Α-glucosidase Inhibitory Properties Research Articles

Molecular networking-driven isolation of 8′-Glycosylated biscoumarins from Cruciata articulata

A molecular networking-guided phytochemical investigation of Cruciata articulata led to the isolation of five unreported biscoumarins, four of which were characterized by a shared 6-methoxy-7,8′-dihydroxy-3,7′-biscoumarin aglycone. These were isolated alongside two known coumarin glycosides, daphnetin-8-O-β-D-glucoside and 6′-acetoxy-daphnetin-8-O-β-D-glucoside. Their structures were elucidated by extensive 1D and 2D NMR experiments, in combination with chemical transformation and MS/MS fragmentation analysis. Four of the biscoumarins were glycosylated at the 8′ position: these are the first examples of this substitution pattern to be described in nature. All compounds were tested for cytotoxic, antimicrobial, anti-inflammatory, and α-glucosidase inhibitory properties, but did not display significant activity.

Cruciasides C-G, monoterpenoid glycosides from Cruciata articulata

Cruciata articulata (L.) Ehrend. is a herbaceous species distributed in parts of Western Asia and the Mediterranean region. While research on other species in the Cruciata genus has revealed the presence of a range of flavonoids and terpenoids, few such studies have been conducted on C. articulata. Thus, in the current study, a phytochemical investigation of C. articulata was carried out. Molecular networking identified a large cluster of compounds sharing distinctive MS-MS fragmentation patterns that were targeted for isolation, leading to the isolation of five undescribed monoterpenoid glycosides, cruciasides C-G, along with two known monoterpenoid glycosides. The structures of these compounds were elucidated by using chemical and spectroscopic analyses, including 1D and 2D NMR, and MS-MS fragmentation. Structures for the ions observed in the MS-MS were proposed, and based on these fragmentation patterns, structures for several of the minor components observed in the molecular network were also proposed. All isolated compounds were tested for cytotoxic, anti-inflammatory, antimicrobial, and α-glucosidase inhibitory properties, but did not display any activity.

Nutritional composition and proteomic analysis of soft-shelled turtle (Pelodiscus sinensis) egg and identification of oligopeptides with alpha-glucosidase inhibitory activity

This study aimed to explore nutritional compositions and proteomics of soft-shelled turtle (SST) egg, as well as identify potential antidiabetic oligopeptides with α-glucosidase inhibitory property. Results revealed that SST egg is a promising source of highly nutritious proteins and minerals (54.64% and 5.81% of dry matter, respectively). Further proteomic analysis showed SST egg proteins contained at least 9 protein families, such as transferrin/iron binding protein and immunoregulation-related protein. Hydrolysis by different enzymes, especially papain, remarkably increased α-glucosidase inhibitory activity and scavenging activity for ABTS, DPPH, hydroxyl and oxygen radicals of SST egg proteins. Peptides from papain hydrolysate were fractionated using ultrafiltration followed by reverse phase chromatography, and 16 peptides were identified in the most active fraction by LC-QTOF-MS/MS. Molecular docking revealed that 14 of these peptides could easily dock into the substrate-binding pocket and/or inhibitor binding sites of α-glucosidase with the docking score below −150 kcal/mol, indicating their potential α-glucosidase inhibitory properties. The five most abundant oligopeptides with potent interaction with α-glucosidase were further synthesized, and oligopeptides HNKPEVEVR, ARDASVLK and SGTLLHK strongly inhibited the activity of α-glucosidase (IC50 of 56, 195 and 289 µmol/L, respectively). Therefore, oligopeptides from enzymatic hydrolysate of SST egg protein exhibit potential antidiabetic activity, making it a promising functional food ingredient.

Comparison of Phenolic and Flavonoid Compound Profiles and Antioxidant and α-Glucosidase Inhibition Properties of Cultivated Soybean (Glycine max) and Wild Soybean (Glycine soja).

