3-Thiazolylcoumarin derivatives 1-14 were synthesized via one-pot two step reactions, and screened for in vitro α-glucosidase inhibitory activity. All compounds showed inhibitory activity in the range of IC50 = 0.12 ± 0.01-16.20 ± 0.23 μM as compared to standard acarbose (IC50 = 38.25 ± 0.12 μM), and also found to be nontoxic. Molecular docking study was carried out in order to establish the structure-activity relationship (SAR) which demonstrated that electron rich centers at one and electron withdrawing centers at the other end of the molecules showed strong inhibitory activity. All the synthesized compounds were characterized by spectroscopic techniques such as EI-MS, HREI-MS, (1)H NMR and (13)C NMR. CHN analysis was also performed.
The high potential of quinoline containing natural products and their derivatives in medicinal chemistry led us to discover a novel series of compounds 6-23 based on the concept of molecular hybridization. Most of the synthesized analogues exhibited potent leishmanicidal potential. The most potent compound (23, IC50=0.10±0.001μM) among the series was found ∼70 times more lethal than the standard drug. The current series 6-23 conceded in the development of fourteen (14) extraordinarily active compounds against leishmaniasis. In silico analysis were also performed to probe the mode of action while all the compounds structure were established by NMR and Mass spectral analysis.
A series of twenty indole hydrazone analogs (1-21) were synthesized, characterized by different spectroscopic techniques such as 1H NMR and EI-MS, and screened for α-amylase inhibitory activity. All analogs showed a variable degree of α-amylase inhibition with IC50 values ranging between 1.66 and 2.65μM. Nine compounds that are 1 (2.23±0.01μM), 8 (2.44±0.12μM), 10 (1.92±0.12μM), 12 (2.49±0.17μM), 13 (1.66±0.09μM), 17 (2.25±0.1μM), 18 (1.87±0.25μM), 20 (1.83±0.63μM), and 19 (1.97±0.02μM) showed potent α-amylase inhibition when compared with the standard acarbose (1.05±0.29μM). Other analogs showed good to moderate α-amylase inhibition. The structure activity relationship is mainly focusing on difference of substituents on phenyl part. Molecular docking studies were carried out to understand the binding interaction of the most active compounds.
Natural products are the main source of motivation to design and synthesize new molecules for drug development. Designing new molecules against β-glucuronidase inhibitory is utmost essential. In this study indole analogs (1-35) were synthesized, characterized using various spectroscopic techniques including 1H NMR and EI-MS and evaluated for their β-glucuronidase inhibitory activity. Most compounds were identified as potent inhibitors for the enzyme with IC50 values ranging between 0.50 and 53.40μM, with reference to standard d-saccharic acid 1,4-lactone (IC50=48.4±1.25μM). Structure-activity relationship had been also established. The results obtained from docking studies for the most active compound 10 showed that hydrogen bond donor features as well as hydrogen bonding with (Oε1) of nucleophilic residue Glu540 is believed to be the most importance interaction in the inhibition activity. It was also observed that hydroxyl at fourth position of benzylidene ring acts as a hydrogen bond donor and interacts with hydroxyl (OH) on the side chain of catalysis residue Tyr508. The enzyme-ligand complexed were being stabilized through electrostatic π-anion interaction with acid-base catalyst Glu451 (3.96Å) and thus preventing Glu451 from functioning as proton donor residue.
A new class of triazinoindole-bearing thiosemicarbazides (1-25) was synthesized and evaluated for α-glucosidase inhibitory potential. All synthesized analogs exhibited excellent inhibitory potential, with IC50 values ranging from 1.30 ± 0.01 to 35.80 ± 0.80 µM when compared to standard acarbose (an IC50 value of 38.60 ± 0.20 µM). Among the series, analogs 1 and 23 were found to be the most potent, with IC50 values of 1.30 ± 0.05 and 1.30 ± 0.01 µM, respectively. The structure-activity relationship (SAR) was mainly based upon bringing about different substituents on the phenyl rings. To confirm the binding interactions, a molecular docking study was performed.
The β-glucuronidase, a lysosomal enzyme, catalyzes the cleavage of glucuronosyl-O-bonds. Its inhibitors play a significant role in different medicinal therapies as they cause a decrease in carcinogen-induced colonic tumors by reducing the level of toxic substances present in the intestine. Among those inhibitors, bisindole derivatives had displayed promising β-glucuronidase inhibition activity. In the current study, hydrazone derivatives of bisindolymethane (1-30) were synthesized and evaluated for in vitro β-glucuronidase inhibitory activity. Twenty-eight analogs demonstrated better activity (IC50 = 0.50-46.5 µM) than standard D-saccharic acid 1,4-lactone (IC50 = 48.4 ± 1.25 µM). Compounds with hydroxyl group like 6 (0.60 ± 0.01 µM), 20 (1.50 ± 0.10 µM) and 25 (0.50 ± 0.01 µM) exhibited the most potent inhibitory activity, followed by analogs with fluorine 21 (3.50 ± 0.10 µM) and chlorine 23 (8.20 ± 0.20 µM) substituents. The presence of hydroxyl group at the aromatic side chain was observed as the main contributing factor in the inhibitory potential. From the docking studies, it was predicted that the active compounds can fit properly in the binding groove of the β-glucuronidase and displayed significant binding interactions with essential residues.
