In-silico modeling and in-vitro studies of 2,1-benzothiazine-2,2-dioxide based hydrazone derivatives as α-glucosidase inhibitors.

Diabetes mellitus (DM) is a metabolic disorder characterized by frequent urination, hunger and high blood sugar level. α-glucosidase inhibitors are considered as a frontline treatment for the DM. This research article deals with the identification of benzothiazine derivatives as α-glucosidase inhibitors through in-silico techniques and then the confirmation through in-vitro analysis. Molecular docking studies were carried out to find out the binding interactions of targeted molecules with receptor molecule i.e., α-glucosidase enzyme. The synthetic compounds 1 (a-n), 2 (a-d) and 3 (a-b) were evaluated for in-vitro alpha glucosidase inhibitory activities that resulted in the discovery of various potent molecules. Majority of the compounds (1c, 1f, 1g, 1k-n, 2a-d and 3a-b) exhibited good inhibitory activity against α-glucosidase. Compounds 1c, 1g, 1k and 1m appeared as the potent active compounds with the IC50 values 17.44, 27.64, 24.43, 42.59 and 16.90 µM respectively. Compounds 1c & 2c were found almost 3-folds more active than the standard acarbose. The study may lead to discover potent drug candidates with less complication for the treatment of the type II diabetes mellitus.

Synthesis and α-Glucosidase Inhibition Activity of 2-[3-(Benzoyl/4-bromobenzoyl)-4-hydroxy-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl]-N-arylacetamides: An In Silico and Biochemical Approach.

Diabetes mellitus (DM) is a chronic disorder and has affected a large number of people worldwide. Insufficient insulin production causes an increase in blood glucose level that results in DM. To lower the blood glucose level, various drugs are employed that block the activity of the α-glucosidase enzyme, which is considered responsible for the breakdown of polysaccharides into monosaccharides leading to an increase in the intestinal blood glucose level. We have synthesized novel 2-(3-(benzoyl/4-bromobenzoyl)-4-hydroxy-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl)-N-arylacetamides and have screened them for their in silico and in vitro α-glucosidase inhibition activity. The derivatives 11c, 12a, 12d, 12e, and 12g emerged as potent inhibitors of the α-glucosidase enzyme. These compounds exhibited good docking scores and excellent binding interactions with the selected residues (Asp203, Asp542, Asp327, His600, Arg526) during in silico screening. Similarly, these compounds also showed good in vitro α-glucosidase inhibitions with IC50 values of 30.65, 18.25, 20.76, 35.14, and 24.24 µM, respectively, which were better than the standard drug, acarbose (IC50 = 58.8 µM). Furthermore, a good agreement was observed between in silico and in vitro modes of study.

Elongation of the side chain by linear alkyl groups increases the potency of salacinol, a potent α-glucosidase inhibitor from the Ayurvedic traditional medicine "Salacia," against human intestinal maltase.

Four chain-extended analogs (12a-12d) and two related de-O-sulfonated analogs (13a and 13c) by introducing alkyl groups (a: R = C3H7, b R = C6H13, c: R = C8H17, d: R = C10H21) to the side chains of salacinol (1), a natural α-glucosidase inhibitor from Ayurvedic traditional medicine "Salacia", were synthesized. The α-glucosidase inhibitory activities of all the synthesized analogs were evaluated in vitro. Against human intestinal maltase, the inhibitory activities of 12a and 13a with seven-carbon side chain were equal to that of 1. In contrast, analogs (12b-12d, and 13c) exhibited higher level of inhibitory activity against the same enzyme than 1 and had equal or higher potency than those of the clinically used anti-diabetics, voglibose, acarbose, and miglitol. Thus, elongation of the side chains of 1 was effective for specifically increasing the inhibitory activity against human intestinal maltase.

Biosynthesis of Metal Nanoparticles from Leaves of Ficus palmata and Evaluation of Their Anti-inflammatory and Anti-diabetic Activities.

