Determination of total flavonoids content in buckwheat and inhibition of α-amylase activity

Diabetes is one of the most difficult chronic diseases to cure in the world,which seriously affects people’s health and quality of life.Flavonoids in buckwheat can regulate blood glucose levels by inhibitingα-amylase activity.Therefore,sweet buckwheat produced in Inner Mongolia was used as the research object,and buckwheat fl avonoids were extracted by ultrasonic-assisted extraction method.Total fl avonoids content was determined by ultraviolet-visible spectrophotometry.With acarbose as the positive control,the inhibition test ofα-amylase was carried out by DNS colorimetry to study the inhibition behavior of fl avonoids onα-amylase activity.The results showed that the extraction process of flavonoids was stable and reliable,and the established method for the determination of flavonoids was simple,accurate and reproducible.The total flavonoids content of buckwheat samples was 2.706 mg/g,buckwheat total fl avonoids extraction solution had an inhibitory eff ect onα-amylase,and its median inhibition concentration(IC_(50))was 38.53 mg/mL.The results of this experiment provide a technical reference for the development and utilization of fl avonoids in Inner Mongolia sweet buckwheat,and provide a theoretical reference for the development and application of flavonoid-rich hypoglycemic food.

Comparative analysis of physicochemical properties,ginsenosides content andα-amylase inhibitory effects in white ginseng and red ginsen

Ginseng(Panax ginseng C.A.Meyer)as a common dietary adjunct is widely applied in Traditional Chinese Medicine due to its health-promoting properties,but the differences between white ginseng and red ginseng was rarely studied.In the present study,color parameters and scanning electron microscope(SEM)were determined to evaluate the differences of ginseng color and microstructure induced by processing procedure.Quantitative analysis of multi-components by a single-marker(QAMS)method and anti-α-amylase activity test were used to assess variations of chemical ingredients and pharmacological activity between white and red ginseng.Finally,molecular docking studies were carried out to screen out the most effective compound againstα-amylase.Results indicated that processing had a significant impact on the physicochemical properties and pharmacological activity of white and red ginseng.After processing,the color value of L*declined significantly.Red ginseng sample displayed a compact structure and presented of a gel layer on the surface compared to white ginseng.Additionally,the content of ginsenosides and the activity of anti-α-amylase decreased.The contents of total ginsenosides were positively correlated with the anti-α-amylase activities of ginseng,and ginsenoside Rb1 might be the most effective compound to inhibit the activity ofα-amylase.

Morphological Characterization of Arbuscular Mycorrhizal Fungi Associated with the Rhizosphere According to the Age of Xanthosoma sagittifolium L. Schott Plants in the Field

The objective of this work was to carry out a morphological characterization of arbuscular mycorrhizal fungi in the rhizosphere of Xanthosoma sagittifolium L. Schott plants. The plant material used was the white and red cultivars of X. sagittifolium, belonging to age intervals of 3 - 6, 6 - 9, and 9 - 12 months. Three harvest sites were chosen in the Central Region of Cameroon. In each site, soil from the rhizosphere and plant roots was collected in a randomized manner. In the field, the agronomic parameters were evaluated. The physicochemical characteristics of the soils, the mycorrhization index, and the morphological characterization of the mycorrhizal types of each site were carried out. The results obtained show that the agronomic growth parameters varied significantly using the Student Newman and Keuls Test depending on the harvest sites. The soils’ pH in all sites was acidic and ranged between 4.6 and 5.8. The Nkometou site has a loamy texture while the Olembe and Soa sites have loam-clay-sandy and loam-clay textures respectively. The highest mycorrhization frequencies appeared at the Nkometou site, with 75 and 87.33% of the white and red cultivars plant roots at 6 - 9 and 3 - 6 months. The relative abundance of AMF arbuscular mycorrhizal fungal spores in the rhizosphere of X. sagittifolium plants varied with age and cultivar. There were 673 spores between 9 - 12 months in Nkometou in the red cultivar. Six AMF genera were identified in all the different soils collected: Acaulospora sp., Funneliformis sp., Gigaspora sp., Glomus sp., Scutellospora sp., and Septoglomus sp. The genus Glomus sp. was the most present at all age intervals in both cultivars.