Piperazine Sulfonamide analogs (1-19) have been synthesized, characterized by different spectroscopic techniques and evaluated for α-amylase Inhibition. Analogs 1-19 exhibited a varying degree of α-amylase inhibitory activity with IC50 values ranging in between 1.571 ± 0.05 to 3.98 ± 0.397 μM when compared with the standard acarbose (IC50 = 1.353 ± 0.232 μM). Compound 1, 2, 3 and 7 showed significant inhibitory effects with IC50 value 2.348 ± 0.444, 2.064 ± 0.04, 1.571 ± 0.05 and 2.118 ± 0.204 μM, respectively better than the rest of the series. Structure activity relationships were established. Molecular docking studies were performed to understand the binding interaction of the compounds.
We have synthesized seventeen Coumarin based derivatives (1-17), characterized by 1HNMR, 13CNMR and EI-MS and evaluated for α-glucosidase inhibitory potential. Among the series, all derivatives exhibited outstanding α-glucosidase inhibition with IC50 values ranging between 1.10 ± 0.01 and 36.46 ± 0.70 μM when compared with the standard inhibitor acarbose having IC50 value 39.45 ± 0.10 μM. The most potent derivative among the series is derivative 3 having IC50 value 1.10 ± 0.01 μM, which are many folds better than the standard acarbose. The structure activity relationship (SAR) was mainly based upon by bring about difference of substituent's on phenyl part. Molecular docking studies were carried out to understand the binding interaction of the most active compounds.
Thymidine phosphorylase (TP) over expression plays role in several pathological conditions, such as rheumatoid arthritis, chronic inflammatory diseases, psoriasis, and tumor angiogenesis. The inhibitor of this enzyme plays an important role in preventing the serious threat due to over expression of TP. In this regard, a series of seventeenanalogs of 3-formylcoumarin (1-17) were synthesized, characterized by 1HNMR and EI-MS and screened for thymidine phosphorylaseinhibitory activity. All analogs showed a variable degree of thymidine phosphorylase inhibition with IC50 values ranging between 0.90 ± 0.01 and 53.50 ± 1.20 μM when compared with the standard inhibitor 7-Deazaxanthine having IC50 value 38.68 ± 1.12 μM. Among the series, fifteenanalogs such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16 and 17 showed excellent inhibition which is many folds better than the standard 7-Deazaxanthine whiletwo analogs 13 and 14 showed good inhibition. The structure activity relationship (SAR) was mainly based upon by bring about difference of substituents on phenyl ring. Molecular docking study was carried out to understand the binding interaction of the most active analogs.
Dengue hemorrhagic fever (DHF) is severe dengue with a hallmark of vascular leakage. β-tryptase has been found to promote vascular leakage in DHF patients, which could be a potential target for DHF treatment. This study aims to develop a theoretical background for designing and selecting human β-tryptase inhibitors through computational studies. Thirty-four α-keto-[1,2,3]-oxadiazoles scaffold-based compounds were used to generate 2D-QSAR models and for molecular docking studies with β-tryptase (PDB Code 4A6L). In addition, molecular dynamics (MD) simulation and molecular mechanics generalised born surface area (MM-GBSA) analysis on the binding of the reported most active compound, compound 11e, towards β-tryptase were performed. Finally, a structure-based pharmacophore model was generated. The selected 2D-QSAR models have statistically proven good models by internal and external validation as well as the y-randomization test. The docking results of compound 11e showed lower CDOCKER energy than the 4A6L co-crystallised ligand and a similar binding pattern as the 4A6L co-crystallised ligand. From molecular dynamics simulation, 4A6L in compound 11e bound state has RMSD below 2 Å throughout the 500 ns simulation, indicating the docked complex is stable. Besides, MM-GBSA analysis suggested the 4A6L-compound 11e docked complex (-66.04 Kcal/mol) is structurally as stable as the 4A6L-native ligand co-crystallized structure (-66.84 Kcal/mol). The best pharmacophore model identified features included hydrogen bond acceptor, ionic interaction, hydrophobic interaction, and aromatic ring, which contribute to the inhibitory potency of a compound. This study supplied insight and knowledge for developing novel chemical compounds with improved inhibition of β-tryptase.Communicated by Ramaswamy H. Sarma.