Metal nanoparticles (AgNPs and ZnONPs) were synthesized using a green methodology with the green leaves extract of the Bedu (Ficus palmata) tree as a reducing agent and the support of natural fibers. The synthesized AgNPs and ZnONPs were characterized by several techniques, including ultraviolet-visible spectral analysis, powder X-ray diffraction crystal analysis, scanning electron microscopy, EDAX, transmission electron microscopy, and Fourier transform infrared spectroscopy, which confirmed that the synthesized particles are in the nano range (1-100 nm), i.e., 30 nm for AgNPs with polydispersity and a spherical shape, whereas the average size of synthesized ZnONPs is 34 nm and they seem to exhibit a distorted spherical shape. The results of thermogravimetric analysis confirmed a weight loss of 18.02% for AgNPs under exothermic conditions due to the desorption of water, and ZnONPs show weight loss between 265 and 500 °C. Both synthesized MNPs are highly thermally stable. Anti-inflammatory and anti-diabetic studies of metal NPs have been evaluated. The AgNPs and ZnONPs of F. palmata leaves showed remarkably highly potent activity for respective strains. In vitro anti-diabetic activity was found for inhibition of α-amylases and α-glucosidases by synthesized silver nanoparticles.

Synthesis and Comparative Structure-Activity Study of Carbohydrate-Based Phenolic Compounds as α-Glucosidase Inhibitors and Antioxidants.

Twenty-one natural and unnatural phenolic compounds containing a carbohydrate moiety were synthesized and their structure-activity relationship (SAR) was evaluated for α-glucosidase inhibition and antioxidative activity. Varying the position of the galloyl unit on the 1,5-anhydro-d-glucitol (1,5-AG) core resulted in changes in the α-glucosidase inhibitory activity and notably, particularly strong activity was demonstrated when the galloyl unit was present at the C-2 position. Furthermore, increasing the number of the galloyl units significantly affected the α-glucosidase inhibition, and 2,3,4,6-tetra-galloyl-1,5-AG (54) and 2,3,4,6-tetra-galloyl-d-glucopyranose (61) exhibited excellent activities, which were more than 13-fold higher than the α-glucosidase inhibitory activity of acertannin (37). Moreover, a comparative structure-activity study suggested that a hemiacetal hydroxyl functionality in the carbohydrate core and a biaryl bond of the 4,6-O-hexahydroxydiphenoyl (HHDP) group, which are components of ellagitannins including tellimagrandin I, are not necessary for the α-glucosidase inhibitory activity. Lastly, the antioxidant activity increased proportionally with the number of galloyl units.

Design, synthesis and biological evaluation of theophylline containing variant acetylene derivatives as α-amylase inhibitors.

A novel pharmacophore with theophylline and acetylene moieties was constructed by using a fragment-based drug design and a series of twenty theophylline containing acetylene conjugates were designed and synthesized, and all the compounds were evaluated by enzyme-based in vitro α-amylase inhibition activity. The in vitro evaluation revealed that most of the compounds displayed good inhibitory activities, and among them nine analogs 13-15, 20, 21 and 24-27 were exhibited more or nearly as equipotent inhibitory activity with IC50 values 1.11 ±â€¯0.07, 1.14 ±â€¯0.17, 1.07 ±â€¯0.01 and 1.21 ±â€¯0.03, 1.33 ±â€¯0.09, 1.17 ±â€¯0.01, 1.05 ±â€¯0.02, 1.61 ±â€¯0.04, 1.02 ±â€¯0.03 µM respectively, as compared with standard, acarbose 1.37 ±â€¯0.26 µM. Further, molecular docking simulation studies were done to identify the interactions and binding mode of synthesized analogs at binding site of α-amylase enzyme (PBD ID: 4GQR). Among the synthesized analogs, two compounds 25 and 27 were selected on the basis of α-amylase inhibition activity and evaluated for in vivo anti-diabetic activity by High Fat Diet-Streptozotocin (HFD-STZ) model in normal rats. At the dose of 10 mg/kg, bw, po these compounds have significantly reduced Plasma Glucose level in rats as compared to pioglitazone. The anti-diabetic activity results showed that the animal treated with the compounds 25 and 27 could better reverse and control the progression of the disease compared to the standard.

Synthesis and glycosidase inhibition of conformationally locked DNJ and DMJ derivatives exploiting a 2-oxo-C-allyl iminosugar.