Soil Physico-Chemical Properties and Different Altitudes Affect Arbuscular Mycorrhizal Fungi Abundance and Colonization in Cacao Plantations of Cameroon

This study aims to investigate the abundance of AMF according to soil properties and altitudes in different cacao plantations of Cameroon. Physico-chemical analyses were made on soil samples collected from three agro-ecological zones. Soil samples were also used to evaluate directly the AMF abundance following the various altitudes and after trapping by sorghum plant. The results showed that soil properties, AMF spore abundances and colonization fluctuated significantly at different altitudes. The most represented texture was sandy loam. The bimodal zone presented a homogeneous texture (sandy loam) in all its localities. Cacao soil chemical characteristics showed that, the highest nitrogen rate (0.47%;p 0.05, Scott-Knott test) was recorded at Melong in a monomodal zone while Tonga in the Western highlands displayed the lowest rate (0.13%). Soil P concentration was significantly high in monomodal zones (Mbanga and Melong). Soil pH level indicated that the soil from Tonga in the Western highlands was neutral (pH = 6.67), and soils of other localities under study were acidic with the lowest (4.75) pH level recorded at Melong in a monomodal zone. In soil samples, the highest spore density (1.03 spores/g soil) was observed at Ntui in Bimodal zone, while the lowest spore density (0.26 spores/g soil) was observed at Bafang in the Western highlands. Root colonization showed that the sample from Bokito in a bimodal zone displayed the best frequency of mycorrhization (86.11%) while the sample from Bafang in the Western highlands recorded the lowest (27.11%). The PCA analysis highlighted that available phosphorus, pH and altitude all strongly correlated with AMF root colonization ability and can be used as a predictor of AMF colonization ability in cacao rhizosphere.

Reclassification and Nomenclature of Common Pathogenic Fungi

The accurate identification of pathogenic fungi is crucial for diagnosing and treating fungal infections. Recent advancements in molecular biotechnology, phylogenetic analysis, and the requirements of the Melbourne Code have led to changes in the classification and naming of fungi. These changes have caused significant confusion for medical laboratories and clinical personnel. This article summarizes the classification and new names of common pathogenic fungi to enhance fungi identification skills and provide accurate information for clinical diagnosis and treatment.

Secondary Metabolites of Entomopathogenic Fungi, Biological Alternative for the Control of Agricultural Pests and Disease: Present and Perspectives

The use of entomopathogenic fungi (EF) in recent years has been highly effective against the different orders of insects considered pests of agricultural importance and their conidia have been commonly applied, but it has been reported that these are sensitive to the environmental conditions. For this reason, biopesticides products have been formulated based on secondary metabolites, recently. These biomolecules participate as biological control agent, such as: cyclic depsipeptides, amino acids, polyketides, polyphenols and terpenoids, affecting their morphology, life cycle and insect behavior. The use of secondary metabolites of entomopathogenic fungi opens the possibility of application in a more efficient way for the control of agricultural pests in a compatible with the environment and human health;therefore, it is important to know, analyzing the type of molecules, their effects, and their different methods of application.

Fungi Associated with Sand and Plants from Marine Coastlines: Potential Relevance for Human Health

The fungal community associated with beach sand and plants located along marine coasts are an under-studied area of research despite its potential relevance to human health. In this study, we isolated and identified the cultivable mycobiota associated with sand and plants collected along the coast of Gran Canaria (Spain) using culture-dependent and -independent methods. Clinically relevant species belonging to Cryptococcus spp. and related genera such as Naganishia and Papilotrema were isolated and identified from shoreline plants. Moreover, Candida tropicalis was isolated from beach sand, and Aspergillus fumigatus and Aspergillus terreus strains were associated with both types of samples (i.e., plants and beach sand). We conclude that beach sand and shoreline plants are potential reservoirs of fungi of high clinical interest. We recommend including beach sand and plants from the environment when assessing the quality of marine coastal systems. Our results open a framework for studying the natural marine environment and its role in the epidemiology of infectious diseases in order to more accurately manage public health.