Wild soybean (Glycine soja Sieb.et Zucc; WS) has been used as a traditional food in China for many years and contains significantly higher levels of isoflavones than cultivated soybean (Glycine max; CS), but the secondary metabolites, including flavonoids and the phenolic composition differences between them, remain unclear. The results showed that WS possessed significantly higher total phenolic and flavonoid content and exhibited better antioxidant and α-glucosidase inhibition activities as well as excellent protective effects against H2O2-induced oxidative injury in a human endothelial cell line. Through metabolomic analysis, 642 metabolites were identified, and 238 showed differential expression, with 151 upregulated and 87 downregulated. A total of 79 flavonoid compounds were identified, 42 of which were upregulated in WS. 2′-Hydroxygenistein, garbanzol, protocatechuic aldehyde, ligustilide, and resveratrol were the most discriminated compounds in WS. The metabolic pathway analysis of differential metabolites related to the biosynthesis of flavonoids and phenolic acids were the biosynthesis of phenylpropanoids, flavonoids, isoflavonoids, flavones, and flavonols. This study substantially elucidated differences in the content of flavonoids and biological activities between WS and CS, which is useful information for the effective utilization of these two black soybean species in food processing.

Optimization of Two Eco-Friendly Extractions of Black Medick (Medicago lupulina L.) Phenols and Their Antioxidant, Cosmeceutical, α-Glucosidase and α-Amylase Inhibitory Properties.

Medicago lupulina is an ancient edible plant from the Fabaceae family. In this work, two eco-friendly methods for extraction of bioactive phenolics from M. lupulina were developed using mixtures of water with two non-toxic, skin- and environmentally-friendly polyol solvents: glycerol and polypropylene glycol. Ultrasound-assisted extractions were optimized using a Box–Behnken design. The independent variables were the concentration of organic solvent in water (X1), extraction temperature (X2) and time (X3), while the response was phenolic content. The optimum conditions for extraction of polyphenols were (X1, X2, X3): (45%, 70 °C, 60 min) and (10%, 80 °C, 60 min) for glycerol and polypropylene glycol extraction, respectively. The extracts prepared at optimum conditions were rich in phenolic compounds, mainly derivatives of apigenin, kaempferol, luteolin, quercetin, caffeic and ferulic acid, as well as coumestrol. Their cosmeceutical and antidiabetic activity was tested. Both extracts demonstrated notable antioxidant, anti-lipoxygenase and anti-α-amylase activity. In addition to those activities, the glycerol extract efficiently inhibited protein coagulation, elastase and α-glucosidase activity. Glycerol present in the extract displayed enzyme-inhibiting activity in several assays and supported the action of the bioactive constituents. Thus, the optimized glycerol extract is a desirable candidate for direct incorporation in antidiabetic food supplements and cosmeceutical products.

Antioxidant and α-glucosidase inhibitory activities of eight neglected fruit extracts and UHPLC-MS/MS profile of the active extracts.

The 70% ethanolic extracts from eight neglected fruits; Muntingia calabura, Leucaena leucocephala, Spondias dulcis, Syzygium jambos, Mangifera caesia, Ardisia elliptica, Cynometra cauliflora and Ficus auriculata were evaluated for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, α-glucosidase inhibitory activities as well as total phenolic content. The results of this study revealed that M. caesia fruit extract demonstrated the most potent radical scavenging activity. Among the fruits examined for α-glucosidase inhibitory activity, M. calabura and F. auriculata exhibited strong activity with no significant difference. The Pearson correlation indicated that the activities of M. caesia and F. auriculata contributed by phenolic compounds. A total of 65 metabolites were tentatively identified by using ultra-high-performance liquid chromatography tandem mass spectrometry (UHLPC-MS/MS). These findings suggested that the possible application of M. caesia and F. auriculata as a functional food with antioxidant and α-glucosidase inhibitory properties.

