylase inhibitory activity may be used as therapeutic agents in the treatment of diabetes mellitus. The present study investigates the hypoglycemic activity and insulinomimetic action of aqueous and ethanolic extracts of Citrullus colocynthis by invitro α-amylase enzyme inhibition and by histopathological studies in streptozotocin (STZ) induced diabetic rats. Male Wistar rats weighing about 180- 250g were taken and divided into fifteen groups. Diabetes was induced by giving streptozotocin (STZ) (30-50mg/kg) intraperitoneally. Rats that showed blood glucose levels > 250mg/dl were selected for the study. Metformin (45mg/kg) was given as standard oral hypoglycemic agent. The aqueous and ethanolic extracts of Citrullus colocynthis (AECC and EECC) at 100mg/kg, 200mg/kg and 300mg/kg were administered to the normal and diabetic rats. The invitro α – amylase inhibitory activity was done by spectrophotometric method. Blood glucose levels were measured by glucose oxidase method. Estimation of glycogen in the lever was carried out with anthrone method. Liver and pancreas were isolated and subjected to histopathological studies. Serum insulin was monitored through chemiluminescence assay. Oral administration of both extracts showed significant inhibition of α-amylase enzyme in-vitro and decrease in blood glucose also. Glycogen and Insulin levels too were found to increase in extract treated groups which attributed for its insulinomimetic activity. The findings revealed that Citrullus colocynthis possess a very strong anti-hyperglycemic potential justifying the use of the drug for the treatment of diabetes mellitus.

The anxiety of dental conditions is very common. Salivary alpha amylase (SAA) enzyme, as a non-invasive biomarker, is considered in assessing dental anxiety.
The present study aimed at investigating the relationship between salivary alpha amylase level and dental anxiety before and after dental restoration.
In this longitudinal study, which was performed in Babol dental faculty during 2015 and 2016, a total of 99 patients (50 females and 49 males) were selected using simple sampling method. To measure anxiety, the patients completed modified dental anxiety scale (MDAS) and demographic questionnaire. Unstimulated whole saliva was collected 3 times: at the day of dental examination in a stress- free condition; immediately before dental restoration; and 15 minutes after dental restoration. Salivary alpha amylase activity was measured by the Caraway starch-iodine modified method. SPSS 20 software and t test, chi square, Pearson correlation, and ANOVA repeated measurement were used for data analysis.
Levels of salivary alpha amylase increased before dental restoration and reduced after dental restoration (P value 0.05).
Salivary alpha amylase can be used as a reliable objective tool for measuring anxiety of dental treatment.