Yeast Α-glucosidase Research Articles

Novel substituted 3-phenyl 1-(4-(5-bromopyridin-3-yl)-6-phenylpyrimidin-2-yl)-thiourea compounds as key small organic molecules for the potential treatment of type II diabetes mellitus: in vitro studies against yeast α-glucosidase

In this paper, we report a series of eighteen novel pyrimidine-based thiourea compounds with good to excellent yields (61–88%). The chemical structures of these heterocycles consist of a central pyrimidine ring with phenyl-substituted thiourea motifs. The enzyme inhibitory potential of these compounds was investigated against α-glucosidase as this enzyme plays a crucial role in treating type II diabetes mellitus. Compounds 4i (IC50 = 22.46 ± 0.65 µM), 4f (IC50 = 25.88 ± 0.40 µM), 4h (IC50 = 27.63 ± 0.49 µM), 4c (IC50 = 29.47 ± 0.42 µM), and 4e (IC50 = 32.01 ± 0.42 µM) delivered better inhibition than the reference compound acarbose (IC50 38.22 ± 0.12 µM). The quantitative structure–activity relationship of the synthesized compounds was also studied.

Facile synthesis, biological evaluation and molecular docking studies of novel substituted azole derivatives

In this study, we synthesized the series of novel azole derivatives and evaluated for enzyme inhibition assays, corresponding kinetic analysis and molecular modeling. Among the investigated bioassays, the oxadiazole derivatives 4a-k were found potent α-glucosidase inhibitors while the Schiff base derivatives 7a-k exhibited considerable potential toward urease inhibition. The inhibition kinetics for the most active compounds were analyzed by the Lineweaver–Burk plots to investigate the possible binding modes of the synthesized compounds toward the tested proteins. Moreover, the detailed docking studies were performed on the synthesized library of 4a-k and 7a-k to study the molecular interaction and binding mode in the active site of the modeled yeast α-glucosidase and Jack Bean Urease, respectively. It could be inferred from docking results that theoretical studies are in close agreement to that of the experimental results. The structure of one of the compound 7k was characterized by the single crystal X-ray diffraction analysis in order to find out the predominant conformation of the molecules.

Constituent analysis of the ethanol extracts of Chimonanthus nitens Oliv. leaves and their inhibitory effect on α-glucosidase activity

The ethanol extracts of Chimonanthus nitens Oliv. leaves were prepared sequentially by ethanol gradient elution and tested for their α-glucosidase inhibitory. The fraction of 50% ethanol eluate (EE) exhibited the notable inhibition with IC50 of 0.376mg/mL. Also, 50% EE was chemically characterized by liquid chromatography–mass spectrometry (LC–MS) analysis. Eight compounds including rutin (1), hyperin (2), isoquercitrin (3), luteoloside (4), astragalin (6), quercetin (13), naringenin (14), kaempferol (15) were identified by compared with standard substances as well as proper luteolin-5-O-glucoside (5), kaempferol-7-O-rhamnoside (9), 5,7,8-trihydroxy-2-methoxyl-flavone-7-O-glucoside (10), kaempferol-7-O-acetyl-galactoside (11). The experiments of ultra-filtration combined with liquid chromatography–mass spectrometry (UF-LC–MS) guided quercetin and kaempferol as the key factors for 50% EE showing highly inhibitory activity on α-glucosidase. Quercetin and kaempferol inhibited yeast α-glucosidase in a mixed-type manner with IC50 of 66.8 and 109μg/mL, respectively. These results would provide theoretical underpinning for the C. nitens Oliv. leaves ethanol extracts used as nutraceutical health supplement in the management of type 2 diabetes.