Effect of Eurotium cristatum fermentation on the α-glucosidase inhibitory activity of mulberry leaves flavonoid extract

Diabetes has become a global chronic disease and alpha-glucosidase inhibitors is an effective ways of treating it. Flavonoids are a group of substances in mulberry leaves that have α-glucosidase inhibitory properties and can reduce blood glucose concentrations effectively. In this paper, flavonoids from mulberry leaves fermented by Eurotium cristatum CY-1 will be used to investigate their inhibitory properties on α-glucosidase. The results indicated that the fermentation would increase the total flavonoid content of mulberry leaves by 196.7%. Meanwhile, the α-glucosidase inhibition efficiency of flavonoids extracted from the fermented mulberry leaves was also enhanced under the same concentration. The IC50 values of the flavonoids extracted from 8 d fermented mulberry leaves and the unfermented mulberry leaf was 4.14 μg/mL and 10.26 μg/mL, respectively. This article will provide a reference for using microbial fermentation to enrich active ingredients of functional Chinese medicine herbs.

GC\u2013MS analysis of phytocompounds and antihyperglycemic property of Hydrocotyle sibthorpioides Lam.

Hydrocotyle sibthorpioides Lam. is a popular medicinal plant of Assam having several ethnomedicinal values. The present study investigated the metallic content, phytochemical contents, α-amylase, and α-glucosidase enzymes inhibitory property of H. sibthorpioides using in-vitro and in-silico methods. Heavy metal contents were analyzed using Atomic Absorption Spectroscopy. GC–MS was used to analyze the phytochemical compounds of the plant. Enzyme inhibition study was carried out by Spectrophotometry methods. The drug-likeness and toxicity properties of the phytocompounds were studied using SwissADME and ADMETlab databases. Docking and molecular visualizations were performed in AutoDock vina and Discovery studio tools. The study found that the extract of H. sibthorpioides contains a negligible amount of toxic elements. GC–MS analysis detected four compounds from the methanolic extract of the plant. Biochemical study showed considerable α-amylase and α-glucosidase enzyme inhibitory property of the crude extract of H. sibthorpioides. The IC50 of the plant extracts were found to be 1.27 mg/ml and 430.39 µg/ml for α-amylase and α-glucosidase enzymes, respectively. All four compounds were predicted to have potential drug-likeness properties with high cell membrane permeability, intestinal absorption, and less toxic effects. The docking study also showed strong binding affinities between the plant compounds and enzymes. Plant compound C2 showed an almost similar binding affinity with the α-amylase enzyme as compared to standard acarbose. The present study, thus, suggests the antihyperglycemic property of H. sibthorpioides and can be a potential source of antidiabetic drug candidates.

Identification of Major Compounds and α-Amylase and α-Glucosidase Inhibitory Activity of Rhizome of Musa balbisiana Colla: An in-vitro and in-silico Study.

α-Amylase and α-glucosidase inhibitors are widely used to suppress postprandial glycemia in the treatment of type-2 diabetes. To evaluate the metallic content, phytocompounds, and α-amylase and α-glucosidase inhibitory activity of Musa balbisiana rhizome using in-vitro and in-silico methods. Heavy metal content was detected by AAS following standard protocol. Major phytochemicals of the plant were analyzed by GC-MS technique. Enzyme inhibition study was carried out by UV/VIS spectrophotometric methods. The drug-likeness and bio-availability properties of major compounds were carried out using computer-aided tools - SwissADME and ADMElab. Docking and visualization were performed in AutoDock vina and Discovery studio tools. The study found that the fruits of M. balbisiana contain a negligible amount of toxic elements. GC-MS analysis showed five major compounds from the rhizome of M. balbisiana. Invitro enzyme assays revealed strong α-amylase and α-glucosidase inhibitory properties of the plant. All five compounds were predicted to have a drug-likeness property with high cell membrane permeability and bio-availability. The compounds were also predicted to have low to moderate toxicity properties. The Docking study showed strong binding affinities of plant compounds with α-amylase and α-glucosidase. Out of five compounds, C5 showed the best binding affinity with active pockets of α-amylase and α-glucosidase. The in-vitro and in-silico study suggests the antihyperglycemic property of the rhizome of Musa balbisiana and a possible candidate for the therapeutic antidiabetic agent(s).