A series of analogs of the iminosugars 1-deoxynojirimycin (DNJ) and 1-deoxymannojirimycin (DMJ), in which an extra five or six-membered ring has been fused to the C1-C2 bond have been prepared. The synthetic strategy exploits a key 2-keto-C-allyl iminosugar, easily accessible from gluconolactam, which upon Grignard addition and RCM furnishes a bicyclic scaffold that can be further hydroxylated at the C[double bond, length as m-dash]C bond. This strategy furnished DNJ mimics with the piperidine ring locked in a 1C4 conformation with all substituents in axial orientation when fused to a six-membered ring. Addition of an extra ring to DNJ and DMJ motif proved to strongly modify the glycosidase inhibition profile of the parent iminosugars leading to modest inhibitors. The 2-keto-C-allyl iminosugar scaffold was further used to access N-acetylglycosamine analogs via oxime formation.

Betulinic acid derivatives: a new class of α-glucosidase inhibitors and LPS-stimulated nitric oxide production inhibition on mouse macrophage RAW 264.7 cells.

Chemical manipulation studies were conducted on betulinic acid (1), twenty-one new rationally designed analogues of 1 with modifications at C-28 were synthesized for their evaluation of inhibitory effects on α-glucosidase and LPS-stimulated nitric oxide production in mouse macrophage RAW 264.7 cells. Compound 2 (IC50 = 5.4 µM) exhibited an almost 1.4-fold increase in α-glucosidase inhibitory activity on yeast α-glucosidase while analogues 5 (IC50 16.4 µM) and 11 (IC50 16.6 µM) exhibited a 2-fold enhanced inhibitory activity on NO-production than betulinic acid.

Structural Modification of Natural Product Ganomycin I Leading to Discovery of a α-Glucosidase and HMG-CoA Reductase Dual Inhibitor Improving Obesity and Metabolic Dysfunction in Vivo.

It is a great challenge to develop drugs for treatment of metabolic syndrome. With ganomycin I as a leading compound, 14 meroterpene derivatives were synthesized and screened for their α-glucosidase and HMG-CoA reductase inhibitory activities. As a result, a α-glucosidase and HMG-CoA reductase dual inhibitor (( R, E)-5-(4-( tert-butyl)phenyl)-3-(4,8-dimethylnona-3,7-dien-1-yl)furan-2(5 H)-one, 7d) with improved chemical stability and long-term safety was obtained. Compound 7d showed multiple and strong in vivo efficacies in reducing weight gain, lowering HbAlc level, and improving insulin resistance and lipid dysfunction in both ob/ob and diet-induced obesity (DIO) mice models. Compound 7d was also found to reduce hepatic steatosis in ob/ob model. 16S rRNA gene sequencing, SCFA, and intestinal mucosal barrier function analysis indicated that gut microbiota plays a central and causative role in mediating the multiple efficacies of 7d. Our results demonstrate that 7d is a promising drug candidate for metabolic syndrome.

Synthesis, in vitro evaluation and molecular docking studies of novel coumarin-isatin derivatives as α-glucosidase inhibitors.

This study synthesized a series of novel coumarin-isatin derivatives and evaluated them for α-glucosidase inhibitory activity. The majority of the screened compounds exhibited excellent inhibition activities with IC50 values of 2.56 ± 0.08-268.79 ± 3.04 µm, when compared to acarbose. Among the newly derivatives, compound 5p was found to be the most active compound in the library of coumarin-isatin derivatives. Furthermore, enzyme kinetic studies showed that compound 5p is a non-competitive inhibitor with a Ki of 2.14 µm. Molecular docking analysis revealed the existence of hydrophobic and hydrogen interactions between compound 5p and the active site of α-glucosidase. Our results indicate that coumarin-isatin derivatives as a new class of α-glucosidase inhibitors.

Synthesis of furostanol glycosides: discovery of a potent α-glucosidase inhibitor.

A convenient approach to the synthesis of furostanol glycosides has been developed with the features of both highly efficient incorporation of a 26-O-ß-d-glucopyranosyl unit and ready formation of hemiketal ring E. The total syntheses of seven furostanol saponins including funlioside B, lilioglycoside, protobioside I, protodioscin, pallidifloside I, coreajaponins A and parisaponin I are efficiently achieved using an easily available 16ß-acetoxy-22-oxo-26-hydroxy-cholestanic derivative as a powerful building block. The α-glucosidase inhibitory activity of the synthesized saponins is also evaluated, which reveals that funlioside B is a highly potential lead for developing α-glucosidase inhibitors.