Green synthesis, inhibition studies of yeast α-glucosidase and molecular docking of pyrazolylpyridazine amines

An efficient and environmentally benign simple fusion reaction of 3-chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)pyridazine (1a) or 3-chloro-6-(3,5-dimethyl-4-nitro-1H-pyrazol-1-yl)pyridazine (2a) with different aliphatic/aromatic amines have produced a series of novel pyrazolylpyridazine amines (4a–4c &5a–5m). All compounds exhibited moderate in vitro yeast α-glucosidase inhibition except m-chloro derivative 5g, which was found potent inhibitor of this enzyme with IC50 value of 19.27±0.005µM. The molecular docking further helped in understanding the structure activity relationship of these compounds including 5g.

α-Glucosidase Inhibitors from Malbranchea flavorosea.

From an extract prepared from the grain-based culture of Malbranchea flavorosea two new polyketides, namely, 8-chloroxylarinol A (1) and flavoroseoside (2), along with the known compounds xylarinol A (3), xylarinol B (4), massarigenins B and C (5 and 6), and clavatol (7), were isolated. The structures of 1 and 2 were elucidated using spectroscopic methods and corroborated by single-crystal X-ray diffraction analysis. In the case of compound 2 the absolute configuration at the stereogenic centers was established according to the method of Flack. In addition, the X-ray structure of compound 6 is reported for the first time. Compounds 3, 4, and 6 significantly inhibited yeast α-glucosidase. Compound 6 also inhibited the postprandial peak during an oral sucrose tolerance assay when tested in vivo, using normal and NA/STZ-induced hyperglycemic mice.

Antidiabetic and anticancer activities of Mangifera indica cv. Okrong leaves.

Diabetes and cancer are a major global public health problem. Plant-derived agents with undesirable side-effects were required. This study aimed to evaluate antidiabetic and anticancer activities of the ethanolic leaf extract of Mangifera indica cv. Okrong and its active phytochemical compound, mangiferin. Antidiabetic activities against yeast α-glucosidase and rat intestinal α-glucosidase were determined using 1 mM of p-nitro phenyl-α-D-glucopyranoside as substrate. Inhibitory activity against porcine pancreatic α-amylase was performed using 1 mM of 2-chloro-4 nitrophenol-α-D-maltotroside-3 as substrate. Nitrophenol product was spectrophotometrically measured at 405 nm. Anticancer activity was evaluated against five human cancer cell lines compared to two human normal cell lines using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Mango leaf extract and mangiferin exhibited dose-dependent inhibition against yeast α-glucosidase with the IC50 of 0.0503 and 0.5813 mg/ml, respectively, against rat α-glucosidase with the IC50 of 1.4528 and 0.4333 mg/ml, respectively, compared to acarbose with the IC50 of 11.9285 and 0.4493 mg/ml, respectively. For anticancer activity, mango leaf extract, at ≥200 μg/ml showed cytotoxic potential against all tested cancer cell lines. In conclusion, mango leaf possessed antidiabetic and anticancer potential in vitro.

Unlocking the in vitro anti-inflammatory and antidiabetic potential of Polygonum maritimum

Context: Several Polygonum species (Polygonaceae) are used in traditional medicine in Asia, Europe and Africa to treat inflammation and diabetes. Objective: Evaluate the in vitro antioxidant, anti-inflammatory and antidiabetic potential of methanol and dichloromethane extracts of leaves and roots of the halophyte Polygonum maritimum L. Material and methods: Antioxidant activity was determined (up to 1 mg/mL) as radical-scavenging activity (RSA) of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), copper (CCA) and iron (ICA) chelating activities and iron reducing power (FRAP). NO production was measured in lipopolysaccharide (LPS)-stimulated macrophages for 24 h at concentrations up to 100 μg/mL and antidiabetic potential was assessed by α-amylase and α-glucosidase inhibition (up to 10 mg/mL) assays. The phytochemical composition of the extracts was determined by gas chromatography-mass spectrometry (GC-MS). Results: The methanol leaf extract had the highest activity against DPPH • (IC50 = 26 μg/mL) and ABTS +• (IC50 = 140 μg/mL), FRAP (IC50 = 48 μg/mL) and CCA (IC50 = 770 μg/mL). Only the dichloromethane leaf extract (LDCM) showed anti-inflammatory activity (IC50 = 48 μg/mL). The methanol root (IC50 = 19 μg/mL) and leaf (IC50 = 29 μg/mL) extracts strongly inhibited baker’s yeast α-glucosidase, but LDCM had higher rat’s α-glucosidase inhibition (IC50 = 2527 μg/mL) than acarbose (IC50 = 4638 μg/mL). GC-MS analysis identified β-sitosterol, stigmasterol, 1-octacosanol and linolenic acid as possible molecules responsible for the observed bioactivities. Conclusions: Our findings suggest P. maritimum as a source of high-value health promoting commodities for alleviating symptoms associated with oxidative and inflammatory diseases, including diabetes.