Response surface methodology based extraction optimization to improve pharmacological properties and 1H NMR based metabolite profiling of Azadirachta indica

BackgroundMany studies shed light on the therapeutic importance of Azadirachta indica leaves extract as a source of drugs and neutracuticles for treatment of different diseases including diabetes mellitus. The extraction of these bioactive phytochemicals is optimized according to different pharmacological applications of extract. Study designThe current study was performed to optimize the extraction from leaves of Azadirachta indica. The temperature, extraction time, solid to liquid ratio, ethanol concentration and ultrasonication frequency were optimized to improve extract yield with improved antioxidant and α-glucosidase inhibitory properties. MethodsUtrasonication assisted extraction from Azadirachta indica leaves was optimized using Response Surface Methodology. Sets of extraction conditions that gave optimum yield, antioxidant activity and α-glucosidase inhibition were determined through statistical analysis. The phytochemicals present in extract were identified by 1H NMR and docked with homology modelled α-glucosidase structure to get and insight of enzyme-phytochemicals interaction. ResultsThe maximum extract yield and α-glucosidase inhibition were observed when plant sample was extracted with 60% ethanol (15% solid-liquid ratio), and ultrasonication was done at 35 °C for 75 min having frequency of 30 KHz. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging observed the same extraction strategy except the time duration for ultasonication which was 52.5 min. The 1H NMR based metabolite profiling revealed the identification of 2α,4α,dihydroxy-pregn-5-en-(6-one-3α-O-D-glu-copyranoside, ferruginol, azadirachtin A, meliatetraolenone, odoratone, 7α‑hydroxy-15-β‑hydroxy-7′15,dioxonimbin, zeeshanol, nimbinene, epoxyazadiradione, azadirachtin B, 17-(5‑methoxy-2-oxo-furan-3-yl)-28-deoxonimbolide, epicatechin, 2-oxo-3-deacetyl salanin (nimbolide derivative), nimonol, nimbic acid B, 3‑methoxy-cumerine 6–0-(1,4) triglycoside, 17‑hydroxy-sandaracopimar-8,15-en-11-one(diterpene), and 23-O-methylnimocinolide. The molecular docking studies provided a deep insight on molecular interactions which might be useful for antidiabetic drug development. ConclusionAzadirachta indica leaves extract contain various bioactive compounds and can be considered as a source of α-glucosidase inhibitors hence, it may also be used for the development of functional foods.

Synthesis, characterization, antidiabetic and antioxidative evaluation of a novel Zn(II)-gallic acid complex with multi-facet activity.

This study was done to synthesize a novel Zn(II)-gallic acid complex with improved antidiabetic and antioxidative properties. The complex was synthesized and characterized using Fourier Transform Infrared (FT-IR) and 1 H NMR. Cytotoxicity was evaluated using Chang liver cells and L6 myotubes. Radical scavenging and Fe3+ -reducing, as well as α-glucosidase, α-amylase and glycation inhibitory properties were measured. Glucose uptake was measured in L6 myotubes, while the complex was docked against glucose transporter type 4 (GLUT-4) and protein kinase B (PKB). Analysis showed that complexation occurred through a Zn(O4 ) coordination; thus, the complex acquired two moieties of gallic acid, which suggests why complexation increased the DPPH (IC50 =48.2µm) and ABTS (IC50 =12.7µm) scavenging and α-glucosidase inhibitory (IC50 =58.5µm) properties of gallic acid by several folds (5.5, 3.6 and 2.7 folds; IC50 =8.79, 3.51 and 21.5µm, respectively). Zn(II) conferred a potent dose-dependent glucose uptake activity (EC50 =9.17µm) on gallic acid, without reducing the viability of L6 myotubes and hepatocytes. Docking analysis showed the complex had stronger interaction with insulin signalling proteins (GLUT-4 and PKB) than its precursor. Data suggest that complexation of Zn(II) with gallic acid resulted in a complex with improved and multi-facet antioxidative and glycaemic control properties.

