α-Glucosidase Inhibitors from Glycyrrhiza uralensis Fisch.

Aim To screen for α-glucosidase inhibitor from Glyeyrrhiza uralensis Fisch.. Methods Glycyrrhizic acid, glycyrrhetinic acid, flavonoids of glycyrrhiza, alkaloids of glycyrrhiza, and glycyrrhiza polysaccharides were isolated from the root of Glycyrrhiza uralensis Fisch. respectively. Three compounds were isolated from the flavonoids of glycyrrhiza as guided by the α-glucosidase inhibitory test in vitro. Moreover, the characteristics of inhibitory kinetics of glycyrol and glycyrrhetinic acid were investi- gated. Results The flavonoids of glycyrrhiza and glycyrrhetinic acid had the strongest α-glucosidase inhibitory activity. Glycyrol,β-sitosterol and liquifitin were isolated and identified. Glycyrol was a fast- binding, reversible, noncompetitive α-glucosidase inhibitor, showing IC50 at 0.26 μg·mL^-1 Glycyrrhetinic acid was a fast-binding, irreversible α-glucosidase inhibitor, showing IC50 at 102.4 μg·mL^-1. Conclusion Glycyrol is an effective α-glucosidase inhibitor.

Effects of α-glucosidase Inhibitors on the Function of Mulberry Leaf Extract as an Additive in Feedstuff

The mulberry juice contains high concentrations of α-glucosidase inhibitors that affect glycometabolism and cause diarrhea in animals, thereby affecting the de-velopment and application of mulberry （Morus alba L.） as feedstuff resources. ln this study, the effects of mulberry leaf extract with and without removal of mulberry juice on starch metabolism were analyzed and compared. The results showed that mul-berry leaf extract with removal of mulberry juice exhibited significantly lower inhibi-tion rate on starch metabolism compared with mulberry leaf extract without removal of mulberry juice. ln animal feeding trials, piglet feedstuff was added with 10% mul-berry leaf powder; compared with mulberry leaf powder without removal of mulberry juice, experimental piglets fed with mulberry leaf powder with removal of mulberry juice exhibited significantly improved weight gain and significantyl reduced diarrhea rate.

α-Glucosidase Inhibitory Activities of Lutein and Zeaxanthin Purified from Green Alga Chlorella ellipsoidea

α-Glucosidase inhibitors are used therapeutically to treat type-2 diabetes mellitus. Through a bioassay-guided fractionation technique, three carotenoids,(all-E)-lutein,(all-E)-zeaxanthin and(9-Z)-zeaxanthin, were purified from the green alga Chlorella ellipsoidea, in which(all-E)-lutein and(9-Z)-zeaxanthin had potent α-glucosidase inhibitory activity. IC_(50) values of(all-E)-lutein and(9-Z)-zeaxanthin were 70 and 53.5 μmol L^(-1) against Saccharomyces cerevisiae α-glucosidase, respectively, with non-competitive inhibition. In addition, IC_(50) values of(9-Z)-zeaxanthin against Bacillus stearothermophilus and rat-intestinal α-glucosidase were 805.1 and 671.2 μmol L^(-1), respectively. The K_i values of(all-E)-lutein and(9-Z)-zeaxanthin against S. cerevisiae α-glucosidase were 78.1 and 16.5 μmol L^(-1), respectively. Therefore, C. ellipsoidea carotenoids might be utilized as a novel candidate to prevent type-2 diabetes mellitus related disorders in food and medical industry.