Thermostability Measurement of an α-Glucosidase Using a Classical Activity-based Assay and a Novel Thermofluor Method.

α-glucosidases (including maltases and isomaltases) are enzymes which release glucose from a set of α-glucosidic substrates. Their catalytic activity, substrate specificity and thermostability can be assayed using this trait. Thermostability of proteins can also be determined using a high-throughput differential scanning fluorometry method, also named Thermofluor. We have shown that Thermofluor can also be applied to predict binding of substrates and inhibitors to a yeast α-glucosidase. The methods described here in detail were used in Viigand et al., 2016 .

Rb2 inhibits α-glucosidase and regulates glucose metabolism by activating AMPK pathways in HepG2 cells

Five ginsenosides were evaluated as α-glucosidase and α-amylase inhibitors by enzymatic kinetics analysis, compared with the market diabetes healer, acarbose. The results indicated that Rb2 and Rd exhibited strong α-glucosidase and α-amylase inhibition. Concentration of Rb2 and Rd to inhibit 50% of α-glucosidase (IC50) were 32.2 and 38.8μM, IC50 for α-amylase were 128 and 167.4μM, respectively. The enzyme kinetic studies revealed that, in the presence of the most potent α-glucosidase inhibitors, Rb2 and Rd, the Michaelis-Menton constant (Km) remained constant but the maximal velocity (Vmax) decreased, revealing a non-competitive type of inhibition. Moreover, Rb2 and Rd were shown to be reversible inhibitors of yeast α-glucosidase with Ki values of 19.4 and 24.5μM, respectively. Moreover, we investigated the effects of Rb2 on metabolism and demonstrated that Rb2 significantly increased glucose consumption in HepG2 cells. The phosphorylation of AMP-activated protein kinase (AMPK) was increased by treatment with Rb2.

New polyhydroxytriterpenoid derivatives from fruits of Terminalia chebula Retz. and their α-glucosidase and α-amylase inhibitory activity

Three new polyhydroxytriterpenoid derivatives, 23-O-neochebuloylarjungenin 28-O-β-d-glycopyranosyl ester (1), 23-O-4′-epi-neochebuloylarjungenin (2), and 23-O-galloylpinfaenoic acid 28-O-β-d-glucopyranosyl ester (17) were isolated from the fruits of Terminalia chebula Retz. along with fourteen known ones. Their structures were elucidated by 1D and 2D NMR spectroscopic data and acid hydrolysis. After evaluating for Baker’s yeast α-glucosidase, rat intestinal α-glucosidase, and porcine pancreatic α-amylase inhibitory activities of all the isolated compounds, 23-O-galloylarjunolic acid (11, IC50 21.7μM) and 23-O-galloylarjunolic acid 28-O-β-d-glucopyranosyl ester (12, IC50 64.2μM) showed potent inhibitory activities against Baker’s yeast α-glucosidase compared to the positive control, acarbose (IC50 174.0μM). However, all the tested compounds except for the positive control, acarbose, had no or only weak inhibitory activity against rat intestinal α-glucosidase and porcine pancreatic α-amylase.