Antidiabetic and Antioxidative Properties of Novel Zn(II)-cinnamic Acid Complex.

The role of zinc in diabetes has been a subject of considerable interest due to the insulin-mimetic properties associated with this mineral. On the other hand, phenolic acids are known as plant-derived polyphenols with antioxidative and antidiabetic pharmacological credence. This study was conducted in order to develop a novel therapeutic nutraceutical with an improved and multi-mode antidiabetic and antioxidative pharmacological property using cinnamic acid and Zn(II) mineral framework. A Zn(II) acetate complex of cinnamic acid was synthesized and characterized using FT-IR and 1HNMR spectroscopy. Cytotoxicity evaluation was done using Chang liver cells and differentiated L6 myotubes. DPPH and ABTS scavenging, as well as Fe3+ reducing effects, were used to evaluate the antioxidant capacity. The antiglycation, as well as α-glucosidase and α-amylase inhibitory properties, were evaluated. Insulin mimetic property was evaluated as glucose uptake in L6 myotubes, while the complex was docked against GLUT-4 and PKB. FTIR and 1HMR suggested that Zn(II) complexed with cinnamic acid through a Zn(O4) coordination mode, thus affording the resulting complex 2 cinnamic acid molecules. Hence, complexation increased (p ˂ 0.05) the antiglycation effect of cinnamic acid (IC50 = 29.3 μM) by 2 folds (IC50 = 13.9 μM). Also, Zn(II) conferred a potent glucose uptake (EC50 = 31 μM) and α-glucosidase inhibitory (IC50 = 59.4 μM) property on cinnamic acid; hence the activity of the complex was 162 and 2.1 folds higher than (p ˂ 0.05) its precursor, respectively. Further molecular docking studies showed that the complex had a stronger interaction with insulin signaling proteins (GLUT-4 and PKB) than its precursor. Interestingly, the complex showed no severe cytotoxicity. Data suggested a structure-activity relationship. Complexation of Zn(II) to cinnamic acid resulted in a complex with improved and multi-facet pharmacological effects, which may be further studied as a safe glycemic control nutraceutical for T2D and glycation-induced complications.

Cheese as a functional food for older adults: comparing the bioactive properties of different cheese matrices following simulated gastrointestinal in vitro digestion

Age-related changes to the gastrointestinal tract (GIT) can impact how food is digested. Studying the effects of these changes can help identify functional foods for older adults. Cheese was digested using two simulated gastrointestinal in vitro digestion (SGID) models representing adult and elderly gastro-intestinal conditions. Antioxidant capacity was measured using DPPH, FRAP and TPC assays. The ability of cheese to inhibit digestive enzymes was determined by the α-glucosidase and lipase inhibition assays. Digestive aging influenced the bioactivity of cheese, as elderly digestates had significantly lower (p < 0.05) antioxidant, α-glucosidase and lipase inhibitory properties compared to adult digestates. However, soft cheese (feta, goats’, brie) demonstrated greatest potential with comparable radical scavenging properties and lipase inhibition, greatest FRAP and α-glucosidase inhibitory potential. Despite age-related changes, the bioactive properties of cheese were evident following digestion with an older adult SGID model, suggesting cheese has potential as a functional food for older adults.

LC-QTOF-MS-based metabolite profiling and evaluation of α-glucosidase inhibitory kinetics of Coccinia grandis fruit.