Study on the synthesis and biological activities of α-substituted arylacetates derivatives.

Anisodamine was isolated from the medicinal herb, it was used in the treatment of gastrointestinal smooth muscle spasm, infective toxic shock and organophosphorus intoxication. But there is no report about anisodamine with α-glucosidase inhibitory activity. In order to find novel α-glucosidase inhibitors, a series of α-substituted arylacetates derivatives have been synthesized based on the active unit of anisodamine. In α-glucosidase assay, compound 9 in Schiff base form and compound 22 in ester form show strong inhibition against α-glucosidase with IC50 value of 46.81µM and 83.76µM, respectively. Compounds 9 and 22 exhibit comparable good antidiabetic activities as commercial drug Glimepiride. In addition, Schiff bases of α-substituted arylacetates show antitumor activities against human cancer cell lines, where compound 9 with thiourea moiety performs the best antitumor activity. We anticipate that our research will provide potential candidate scaffolds for antidiabetic drug design.

Synthesis of new oxadiazole derivatives as α-glucosidase inhibitors.

Oxadiazole derivatives (6-28) having hydrazone linkage, were synthesized through condensation reaction between benzohydrazide 5 with various benzaldehydes. The oxadiazoles derivatives (6-28) were evaluated for their α-glucosidase inhibitory activity. The IC50 values for inhibition activity vary in the range between 2.64 ± 0.05 and 460.14 ± 3.25 µM. The IC50 values were being compared to the standard acarbose (IC50=856.45 ± 5.60 µM) and it was found that compounds 6-9, 12, 13, 16, 18, 20, 22-28 were found to be more active than acarbose, while other compounds showed no activity. Structure-activity relationship (SAR) studies suggest that oxadiazole benzohydrazones (6-28) inhibitory potential is dependent on substitution of the N-benzylidene part. Compound 18 (IC50=2.64 ± 0.05 µM), which has trihydroxy substitution at C-2', C-4', and C-5' on N-benzylidene moiety, recorded the highest inhibition activity that is three-hundred times more active than the standard drug, acarbose (IC50=856.45 ± 5.60 µM). Compound 23 (IC50=34.64 ± 0.35 µM) was found to be the most active among compounds having single hydroxyl substitution. Shifting hydroxyl from C-2' to C-4' (6) and C-3' (7) reduces inhibitory activity significantly. Compounds with chlorine substituent (compounds 16, 28, and 27) showed potent activities but lower as compared to hydroxyl analogs. Substituent like nitro or methyl groups at any position suppresses enzyme inhibition activity. This reveals the important presence of hydroxyl and halo groups to have enzyme inhibitory potential.

3-Hydroxypyrrolidine and (3,4)-dihydroxypyrrolidine derivatives: inhibition of rat intestinal α-glucosidase.

Thirteen pyrrolidine-based iminosugar derivatives have been synthesized and evaluated for inhibition of α-glucosidase from rat intestine. The compounds studied were the non-hydroxy, mono-hydroxy and dihydroxypyrrolidines. All the compounds were N-benzylated apart from one. Four of the compounds had a carbonyl group in the 2,5-position of the pyrrolidine ring. The most promising iminosugar was the trans-3,4-dihydroxypyrrolidine 5 giving an IC50 of 2.97±0.046 and a KI of 1.18 mM. Kinetic studies showed that the inhibition was of the mixed type, but predominantly competitive for all the compounds tested. Toxicological assay results showed that the compounds have low toxicity. Docking studies showed that all the compounds occupy the same region as the DNJ inhibitor on the enzyme binding site with the most active compounds establishing similar interactions with key residues. Our studies suggest that a rotation of ∼90° of some compounds inside the binding pocket is responsible for the complete loss of inhibitory activity. Despite the fact that activity was found only in the mM range, these compounds have served as simple molecular tools for probing the structural features of the enzyme, so that inhibition can be improved in further studies.