Isolation and identification of terpenoids from chicory roots and their inhibitory activities against yeast α-glucosidase

Chicory (Cichorium intybus L.var. sativum L., Asteraceae) is a multipurpose plant cultivated as vegetable and coffee substitute in Europe and North America, also as folk medicine in China. The extracts from chicory roots showed significant effect on inhibition against α-glucosidase. By a bioassay-guided approach, the chemical fraction with high α-glucosidase inhibition was found and its chemical profile was tentatively described by UPLC-Q-TOF/MS to include 28 compounds. Further chemical isolation yielded six compounds, their chemical structures were elucidated as 11β-13-dihydrolactucin (1), lactucin (2), 8-deoxylactucin (3), jacquinelin (4), 11β,13-dihydrolactucopicrin (5) and lactucopicrin (6), and among them, the compound 4 showed the strongest inhibitory activity against yeast α-glucosidase with IC50 value of 4.180 μM. The present results suggest that chicory roots can eventually exhibit anti-diabetic effect and the sesquiterpenes may be responsible for the activity.

Anti-hyperglycemic, antioxidant, and anti-inflammatory activities of extracts and metabolites from Sida acuta and Sida rhombifolia

Species of genus Sida are used around the world for a large amount of therapeutic treatments, including hyperglycemia. α-Glucosidase inhibitors are recognized as valuable tools for reducing postprandial hyperglycemia by retarding absorption of glucose. The effect of extracts and isolated compounds of S. acuta and S. rhombifolia on inhibition of α-glucosidase as primary screening of anti-hyperglycemic activity was tested using yeast and mammalian α-glucosidases. When yeast α-glucosidase was used the acetone extracts of S. acuta and S. rhombifolia showed IC50 values of 8.49 ± 0.66 and 8.10 ± 0.34 µg mL-1, respectively, and the most active compound was p-hydroxyphenethyl trans-ferulate (IC50 19.24 ± 1.73 µmol L-1) followed by β-sitosteryl glucopyranoside (IC5032.70 ± 1.35 µmol L-1). However, the activity of extracts and isolated compounds decreased significantly when mammalian α-glucosidase was used, indicating that substrates affinity is higher for type 1 enzymes. The antioxidant and anti-inflammatory activities of extracts and isolates were also tested since many diabetic complications are associated to the oxidative stress and inflammatory immune responses. Acetone extracts were the most active in all evaluations. p-Hydroxyphenethyl trans-ferulate, could be associated to these activities, since it was active in the three evaluations. This effect could be related to its phenolic character.

α-Glucosidase Inhibitors from Preussia minimoides ‡.

Extensive fractionation of an extract from the grain-based culture of the endophytic fungus Preussia minimoides led to the isolation of two new polyketides with novel skeletons, minimoidiones A (1) and B (2), along with the known compounds preussochromone C (3), corymbiferone (4), and 5-hydroxy-2,7-dimethoxy-8-methylnaphthoquinone (5). The structures of 1 and 2 were elucidated using 1D and 2D NMR data analysis, along with DFT calculations of 1H NMR chemical shifts. The absolute configuration of 1 was established by a single-crystal X-ray diffraction analysis and TDDFT-ECD calculations. Compounds 1-4 significantly inhibited yeast α-glucosidase.

Alkaloids from the Fungus Penicillium spathulatum as α-Glucosidase Inhibitors.