Coccinia grandis is an important food crop of the Cucurbitaceae family, widely used for culinary purposes in India. It is reported to possess hypoglycemic, hypolipidemic and antioxidant activities. The current study was aimed to explore the inhibition kinetics as well as major constituents of the active fraction of C. grandis against α-glucosidase. The kinetic study was performed through spectrophotometric assay, with p-nitrophenyl-α-d-glucopyranoside as a substrate with varying concentrations. An in vitro antioxidant study was performed by DPPH assay. In addition, UPLC-QTOF-MS analysis was carried out for metabolite profiling of the bioactive fraction of C. grandis. The results showed that the difference between the α-glucosidase inhibitory activity of the ethyl acetate fraction of C. grandis (EFCG) (IC50 2.43 ± 0.27 mg/ml), and standard inhibitor, acarbose (2.08 ± 0.19 mg/ml), was not statistically significant at a P-value of 0.05. The enzyme kinetics confirmed the inhibition mode in a mixed manner. The EFCG also showed the highest antioxidant activity (101.74 ± 1.95 μg/ml) among all of the fractions. A significant correlation between antioxidant and α-glucosidase inhibitory activity of EFCG was observed. The LC-QTOF-MS study of the EFCG putatively identified 35 metabolites, which may be responsible for its antioxidant and α-glucosidase inhibitory properties. Thus, C. grandis fruits can serve as a functional food to address diabetes-related disorders associated with α-glucosidase.

Synthesis, anti-cholinesterease, α-glucosidase inhibitory, antioxidant and DNA nuclease properties of non-peripheral triclosan substituted metal-free, copper(II), and nickel(II) phthalocyanines

In this paper, phthalonitrile (3) and non-peripherally tetra triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) substituted phthalocyanine (4) and its metallo-phthalocyanine derivatives (5 and 6) were prepared. The structures of novel compounds (3–6) were characterized by spectrophotometric measurements. The acetylcholinesterase (AChE) from Electrophorus electricus, butyrylcholinesterase (BuChE) from equine serum, α-glucosidase from Saccharomyces cerevisiae, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging properties of the compounds (3–6) were investigated using spectrophotometric method. The supercoiled plasmid pBR322 DNA hydrolytic nuclease effects of the compounds (3–6) were investigated on the agarose gel. The compound 5 showed the strongest AChE and BuChE inhibitory properties with IC50 values of 0.86 ± 0.01 and 20.46 ± 2.47 μM, respectively and the SI value of 5 was 23.79. Also, 5 showed the highest α-glucosidase inhibitory and DPPH radical scavenging actions with IC50 values of 25.12 ± 0.62 μM and 1.11 ± 0.02 μM, respectively. The compounds showed no hydrolytic nuclease effects at increasing concentrations against supercoiled plasmid DNA. These results showed that 5 may be a lead compound for further research to develop a novel inhibitor for the treatments of Alzheimer’s diseases and Diabetes mellitus.

Antioxidant, α-amylase and α-glucosidase activity of various solvent fractions of I. obliquus and the preventive role of active fraction against H2 O2 induced damage in hepatic L02 cells as fungisome.

Inonotus obliquus is a traditional mushroom well known for its therapeutic value. In this study, various solvent fractions of I. obliquus were preliminarily screened for their antioxidant, α-amylase and α-glucosidase inhibition properties. To improve the drug delivery, the active fraction (ethyl acetate fraction) of I. obliquus was synthesized into fungisome (ethyl acetate phophotidyl choline complex, EAPC) and its physical parameters were assessed using Fourier transform infrared spectroscopy (FTIR), High performance liquid chromatography (HPLC), Scanning electron microscope (SEM), and ς potential analysis. Then normal human hepatic L02 cells was used to evaluate the cytotoxicity of EAPC. The results showed that EA fraction possesses significant free radical scavenging, α-amylase and α-glucosidase inhibition properties. FTIR, SEM, and HPLC analysis confirmed the fungisome formation. The particle size of EAPC was 102.80±0.42nm and the ς potential was -54.30±0.61mV. The percentage of drug entrapment efficiency was 97.13% and the drug release rates of EAPC in simulated gastric fluid and simulated intestinal fluid were 75.04±0.29% and 93.03±0.36%, respectively. EAPC was nontoxic to L02 cells, however it could selectively fight against the H2 O2 induced oxidative damage in L02 cells. This is the first study to provide scientific information to utilize the active fraction of I. obliquus as fungisome. PRACTICAL APPLICATIONS: Inonotus obliquus (IO) is a traditional medicinal fungus. The extracts of IO have obvious antioxidant and hypoglycemic activities. Ethyl acetate (EA) fraction of IO was encapsulated in liposomes to form EAPC. EAPC has a sustained-release effect. It has nontoxic to L02 cells and could protect L02 cells from oxidative damage caused by hydrogen peroxide. This study could provide new ideas for the treatment of diabetes.