Resistance of Microbial Community of Artemisia annua L.to Pathogenic Fungi

[Objectives]This paper was to figure out whether the dominant bacterial community has the role and effect of bacterial community and its defense mechanism against potential pathogenic fungi in Artemisia annua,and thus establish a systematic model of bacteria-fungus-plant.[Methods]Fifty-eight strains of bacteria and one strain of pathogenic fungi,Globisporangium ultimatum,were used for the experiments.These 58 bacterial strains were assembled into a bacterial community,and the bacteria with abundance in the top 1%were reassembled into a dominant bacterial community as measured by 16S rDNA.[Results]The growth of A.annua seedlings inoculated with bacterial communities and pathogenic fungi or dominant bacterial communities and pathogenic fungi was significantly better than that of A.annua seedlings inoculated with pathogenic fungi during in vitro confrontation,which was evident in both enzymatic and non-enzymatic antioxidant assays.[Conclusions]The results suggest that the dominant bacterial community has a crucial role as a representative core microbial community of synthetic bacterial community,which can protect plants by interfering with the growth of phytopathogenic fungi mediated by chemical signals,and can be used as the main synthetic community of biocides to achieve the effect of biocontrol.

The Effect of the Extracts of Endophytic Fungi on Pancreatic a-Amylase Activity

Inhibitors of pancreatic a-amylase offer an effective strategy to lower the levels of postprandial hyperglycemia by controlof starch breakdown. Among 86 fungal endophytes isolated from 15 medicinal plants Aspergillus terreus-AFl04S, Aspergillusegypticus-HT166S and Penicillium sp.-CC200 exhibited strong pancreatic amylase inhibitory potential were selected. Endophyteswere subjected to ethyl acetate extraction and tested for a-amylase inhibition, in order to assess and evaluate their inhibitory potentialon pancreatic a-amylase. Analysis showed concentration dependent enzyme inhibition up to 83% with half inhibition （IC50） valuesfor less 25 mg.mL1, which is lower than acarbose as control. It was observed 3-fold increasing of Vmax and maintenance Km atcontrol level in the presence of extracts A. terreus-AFl04S and Penicillium sp.-CC200, while in presence of extract A.egypticus-HT166S Km was doubled, and Vmax was maintained at the control level. Kinetic studies allow proposing the competitivemode of a-amylase inhibition by extracts A. egypticus-HT166S and uncompetitive inhibition by extracts A, terreus-AFl04S andPenicillium sp.-CC200.

Chemical Constituents of Pu-erh Tea and Its Inhibition Effect on α-amylase in vitro

[Objective]The aim was to clarify the chemical substance basis of hypoglycemic and lipid-lowering effects of Pu-erh Tea. [Method]Pu-erh Tea was extracted with 95% ethanol,followed by petroleum ether,chloroform,ethyl acetate and n-butanol extraction,after the further purification and through the NKA-9 macroporous resin and many times of Sephadex column chromatography,two compounds were isolated,in the same time,the effect of Uracil and Gallic acid on α-amylase was studied. [Result]The Uracil and Gallic acid were isolated and identified respectively from Pu-erh Tea and the Uracil was firstly isolated from Pu-erh Tea; Gallic acid had strong inhibition on α-amylase. [Conclusion]It could provide some theories on the hypoglycemic and lipid-lowering effects of Pu-erh Tea.

Analysis of α-amylase Inhibitor Content Change in Pu-erh Tea During Pile-fermentation Process

The study was to investigate the changes of α-amylase inhibitor content in Pu-erh tea during pile-fermentation process. Pu-erh tea samples from two regions of Shuangjiang County and Jinggu Dai and Yi Autonomous County of Yunnan Province at various fermentation stages were used as experimental materials to investigate the effect of different fermentation stages on the inhibitory effect to α-amylase; and the change law of the inhibitory effect of c-amylase inhibitor during processing was meanwhile studied by determining the contents of tea polyphenol and amino acid. The results showed that crude meterial of Pu-erh tea presented strong inhibitory effect to α-amylase; this inhibitory effect assumed a de： creasing trend to the minimum at the middle stage of fermentation, whereafter it increased to some extent. Made tea also showed a strong inhibitory effect to α-amylase. During whole processing period, contents of tea polyphenol and amino acid generally assumed a remarkably decreasing trend. Our results provided references for further isolating co-amylase inhibitor from Pu-erh tea and discussing the mechanism of its health care function.

