Objective:To investigate the relationship between triterpenoid saponin content and antioxidant,antimicrobial,and α-glucosidase inhibitory activities of 70%ethanolic,butanolic,aqueous,supernate and precipitate extract...Objective:To investigate the relationship between triterpenoid saponin content and antioxidant,antimicrobial,and α-glucosidase inhibitory activities of 70%ethanolic,butanolic,aqueous,supernate and precipitate extracts of Juglans regia leaves.Methods:Triterpenoid saponins of different Juglans regia leaf extracts were measured by the vanillin method.Antioxidant activity was evaluated against DPPH and ABTS free radicals.We also assessed α-glucosidase inhibitory and antimicrobial activities of the leaf extracts.Pearson’s correlation coefficient was evaluated to determine the correlation between the saponin content and biological activities.Results:The butanolic extract was most effective against DPPH with an IC50of 6.63μg/mL,while the aqueous extract showed the highest scavenging activity against ABTS free radical with an IC50of 42.27μg/mL.Pearson’s correlation analysis indicated a strong negative correlation (r=-0.956) between DPPH radical scavenging activity (IC50) and the saponin content in the samples examined.In addition,the aqueous extract showed the best α-glucosidase inhibitory activity compared with other extracts.All the extracts had fair antibacterial activity against Bacillus subtilis,Escherichia coli,and Klebsiella pneumoniae except for the aqueous extract.Conclusions:Juglans regia extracts show potent antioxidant,antimicrobial,and α-glucosidase inhibitory activities.There is a correlation between saponin levels in Juglans regia leaf extracts and the studied activities.However,additional research is required to establish these relationships by identifying the specific saponin molecules responsible for these activities and elucidating their mechanisms of action.展开更多
Objective:To explore the anti-diabetic effects and its underlying mechanism of Annona muricata Linn fruit ethanol extract(AME).Methods:Streptozotocin-induced type 2 diabetic(T2DM)mouse model was constructed.Those diab...Objective:To explore the anti-diabetic effects and its underlying mechanism of Annona muricata Linn fruit ethanol extract(AME).Methods:Streptozotocin-induced type 2 diabetic(T2DM)mouse model was constructed.Those diabetic mice were randomly grouped and given 50 mg/kg acarbose or AME(200 mg/kg,100 mg/kg or 50 mg/kg)for four weeks.The body weight,postprandial blood glucose and glycosylated hemoglobin levels were measured during the administration.After the administration,a glucose tolerance test was performed,and the levels of triglycerides,cholesterol and low-density lipoproteins in mice were detected by biochemical test kits.The inhibitory activity of AME onα-glucosidase in vivo and in vitro was determined by enzyme inhibition tests.Results:AME significantly reduced weight gain,postprandial blood glucose,glycosylated hemoglobin and low-density lipoprotein levels in T2DM mice;enhanced glucose tolerance and pancreaticβ-cell function of T2DM mice;inhibitedα-glucosidase activity in mouse intestine in an noncompetitive manner.Conclusion:AME may noncompetitive inhibitα-glucosidase activity and reduce postprandial glucose intake to achieve a therapeutic and regulatory effect on type 2 diabetes.展开更多
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 a...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.展开更多
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 e...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.展开更多
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 pu...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.展开更多
Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-...Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-hyperglycemia in comparison to other teas such as green or black tea.However,the bioactive compounds of LYT are still undiscovered so far.For this purpose,5 fractions of LYT were prepared by sequential extraction.The in vitro bioassay results indicated that the ethyl acetate fraction of LYT had the strongest inhibitory effects onα-glucosidase andα-amylase.Fluorescence-quenching analysis and proteinbinding test revealed that the compounds of ethyl acetate fraction could inhibitα-glucosidase andα-amylase activities through binding to enzymes or other mechanisms.All chromatographic peaks of high-performance liquid chromatography(HPLC)of ethyl acetate fraction were separated and collected.The purified compounds were identified by liquid chromatography-mass spectrometry(LC-MS),and subsequently screened by calculating their inhibition ratio onα-glucosidase at the real concentration in LYT infusion.The results showed that(-)-epigallocatechin gallate,(-)-gallocatechin gallate,caffeine,N-ethyl-2-pyrrolidone-substituted flavan-3-ols were effective inhibitors forα-glucosidase.展开更多
Antioxidant andα-glucosidase inhibitiory active compounds of Cercis chinensis flowers were investigated with bio-assay guiding method.Ethyl acetate fraction(CLEa)and n-butanol fraction(CLBu)exhibited antioxidant and...Antioxidant andα-glucosidase inhibitiory active compounds of Cercis chinensis flowers were investigated with bio-assay guiding method.Ethyl acetate fraction(CLEa)and n-butanol fraction(CLBu)exhibited antioxidant andα-glucosidase inhibitiory activity in vitro,and the corresponding active fractions,EaFr.3,EaFr.5 and BuFr.1,exhibited higher antioxidant andα-glucosidase inhibitiory activity than those of other fractions.Eight compounds,ethyl gallate(1),stearic acid(2),docosanoic acid(3),5α-stigmast-9(11)-en-3β-ol(4),kaempferol-3-O-α-rhamnopyranoside(5),vanillic acid(6),fisetin(7),andβ-sitosterol(8),were isolated and identified from CLEa and CLBu.Ethyl gallate shown the highest antioxidant activity by scavenging DPPH radical and reducing ferric compared.Docosanoic acid and vanillic acid shown strongerα-glucosidase inhibitory activity than that of acarbose.展开更多