Inhibitory effects of selected antibiotics on the activities of α-amylase and α-glucosidase: In-vitro, in-vivo and theoretical studies

Antibiotics are effective drugs that are used to treat infectious diseases either by killing bacteria or slowing down their growth. The well-adapted structural features of antibiotics for the inhibition/activation of enzymes include several available hydrogen bond (H-bond) acceptors and donors, flexible backbone and hydrophobic nature. The substrates of α-amylase and α-glucosidase, known as key absorbing enzymes, have functional groups (OH groups) rembling antibiotics. Given the possibility of developing in diabetics and the significant association between diabetes and infection, the present study was conducted to investigate the influences of tetracycline (TET), kanamycin (KANA), lincomycin (LIN), erythromycin (ERM) and azithromycin (AZM) on α-glucosidase and α-amylase activities with calculating IC50 and Ki values. Also, the efficacy of antibiotics after oral administration was evaluated by analysis of blood glucose concentrations in rats, as well as a molecular docking analysis was explored. α-glucosidase and α-amylase activities were inhibited in a dose dependent fashion by TET with an IC50 of 38.7 ± 1.4 and 47.8 ± 3.2 μM respectively, by KANA with an IC50 of 46.2 ± 1.6 and 65.1 ± 1.6, by LIN with an IC50 of 59.1 ± 2.1 and 51.3 ± 4.1, by ERM with an IC50 of 94.9 ± 4.7 and 65.7 ± 3.8 and by AZM with an IC50 of 69.4 ± 4.4 and 103.6 ± 6.2. Moreover, the Ki values of TET were calculated as 4.4 ± 0.6 and 8.4 ± 0.8 μM for α-glucosidase and α-amylase in a competitive-mode and mixed-mode inhibition. In addition, to communicate with the active site of α-glucosidase and α-amylase respectively, TET presented a binding energy of −9.8 and −8.8 kcal/mol, KANA −7.9 and −7.1, LIN -7.8 and −6.7, ERM −6.8 and −6.4, and AZM −6.4 and −7.5 kcal/mol. In-vivo studies also suggested a decrease in the blood glucose concentration after administering TET compared to the positive controls (P < 0.01). The results obtained from the present research can therefore help the scientific community explore the possible interconnection between the clinical side-effects of antibiotics and their α-glucosidase and α-amylase inhibitory properties, as the target enzymes in hypoglycemia conditions.

Investigation of the Antioxidant, α-Glucosidase Inhibitory, Anti-inflammatory, and DNA Protective Properties of Vaccinium arctostaphylos L.