In an effort to design and synthesize a new class of α-glucosidase inhibitor, we synthesized benzothiazole hybrid having benzohydrazide moiety (5). Compound 5 was reacted with various substituted aryl aldehyde to generate a small library of compounds 6-35. Synthesis of compounds was confirmed by the spectral information. These compounds were screened for their α-glucosidase activity. They showed a varying degree of α-glucosidase inhibition with IC50 values ranging between 5.31 and 53.34 μM. Compounds 6, 7, 9-16, 19, 21-30, 32-35 showed superior activity as compared to standard acarbose (IC50 = 906 ± 6.3 μM). This has identified a new class of α-glucosidase inhibitors. The predicted physico-chemical properties indicated the drug appropriateness for most of these compounds, as they obey Lipinski's rule of five (RO5). A hybrid B3LYP density functional theory (DFT) was employed for energy, minimization of 3D structures for all synthetic compounds using 6-311 + G(d,p) basis sets followed by molecular docking to explore their interactions with human intestinal C- and N-terminal domains of α-glucosidase. All compounds bind to the prospective allosteric site of the C- terminal domain, and consequently, may be considered as mixed inhibitors. It was hypothesized that both the dipole moment and H-bond interactions govern the biological activation of these compounds.
Benzimidazole analogs 1-27 were synthesized, characterized by EI-MS and (1)HNMR and their α-glucosidase inhibitory activities were found out experimentally. Compound 25, 19, 10 and 20 have best inhibitory activities with IC50 values 5.30±0.10, 16.10±0.10, 25.36±0.14 and 29.75±0.19 respectively against α-glucosidase. Compound 6 and 12 has no inhibitory activity against α-glucosidase enzyme among the series. Further studies showed that the compounds are not showing any cytotoxicity effect. The docking studies of the compounds as well as the experimental activities of the compounds correlated well. From the molecular docking studies, it was observed that the top ranked conformation of all the compounds fit well in the active site of the homology model of α-glucosidase.
6-Chloro-2-Aryl-1H-imidazo[4,5-b]pyridine derivatives 1-26 were synthesized and characterized by various spectroscopic techniques. All these derivatives were evaluated for their antiglycation, antioxidant and β-glucuronidase potential followed their docking studies. In antiglycation assay, compound 2 (IC50=240.10±2.50μM) and 4 (IC50=240.30±2.90μM) was found to be most active compound of this series, while compounds 3 (IC50=260.10±2.50μM), 6 (IC50=290.60±3.60μM), 13 (IC50=288.20±3.00μM) and 26 (IC50=292.10±3.20μM) also showed better activities than the standard rutin (IC50=294.50±1.50μM). In antioxidant assay, compound 1 (IC50=69.45±0.25μM), 2 (IC50=58.10±2.50μM), 3 (IC50=74.25±1.10μM), and 4 (IC50=72.50±3.30μM) showed good activities. In β-glucuronidase activity, compounds 3 (IC50=29.25±0.50μM), compound 1 (IC50=30.10±0.60μM) and compound 4 (IC50=46.10±1.10μM) showed a significant activity as compared to than standard D-Saccharic acid 1,4-lactonec (IC50=48.50±1.25μM) and their interaction with the enzyme was confirm by docking studies.
Twenty five 4, 6-dichlorobenzimidazole derivatives (1-25) have been synthesized and evaluated against β-glucuronidase inhibitory activity. The compounds which actively inhibit β-glucuronidase activity have IC50 values ranging between 4.48 and 46.12 μM and showing better than standard d-saccharic acid 1,4 lactone (IC50=48.4 ± 1.25 μM). Molecular docking provided potential clues to identify interactions between the active molecules and the enzyme which further led us to identify plausible binding mode of all the benzimidazole derivatives. This study confirmed that presence of hydrophilic moieties is crucial to inhibit the human β-glucuronidase.
A new series of oxadiazole with thiadiazole moiety (6-27) were synthesized, characterized by different spectroscopic techniques and evaluated for β-glucuronidase inhibitory potential. Sixteen analogs such as 6, 7, 8, 9, 10, 12, 13, 14, 17, 18, 20, 23, 24, 25, 26 and 27 showed IC50 values in the range of 0.96 ± 0.01 to 46.46 ± 1.10 μM, and hence were found to have excellent inhibitory potential in comparison to standard d-saccharic acid 1,4-lactone (IC50 = 48.4 ± 1.25 μM). Two analogs such as 16 and 19 showed moderate inhibitory potential while analogs 11, 15, 21 and 22 were found inactive. Our study identifies new series of potent β-glucuronidase inhibitors for further investigation. Structure activity relationships were established for all compounds which showed that the activity is varied due to different substituents on benzene ring. The interaction of the compounds with enzyme active site were confirmed with the help of docking studies, which reveals that the electron withdrawing group and hydroxy group make the molecules more favorable for enzyme inhibition.
