Introduction
Medical research present that postprandial hyperglycemia is a key threat issue for heart problems in diabetics,1 thus, controlling postprandial blood glucose is of nice significance in decreasing the issues of diabetes. The complicated carbohydrates break right down to glucose, by way of α-amylase enzymes, and result in the fast absorption of glucose into the bloodstream resulting in hyperglycemia.2 Pancreatic α-amylase is a key enzyme in catalyzing the preliminary step of complicated carbohydrates (starch and glycogen) into shorter oligosaccharides, that are degraded to glucose by α-amylase within the small gut.3 α-Amylase inhibitors primarily inhibit the hydrolysis of polysaccharides into glucose by competing with the maltase and α-amylase on the floor of the small gut mucosa, thereby delaying the absorption of sugars, and decreasing postprandial hyperglycemia, the stimulation of pancreatic islet β cells, and the insulin secretion.4 So, these appropriate inhibitors had been thought of for use to regulate and regulate the exercise of α-amylase for the remedy of diabetes. Nonetheless, there are too few forms of α-amylase inhibitors in scientific functions. Furthermore, there are a number of adversarial reactions of α-amylase inhibitors in scientific makes use of, akin to gastrointestinal discomfort (bloating, stomach ache) and so forth.5,6 Due to this fact, searching for high-efficiency α-amylase inhibitors from pure merchandise is attracting increasingly more consideration.7,8
Polygonum capitatum (Polygonum capitatum Buch.-Ham. ex D. Don) belongs to the Polygonaceae, genus Polygonum, primarily distributed in Hunan, Hubei, Sichuan, and Guizhou provinces in China. Earlier research have confirmed that P. capitatum has a major inhibitory exercise towards α-glucosidase, and insulin sensitization impact.9,10 Our earlier examine has revealed P. capitatum possessed α-amylase inhibition impact.11 As a steady examine, we used α-amylase take a look at and OSTT experiment to bio-guided hint the impact fraction of P. capitatum, which recognized two new triterpenoid saponins with anti-α-amylase exercise. Furthermore, the underlying believable molecular targets had been additional explored by molecular docking evaluation.
Supplies and Strategies
Supplies
The aerial a part of P. capitatum was collected from Bozhou, Anhui province in China in Might 2008. The plant was recognized and deposited in College of Pharmacy of Second Army Medical College (PC20080517). Distilled natural solvents used for extraction and purification included methanol, ethanol, petroleum ether, ethyl acetate, n-butanol, and acetonitrile, whereas the chemical compounds used for spectroscopic evaluation had been deuterated grades. Chromatographic separations had been carried out on Silica gel (200–300 and 300–400 mesh) (Sino Pharm, Shanghai, China), ODS RP-18 (50 µm) (Merck, Darmstadt, Germany), and HL-20 (GE Sephadex, MA, USA) columns. Silica GF254 plates (0.25 mm, Aladdin, Shanghai, China) and ODS RP-18 F254S (0.25 mm, Merck) plates had been used for thin-layer chromatography (TLC) and detection achieved by spraying with 5% H2SO4 in ethanol (v/v), adopted by heating.
α-Amylase was bought from Sigma-Aldrich (#A4268, Saint Louis, MO, USA). 6-week-old male ICR mice (physique weight 22±3 g) had been obtained from Shanghai SLAC Laboratory Animal Co. Ltd and saved underneath managed environmental situations at room temperature (22±2 °C) and humidity (50±10%). The 12/12 h mild/darkish (8 am–8 pm) cycle was maintained all through the examine. Blood glucose take a look at strips had been bought from Main Biosystem Corp (Taipei, China). Starch was obtained from Shandong Shengqi Biology Co., Ltd, and acarbose was bought from Bayer (Leverkusen, Germany).
OSTT (Oral Starch Tolerance Check)
Forty mice had been divided into 5 teams (n=8): the management group (Con, water); P. capitatum group (PC, 1200 mg/kg), n-butanol fraction group (PCB, 400 mg/kg), mannequin group (Starch, 2000 mg/kg), and constructive group (Acarbose, 25 mg/kg). Briefly, forty ICR mice had been reared adaptively for two–3 days, and randomly grouped in response to physique weight (n=8). Meals and litter had been eliminated 12 hours earlier than the experiment. Acarbose (50 mg), PC (1200 mg), and PCB (200 mg) had been dissolved in 5 mL 0.5% sodium carboxymethyl cellulose (CMCNa), respectively. Then, all above samples had been blended with 2.5 g/kg starch in equal quantity after which administered by gavage collectively. The administration quantity was 0.1 mL/10 g physique weight, and the management group was given an equal quantity of car. Blood glucose was measured at 30 min, 60 min and 120 min after starch administration. The blood glucose earlier than administration was recorded as 0 min. The animal experiments had been accepted by the Ethics Committee of Second Army Medical College (Shanghai, China), in response to the Information for the Care and Use of Laboratory Animal revealed by the Nationwide Institutes of Well being (Bethesda, MD, USA).
