scholarly journals In Silico Approaches to Identify Polyphenol Compounds as α-Glucosidase and α-Amylase Inhibitors against Type-II Diabetes

Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1877
Author(s):  
Jirawat Riyaphan ◽  
Dinh-Chuong Pham ◽  
Max K. Leong ◽  
Ching-Feng Weng

Type-II diabetes mellitus (T2DM) results from a combination of genetic and lifestyle factors, and the prevalence of T2DM is increasing worldwide. Clinically, both α-glucosidase and α-amylase enzymes inhibitors can suppress peaks of postprandial glucose with surplus adverse effects, leading to efforts devoted to urgently seeking new anti-diabetes drugs from natural sources for delayed starch digestion. This review attempts to explore 10 families e.g., Bignoniaceae, Ericaceae, Dryopteridaceae, Campanulaceae, Geraniaceae, Euphorbiaceae, Rubiaceae, Acanthaceae, Rutaceae, and Moraceae as medicinal plants, and folk and herb medicines for lowering blood glucose level, or alternative anti-diabetic natural products. Many natural products have been studied in silico, in vitro, and in vivo assays to restrain hyperglycemia. In addition, natural products, and particularly polyphenols, possess diverse structures for exploring them as inhibitors of α-glucosidase and α-amylase. Interestingly, an in silico discovery approach using natural compounds via virtual screening could directly target α-glucosidase and α-amylase enzymes through Monte Carto molecular modeling. Autodock, MOE-Dock, Biovia Discovery Studio, PyMOL, and Accelrys have been used to discover new candidates as inhibitors or activators. While docking score, binding energy (Kcal/mol), the number of hydrogen bonds, or interactions with critical amino acid residues have been taken into concerning the reliability of software for validation of enzymatic analysis, in vitro cell assay and in vivo animal tests are required to obtain leads, hits, and candidates in drug discovery and development.

2002 ◽  
Vol 367 (3) ◽  
pp. 913-920 ◽  
Author(s):  
Victor A. GAULT ◽  
Peter R. FLATT ◽  
Clifford J. BAILEY ◽  
Patrick HARRIOTT ◽  
Brett GREER ◽  
...  

Glucose-dependent insulinotropic polypeptide (GIP) is an important incretin hormone, which potentiates glucose-induced insulin secretion. Antihyperglycaemic actions of GIP provide significant potential in Type II diabetes therapy. However, inactivation of GIP by the enzyme dipeptidyl peptidase IV (DPP IV) and its consequent short circulating half-life limit its therapeutic use. Therefore two novel Tyr1-modified analogues of GIP, N-Fmoc-GIP (where Fmoc is 9-fluorenylmethoxycarbonyl) and N-palmitate-GIP, were synthesized and tested for metabolic stability and biological activity. Both GIP analogues were resistant to degradation by DPP IV and human plasma. In Chinese hamster lung (CHL) cells expressing the cloned human GIP receptor, both analogues exhibited a 2-fold increase in cAMP-generating potency compared with native GIP (EC50 values of 9.4, 10.0 and 18.2nM respectively). Using clonal BRIN-BD11 cells, both analogues demonstrated strong insulinotropic activity compared with native GIP (P<0.01 to P<0.001). In obese diabetic (ob/ob) mice, administration of N-Fmoc-GIP or N-palmitate-GIP (25nmol/kg) together with glucose (18mmol/kg) significantly reduced the peak 15min glucose excursion (1.4- and 1.5-fold respectively; P<0.05 to P<0.01) compared with glucose alone. The area under the curve (AUC) for glucose was significantly lower after administration of either analogue compared with glucose administered alone or in combination with native GIP (1.5-fold; P<0.05). This was associated with a significantly greater AUC for insulin (2.1-fold; P<0.001) for both analogues compared with native GIP. A similar pattern of in vivo responsiveness was evident in lean control mice. These data indicate that novel N-terminal Tyr1 modification of GIP with an Fmoc or palmitate group confers resistance to degradation by DPP IV in plasma, which is reflected by increased in vitro potency and greater insulinotropic and antihyperglycaemic activities in an animal model of Type II diabetes mellitus.