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 th...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.展开更多
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 ...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.展开更多
Objective:To provide in vitro evidence for antidiabetic activity through potential inhibition of α-glucosidase enzyme,glucose diffusion and enhancement in the wound healing using methanolic extract and fractions from...Objective:To provide in vitro evidence for antidiabetic activity through potential inhibition of α-glucosidase enzyme,glucose diffusion and enhancement in the wound healing using methanolic extract and fractions from Hibiscus sabdariffa Linn.fruit.Methods:The inhibitory action of methanolic extract and fractions of such fruit on aglucosidase enzyme and glucose movement through in vitro assay assessment was reported.Their activities on wound healing were tested using the scratch assay.Results:Ethyl acetate fraction at 50 mg/m L concentration exhibited significant aglucosidase inhibition(95.79 mg/m L) with P < 0.05.At the same concentration,the methanolic extract as well as other fractions revealed lower α-glucosidase inhibition and higher glucose diffusion retardation across the dialysis tube than the control.Ethyl acetate and butanol fractions displayed notably higher glucose diffusion inhibitory activity of 5.21 mmol/L and 5.2 mmol/L,respectively as compared to methanolic extract and n-hexane fraction of 6.58 mmol/L and 6.49 mmol/L,respectively.Conversely,compared to other fractions the methanolic extract and ethyl acetate fraction manifested proliferative effect at the incubation time of 6 h during the wound healing study.Conclusions:It is established that methanolic extract and fractions from H.sabdariffa Linn.fruit can inhibit the α-glucosidase enzyme and glucose movement as well as influence the wound healing activity positively.展开更多
Background:To explore the differences of 14 batches of Citri Reticulatae Pericarpium from different regions.Methods:The main aim of this study was to develop a high-performance liquid chromatography method-photodiode ...Background:To explore the differences of 14 batches of Citri Reticulatae Pericarpium from different regions.Methods:The main aim of this study was to develop a high-performance liquid chromatography method-photodiode array detection for determining the contents of five flavonoids and the chromatographic fingerprints of Citri Reticulatae Pericarpium from different regions.Theα-glucosidase inhibitory activities and antioxidant properties of Citri Reticulatae Pericarpium,based on free-radical scavenging assays against 1,1-diphenyl-2-picrylhydrazyl,2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),and hydroxyl radicals,were estimated and compared.Results:Among the tested compounds,the content of hesperidin(13.386-68.235 mg/g)was the highest and that of hesperitin(0.045-0.277 mg/g)was the lowest.In comparing different sources of Citri Reticulatae Pericarpium,the contents of narirutin in Citri Reticulatae Pericarpium from Guangdong(0.824-0.851 mg/g)and Sichuan(1.069-1.204 mg/g)provinces of China were lower than in other provinces.In contrast,nobiletin(8.429-12.237 mg/g)and tangeretin(3.947-4.613 mg/g)were most abundant in Guangdong sources of Citri Reticulatae Pericarpium,followed by samples from Sichuan Province(nobiletin:6.761-7.658 mg/g;tangeretin:3.422-3.933 mg/g).Correlation analysis showed that nobiletin and tangeretin were the main contributors to the antioxidant capacity,and narirutin was the main active component inhibiting theα-glucosidase activity of Citri Reticulatae Pericarpium.Conclusion:This work revealed that the intrinsic quality of Citri Reticulatae Pericarpium was affected by different growing regions,which provides a scientific basis for controlling the quality of Citri Reticulatae Pericarpium and rationally developing and utilizing Citri Reticulatae Pericarpium.展开更多
Brassica rapa var.rapa(turnip)is an important crop in Qinghai-Tibet Plateau(QTP)with anti-hypoxic effect.Turnip is rich in glucosinolates,isothiocyanates and phenolic compounds with diverse biological activities,invol...Brassica rapa var.rapa(turnip)is an important crop in Qinghai-Tibet Plateau(QTP)with anti-hypoxic effect.Turnip is rich in glucosinolates,isothiocyanates and phenolic compounds with diverse biological activities,involving anti-oxidant,anti-tumor,anti-diabetic,anti-inflammatory,anti-microbial,hypolipidemic,cardioprotective,hepatoprotective,nephroprotective and analgesic properties.In this study,the ethyl acetate(EtOAc)and butanol parts of Brassica rapa were first revealed with inhibitory effects onα-glucosidase,whereas the water part was inactive.Subsequent bioassay-guided isolation on the EtOAc and butanol parts yielded 12 compounds,involving three indole derivatives,indole-3-acetonitrile(1)4-methoxyindole-3-acetonitrile(2)and indole-3-aldehyde(3)two flavonoids,liquiritin(4)and licochalcone A(5)two phenylpropanoids,sinapic acid(6)and caffeic acid(7)two phenylethanol glycosides,2-phenylethylβ-glucopyranoside(8)and salidroside(9)and three other compounds,syringic acid(10)adenosine(11)and(3β,20E)-ergosta-5,20(22)-dien-3-ol(12)Licochalcone A(5)and caffeic acid(7)showedα-glucosidase inhibitory activity with IC 50 values of 62.4±8.0μM and 162.6±3.2μM,comparable to the positive control,acarbose(IC 50=142±0.02μM).Docking study suggested that licochalcone A(5)could well align in the active site ofα-glucosidase(docking score=-52.88)by forming hydrogen bonds(Gln1372,Asp1420,Gln1372,Arg1510),hydrophobic effects(Tyr1251,Tyr1251,Trp1355,Phe1560,Ile1587,Trp1355,Phe1559,Phe1559)andπ-πstacking interaction(Trp1355).This study provides valuable information for turnip as a new resource in searching anti-diabetic candidates.展开更多