α-Amylase Exercise
Six teams, together with 5 pattern teams, and constructive group (acarbose), had been put in 96-well plates, every with 6 replicate wells. The operation methodology is as follows: 25 μL pattern answer, distilled water, and 12.5 μL α-amylase answer (27.8 μg/mL) had been transferred into 96-well plates, and incubated at 37 °C for 10 min. Then, 12.5 μL starch answer was added to every nicely, and incubated at 37 °C for 10 min. After that, 500 μL colour reagent was added to every nicely to cease the response. The absorbance (A) was measured at 630 nm wavelength, which displays the exercise of amylase. The calculation components of the inhibition charge (%) is as follows:
Inhibition charge (%)=[1–(A sample without enzyme–A sample with enzyme)/(A blank control without enzyme–A blank control with enzyme)]×100%.
Kinetic Research of α-Amylase Inhibition
On this examine, PCB was chosen to carry out the kinetic examine primarily based on earlier examine.12 In short, 12.5 μL of α-amylase answer (27.8 μg/mL) along with 25 μL of the PCB (600 μg/mL) was incubated for 10 min at 25 °C whereas the management group was incubated with 12.5 μL of 0.5% CMCNa. 12.5 µL of varied concentrations of starch answer (0.3125 mg/mL, 0.625 mg/mL, 1.25 mg/mL, 2.5 mg/mL, 5.0 mg/mL) had been added into the response system incubating for 10 min at 25 °C, which had been adopted by boiling for five min with 100 µL of three,5-dinitrosalicylic acid (DNS) for terminating the response. The decreasing sugars had been decided primarily based on maltose normal curve utilizing spectrophotometry (630 nm). A Lineweaver–Burk double reciprocal curve was plotted utilizing 1/[S] because the abscissa and 1/v because the ordinate to find out the kind of inhibition of PCB to α-amylase, through which v is response velocity and [S] is substrate focus.
Isolation of Elements of P. capitatum
Air-dried P. capitatum (18 kg) was floor into powder and extracted with 80% ethanol, and concentrated with a rotary evaporator underneath strain to yield crude (2730 g). The crude was suspended in distilled water (1.5 L), and fractioned with petroleum ether (PCP), ethyl acetate (PCE), n-butanol (PCB), and water (PCW). The n-butanol (800 g) fraction was topic to microporous resin (3000 g), and eluted with distilled water, 10% ethanol, 30% ethanol, 70% ethanol, and 95% ethanol, to acquire 5 fractions (Fr.1–Fr.5) primarily based on TLC evaluation. Fr.3 (22.07 g) was additional fractionated through MCI column chromatography, and eluted with distilled water, 10% methanol, 30% methanol, 50% methanol, 70% methanol, and 95% methanol, to acquire seven fractions (Fr.3-1–Fr.3-7). The Fr.3-4 (287 mg) subfraction was purified through column chromatography on an ODS RP-18 column and eluted utilizing H2O–MeOH at a gradient of 10% (v/v) to yield compounds 1 (5.7 mg) and 2 (5.5 mg).
Molecular Docking
The three-dimensional (3D) construction of α-amylase (PDB id: 1DHK) had been obtained from protein information financial institution. PyMOL v2.5 was used to research the protein construction, with crystallographic waters eradicating. After that, autodocktool-1.5.6 was used so as to add hydrogen atoms in earlier construction with GA run 10. The 3D interactions of the docked ligands had been visualized utilizing autodocktool-1.5.6, to research their relative positional relationships.
Statistical Evaluation
Knowledge are expressed because the imply±SD for this analysis. Statistical comparisons of the outcomes had been carried out utilizing one-way evaluation of variance (ANOVA), with considerably completely different at p<0.05 by utilizing publish hoc Tukey’s take a look at.