Benzomalvin A (1), quinolactacins A1 (2), A2 (3) and B (4), quinolonimide (5), asperphenamate (6), and a new halogenated polyhydroxyanthraquinone, namely 2-chloro-6-[2'(S)-hydroxypropyl]-1,3,8-trihydroxy-anthraquinone (7), were isolated from an organic extract obtained from the solid culture of Penicillium spathulatum B35. Compounds 2 and 3 were isolated as an epimeric mixture, and compound 4 as a racemate. The structure of 7 was elucidated using 1D and 2D NMR, combined with computational methods (density functional theory). Compound 1, the mixture of 2 and 3, racemate 4, and compound 6 inhibited the yeast α-glucosidase in a concentration-dependent fashion with IC50 values of 383.2, 273.3, 57.3, and 8.3 µM, respectively. The α-glucosidase inhibitory properties of 1 were confirmed in vivo with an oral sucrose tolerance test in normal and hyperglycemic mice (p < 0.05). Furthermore, docking studies predicted that the most stable conformers of 1 bind to yeast and mammalian α-glucosidases with a higher affinity than acarbose. Finally, 1 also showed antihyperalgesic activity when tested in the formalin assay in hyperglycemic mice (p < 0.05).

Effect and potential mechanism of action of sea cucumber saponins on postprandial blood glucose in mice.

Postprandial blood glucose control is the major goal in the treatment of diabetes. Here, we investigated the effect of sea cucumber saponins (SCSs) on postprandial blood glucose levels. SCS inhibited yeast as well as rat intestinal α-glucosidase activity in a dose-dependent manner and showed better inhibition of yeast α-glucosidases compared to the positive control. Further studies were performed using ICR mice treated with SCS and starch or SCS alone by oral gavage. Unexpectedly, SCS increased postprandial blood glucose levels a short time (1h) after oral gavage. The serum corticosterone (CORT) level showed a consistent correlation with glucose levels. In vitro experiments confirmed that SCS treatment increased the secretion of CORT in the Y1 adrenal cell line. Overall, these studies demonstrated that SCS gavage could inhibit α-glucosidase activity but cannot attenuate postprandial blood glucose level within short time periods. The underlying mechanisms are probably related to increased serum CORT levels.

CuAAC click chemistry with N-propargyl 1,5-dideoxy-1,5-imino-D-gulitol and N-propargyl 1,6-dideoxy-1,6-imino-D-mannitol provides access to triazole-linked piperidine and azepane pseudo-disaccharide iminosugars displaying glycosidase inhibitory properties

Protecting group-free synthesis of 1,2:5,6-di-anhydro-D-mannitol, followed by ring opening with propargylamine and subsequent ring closure produced a separable mix of piperidine N-propargyl 1,5-dideoxy-1,5-imino-D-gulitol and azepane N-propargyl 1,6-dideoxy-1,6-imino-D-mannitol. In O-acetylated form, these two building blocks were subjected to CuAAC click chemistry with a panel of three differently azide-substituted glucose building blocks, producing iminosugar pseudo-disaccharides in good yield. The overall panel of eight compounds, plus 1-deoxynojirimycin (DNJ) as a benchmark, was evaluated as prospective inhibitors of almond β-glucosidase, yeast α-glucosidase and barley β-amylase. The iminosugar pseudo-disaccharides showed no inhibitory activity against almond β-glucosidase, while the parent N-propargyl 1,5-dideoxy-1,5-imino-D-gulitol and N-propargyl 1,6-dideoxy-1,6-imino-D-mannitol likewise proved to be inactive against yeast α-glucosidase. Inhibitory activity could be reinstated in the former series by appropriate substitution on nitrogen. The greater activity of the piperidine could be rationalized based on docking studies. Further, potent inhibition of β-amylase was observed with compounds from both the piperidine and azepane series.

Total Phenolics, Antioxidant Activity and Anti-Diabetic Capacities of Selected Iraqi Medicinal Plants