Xylariaceae sp.QGS 01,an endophytic fungus isolated from the stem of Quercus gilva Blume showed high-glucosidase inhibitory activity.α-Glucosidase inhibitor have the role as one of carbohydrate-hydrolyzing enzymes to...Xylariaceae sp.QGS 01,an endophytic fungus isolated from the stem of Quercus gilva Blume showed high-glucosidase inhibitory activity.α-Glucosidase inhibitor have the role as one of carbohydrate-hydrolyzing enzymes to postpone absorption of glucose in the digestive organs.The α-glucosidase inhibitor constituents were isolated from the ethyl acetate extract of the mycellium of endophytic fungi Xylariaceae sp.QGS 01 using a bioassay-guided fractionation technique.Further separation and purification of the active fraction led to the isolation of constituents with strong inhibitory activities against-glucosidase:8-hydroxy-6,7-dimethoxy-3-methylisocoumarine(1)with inhibitory concentration(IC50)values against-glucosidase from Saccharomyces cerevisiae of 41.75μg/mL,while quercetin as the standard had an IC50 value of 4.80g/mL.The results of the present study showed that the endophytic fungus Xylariaceae sp.QGS 01 is potentially a rich source of antidiabetic medicine.展开更多
Red rice(Oryza punctata) is a type of unpolished rice which has higher nutritional value compared to white rice or even polished rice. Owing to higher nutritive content and metabolites, dieticians strongly advise red ...Red rice(Oryza punctata) is a type of unpolished rice which has higher nutritional value compared to white rice or even polished rice. Owing to higher nutritive content and metabolites, dieticians strongly advise red rice for peoples with metabolic disorders including diabetics. However, the mechanism of action and contents of secondary metabolites in Indian red rice variety not reported scientifically. Therefore, the present study aimed to evaluate its mechanism of action through inhibitory effect of α-amylase and α-glucosidase. Initially, the whole grain of red rice was macerated with methanol at room temperature for 2 weeks. Then, the dried and powdered, samples at different concentrationfi(2.5, 10, 40, and 80 μg/m L) were employed to nd out in vitro inhibitory effects on α-amylase and α-glucosidase. In addition, an enzyme kinetics of effective extract was calculated by Line-weaver Burk(LWB) plot analysis. Moreover,the valuable metabolites in the efficient methanolic extract were quantified using high performance liquid chromatography(HPLC). The results demonstrated that red rice methanolic extract(RRMEt) possess strong inhibitory activity onα-amylase and α-glucosidase compared with acarbose(P < 0.01). The IC50 values of RRMEt was found to be 29.7 ±7.43 μg/m L for α-amylase and 20.4 ± 0.25 μg/m L for α-glucosidase. LWB indicated that RRMEt is an uncompetitive inhibitor. Further, HPLC analysis revealed protocatechuic acid, catechin, and chlorogenic acids were more abundant in RRMEt among the fourteen metabolites. We conclude, the efficiency of enzyme inhibition through the influence of phenolic compounds in RRMEt.展开更多
Objective:To investigate the inhibitory effect of Telfairia occidentalis Hook f.(Curcubitaceae)(T.occidentalis)leaf on key enzyme linked to type-2 diabetes(α-amylase andα-glucosidase)as well as assess the effect of ...Objective:To investigate the inhibitory effect of Telfairia occidentalis Hook f.(Curcubitaceae)(T.occidentalis)leaf on key enzyme linked to type-2 diabetes(α-amylase andα-glucosidase)as well as assess the effect of blanching(a commonly practiced food processing technique)of the vegetable on these key enzymes.Methods:Fresh leaves of T.occidentalis were blanched in hot water for 10 minutes,and the extracts of both the fresh and blanched vegetables were prepared and used for subsequent analysis.The inhibitory effect of the extract onα-amylase andα-glucosidase activities as well as some antioxidant parameter was determined in vitro.Results:The result revealed that unprocessed T.occidentalis leaf reduce Fe^(3+)to Fe^(2+)and also inhibitedα-amylase andα-glucosidase activities in a dose dependent manner.However,blanching of the leafy vegetables caused a significant(P<0.05)increase in the antioxidant properties but decrease their ability to inhibitα-amylase andα-glucosidase activities.Conclusions:This antioxidant properties and enzyme inhibition could be part of the mechanism by which they are used in the treatment/prevention of type-2 diabetes.However,the blanched vegetable reduces their ability to inhibit bothα-amylase andα-glucosidase activity in vitro.展开更多
Diabetes is an urgent health issue characterized by ethnic and regional variations,and is inseparable from the differ-ent dietary habits.It is worthy to note that the incidence of diabetes in Bai nationality has been ...Diabetes is an urgent health issue characterized by ethnic and regional variations,and is inseparable from the differ-ent dietary habits.It is worthy to note that the incidence of diabetes in Bai nationality has been reported to be much lower than Han in China.As a daily vegetable of Bai,the phytochemical and antidiabetic study of Ottelia acuminata var.acuminata had not been carried out.In this study,41 metabolites with diverse diarylheptanoid(six new ones,Otteacumienes A-F),flavone,sesquiterpenoid,coumarin,lignan,polyacetylene,and alkaloid skeletons were charac-terized from O.acuminata var.acuminata.Among them,the racemic nature of 3 was characterized by chiral resolution and calculated ECD methods.The biological study revealed diarylheptanoids showed significantα-glucosidase inhibi-tory activities with 5 as the most effective one(60-fold stronger than acarbose).Molecular docking studies indicated that these structures have different binding cavities with acarbose.This study demonstrated that O.acuminata var.acuminata might correlated with the low incidence diabetes of Bai and the diarylheptanoids may have potential therapeutic value for diabetes mellitus.展开更多