Outcomes
α-Amylase Inhibition Screening
Within the seek for phytocomponents with α-amylase and α-glucosidase inhibition actions, ethanol extracts of P. capitatum (PC) and its fractioned elements (PCP, PCE, PCB, and PCW) had been first chosen for organic analysis. In our analysis, all samples had been ready in 139 μg/mL (Table 1), and the inhibitory charge of the constructive management drug acarbose was recorded as 100%. From Table 1, PC and PCB confirmed robust α-amylase inhibition. Particularly for PCB elements, the α-amylase inhibitory values had been 147.37±10.82%, which confirmed stronger exercise than constructive medication.
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Desk 1 PC and Completely different Fractions In opposition to α-Amylase and α-Glucosidase Inhibitory Impact (n=3) |
From the outcomes of in vitro screening, it may be preliminarily decided that the n-butanol fractioned a part of P. capitatum has robust enzyme inhibitory exercise on α-amylase, which guided us to discover the lively elements. The mode of inhibition of α-amylase exercise by the PCB was decided utilizing the Lineweaver–Burk plot which confirmed that PCB displayed a noncompetitive inhibition of the enzyme exercise (Figure 1).
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Determine 1 Inhibition kinetics of P. capitatum n-butanol fraction (PCB) towards α-amylase. |
Inhibition of PC and PCB in Starch Digestion
From the above outcomes, PCB has confirmed a possible hypoglycemic impact. With the intention to verify this speculation, we did the experimental take a look at for decreasing blood glucose with extract of P. capitatum (PC) and its fractioned elements (PCB) in starch-induced hyperglycemia mice. OSTT confirmed that PC and PCB exerted glucose inhibition as in contrast with the mannequin group (Table 2), particularly for the PCB remedy, the glucose ranges had been very near acarbose from 30 min to 120 min. And the altered pattern of blood glucose ranges proven as AUC additionally confirmed PCB was very potent when put next with the reference drug acarbose (Table 2), suggesting the helpful impact of PCB on suppressing starch digestion.
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Desk 2 The Decreasing Blood Glucose of PC and PCB in Starch-Induced Mice ( |
Structure Characterization of Compounds 1 and 2
Compound 1 (Figure 2), remoted as a white powder, was decided to have a molecular components of C48H78O20 by its HRESIMS (m/z 997.4984, [M+Na]+ calc. 974.5091) and NMR information evaluation (Supplementary Figure S1). The IR absorptions instructed the presence of hydroxyl (3422 cm−1), and carbonyl (1738 cm−1). The 1H-NMR spectrum (Table 3, Supplementary Figure S2) of 1 displayed a number of attribute proton alerts for seven methyl proton alerts at δH 1.82 (3H, s), 1.74 (3H, s), 1.72 (3H, s), 1.09 (3H, s), 0.86 (3H, d, J = 6.4 Hz), 0.93 (3H, s), and 1.69 (3H, d, J = 6.4 Hz). As well as, an olefinic proton sign at δH 5.51 (1H, d, J = 6.8 Hz), and three anomeric methines at δH 6.13 (1H, d, J = 7.8 Hz), 5.84 (1H, brs), 4.96 (1H, d, J = 1.8 Hz) had been noticed within the 1H-NMR spectrum. Within the 13C-NMR and DEPT NMR spectra of 1 (Supplementary Figures S3 and S4), seven major carbon alerts at δC 16.6, 18.8, 17.8, 24.2, 21.7, 18.8, and 19.8 had been readily assigned to seven methyl teams, one quaternary carbon at δC 176.2 was assigned to carbonyl teams, and two olefinic carbon alerts at δC 126.8 and 138.2 had been detected. Furthermore, within the 13C-NMR spectra of 1, three alerts at δC 96.9, 105.4, and 102.7 had been assigned to the anomeric carbons for 2 glucoses and one L-rhamnose with the help of HMQC and 1H–1H COSY spectrum (Figure 3, Supplementary Figures S5 and S6). The configurations of anomeric protons had been outlined as α-glucose, β-glucose, and α-rhamnose primarily based on the coupling fixed at δH 4.96 (1H, d, J = 1.8 Hz), 6.13 (1H, d, J = 7.8 Hz), 5.84 (1H, brs), respectively. The sugar residues had been additional