Antioxidant and α-glucosidase inhibitor activities of natural compounds isolated from Quercus gilva Blume leaves

Objective: To isolate and investigate antioxidant and α-glucosidase inhibitor compounds in the leaves of Quercus gilva Blume(Q. gilva).Methods: Dry leaves of Q. gilva were extracted with methanol and the methanolic extract was further separated by silica gel column chromatography using several solvents with increasing polarity. The antioxidant activities of the isolated compounds were evaluated using various in vitro assays: 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, hydrogen peroxide radical scavenging activity, β-carotene bleaching assay, and reducing power assay. The α-glucosidase inhibitory assay was conducted against α-glucosidase from Saccharomyces cerevisiae.Results: Three compounds were isolated and their structures were identii ed as catechin(1), epicatechin(2), and tiliroside(3) using an instrumental analysis. Compound 2 had higher antioxidant activity with inhibitory concentrations(IC50) of(22.55 ± 2.23) μmol/L than that of quercetin, which was used as the standard, with an IC50 of(28.08 ± 2.39) μmol/L, followed by compound 1 with IC50 of(40.86 ± 3.45) μmol/L. On the other hand, compound 3 had the lowest antioxidant activity with an IC50 of(160.24 ± 8.15) μmol/L. However, compound 3 had the highest α-glucosidase inhibitory activity with an IC50 of(28.36 ± 0.11) μmol/L, followed by compounds 1 and 2 with(168.60 ± 5.15) and(920.60 ± 10.10) μmol/L, respectively.Conclusions: The results obtained for the antioxidant activities and α-glucosidase inhibitory activities in a methanolic extract from the leaves of Q. gilva coni rmed the potential of this plant as a source of natural antioxidants and antidiabetic medicine.

1-Deoxynojirimycin Content and Alfa-Glucosidase Inhibitory Activity and Heat Stability of 1-Deoxynojirimycin in Silkworm Powder

Silkworm powder containing 1-deoxynojirimycin (DNJ) has α-glucosidase inhibitory activity and is promising as a complementary and alternative medicine (CAM) agent in Japan. Silkworm powder produced in Korea was extracted with 75% ethanol. The extract was derivatized with 9-fluorenylmethyl chloroformate (FMOC-Cl), and DNJ-FMOC content was measured by HPLC. Then, alfa-glucosidase inhibition by silkworm and mulberry powder in pig liver crude enzyme was assayed using 4-nitrophenyl-alfa-D-glucopyranoside as a substrate. Silkworm powder DNJ content (0.39 to 0.58%) was higher than that in mulberry powder (0.08 to 0.12%). The alfa-glucosidase inhibitory activity of silkworm powder was more potent than that of mulberry leaves and green tea. Silkworm powder DNJ was stable upon heating to 121?C for up to 15 min.

Isolation and screening of glucosidase inhibitors from Chinese medicines

Objective: To search for glucosidase inhibitors from Chinese medicines. Methods: Six kinds of widely-used Chinese medicines with the activity of decreasing blood glucose were prepared by the process of boiling, condensing, precipitating, exchanging with resins and rinsing. In vitro glucosidase inhibitory activities were examined by photometric bioassay derived from rats, yeast and almond of all the Chinese medicine extracts. Diabetic ICR mice models were established by intraperitoneal injection of STZ (200 mg/kg). To investigate the in vivo effect of lowering blood glucose, the mouse blood glucose level was assayed at 30 min after being given 2.5 g/kg starch and acarbose or varied concentrations of different constituents of some Chinese medicines by stomach tube. Results: The constituents of Sangye, Sangzhi, Sangbaipi, Dihuang and Yuzhu showed potent inhibitory activities against glucosidase. Furthermore, the first kind of constituents was proved to be beneficial in reducing blood glucose by in vivo glucose tolerance experiments. Conclusion: The constituents of Chinese medicines with reducing blood glucose effect have been discovered, thus providing a clue to novel drugs.