Ten cucurbitane-type triterpene glycosides,including five new compounds named charantosides H(1),J(2),K(3),momor-characoside A(4),goyaglycoside-l(5),and five known compounds(6-10),were isolated from the EtOAc extract ...Ten cucurbitane-type triterpene glycosides,including five new compounds named charantosides H(1),J(2),K(3),momor-characoside A(4),goyaglycoside-l(5),and five known compounds(6-10),were isolated from the EtOAc extract of Momor-dica charantia fruits.The chemical structures of these compounds were identified by 1D and 2D NMR and HRESIMS spectroscopic analyses.Configurations of new compounds were determined by ROESY correlations and comparison of their 13C NMR data with literature reported values.All compounds were evaluated for their inhibition againstα-glucosidase,in which compounds 2,5,7,8,9 showed moderate inhibitory activities with IC50 values ranging from 28.40 to 63.26μM comparing with the positive control(acarbose,IC5087.65±6.51μM).展开更多
Objective The Morus alba root bark is a well-known Chinese herbal medicine called Sang-Bai-Pi and has often been used to relieve the hyperglycemic symptom of diabetes patients.The current work aims to further explore ...Objective The Morus alba root bark is a well-known Chinese herbal medicine called Sang-Bai-Pi and has often been used to relieve the hyperglycemic symptom of diabetes patients.The current work aims to further explore its bioactive constituents with α-glucosidase inhibitory activity for the potential treatment of diabetes.Methods A combination of different separating techniques including routine column chromatograph and HPLC especially on chiral columns were applied for the isolation of target molecules,while comprehensive spectroscopic experiments comprising MS,NMR,ECD,etc.were carried out to complete the structural assignment.The anti-hyperglycemic property of the isolates was evaluated by an in vitro α-glucosidase inhibitory bioassay.Results Two pairs of new flavanone-monoterpene hybrid enantiomers were isolated and identified,and an interesting phenomenon of mutual transformation between these cometabolites were detected,which resulted in their regio-isomerization and enantiomerization.The bioassay results revealed remarkable α-glucosidase inhibitory activity for these fascinating molecules.Conclusions The Morus alba root bark is a rich source of bioactive flavonoid derivatives and deserves further investigations to develop new potential chemotherapies for diabetes control and treatment.展开更多
There are many reports that divalent alkaline earth, first-row transition metals, and Zn(II) ions have α-glucosidase inhibitory effects. Cu(II) and Zn(II) ions, in particular, have strong α-glucosidase inhibitory ef...There are many reports that divalent alkaline earth, first-row transition metals, and Zn(II) ions have α-glucosidase inhibitory effects. Cu(II) and Zn(II) ions, in particular, have strong α-glucosidase inhibitory effects. Several Schiff bases also display α-glucosidase inhibitory effects. In this study, we focused on safe and highly effective complexes including Zn(II) ion. We prepared and characterized the Zn(II) complexes with four different Schiff bases (N-salicylidene-β-alanine (N-sβ), N-N’-bis (salicylidene) ethylenediamine (N-bsE), N, N’-bis (salicylidene)-phenylenediamine (N-bsP), and 1-[(2-dimethylaminoethylimino) methyl]naphtholate (DMN)) and investigated their α-glucosidase inhibitory effects in vitro, using α-glycosidases from Saccharomyces sp. and rat small intestine, and in vivo, using a sucrose tolerance test. The Zn(II) complexes with DMN showed the highest in vitro and in vivo α-glucosidase inhibitory effects in this study.展开更多
Monitoringα-glucosidase(α-Glu)activity is of great significance for the early diagnosis of typeⅡdiabetes.Here the blue fluorescent carbon dots(CDs)were integrated with two different recognizing molecules,β-cyclode...Monitoringα-glucosidase(α-Glu)activity is of great significance for the early diagnosis of typeⅡdiabetes.Here the blue fluorescent carbon dots(CDs)were integrated with two different recognizing molecules,β-cyclodextrin and phenylboronic acid,for assembling a multifunctional CDs(mCDs)nanoplatform for sensitively analyzingα-Glu and its inhibitors.The hydrolyzed product of 4-nitrophenyl-α-D-glucopyranoside(α-Glu substrate),p-nitrophenol,could efficiently quench the fluorescence of mCDs due to its cooperative molecular recognition withβ-cyclodextrin and phenylboronic acid.The mCDs could be utilized for the detection ofα-Glu activity with the limit of detection of 0.030 U/L.Moreover,the presentα-Glu detection platform revealed a high selectivity,and other natural enzymes showed scarcely any effect on the present mCDs system.The proposed method could be facilely used to screenα-Glu inhibitors with satisfying performance.The rational mCDs is expected to supplement more comprehensive biosensing platforms for highly sensitive and specific recognition of disease-relevant biomarkers with clinical importance.展开更多
基金supported by the Deanship of Scientific Research at Umm Al-Qura University(Grant code:22UQU4331128DSR77).