The scope of this study was to investigate the total phenolic, anthocyanin, and flavonoid contents and the biological properties of ethanol extract (EE), methanol extract (ME), and aqueous extract (AE) from Vaccinium arctostaphylos L. EE, ME, and AE of V. arctostaphylos were prepared. Various biological activities such as total phenolic, anthocyanin, and flavonoid contents, and antioxidant (2,2'-diphenyl-1-picrylhydrazyl ferrous ion-chelating, and ferric reducing antioxidant power assays), α-glucosidase inhibitory, anti-inflammatory, and DNA protective properties of these extracts were studied. EE exhibited the highest total phenolic, anthocyanin, and flavonoid contents with 44.42±1.22 mg gallic acid equivalents/g dry weight, 8.46±0.49 mg/Cyaniding-3-glucoside equivalents/g dry weight, and 9.22±0.92 mg quercetin equivalents/g dry weight, respectively. The antioxidant activities of the extracts followed the order: EE>ME>AE. EE and ME inhibited α-glucosidase enzyme and their IC50 values were 0.301±0.002 mg/mL and 0.477±0.003 mg/mL, respectively. In addition, EE and ME were determined as noncompetitive inhibitors with inhibitory constant (Ki ) values of 0.48±0.02 mg/mL and 0.46±0.01 mg/mL, respectively. EE in 100 and 300 mg/kg doses caused a significant reduction in formalin-induced edema in mice, demonstrating the anti-inflammatory effect of EE. In DNA protective studies, all of the extracts protected supercoiled plasmid pBR322 DNA against damage caused by Fenton's reagents due to their radical scavenging activities. Our results demonstrated that EE of V. arctostaphylos L. had strong antioxidant, anti-inflammatory, α-glucosidase inhibitory, and DNA protective effects, suggesting that it might be an effective medical plant to prevent or treat diseases associated with oxidative damage and inflammation.

Enzymes inhibitory property, antioxidant activity and phenolics profile of raw and roasted red sorghum grains in vitro

Whole grain cereals are important dietary sources for management of metabolic diseases due to the bioactive components they contain. Hence, this study investigated enzymes (pancreatic lipase, α-amylase, α-glucosidase, xanthine oxidase and angiotensin 1-converting enzyme) inhibitory property, antioxidant activity and phenolics profile of raw and roasted red sorghum (Sorghum bicolor) grains in vitro. Extracts of flours of raw and roasted (150 °C and 180 °C, for 20 min) grains were assayed for enzymes inhibitory and antioxidant activities using spectrophotometric methods; while their phenolic constituents were characterized using HPLC-DAD. The raw grains exhibited strong enzymes inhibitory and antioxidant activities, and contained phenolic acids (gallic, chlorogenic, caffeic, ellagic and p-coumaric acids) and flavonoids (quercetin, luteolin and apigenin). However, whereas the enzymes inhibitory activity and levels of the phenolic compounds in the grains decreased significantly (p < 0.05) with increasing roasting temperature, the antioxidant activity increased. Hence, roasting at high temperature may not be recommended for the optimum retention of the enzymes inhibitory property and phenolic compounds of red sorghum grains.

Effect of roasting on phenolics composition, enzymes inhibitory and antioxidant properties of cowpea pulses

Research has shown that different processing techniques affect the bioactive components in grain foods and their bioactivities. Hence, this study evaluated effect of roasting temperature (150 and 180 °C; 20 min) on phenolics composition, enzymes (pancreatic lipase, angiotensin 1-converting enzyme, α-amylase, α-glucosidase and xanthine oxidase) inhibitory and antioxidant properties of whole cowpea (Vigna unguiculata) pulses. Phenolic compounds were characterized using HPLC–DAD; enzymes inhibitory and antioxidant activities were assayed by spectrophotometric methods. Extract of raw cowpea contained flavonoids (catechin, quercitrin, quercetin, kaempferol and apigenin) and phenolic acids (gallic and caffeic acids). The extract strongly inhibited all the enzymes tested and displayed potent antioxidant activity. However, the levels of individual phenolics and enzymes inhibitory activity decreased significantly (p < 0.05) as the roasting temperature increased; whereas the antioxidant activity increased. Through the inhibition of these enzymes, whole cowpea pulses may help decelerate the rate of formation of fatty acids, angiotensin II, glucose and uric acid, which is an approach for managing obesity, hypertension, type 2 diabetes and hyperuricemia, respectively. However, roasting at high temperature may not be suitable for the retention of these benefits.