Identification of α-glucosidase inhibitors from Clinacanthus nutans leaf extract using liquid chromatography-mass spectrometry-based metabolomics and protein-ligand interaction with molecular docking

The present study used in vitro and in silico techniques, as well as the metabolomics approach to characterise α-glucosidase inhibitors from different fractions of Clinacanthus nutans. C. nutans is a medicinal plant belonging to the Acanthaceae family, and is traditionally used to treat diabetes in Malaysia. nHexane, n-hexane: ethyl acetate(1:1, v/v), ethyl acetate, ethyl acetate: methanol(1:1, v/v), and methanol fractions were obtained via partitioning of the 80% methanolic crude extract. The in vitro α-glucosidase inhibitory activity was analyzed using all the fractions collected, followed by profiling of the metabolites using liquid chromatography combined with mass spectrometry. The partial least square(PLS) statistical model was developed using the SIMCA P^+14.0 software and the following four inhibitors were obtained:(1) 4,6,8-Megastigmatrien-3-one;(2) N-Isobutyl-2-nonen-6,8-diynamide;(3) 1′,2′-bis(acetyloxy)-3′,4′-didehydro-2′-hydro-β, ψ-carotene; and(4) 22-acetate-3-hydroxy-21-(6-methyl-2,4-octadienoate)-olean-12-en-28-oic acid. The in silico study performed via molecular docking with the crystal structure of yeast isomaltase(PDB code: 3 A4 A) involved a hydrogen bond and some hydrophobic interactions between the inhibitors and protein. The residues that interacted include ASN259, HID295, LYS156, ARG335,and GLY209 with a hydrogen bond, while TRP15, TYR158, VAL232, HIE280, ALA292, PRO312, LEU313,VAL313, PHE314, ARG315, TYR316, VAL319, and TRP343 with other forms of bonding.

Pneumatosis cystoides intestinalis following alpha-glucosidase inhibitor treatment:A case report and review of the literature

A 69-year-old man was diagnosed as having myasthenia gravis (MG) in September 2004,and treated with thymectomy and prednisolone. He was then diagnosed as having steroid-induced diabetes mellitus,and received sulfonylurea (SU) therapy in May 2005. An alpha-glucosidase inhibitor (αGI) was added in March 2006,resulting in good glycemic control. He experienced symptoms of abdominal distention,increased flatus,and constipation in October 2007,and was admitted into our hospital in late November with hematochezia. Plain abdominal radiography revealed small linear radiolucent clusters in the wall of the colon. Computed tomography (CT) showed intramural air in the sigmoid colon. Colonoscopy revealed multiple smooth surfaced hemispherical protrusions in the sigmoid colon. The diagnosis of pneumatosis cystoides intestinalis (PCI) was made on the basis of these findings. As the αGI voglibose was suspected as the cause of this patient's PCI,treatment was conservative,ceasing voglibose,with fasting and fluid supplementation. The patient progressed well,and was discharged 2 wk later. Recently,several reports of PCI associated with αGI therapy have been published,predominantly in Japan where αGIs are commonly used. If the use of αGIs becomes more widespread,we can expect more reports of this condition on a global scale. The possibility of PCI should be considered in diabetic patients complaining of gastrointestinal symptoms,and the gastrointestinal tract should be thoroughly investigated in these patients.

Inhibitory activities of microalgal fucoxanthin againstα-amylase,α-glucosidase, and glucose oxidase in 3T3-L1cells linked to type 2 diabetes

Postprandial hyperglycemia is an early indication of type 2 diabetes and the target of many anti-diabetic and anti-obesity studies.α-Glucosidase and α-amylase are the crucial factors in regulating starch digestion and glucose absorption,making them key targets for many studies to treat postprandial hyperglycemia.We studied the inhibitory activities of microalgal fucoxanthin against rat-intestinalα-glucosidase and pancreaticα-amylase along with the antidiabetic eff ect to induce diff erentiation in 3T3-L1 pre-adipocytes using Oil Red-O staining.Fucoxanthin displayed strong hindrance activities towardα-amylase in a concentration-dependent manner,with an IC50 value of 0.68mmol/L,whereas weak inhibitory activity against α-glucosidase,with an IC 50 value of 4.75 mmol/L.Fucoxanthin also considerably elevated glucose oxidase activity in 3T3-L1 cells by 31.3%at 5μmol/L.During adipocyte differentiation,fucoxanthin showed lipid accumulation in 3T3-L1 cells with no cytotoxicity up to 20μmol/L.However,fucoxanthin had no inhibitory activity on glucose-6-phosphate dehydrogenase.These results suggest that fucoxanthin might be useful for the prevention of obesity or diabetes by inhibiting carbohydrate-hydrolyzing enzymes and lipid accumulation and be utilized as an ingredient for a functional food or dietary supplement.