文摘Objective:To investigate the relationship between triterpenoid saponin content and antioxidant,antimicrobial,and α-glucosidase inhibitory activities of 70%ethanolic,butanolic,aqueous,supernate and precipitate extracts of Juglans regia leaves.Methods:Triterpenoid saponins of different Juglans regia leaf extracts were measured by the vanillin method.Antioxidant activity was evaluated against DPPH and ABTS free radicals.We also assessed α-glucosidase inhibitory and antimicrobial activities of the leaf extracts.Pearson’s correlation coefficient was evaluated to determine the correlation between the saponin content and biological activities.Results:The butanolic extract was most effective against DPPH with an IC50of 6.63μg/mL,while the aqueous extract showed the highest scavenging activity against ABTS free radical with an IC50of 42.27μg/mL.Pearson’s correlation analysis indicated a strong negative correlation (r=-0.956) between DPPH radical scavenging activity (IC50) and the saponin content in the samples examined.In addition,the aqueous extract showed the best α-glucosidase inhibitory activity compared with other extracts.All the extracts had fair antibacterial activity against Bacillus subtilis,Escherichia coli,and Klebsiella pneumoniae except for the aqueous extract.Conclusions:Juglans regia extracts show potent antioxidant,antimicrobial,and α-glucosidase inhibitory activities.There is a correlation between saponin levels in Juglans regia leaf extracts and the studied activities.However,additional research is required to establish these relationships by identifying the specific saponin molecules responsible for these activities and elucidating their mechanisms of action.
基金supported by 2020 College Students Innovation and Entrepreneurship Training Program(X202011810069)the National Natural Science Foundation of China(81460591)。
文摘Objective:To explore the anti-diabetic effects and its underlying mechanism of Annona muricata Linn fruit ethanol extract(AME).Methods:Streptozotocin-induced type 2 diabetic(T2DM)mouse model was constructed.Those diabetic mice were randomly grouped and given 50 mg/kg acarbose or AME(200 mg/kg,100 mg/kg or 50 mg/kg)for four weeks.The body weight,postprandial blood glucose and glycosylated hemoglobin levels were measured during the administration.After the administration,a glucose tolerance test was performed,and the levels of triglycerides,cholesterol and low-density lipoproteins in mice were detected by biochemical test kits.The inhibitory activity of AME onα-glucosidase in vivo and in vitro was determined by enzyme inhibition tests.Results:AME significantly reduced weight gain,postprandial blood glucose,glycosylated hemoglobin and low-density lipoprotein levels in T2DM mice;enhanced glucose tolerance and pancreaticβ-cell function of T2DM mice;inhibitedα-glucosidase activity in mouse intestine in an noncompetitive manner.Conclusion:AME may noncompetitive inhibitα-glucosidase activity and reduce postprandial glucose intake to achieve a therapeutic and regulatory effect on type 2 diabetes.
基金a part of the project titled ’Future Marine Technology Development’ funded by the Ministry of Oceans and Fisheries, Republic of Korea
文摘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.
文摘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.
基金a part of the project titled ‘Future Marine Technology Development’ funded by the Ministry of Oceans and Fisheries,Republic of Korea
文摘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.
基金supported by Natural Science Foundation of China(32072633,32072634,31201335)earmarked fund for China Agriculture Research System(CARS-19)+1 种基金Anhui Key research and development plan(1804b06020367,202004b11020004)Young Elite Scientist Sponsorship Program by National CAST(2016QNRC001)。
文摘Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-hyperglycemia in comparison to other teas such as green or black tea.However,the bioactive compounds of LYT are still undiscovered so far.For this purpose,5 fractions of LYT were prepared by sequential extraction.The in vitro bioassay results indicated that the ethyl acetate fraction of LYT had the strongest inhibitory effects onα-glucosidase andα-amylase.Fluorescence-quenching analysis and proteinbinding test revealed that the compounds of ethyl acetate fraction could inhibitα-glucosidase andα-amylase activities through binding to enzymes or other mechanisms.All chromatographic peaks of high-performance liquid chromatography(HPLC)of ethyl acetate fraction were separated and collected.The purified compounds were identified by liquid chromatography-mass spectrometry(LC-MS),and subsequently screened by calculating their inhibition ratio onα-glucosidase at the real concentration in LYT infusion.The results showed that(-)-epigallocatechin gallate,(-)-gallocatechin gallate,caffeine,N-ethyl-2-pyrrolidone-substituted flavan-3-ols were effective inhibitors forα-glucosidase.
基金This work was supported by Key Project in Science and Technology Agency of Henan Province(192102110112,192102110214 and 182102410083)Innovation Training Program for College Students(201910475107 and MSCXSY2019036).
文摘Antioxidant andα-glucosidase inhibitiory active compounds of Cercis chinensis flowers were investigated with bio-assay guiding method.Ethyl acetate fraction(CLEa)and n-butanol fraction(CLBu)exhibited antioxidant andα-glucosidase inhibitiory activity in vitro,and the corresponding active fractions,EaFr.3,EaFr.5 and BuFr.1,exhibited higher antioxidant andα-glucosidase inhibitiory activity than those of other fractions.Eight compounds,ethyl gallate(1),stearic acid(2),docosanoic acid(3),5α-stigmast-9(11)-en-3β-ol(4),kaempferol-3-O-α-rhamnopyranoside(5),vanillic acid(6),fisetin(7),andβ-sitosterol(8),were isolated and identified from CLEa and CLBu.Ethyl gallate shown the highest antioxidant activity by scavenging DPPH radical and reducing ferric compared.Docosanoic acid and vanillic acid shown strongerα-glucosidase inhibitory activity than that of acarbose.