In search of potent α-amylase inhibitor we have synthesized eighteen indole analogs (1-18), characterized by NMR and HR-EIMS and screened for α-amylase inhibitory activity. All analogs exhibited a variable degree of α-amylase inhibition with IC50 values ranging between 2.031 ± 0.11 and 2.633 ± 0.05 μM when compared with standard acarbose having IC50 values 1.927 ± 0.17 μM. All compounds showed good α-amylase inhibition. Compound 14 was found to be the most potent analog among the series. Structure-activity relationship has been established for all compounds mainly based on bringing about the difference of substituents on phenyl ring. To understand the binding interaction of the most active analogs molecular docking study was performed.
New series of quinoline-based thiadiazole analogs (1-20) were synthesized, characterized by EI-MS, 1H NMR and 13C NMR. All synthesized compounds were subjected to their antileishmanial potential. Sixteen analogs 1-10, 12, 13, 16, 17, 18 and 19 with IC50 values in the range of 0.04 ± 0.01 to 5.60 ± 0.21 µM showed tremendously potent inhibition as compared to the standard pentamidine with IC50 value 7.02 ± 0.09 µM. Analogs 11, 14, 15 and 20 with IC50 8.20 ± 0.35, 9.20 ± 0.40, 7.20 ± 0.20 and 9.60 ± 0.40 µM respectively showed good inhibition when compared with the standard. Structure-activity relationships have been also established for all compounds. Molecular docking studies were performed to determine the binding interaction of the compounds with the active site target.
Eight new bis-styryllactones, goniolanceolatins A-H (1-8), possessing a rare α,β-unsaturated δ-lactone moiety with a (6S)-configuration, were isolated from the CH2Cl2 extract of the stembark and roots of Goniothalamus lanceolatus Miq., a plant endemic to Malaysia. Absolute structures were established through extensive 1D- and 2D-NMR data analysis, in combination with electronic dichroism (ECD) data. All of the isolates were evaluated for their cytotoxicity against human lung and colorectal cancer cell lines. Compounds 2 and 4 showed cytotoxicity, with IC50 values ranging from 2.3 to 4.2 μM, and were inactive toward human noncancerous lung and colorectal cells. Compounds 1, 3, 6, 7, and 8 showed moderate to weak cytotoxicity. Docking studies of compounds 2 and 4 showed that they bind with EGFR tyrosine kinase and cyclin-dependent kinase 2 through hydrogen bonding interactions with the important amino acids, including Lys721, Met769, Asn818, Arg157, Ile10, and Glu12.
In searchof the potenttherapeutic agent as an α-glucosidase inhibitor, we have synthesized twenty-five analogs (1-25) of quinoline-based Schiff bases as an inhibitoragainst α-glucosidase enzyme under positive control acarbose (IC50 = 38.45 ± 0.80 µM). From the activity profile it was foundthat analogs 1, 2, 3, 4, 11, 12 and 20with IC50values 12.40 ± 0.40, 9.40 ± 0.30, 14.10 ± 0.40, 6.20 ± 0.30, 14.40 ± 0.40, 7.40 ± 0.20 and 13.20 ± 0.40 µMrespectively showed most potent inhibition among the series even than standard drug acarbose (IC50 = 38.45 ± 0.80 µM). Here in the present study analog 4 (IC50 = 6.20 ± 0.30 µM) was found with many folds better α-glucosidase inhibitory activity than the reference drug. Eight analogs like 5, 7, 8, 16, 17, 22, 24 and 25 among the whole series displayed less than 50% inhibition. The substituents effects on phenyl ring thereby superficially established through SAR study. Binding interactions of analogs and the active site of ligands proteins were confirmed through molecular docking study. Spectroscopic techniques like 1H NMR, 13C NMR and ESIMS were used for characterization.
We synthesized a series of novel 5-24 derivatives of oxindole. The synthesis started from 5-chlorooxindole, which was condensed with methyl 4-carboxybezoate and result in the formation of benzolyester derivatives of oxindole which was then treated with hydrazine hydrate. The oxindole benzoylhydrazide was treated with aryl acetophenones and aldehydes to get target compounds 5-24. The synthesized compounds were evaluated for urease inhibition; the compound 5 (IC50 = 13.00 ± 0.35 μM) and 11 (IC50 = 19.20 ± 0.50 μM) showed potent activity as compared to the standard drug thiourea (IC50 = 21.00 ± 0.01 μM). Other compounds showed moderate to weak activity. All synthetic compounds were characterized by different spectroscopic techniques including (1)H NMR, (13)C NMR, IR and EI MS. The molecular interactions of the active compounds within the binding site of urease enzyme were studied through molecular docking simulations.