α-Glucosidase inhibitors isolated from medicinal plants

Objective:α-Glucosidase inhibitors can be used as a new class of antidiabetic drug.By competitively inhibiting glycosidase activity,these inhibitors help to prevent the fast breakdown of sugars and thereby control the blood sugar level.This study provides a wealth of information aboutα-glucosidase inhibitors isolated from medicinal plants;this knowledge will be useful in finding more potent antidiabetic candidates from the natural resources for the clinical development of antidiabetic therapeutics.Results:411 compounds exhibitingα-glucosidase inhibitory activity were summarized and isolated them from medicinal plants.The compound classes isolated include:terpenes(61)from 14 genus,alkaloids(37)from 11 genus,quinines(49)from 4 genus,flavonoids(103)from 24 genus,phenols(37)from 9 genus,phenylpropanoids(73)from 20 genus,sterides(8)from 5 genus,and other types of compounds(43).Conclusion:Compounds withα-glucosidase inhibitory activity are abundant in nature and can be obtained from several sources.They have highα-glucosidase inhibitory potential,and can be clinically developed for treating diabetes mellitus.

Chemical Constituents from Mentha haplocalyx Briq.(Mentha canadensis L.)and Theirα‑Glucosidase Inhibitory Activities

Mentha haplocalyx(Mentha canadensis)is widely used as a medicinal plant in traditional Chinese medicine,and the extracts of its aerial parts are found to signifcantly inhibit the activity ofα-glucosidase with an IC_(50) value of 21.0μg/mL.Bioactivity-guided isolation of the extracts aforded two new compounds(1 and 2),together with 23 known ones(3-25).Their structures were established by extensive spectroscopic analyses(1D and 2D NMR,MS,IR and UV).Compounds 1-17 and 21-25 were evaluated for theirα-glucosidase inhibitory activities.Compound 11 was the most active ones with an IC_(50) values of 83.4μM.These results verify theα-glucosidase inhibitory activity of M.haplocalyx(M.canadensis)and specify its active compounds for the frst time.

Macroalage as a source of alpha-glucosidase inhibitors

Alpha-glucosidase inhibitors were screened from organic solvent extracts of macroalgae by a spec- trophotometrical method with p-nitrophenyl-D-glucopyranosidase as the substrate. The result indicates that or- ganic crude extracts from some macroalgae such as Rhodomela confervoides (Huds.) Silva, Gracilaria textorii (Suringar) DeToni, Plocamium telfairiae Harv., Dictyopteris divaricata (Okam.) Okam, Ulval pertusa and En- teromorpha intestinalis (L.) Link et al. show strong inhibitory activity of alpha-glucosidase at concentration of 79.6 μg/ml.

Bioactive constituents from the leaves of Quercus phillyraeoides A.Gray for-glucosidase inhibitor activity with concurrent antioxidant activity

Severalα-glucosidase inhibitory constituents were isolated from the methanolic extract of the leaves of Quercus phillyraeoides A.Gray(Q.phillyraeoides)using a bioassay-guided fractionation technique.Further separation and purification of the methanol-soluble fraction led to the isolation of constituents with moderate and strong inhibitory activities againstα-glucosidase:α-sitosterol-d-glucoside(1)and condensed tannin fractions(2,3,4,5,and 6).Compound 1 and fractions 2-6 had inhibitory concentration(IC50)values againstm-glucosidase from Saccharomyces cerevisiae of 118.8,2.79,2.78,3.10,2.60,and 3.14μg/mL,respectively,while quercetin as the standard had an IC50 value of 4.80mg/mL.Furthermore,the significant antioxidant activities were evaluated using several assays,such as the DPPH radical scavenging,hydrogen peroxide radical scavenging,reducing power,andβ-carotene-linoleate bleaching assays,and the results suggested that the isolated constituents showed their possible application for treating the hyperglycemia-induced oxidative stress.The results of the present study showed the potential of Q.phillyraeoides as a rich source of natural antidiabetic medicine.