基金This research was supported by Key Project in Science and Technology Agency of Henan Province(Nos.132102310261 and 142102310147)Natural Science Project in Department of Education of Henan Province(Nos.13B360981 and 14B360011)+1 种基金Henan Province Department of Education Teachers,the backbone of Youth Fund(2013GGJS-220)and Key Project in Science and Technology Agency of Zhengzhou City(No.120140790).
文摘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.
基金the Ministry of Agriculture of Malaysia for NKEA Research Grant Scheme fund (NRGS SP15-0600182)International Islamic University Malaysia for Publication Research Initiative Grant fund (PRIGS18-027-0027)
文摘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.
基金the ministry of higher education of Iraq for financial support
文摘Objective:To provide in vitro evidence for antidiabetic activity through potential inhibition of α-glucosidase enzyme,glucose diffusion and enhancement in the wound healing using methanolic extract and fractions from Hibiscus sabdariffa Linn.fruit.Methods:The inhibitory action of methanolic extract and fractions of such fruit on aglucosidase enzyme and glucose movement through in vitro assay assessment was reported.Their activities on wound healing were tested using the scratch assay.Results:Ethyl acetate fraction at 50 mg/m L concentration exhibited significant aglucosidase inhibition(95.79 mg/m L) with P < 0.05.At the same concentration,the methanolic extract as well as other fractions revealed lower α-glucosidase inhibition and higher glucose diffusion retardation across the dialysis tube than the control.Ethyl acetate and butanol fractions displayed notably higher glucose diffusion inhibitory activity of 5.21 mmol/L and 5.2 mmol/L,respectively as compared to methanolic extract and n-hexane fraction of 6.58 mmol/L and 6.49 mmol/L,respectively.Conversely,compared to other fractions the methanolic extract and ethyl acetate fraction manifested proliferative effect at the incubation time of 6 h during the wound healing study.Conclusions:It is established that methanolic extract and fractions from H.sabdariffa Linn.fruit can inhibit the α-glucosidase enzyme and glucose movement as well as influence the wound healing activity positively.
基金supported by the National Natural Science Foundation of China(No.81872956)National Key R&D Program of China(No.2019YFC1710604)+1 种基金Key Project at Central Government Level(No.2060302)the Science and Technology Project of Tianjin(No.18ZXXYSY00080).
文摘Background:To explore the differences of 14 batches of Citri Reticulatae Pericarpium from different regions.Methods:The main aim of this study was to develop a high-performance liquid chromatography method-photodiode array detection for determining the contents of five flavonoids and the chromatographic fingerprints of Citri Reticulatae Pericarpium from different regions.Theα-glucosidase inhibitory activities and antioxidant properties of Citri Reticulatae Pericarpium,based on free-radical scavenging assays against 1,1-diphenyl-2-picrylhydrazyl,2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),and hydroxyl radicals,were estimated and compared.Results:Among the tested compounds,the content of hesperidin(13.386-68.235 mg/g)was the highest and that of hesperitin(0.045-0.277 mg/g)was the lowest.In comparing different sources of Citri Reticulatae Pericarpium,the contents of narirutin in Citri Reticulatae Pericarpium from Guangdong(0.824-0.851 mg/g)and Sichuan(1.069-1.204 mg/g)provinces of China were lower than in other provinces.In contrast,nobiletin(8.429-12.237 mg/g)and tangeretin(3.947-4.613 mg/g)were most abundant in Guangdong sources of Citri Reticulatae Pericarpium,followed by samples from Sichuan Province(nobiletin:6.761-7.658 mg/g;tangeretin:3.422-3.933 mg/g).Correlation analysis showed that nobiletin and tangeretin were the main contributors to the antioxidant capacity,and narirutin was the main active component inhibiting theα-glucosidase activity of Citri Reticulatae Pericarpium.Conclusion:This work revealed that the intrinsic quality of Citri Reticulatae Pericarpium was affected by different growing regions,which provides a scientific basis for controlling the quality of Citri Reticulatae Pericarpium and rationally developing and utilizing Citri Reticulatae Pericarpium.
基金This work was supported by the Yunnan Science Fund for Excellent Young Scholars,the National Natural Science Foundation of China(81773612)the Youth Innovation Promotion Association,CAS(2013252)the Reserve Talents of Young and Middle-aged Academic and Technical Leaders in Yunnan Province.