Studies on the Isolation and Screening of α-amylase Producing Strain and Their Enzymatic Properties

[Objective] The aim was to obtain α-amylase producing strains with some excellent properties like high temperature resistance,strong acid resistance,strong alkali resistance,etc..[Method] α-amylase producing strains were isolated and screened; furthermore their enzymatic properties were studied.[Result] 10 strains with an obvious starch hydrolysis cycle were screened out from starch screening plate coated by diluted sample,from which 3 strains with higher α-amylase activity were screened out,that was X6,X8 and X10.As for X6,X8 and X10,their optimum pH values all belonged to neutral,and their optimum temperatures were all 60 ℃.Meanwhile,Ca^2＋ could increase their enzyme thermal stability.When the concentration of Ca^2＋ was 0.02-0.04 mol/L,the enzyme thermal stability of X6 and X8 reached the highest; When the concentration of Ca^2＋ was 0.03-0.04 mol/L,that of X10 reached the highest; When the concentration of Ca^2＋ was increased continuously,those of the 3 strains all decreased.[Conclusion] The research provides theoretical basis for satisfying the demands of different industries for α-amylase with different characteristics.

Germination and Expression of α-Amylase of KF0680-1 and KF0680-2(Cultivars of Sweet Sorghum) under Salt Stress

[Objective] The aim was to study on germination and expression of α-amy- lase of KF0680-1 and KF0680-2 （cultivars of sweet sorghum） under salt stress. [Method] In the research, KF0680-1 and KF0680-2, cultivars of sweet sorghum, were used to measure related indices of germination and expression of co-amylase to discuss effect of salt stress on two cultivars. [Result] Germination of sweet sorghum would be promoted if treated with salt in low concentration and inhibited if treated in high concentration. In the latter condition, roots and seedlings were smaller than that of control group in length, but expression of s-amylase in the two cultivars was pro- moted under proper salt stress. [Conclusion] The research indicates that KF0680-1 and KF0680-2 are inhibited in growth by salt stress and the latter is stronger in salt resis- tance than the former under low salt concentration. In addition, expression of α-amy- lase could be promoted by salt in proper volume. The results provide references for selection of sweet sorghum which could be planted in northwestern areas.

In vitro α-amylase inhibitory activity and in vivo hypoglycemic effect of methanol extract of Citrus macroptera Montr.fruit

Objective:To investigate the therapeutic effects of methanol extract of Citrus macroptera Montr,fruit inα-amylase inhibitory activity(in vitro)and hypoglycemic activity in normal and glucose induced hyperglycemic rats(in vivo).Methods:Fruits of Citrus macroptera without rind was extracted with pure methanol following cold extraction and tested for presence of phytochemical constituents,α-amylase inhibitory activity,and hypoglycemic effect in normal rats and glucose induced hyperglycemic rats.Results:Presence of saponin,steroid and terpenoid were identified in the extract.The results showed that fruit extract had moderateα-amylase inhibitory activity[IC_(50)value=(3.638±0.190)mg/mL]as compared to acarbose.Moreover at 500 mg/kg and 1000 mg/kg doses fruit extract significantly(P<0.05 and P<0.01 respectively)reduced fasting blood glucose level in normal rats as compared to glibenclamide(5 mg/kg).In oral glucose tolerance test,500 mg/kg dose significantly reduced blood glucose level(P<0.05)at 2 h but 1000 mg/kg dose significantly reduced blood glucose level at 2 h and 3 h(P<0.05 and P<0.01 respectively)whereas glibenclamide(5 mg/kg)significantly reduced glucose level at every hour after administration.Overall time effect is also considered extremely significant with F value=23.83 and P value=0.0001 in oral glucose tolerance test.Conclusion:These findings suggest that the plant may be a potential source for the development of new oral hypoglycemic agent.

Comparisons of phaseolin type and α-amylase inhibitor in common bean(Phaseolus vulgaris L.)in China

The objective of this study was to characterize the phaseolin type and a-amylase(αAI) level in common bean(Phaseolus vidgaris L.) accessions deposited in the Chinese National Genebank.The 40 accessions sampled were common varieties originating in Asia,North America,South America,Europe,and Africa.No Inca(I-) phaseolin was observed in the accessions.Only four accessions contained Tendergreen(T-) phaseolin and the remaining36 contained Sanilac(S-) phaseolin.aAI proteins extracted from nine accessions showed higher a-amylase inhibitory activity than the control(Phase 2,IC_(50) = 0.65 μg).These common bean accessions have potential use as nutraceutical ingredients.