Assessing the corrosion protection property of coatings loaded with corrosion inhibitors using the real-time atmospheric corrosion monitoring technique

The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties of organic coatings.This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors,both applied on ACM sensors,to observe their corrosion protection properties over time.Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments,which allowed for monitoring galvanic corrosion currents in real-time.Throughout the corrosion tests,the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating.The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis.This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings.Compared with the blank epoxy coating,the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.

α-Glucosidase Inhibitory Activity-guided Identification of Compounds from Clerodendrum bungei Steud by HPLC-ESI-QTOF-MS/MS

Objective To identify the compounds withα-glucosidase inhibitory activity from Clerodendrum bungei Steud(Chou Mu Dan,臭牡丹)using HPLC-ESI-QTOF-MS/MS.Methods The ethanol extracts of Clerodendrum bungei Steud(Chou Mu Dan,臭牡丹)were partitioned with petroleum ether,ethyl acetate,n-butanol,and water.The assay forα-glucosidase inhibitory activity revealed strongα-glucosidase inhibitory activity in the ethyl acetate fraction,and the bioactive compounds present in this fraction were identified by the HPLCESI-QTOF-MS/MS method.Results A total of 29 compounds were determined,among the identified bioactive components;these included 12 phenylethanoid glycosides(compounds 5,6,17,20-22,24),7 flavonoids(compounds 10,19,23,25-28),5 phenolic acids(compounds 2-4,7,9),and 5 other compounds.Compounds 2-4,7,9-10,12-13,15,19,and 26,with a potentialα-glucosidase inhibitory activity,have been reported previously.Conclusions Our results show that the methodology used in this study is feasible,credible,and rapid in identifying known compounds and also for characterizing new natural glucosidase inhibitory candidates from Clerodendrum bungei Steud(Chou Mu Dan,臭牡丹).

Proton pump inhibitors and all-cause mortality risk among cancer patients

BACKGROUND Proton pump inhibitors(PPIs)are widely used,including among cancer patients,to manage gastroesophageal reflux and other gastric acid-related disorders.Recent evidence suggests associations between long-term PPI use and higher risks for various adverse health outcomes,including greater mortality.AIM To investigate the association between PPI use and all-cause mortality among cancer patients by a comprehensive analysis after adjustment for various confounders and a robust methodological approach to minimize bias.METHODS This retrospective cohort study used data from the TriNetX research network,with electronic health records from multiple healthcare organizations.The study employed a new-user,active comparator design,which compared newly treated PPI users with non-users and newly treated histamine2 receptor antagonists(H2RA)users among adult cancer patients.Newly prescribed PPIs(esomeprazole,lansoprazole,omeprazole,pantoprazole,or rabeprazole)users were compared to non-users or newly prescribed H2RAs(cimetidine,famotidine,nizatidine,or ranitidine)users.The primary outcome was all-cause mortality.Each patient in the main group was matched to a patient in the control group using 1:1 propensity score matching to reduce confounding effects.Multivariable Cox regression models were used to estimate hazard ratios(HRs)and 95% confidence interval(CI).RESULTS During the follow-up period(median 5.4±1.8 years for PPI users and 6.5±1.0 years for non-users),PPI users demonstrated a higher all-cause mortality rate than non-users after 1 year,2 years,and at the end of follow up(HRs:2.34-2.72).Compared with H2RA users,PPI users demonstrated a higher rate of all-cause mortality HR:1.51(95%CI:1.41-1.69).Similar results were observed across sensitivity analyses by excluding deaths from the first 9 months and 1-year post-exposure,confirming the robustness of these findings.In a sensitivity analysis,we analyzed all-cause mortality outcomes between former PPI users and individuals who have never used PPIs,providing insights into the long-term effects of past PPI use.In addition,at 1-year follow-up,the analysis revealed a significant difference in mortality rates between former PPI users and non-users(HR:1.84;95%CI:1.82-1.96).CONCLUSION PPI use among cancer patients was associated with a higher risk of all-cause mortality compared to non-users or H2RA users.These findings emphasize the need for cautious use of PPIs in cancer patients and suggest that alternative treatments should be considered when clinically feasible.However,further studies are needed to corroborate our findings,given the significant adverse outcomes in cancer patients.