文摘Brassica rapa var.rapa(turnip)is an important crop in Qinghai-Tibet Plateau(QTP)with anti-hypoxic effect.Turnip is rich in glucosinolates,isothiocyanates and phenolic compounds with diverse biological activities,involving anti-oxidant,anti-tumor,anti-diabetic,anti-inflammatory,anti-microbial,hypolipidemic,cardioprotective,hepatoprotective,nephroprotective and analgesic properties.In this study,the ethyl acetate(EtOAc)and butanol parts of Brassica rapa were first revealed with inhibitory effects onα-glucosidase,whereas the water part was inactive.Subsequent bioassay-guided isolation on the EtOAc and butanol parts yielded 12 compounds,involving three indole derivatives,indole-3-acetonitrile(1)4-methoxyindole-3-acetonitrile(2)and indole-3-aldehyde(3)two flavonoids,liquiritin(4)and licochalcone A(5)two phenylpropanoids,sinapic acid(6)and caffeic acid(7)two phenylethanol glycosides,2-phenylethylβ-glucopyranoside(8)and salidroside(9)and three other compounds,syringic acid(10)adenosine(11)and(3β,20E)-ergosta-5,20(22)-dien-3-ol(12)Licochalcone A(5)and caffeic acid(7)showedα-glucosidase inhibitory activity with IC 50 values of 62.4±8.0μM and 162.6±3.2μM,comparable to the positive control,acarbose(IC 50=142±0.02μM).Docking study suggested that licochalcone A(5)could well align in the active site ofα-glucosidase(docking score=-52.88)by forming hydrogen bonds(Gln1372,Asp1420,Gln1372,Arg1510),hydrophobic effects(Tyr1251,Tyr1251,Trp1355,Phe1560,Ile1587,Trp1355,Phe1559,Phe1559)andπ-πstacking interaction(Trp1355).This study provides valuable information for turnip as a new resource in searching anti-diabetic candidates.
文摘Xylariaceae sp.QGS 01,an endophytic fungus isolated from the stem of Quercus gilva Blume showed high-glucosidase inhibitory activity.α-Glucosidase inhibitor have the role as one of carbohydrate-hydrolyzing enzymes to postpone absorption of glucose in the digestive organs.The α-glucosidase inhibitor constituents were isolated from the ethyl acetate extract of the mycellium of endophytic fungi Xylariaceae sp.QGS 01 using a bioassay-guided fractionation technique.Further separation and purification of the active fraction led to the isolation of constituents with strong inhibitory activities against-glucosidase:8-hydroxy-6,7-dimethoxy-3-methylisocoumarine(1)with inhibitory concentration(IC50)values against-glucosidase from Saccharomyces cerevisiae of 41.75μg/mL,while quercetin as the standard had an IC50 value of 4.80g/mL.The results of the present study showed that the endophytic fungus Xylariaceae sp.QGS 01 is potentially a rich source of antidiabetic medicine.
基金Department of Science and Technology,Government of India,for providing INSPIRE Fellowshipauthorities of Annamalai University for providing necessary support
文摘Red rice(Oryza punctata) is a type of unpolished rice which has higher nutritional value compared to white rice or even polished rice. Owing to higher nutritive content and metabolites, dieticians strongly advise red rice for peoples with metabolic disorders including diabetics. However, the mechanism of action and contents of secondary metabolites in Indian red rice variety not reported scientifically. Therefore, the present study aimed to evaluate its mechanism of action through inhibitory effect of α-amylase and α-glucosidase. Initially, the whole grain of red rice was macerated with methanol at room temperature for 2 weeks. Then, the dried and powdered, samples at different concentrationfi(2.5, 10, 40, and 80 μg/m L) were employed to nd out in vitro inhibitory effects on α-amylase and α-glucosidase. In addition, an enzyme kinetics of effective extract was calculated by Line-weaver Burk(LWB) plot analysis. Moreover,the valuable metabolites in the efficient methanolic extract were quantified using high performance liquid chromatography(HPLC). The results demonstrated that red rice methanolic extract(RRMEt) possess strong inhibitory activity onα-amylase and α-glucosidase compared with acarbose(P < 0.01). The IC50 values of RRMEt was found to be 29.7 ±7.43 μg/m L for α-amylase and 20.4 ± 0.25 μg/m L for α-glucosidase. LWB indicated that RRMEt is an uncompetitive inhibitor. Further, HPLC analysis revealed protocatechuic acid, catechin, and chlorogenic acids were more abundant in RRMEt among the fourteen metabolites. We conclude, the efficiency of enzyme inhibition through the influence of phenolic compounds in RRMEt.
基金the financial backing of International Foundation for Science(IFS)for granting Dr.G.Oboh the research grant forthe execution of this work(IFS Grant Agreement No.E/4625-1)
文摘Objective:To investigate the inhibitory effect of Telfairia occidentalis Hook f.(Curcubitaceae)(T.occidentalis)leaf on key enzyme linked to type-2 diabetes(α-amylase andα-glucosidase)as well as assess the effect of blanching(a commonly practiced food processing technique)of the vegetable on these key enzymes.Methods:Fresh leaves of T.occidentalis were blanched in hot water for 10 minutes,and the extracts of both the fresh and blanched vegetables were prepared and used for subsequent analysis.The inhibitory effect of the extract onα-amylase andα-glucosidase activities as well as some antioxidant parameter was determined in vitro.Results:The result revealed that unprocessed T.occidentalis leaf reduce Fe^(3+)to Fe^(2+)and also inhibitedα-amylase andα-glucosidase activities in a dose dependent manner.However,blanching of the leafy vegetables caused a significant(P<0.05)increase in the antioxidant properties but decrease their ability to inhibitα-amylase andα-glucosidase activities.Conclusions:This antioxidant properties and enzyme inhibition could be part of the mechanism by which they are used in the treatment/prevention of type-2 diabetes.However,the blanched vegetable reduces their ability to inhibit bothα-amylase andα-glucosidase activity in vitro.
基金supported financially by the Second Tibetan Plateau Scientific Expedition and Research program (2019QZKK0502)State Key Laboratory of Phytochemistry and Plant Resources in West China (E0230211Z1 and P2019-ZZ05).