Relationship between malt qualities and β-amylase activity and protein content as affected by timing of nitrogen fertilizer application

The effects of different timing of N fertilizer application at the same rate on grain β-amylase activity, protein con- centration, weight and malt quality of barley were studied. Grain β-amylase activity and protein concentration were significantly higher in treatments where all top-dressed N fertilizer was applied at booting stage only or equally applied at two-leaf stage and booting stage than in the treatment where all top-dressed N fertilizer was applied at two-leaf age stage only. On the other hand, grain weight and malt extract decreased with increased N application at booting stage. There were obvious differences between barley varieties and experimental years in the grain and malt quality response to the timing of N fertilizer application. It was found that grain protein concentration was significantly and positively correlated with β-amylase activity, but significantly and nega- tively correlated with malt extract and Kolbach index. The effect of grain protein concentration on malt quality was predominant over the effect of grain β-amylase activity.

Effects of Ionic Surfactants on Bacterial Luciferase and α-Amylase

In order to study the effects of ionic surfactants on bacterial luciferase,the cationic surfactant dodecyltrimethylammonium biomide (DTAB) and anionic surfactant sodium dodecylsulfate (SDS) were chosen.For comparison with bacterial luciferase,α-amylase was used since these two enzymes have similar electrostatic potential and charged active sites.After the enzymes were treated with the surfactants,the catalytic properties of bacterial luciferase andα-amylase were assayed,and fluorescence spectroscopy and circular dichroism (CD) were used to analyze the alteration of the protein structure.The results showed that when the DTAB concentration was low,the cationic surfactant DTAB enhanced the enzymatic activities of bacterial luciferase andα-amylase.On the other hand,the anionic surfactant SDS did not alter the enzymatic activity.The main interaction of cationic surfactant DTAB and the negatively charged surface of the proteins was the ionic interaction,which could alter the environment for the enzyme to work when the DTAB/enzyme molar ratio was low.However,at high cationic surfactant concentration,the ionic interaction and hydrophobic interaction might destroy the secondary and tertiary structures of the proteins,leading to the loss of enzymatic activities.

Topographies of Organized Monolayer of α-Amylase Observed by Atomic Force Microscopy

In this paper, (-amylase organized monolayer was assembled on the surface of the PET-CO2- substrate in different conditions. The different topography of the (-amylase/PET monolayer was obtained by AFM in tapping mode.

Effect of microwave irradiation on secondary structure of α-amylase by circular dichroism

Based on the starch hydrolysis reaction accelerated by microwave irradiation with α-amylase, the circular dichroism （CD） and secondary structure changes of α-amylase under the condition of microwave irradiation and water bath were studied by circular dichroism spectra. The results showed that, both the peak heights （at 2=193 nm） of the CD spectra of the samples treated by microwave irradiation and water bath reduced. The reduced rate by microwave irradiation ranged from 140% to 220%, while the reduced rate by water bath ranged from 60% to 140%. The peak of the sample treated by microwave irradiation for 60 min disappeared at λ=193 nm, while the sample showed a wake peak by water bath. The peak position by microwave irradiation emerged a blue shift in the range of 5-8 nm at λ=204 nm and λ=220 nm, while it emerged in the range of 3-5 nm by water bath. With time going on, the microwave irradiation and water bath have prompted the secondary structure of α-helix, β-sheet, β-turn and the mutual transformations of random coil, but the trends were different.

The Dynamics of Changes in Starch and Lipid Droplets and Sub-Cellular Localization of β-Amylase During the Growth of Lily Bulbs

The ultra-structure of mother and outer daughter scales of Lilium Oriental hybrid Sorbonne were studied using transmission electron microscope to examine the sub-cellular localization of starch and lipid droplets during growth and development from shoot emergence to senescence.The contents of starch granules and lipid droplets in the cell of the mother scales decreased significantly from shoot emergence to anthesis,indicating that these scales served as a source for growth and development.After flowering,the number of starch granules and lipid droplets increased dramatically,and finally the cells were filled with the above molecules indicating that the bulb becomes a major sink during bulb enlargement.Ultrastructure observation also showed that symplastic pathway is the main pathway in cells in the exchange and transportation of material during bulb development.The activity of β-amylase,one of the key enzymes catalyzing starch breakdown,showed a similar trend.The enzyme sub-cellular localization via immune-gold electron-microscopy showed that βamylase was predominantly located together with starch granules,while the gold particles were scarcely found in other sub-cellular compartments.The result suggested that this enzyme is compartmented together with its functional substrate supporting its function in catalyzing starch breakdown in living plant cells.