Computational Study on the Comparative Differences in the Activity of Inhibitors of Human versus Rat Alpha-Glucosidase

Differences between the inhibitory activities of specific compounds on analogous enzymes isolated from different animal species are one of the critical issues to evaluate when exploring structure-activity relationships. The activity of acarbose is about ten times stronger in rat than in human, and that of neosalacinol is similar in both species. Binding affinities of acarbose and neosalacinol to four catalytic domains of alpha-glucosidases in human and rat were compared to investigate the cause of activity differences among species. Species difference was brought about complicatedly by the balance of interaction with four domains, and the result was indicated that larger ligand would show larger species difference in activity.

利用TAIL-PCR技术克隆猴头菇β-glucosidase基因

根据已知的β-glucosidase基因的保守序列设计引物,从猴头菇的菌丝体中克隆到β-glucosidase基因片段B1,再利用TAIL-PCR技术扩增B1两端的侧翼序列B2和B3,B2和B3序列经Blastn、ORF和Primer5·0软件分析后,再设计B2和B3侧翼序列的特异引物对猴头菇的基因组DNA进行扩增,最终扩增到全长的β-glucosidase基因,其大小为2226bp。

好氧堆肥高温期纤维素酶活及β-glucosidase GH1家族阳性微生物群落的相关研究

以固相酶活试验方法检测牛粪-稻草堆肥高温期的CMC酶活性和β-葡萄糖苷水解酶活性,分析结果表明,两种酶活变化存在相关性,并受堆肥过程中的理化因素影响。设计简并引物,应用PCR-DGGE技术对β-葡萄糖苷水解酶GH1家族阳性的微生物群落的组成,及其时空分布进行研究,试验结果显示β-葡萄糖苷水解酶相关的功能性微生物群落在堆肥的进程中存在演替现象。

Updated clinical and glycomic features of mannosyl-oligosaccharide glucosidase deficiency:Two case reports

BACKGROUND Mannosyl-oligosaccharide glucosidase(MOGS)deficiency is an extremely rare type of congenital disorder of glycosylation(CDG),with only 12 reported cases.Its clinical,genetic,and glycomic features are still expanding.Our aim is to update the novel clinical and glycosylation features of 2 previously reported patients with MOGS-CDG.CASE SUMMARY We collected comprehensive clinical information,and conducted the immunoglobulin G1 glycosylation assay using nano-electrospray ionization source quadruple time-of-flight mass spectrometry.Novel dysmorphic features included an enlarged tongue,forwardly rotated earlobes,a birth mark,overlapped toes,and abnormal fat distribution.Novel imaging findings included pericardial effusion,a deep interarytenoid groove,mild congenital subglottic stenosis,and laryngomalacia.Novel laboratory findings included peripheral leukocytosis with neutrophil predominance,elevated C-reactive protein and creatine kinase,dyslipidemia,coagulopathy,complement 3 and complement 4 deficiencies,decreased proportions of T lymphocytes and natural killer cells,and increased serum interleukin 6.Glycosylation studies showed a significant increase of hypermannosylated glycopeptides(Glc3Man7GlcNAc2/N2H10 and Man5GlcNAc2/N2H5)and hypersialylated glycopeptides.A compensatory glycosylation pathway leading to an increase in Man5GlcNAc2/N2H5 was indicated with the glycosylation profile.CONCLUSION We confirmed abnormal glycomics in 1 patient,expanding the clinical and glycomic spectrum of MOGS-CDG.We also postulated a compensatory glycosylation pathway,leading to a possible serum biomarker for future diagnosis.