recognized as D-glucose and L-rhamnose in response to acid hydrolysis and TLC comparability primarily based on the strategies beforehand reported. The 1H-NMR and 13C-NMR spectroscopic information instructed that the skeleton of 1 was similar to Terminolic acid,13 aside from the presence of sugar moieties in 1. The double bond was positioned between C-12 and C-13 in view of the HMBC correlations of H-18 (δH 2.49) with C-12 (δC 126.8) and C-13 (δC 138.2) (Supplementary Figure S7). The chemical shifts of C-6, C-2 and C-3 at δC 67.9, 69.5 and 78.7 instructed the equatorial place of the hydroxyl teams at C-6, C-2 and C-3. Within the NOESY spectrum of 1, the apparent cross alerts of H-2 (δH 4.65)/H-25 (δH 1.74), H-2 (δH 4.65)/H-23 (δH 1.82), H-5 (δH 1.98)/H-24 (δH 4.06) and H-3 (δH 4.08)/H-5 (δH 1.98) additional confirmed the stereochemistries of H-2, H-3 and the presence of an oxygen atom linked to C-24, whereas the correlation between H-6 (δH 5.07) and H-24 (δH 4.06) within the NOESY spectrum verified the stereochemistry of H-6. A glucose residue was confirmed to be linked to C-28 of the aglycone as a result of HMBC correlation between the anomeric proton at δH 6.13 (1H, d, J = 7.8 Hz) and the methylene sign at δC 176.2 (C-28). The opposite two sugar moieties had been verified by the next essential HMBC correlations from H-1″ (δH 4.96) of Glc-1″ to C-4ʹ (δC 71.5), and H-1″ʹ (δH 5.84) of Rha to C-4″ (δC 78.8) of Glc-1″ (Figure 3). Lastly, compound 1 was established as 2α,3β,6β,24-tetrahydroxy-olean-13-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1→3)-O-α-D-glucopyranosyl-(1→4)-O-β-D-glucopyranosyl ester.
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Desk 3 NMR Knowledge for Compounds 1 and 2 (in C5D5N, δ in ppm, J in Hz) |
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Determine 2 Buildings of compounds 1 and 2. |
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Determine 3 Key HMBC ( |
Compound 2 (Figure 2), remoted as a white powder, was decided to have a molecular components of C48H78O19 by its HRESIMS (m/z 959.5227 [M+H]+, calc. 958.5137) and NMR information evaluation (Supplementary Figure S8). The IR absorptions instructed the presence of hydroxyl (3421 cm−1), and carbonyl (1738 cm−1). Comparability of the 1H-NMR and 13C-NMR information (Table 3; Supplementary Figures S9 and S10) of 1 and 2, instructed the chemical constructions of those two compounds had been very related, besides the apparent chemical shift of C-6. The upfield chemical shift of C-6 at δC 34.1 in 2 instructed the hydroxyl group was changed with a hydrogen in contrast with 1, which was confirmed by the looks of secondary carbon at δC 34.1 within the DEPT and HMQC spectrum (Supplementary Figures S11 and S12). The double methyl proton sign assigned to H-29 at δH 0.93 (3H, d, J = 3.12 Hz) confirmed an HMBC correlation with C-18 (δC 54.1), whereas one other double methyl proton sign assigned to H-30 at δH 0.89 (3H, d, J = 2.40 Hz) exhibited HMBC correlations with C-19 (δC 40.2) and C-21 (δC 31.7), suggesting the ursane-type aglycone of two (Supplementary Figure S13). Within the NOESY spectrum of 2 (Supplementary Figure S14), the apparent cross alerts of H-2 (δH 4.70)/H-25 (δH 1.16), H-2 (δH 4.70)/H-23 (δH 1.11), H-5 (δH 2.35)/H-24 (δH 4.24) and H-3 (δH 4.13)/H-5 (δH 2.35) additional confirmed the stereochemistries of H-2, H-3 and the presence of an oxygen atom linked to C-24. All of the spectroscopic information in 2 had been similar to 2α,3β,24-trihydroxy-olean-13-en-28-oic acid.14 The sugar chain at C-28 of the aglycone was verified by the next essential HMBC and 1H–1H COSY correlations (Supplementary Figures S13 and S15) from H-1ʹ (δH 6.123) of Glc-1ʹ to C-28 (δC 177.2), H-1″ (δH 5.02) of Glc-1″ to C-4ʹ (δC 71.9) of Glc-1″, and H-1″ʹ (δH 5.84) of Rha to C-4″ (δC 78.9) of Glc-1″ (Figure 2). Lastly, compound 2 was established as 2α, 3β, 24-trihydroxy-olean-13-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→4)-O-β-D-glucopyranosyl ester.