文摘Diabetes is an urgent health issue characterized by ethnic and regional variations,and is inseparable from the differ-ent dietary habits.It is worthy to note that the incidence of diabetes in Bai nationality has been reported to be much lower than Han in China.As a daily vegetable of Bai,the phytochemical and antidiabetic study of Ottelia acuminata var.acuminata had not been carried out.In this study,41 metabolites with diverse diarylheptanoid(six new ones,Otteacumienes A-F),flavone,sesquiterpenoid,coumarin,lignan,polyacetylene,and alkaloid skeletons were charac-terized from O.acuminata var.acuminata.Among them,the racemic nature of 3 was characterized by chiral resolution and calculated ECD methods.The biological study revealed diarylheptanoids showed significantα-glucosidase inhibi-tory activities with 5 as the most effective one(60-fold stronger than acarbose).Molecular docking studies indicated that these structures have different binding cavities with acarbose.This study demonstrated that O.acuminata var.acuminata might correlated with the low incidence diabetes of Bai and the diarylheptanoids may have potential therapeutic value for diabetes mellitus.
基金supported by a program of the National Natural Science Foundation of China(Nos.31872675 and 81373288)the cooperation program between Chinese Academy of Sciences and Guangdong Province(2013B09110011).
文摘Ten cucurbitane-type triterpene glycosides,including five new compounds named charantosides H(1),J(2),K(3),momor-characoside A(4),goyaglycoside-l(5),and five known compounds(6-10),were isolated from the EtOAc extract of Momor-dica charantia fruits.The chemical structures of these compounds were identified by 1D and 2D NMR and HRESIMS spectroscopic analyses.Configurations of new compounds were determined by ROESY correlations and comparison of their 13C NMR data with literature reported values.All compounds were evaluated for their inhibition againstα-glucosidase,in which compounds 2,5,7,8,9 showed moderate inhibitory activities with IC50 values ranging from 28.40 to 63.26μM comparing with the positive control(acarbose,IC5087.65±6.51μM).
基金Financial support is from the Natural Science Foundation of Shandong Province for Distinguished Young Scholars(No.JQ201721).
文摘Objective The Morus alba root bark is a well-known Chinese herbal medicine called Sang-Bai-Pi and has often been used to relieve the hyperglycemic symptom of diabetes patients.The current work aims to further explore its bioactive constituents with α-glucosidase inhibitory activity for the potential treatment of diabetes.Methods A combination of different separating techniques including routine column chromatograph and HPLC especially on chiral columns were applied for the isolation of target molecules,while comprehensive spectroscopic experiments comprising MS,NMR,ECD,etc.were carried out to complete the structural assignment.The anti-hyperglycemic property of the isolates was evaluated by an in vitro α-glucosidase inhibitory bioassay.Results Two pairs of new flavanone-monoterpene hybrid enantiomers were isolated and identified,and an interesting phenomenon of mutual transformation between these cometabolites were detected,which resulted in their regio-isomerization and enantiomerization.The bioassay results revealed remarkable α-glucosidase inhibitory activity for these fascinating molecules.Conclusions The Morus alba root bark is a rich source of bioactive flavonoid derivatives and deserves further investigations to develop new potential chemotherapies for diabetes control and treatment.
文摘There are many reports that divalent alkaline earth, first-row transition metals, and Zn(II) ions have α-glucosidase inhibitory effects. Cu(II) and Zn(II) ions, in particular, have strong α-glucosidase inhibitory effects. Several Schiff bases also display α-glucosidase inhibitory effects. In this study, we focused on safe and highly effective complexes including Zn(II) ion. We prepared and characterized the Zn(II) complexes with four different Schiff bases (N-salicylidene-β-alanine (N-sβ), N-N’-bis (salicylidene) ethylenediamine (N-bsE), N, N’-bis (salicylidene)-phenylenediamine (N-bsP), and 1-[(2-dimethylaminoethylimino) methyl]naphtholate (DMN)) and investigated their α-glucosidase inhibitory effects in vitro, using α-glycosidases from Saccharomyces sp. and rat small intestine, and in vivo, using a sucrose tolerance test. The Zn(II) complexes with DMN showed the highest in vitro and in vivo α-glucosidase inhibitory effects in this study.
基金supported by National Natural Science Foundation of China(Nos.32202171,22274121 and 22274123)。
文摘Monitoringα-glucosidase(α-Glu)activity is of great significance for the early diagnosis of typeⅡdiabetes.Here the blue fluorescent carbon dots(CDs)were integrated with two different recognizing molecules,β-cyclodextrin and phenylboronic acid,for assembling a multifunctional CDs(mCDs)nanoplatform for sensitively analyzingα-Glu and its inhibitors.The hydrolyzed product of 4-nitrophenyl-α-D-glucopyranoside(α-Glu substrate),p-nitrophenol,could efficiently quench the fluorescence of mCDs due to its cooperative molecular recognition withβ-cyclodextrin and phenylboronic acid.The mCDs could be utilized for the detection ofα-Glu activity with the limit of detection of 0.030 U/L.Moreover,the presentα-Glu detection platform revealed a high selectivity,and other natural enzymes showed scarcely any effect on the present mCDs system.The proposed method could be facilely used to screenα-Glu inhibitors with satisfying performance.The rational mCDs is expected to supplement more comprehensive biosensing platforms for highly sensitive and specific recognition of disease-relevant biomarkers with clinical importance.