2015 ◽  
Vol 42 (7) ◽  
pp. 1042-1049 ◽  
Author(s):  
Yu Zhang ◽  
Ying Zhong ◽  
Mei Hu ◽  
Nanxi Xiang ◽  
Yao Fu ◽  
...  

Author(s):  
Jirawat Riyaphan ◽  
Chien-Hung Jhong ◽  
May-Jwan Tsai ◽  
Der-Nan Lee ◽  
Max K. Leong ◽  
...  

The inhibition of alpha-glucosidase and alpha-amylase is one of clinic strategies for remedy the type II diabetes. Herbal medicines are reported to alleviate hyperglycemia. However, the constituents from those sources whether are targeted to the alpha-glucosidase and alpha-amylase still unexplored. This study attempted to select the compounds for efficacy of hypoglycemia via cellular and mouse levels. The results illustrated that the cytotoxicity in all tested compounds at various concentrations except the concentration of 16-hydroxy-cleroda-3,13-dine-16,15-olide (HCD) at 30 &micro;M were not significant difference (p &gt; 0.05) when compared with the untreated control. Acarbose (reference drug), Antroquinonol, Catechin, Quercetin, Actinodaphnine, Curcumin, HCD, Docosanol, Tetracosanol, Berberine, and Rutin could effectively inhibit the alpha-glucosidase activity of Caco-2 cells when compared with the control (maltose). The compounds (Curcumin, HCD, Tetracosanol, Antroquinonol, Berberine, Catechin, Actinodaphnine, and Rutin) could reduce blood sugar level at 30 min in tested mice. The effects of tested compounds on area under curve (AUC) were significant (p &lt; 0.05) among Acarbose, Tetracosanol, Antroquinonol, Catechin, Actinodaphnine, and Rutin along with Berberine and Quercetin. In in vitro (alpha-glucosidase) with in vivo (alpha-amylase) experiments suggest that bioactive compounds can be a potential inhibitor candidate of alpha-glucosidase and alpha-amylase for the alleviation of type II diabetes.


1983 ◽  
Vol 104 (4_Suppl) ◽  
pp. S67-S69
Author(s):  
Ulf Smith

ABSTRACT. Insulin resistance plays a major role for the reduced glucose tolerance in obesity, type II diabetes and stress. Both in vivo and in vitro studies strongly support the major importance of post-receptor perturbations as the cause of the insulin resistance in these conditions. One likely level for the post-receptor alterations is the reported reduction in glucose transport. Key words: Insulin resistance, diabetes, obesity, insulin receptors, glucose transport.


2005 ◽  
Vol 109 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Mike J. Sampson ◽  
Simon Braschi ◽  
Gavin Willis ◽  
Sian B. Astley

The HDL (high-density lipoprotein)-associated enzyme PON (paraoxonase)-1 protects LDL (low-density lipoprotein) from oxidative modification in vitro, although it is unknown if this anti-atherogenic action occurs in vivo. In a cross-sectional study of 58 Type II diabetic subjects and 50 controls, we examined the fasting plasma LDL basal conjugated diene concentration [a direct measurement of circulating oxLDL (oxidatively modified LDL)], lipoprotein particle size by NMR spectroscopy, PON-1 polymorphisms (coding region polymorphisms Q192R and L55M, and gene promoter polymorphisms −108C/T and −162G/A), PON activity (with paraoxon or phenyl acetate as the substrates) and dietary antioxidant intake. Plasma oxLDL concentrations were higher in Type II diabetic patients (males, P=0.048; females, P=0.009) and unrelated to NMR lipoprotein size, PON-1 polymorphisms or PON activity (with paraoxon as the substrate) in any group. In men with Type II diabetes, however, there was a direct relationship between oxLDL concentrations and PON activity (with phenyl acetate as the substrate; r=0.611, P=0.0001) and an atherogenic NMR lipid profile in those who were PON-1 55LL homozygotes. Circulating oxLDL concentrations in vivo were unrelated to PON-1 genotypes or activity, except in male Type II diabetics where there was a direct association between PON activity (with phenyl acetate as the substrate) and oxLDL levels. These in vivo data contrast with in vitro data, and may be due to confounding by dietary fat intake. Male Type II diabetic subjects with PON-1 55LL homozygosity have an atherogenic NMR lipid profile independent of LDL oxidation. These data do not support an in vivo action of PON on LDL oxidation.


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