α-Amylase Inhibition and Molecular Docking of 1 and a couple of
Within the current examine, compounds 1 and 2 had been evaluated for his or her inhibitory results towards α-amylase (Table 4). Though, the constructions of 1 and 2 had been very related, the α-amylase inhibitory results had been somewhat bit completely different. Thus, determining the construction–exercise relationship (SAR) of those triterpene saponins will profit construction modification of pure product. With the intention to exhibit the potential of mechanism of those compounds, molecular docking of the compounds was carried out towards α-amylase (1DHK). Apparently, the binding vitality of 1 was larger than that of 2 (Table 4), which was in keeping with the α-amylase inhibition impact. To additional visualize the binding web site, the interplay fashions of triterpene saponins with 1DHK are proven in Figure 4. The evaluation suggests that there have been 4 amino acid residues (Ser289, Professional332, Asp402, Arg398) within the lively web site of 1DHK interacting with 1 by hydrogen bonding (Figure 4A), whereas compound 2 bounded with three amino acid resides (Ser289, Professional332, Arg421) of 1DHK (Figure 4B), suggesting that the expected variety of facet chains of 1DHK lively web site concerned within the binding interplay with a triterpene saponins is essentially correlated with the binding affinity of the triterpene saponins to the enzyme.
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Desk 4 α-Amylase Inhibition and Binding Power of 1 and 2 |
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Determine 4 Molecular docking for binding interactions between compound 1 (A), compound 2 (B) and α-amylase. |
Dialogue
Diabetes mellitus (DM) is a sort of metabolic illness attributable to impaired insulin motion or inadequate secretion. It’s primarily attributable to metabolic problems of sugar, fats, and protein.15 It’s characterised by persistent elevated blood sugar and accompanied by the incidence of multi-system and multi-organ issues. Starch, derived from varied meals, is the principle supply of blood sugar, which may be absorbed after α-amylase hydrolysis to generate monosaccharides.16 α-Amylase is principally originated from the pancreas, abdomen, and small gut and has an essential affect on the construction of glycosyls, which might hydrolyze the glycosidic bonds in varied sugar-containing compounds by endo or exocytosis.17 Due to this fact, α-amylase is a key enzyme that regulates postprandial blood sugar for the remedy of diabetes. On this examine, bio-guided isolation of P. capitatum, primarily based on α-glucosidase and α-amylase inhibition screening, yielded two new triterpenoid saponins. Furthermore, the potential binding websites of those triterpenoid saponins for α-amylase was evaluated in response to molecular docking evaluation, which is perhaps helpful for construction modification of triterpenoid saponins for attenuating blood sugar stage.
Starch digestibility has been reported to narrate to elevated postprandial blood glucose. One of many methods to scale back postprandial hyperglycemia is to restrict the exercise of carbohydrate digestive enzymes within the intestinal tract. α-Amylase is the important thing enzyme that degrades the polymeric substrate into shorter oligomers by catalyzing the hydrolysis of α-1,4-glucan linkages current in starch, maltodextrins, and different associated carbohydrates.18 Thus, pursuing environment friendly α-amylase inhibitor can scale back the excessive frequency of postprandial hyperglycaemia in diabetes. Because of the extremely considerable compounds in nature and for his or her promising organic actions, vegetation supply glorious alternate options to handle postprandial hyperglycaemia through inhibiting α-amylase. Polygonum capitatum belongs to the Polygonaceae, genus Polygonum, and has been reported to be concerned in clearing warmth and draining dampness in TCM idea, which is perhaps related to hypoglycemia. In our analysis, we used α-amylase inhibitory experiment to guided separate lively components in P. capitatum. In contrast with the entire plant extract, the n-butanol fractioned half confirmed extra α-amylase inhibitory actions. Thus, n-butanol fractioned half was chosen to analyze the lively components of P. capitatum.