DOI: 10.20286/ajlsr-040285 In Iraq, medicinal plants have not received much attention in terms of quantifying their antioxidant and other biological/pharmacological activities so the objective of the present study was to assess the antioxidant activity of selected medicinal plants grown in Iraq and relate it to their total phenolic contents and their inhibitory effect on carbohydrate-hydrolyzing enzymes. Antioxidant activity was assessed by ferric reducing antioxidant power (FRAP) and oxygen reactive absorbance capacity (ORAC) methods. The possible inhibitory effect on carbohydrate-hydrolyzing enzymes was also investigated. In almost all the parameters used, the aqueous extracts from Mentha piperita showed significantly higher (P&lt; 0.0001) activities than other plants. Antioxidant activity was significantly correlated (P&lt; 0.0001) with TPC among all the plants studied. In addition, the plant extracts showed strong inhibition against pancreatic α-amylase and yeast α-glucosidase. Only Cyperus rotundus and Prosopis farcta have been used traditionally for the treatment of diabetes in Iraq. In conclusion, to the best of our knowledge, the remaining four plants and herbs ( Glycyrrhiza glabra , H. Sabdariffa, Matricaria chamomilla, and M. piperita ) have no records in the literature for their antidiabetic effects. Consequently, this study identifies these four medicinal plants as novel inhibitors of key enzymes (α-glucosidase and α-amylase) relevant for type 2 diabetes that showed even higher activity than the currently being used for the treatment of diabetes by the Iraqi herbalists.

Dihydropyrano [2,3-c] pyrazole: Novel in vitro inhibitors of yeast α-glucosidase

Inhibition of α-glucosidase enzyme activity is a reliable approach towards controlling post-prandial hyperglycemia associated risk factors. During the current study, a series of dihydropyrano[2,3-c] pyrazoles (1–35) were synthesized and evaluated for their α-glucosidase inhibitory activity. Compounds 1, 4, 22, 30, and 33 were found to be the potent inhibitors of the yeast α-glucosidase enzyme. Mechanistic studies on most potent compounds reveled that 1, 4, and 30 were non-competitive inhibitors (Ki=9.75±0.07, 46±0.0001, and 69.16±0.01μM, respectively), compound 22 is a competitive inhibitor (Ki=190±0.016μM), while 33 was an uncompetitive inhibitor (Ki=45±0.0014μM) of the enzyme. Finally, the cytotoxicity of potent compounds (i.e. compounds 1, 4, 22, 30, and 33) was also evaluated against mouse fibroblast 3T3 cell line assay, and no toxicity was observed. This study identifies non-cytotoxic novel inhibitors of α-glucosidase enzyme for further investigation as anti-diabetic agents.

Novel thiosemicarbazide–oxadiazole hybrids as unprecedented inhibitors of yeast α-glucosidase and in silico binding analysis

Novel hybrids of thiosemicarbazide–oxadiazole as potent α-glucosidase agents.

Synthesis of novel flavone hydrazones: In-vitro evaluation of α-glucosidase inhibition, QSAR analysis and docking studies

Thirty derivatives of flavone hydrazone (5–34) had been synthesized through a five-step reaction and screened for their α-glucosidase inhibition activity. Chalcone 1 was synthesized through aldol condensation then subjected through oxidative cyclization, esterification, and condensation reaction to afford the final products. The result for baker's yeast α-glucosidase (EC 3.2.1.20) inhibition assay showed that all compounds are active with reference to the IC50 value of the acarbose (standard drug) except for compound 3. Increase in activity observed for compounds 2 to 34 clearly highlights the importance of flavone, hydrazide and hydrazone linkage in suppressing the activity of α-glucosidase. Additional functional group on N-benzylidene moiety further enhances the activity significantly. Compound 5 (15.4 ± 0.22 μM), a 2,4,6-trihydroxy substituted compound, is the most active compound in the series. Other compounds which were found to be active are those having chlorine, fluorine, and nitro substituents. Compounds with methoxy, pyridine, and methyl substituents are weakly active. Further studies showed that they are not active in inhibiting histone deacetylase activity and do not possess any cytotoxic properties. QSAR model was being developed to further identify the structural requirements contributing to the activity. Using Discovery Studio (DS) 2.5, various 2D descriptors were being used to develop the model. The QSAR model is able to predict the pIC50 and could be used as a prediction tool for compounds having the same skeletal framework. Molecular docking was done for all compounds using homology model of α-glucosidase to identify important binding modes responsible for inhibition activity.