After cautious isolation of the n-butanol half, two new triterpenoid saponins had been recognized. Earlier research have revealed varied triterpenoids exhibited α-glucosidase inhibitory exercise. As well as, construction–exercise relationship (SAR) evaluation indicated that the facet chain construction performs a significant position within the inhibition of α-glucosidase exercise.19 Primarily based on this speculation, Nie et al constructed a linkage between oleanolic acid and cinnamic amides, and confirmed robust α-glucosidase inhibitory exercise.20 In our analysis, the facet chains (three sugar teams) in 1 and 2 had been binding to amino acid residues of α-amylase, which was constant to the earlier examine after molecular docking evaluation.19
Molecular docking evaluation instructed that the interplay of hydrogen between amino acid residue and triterpenoid saponins might play an essential position in inhibiting amylase (Figure 4). Earlier X-crystal research of α-amylase have revealed varied amino acid residues (Asp197, Glu233 and Asp300) had been regarded as essential residue for α-amylase catalysis, through which Asp197 was thought of a catalytic nucleophilic reagent within the technique of starch hydrolysis, whereas Asp300 is principally used for substrate orientation optimization.21–23 Within the examine of the binding properties of the compound 1 (Figure 4), the hydrogen at H-6″ varieties connections each with Arg398 and Asp402, whereas two hydrogen bond contacts with Ser289 and Professional332 in Glc-1ʹ. In the meantime, Figure 3B exhibits the binding properties of the compound 2, the place two hydrogen bond contacts with Ser289, Professional332, and Arg421 in Glc-1ʹ. Comparability the constructions between 1 and 2, each hydrogen at H-6ʹ in Glc-1ʹ shaped reference to Ser289 and Professional33. Nonetheless, 1,4-glycosidic bond in 2 varieties a extra inflexible construction than 1,3-glycosidic bond of 1, which made a better distance from the lively web site (Asp402). General, the in silico evaluation of the ligand–protein interplay of recent triterpenoid saponins with amino acid residues gave credence to the inhibitory impact of triterpenoid saponins reported on this examine.
Conclusion
We used α-amylase and α–amylase screening methodology to information isolation of two novel triterpenoid saponins (1 and 2) from the n-butanol fractioned a part of P. capitatum. Each compounds confirmed α-amylase inhibitory impact, though there was somewhat exercise distinction for them. Docking simulation and binding affinity experiments revealed that compound 1 was simpler in inhibiting α-amylase, and revealed a potential mechanism of 1 and 2 in α-amylase inhibition. Furthermore, the lively group of 1 and 2 in α-amylase inhibition would possibly present a brand new sight of structural modification of triterpenoid saponins in screening lively compounds of α-amylase inhibition.
Acknowledgments
The authors acknowledge the College of Pharmacy in Second Army Medical College for the assist.
Funding
This analysis mission was supported by the Nationwide Key R&D Program of China (2019YFC1711000).
Disclosure
The authors report no conflicts of curiosity on this work.
References
1. Ceriello A. Postprandial hyperglycemia and diabetes issues: is it time to deal with? Diabetes. 2005;54(1):1–7. doi:10.2337/diabetes.54.1.1
2. Mata R, Cristians S, Escandón-Rivera S, Juárez-Reyes Okay, Rivero-Cruz I. Mexican antidiabetic herbs: invaluable sources of inhibitors of α-glucosidases. J Nat Prod. 2013;76(3):468–483. doi:10.1021/np300869g
3. Kajaria D, Ranjana TJ, Tripathi YB, Tiwari S. In-vitro α amylase and glycosidase inhibitory impact of ethanolic extract of antiasthmatic drug – Shirishadi. J Adv Pharm Technol Res. 2013;4(4):206–209. doi:10.4103/2231-4040.121415
4. Tan Y, Chang SKC, Zhang Y. Comparability of α-amylase, α-glucosidase and lipase inhibitory exercise of the phenolic substances in two black legumes of various genera. Meals Chem. 2017;214:259–268. doi:10.1016/j.foodchem.2016.06.100
5. Inzucchi SE, Matthews DR, et al; Response to Feedback on Inzucchi. Administration of hyperglycemia in kind 2 diabetes, 2015: a patient-centered method. Replace to a place assertion of the American diabetes Affiliation and the European Affiliation for the Research of diabetes. Diabetes Care 2015;38:140–149. Diabetes Care. 2015;38(8):e128–e129. doi:10.2337/dc15-0812
6. Hanefeld M. Cardiovascular advantages and security profile of acarbose remedy in prediabetes and established kind 2 diabetes. Cardiovasc Diabetol. 2007;6:20. doi:10.1186/1475-2840-6-20
7. Kim KY, Nam KA, Kurihara H, Kim SM. Potent alpha-glucosidase inhibitors purified from the purple alga grateloupia elliptica. Phytochemistry. 2008;69(16):2820–2825. doi:10.1016/j.phytochem.2008.09.007
8. Ortiz-Andrade RR, García-Jiménez S, Castillo-España P, Ramírez-Avila G, Villalobos-Molina R, Estrada-Soto S. alpha-glucosidase inhibitory exercise of the methanolic extract from tournefortia hartwegiana: an anti-hyperglycemic agent. J Ethnopharmacol. 2007;109(1):48–53. doi:10.1016/j.jep.2006.07.002
9. Liu BY, Tong NS, Li YY, Huang SW. Hypoglycemic mechanism of Polygonum capitatum extract on spontaneous mannequin of kind 2 diabetic db/db mice. Chin Pharm J. 2017;52(5):384–390.
10. Chen BQ, Li CQ, Chang X, Kang WY. Inhibitory exercise of polygonum capitatum to α-glucosidase. Chin J Exp Tradit Med Type. 2010;16(8):151–153.
11. Ye QZHG, Huang DD, Lv SS, Wu ZJ, Solar LN. Research on lignans of Polygonum capitatum and their hypoglycemic exercise. J Chin Med Mater. 2017;40(1):107–110.
12. Kazeem MI, Mayaki AM, Ogungbe BF, Ojekale AB. Research on leaf extracts as inhibitors of key enzymes linked to diabetes mellitus. Iran J Pharm Res. 2016;15(Suppl):37–44.
13. Kenfack JN, Ponou BK, Jonas T, et al. A brand new flavonol glycoside from tristemma hirtum (melastomataceae). Nat Prod Res. 2018;28(3):213. doi:10.20307/nps.2018.24.3.213
14. Ren B, Luo W, Xie MJ, Zhang M. Two new triterpenoid saponins from centella asiatica. Phytochem Lett. 2021;44:102–105. doi:10.1016/j.phytol.2021.06.012
15. Luo Z, Fu C, Li T, et al. Hypoglycemic results of licochalcone A on the streptozotocin-induced diabetic mice and its Mechanism Research. J Agric Meals Chem. 2021;69(8):2444–2456. doi:10.1021/acs.jafc.0c07630
16. Zeng X-Y, Wang Y-P, Cantley J, et al. Oleanolic acid reduces hyperglycemia past remedy interval with Akt/FoxO1-induced suppression of hepatic gluconeogenesis in type-2 diabetic mice. PLoS One. 2012;7(7):e42115. doi:10.1371/journal.pone.0042115
17. Moorthy NSHN, Ramos MJ, Fernandes PA. Topological, hydrophobicity, and different descriptors on α-glucosidase inhibition: a QSAR examine on xanthone derivatives. J Enzyme Inhib Med Chem. 2011;26(6):755–766. doi:10.3109/14756366.2010.549089
18. Vocadlo DJ, Davies GJ. Mechanistic insights into glycosidase chemistry. Curr Opin Chem Biol. 2008;12(5):539–555. doi:10.1016/j.cbpa.2008.05.010
19. Tchoukoua A, Tomfeun Nganou SC, Dabole B, et al. Polythosides A and B, two new triterpenoid saponins from the roots of acacia polyacantha Willd. (Mimosaceae). Phytochem Lett. 2021;43:190–195. doi:10.1016/j.phytol.2021.04.007
20. Nie W, Luo J-G, Wang X-B, et al. Synthesis of recent α-glucosidase inhibitors primarily based on oleanolic acid incorporating cinnamic amides. Chem Pharm Bull. 2011;59(8):1051–1056. doi:10.1248/cpb.59.1051
21. MacGregor EA, Janecek S, Svensson B. Relationship of sequence and construction to specificity within the alpha-amylase household of enzymes. Biochim Biophys Acta. 2001;1546(1):1–20. doi:10.1016/s0167-4838(00)00302-2
22. Alqahtani AS, Hidayathulla S, Rehman MT, et al. Alpha-amylase and alpha-glucosidase enzyme inhibition and antioxidant potential of 3-oxolupenal and katononic acid remoted from. Biomolecules. 2019;10(1):61. doi:10.3390/biom10010061
23. Kikiowo B, Ogunleye JA, Iwaloye O, Ijatuyi TT. Therapeutic potential of Chromolaena odorata phyto-constituents towards human pancreatic α-amylase. J Biomol Struct Dyn. 2020;1–12. doi:10.1080/07391102.2020.1833758
