Alzheimer's disease (AD) is a prevalent neurodegenerative disorder, which affected 35 million people in the world. The most practiced approach to improve the life expectancy of AD patients is to increase acetylcholine neurotransmitter level at cholinergic synapses by inhibition of cholinesterase enzymes. A series of unreported piperidone grafted spiropyrrolidines 8(a-p) were synthesized and evaluated in vitro for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. Therein, compounds 8h and 8l displayed more potent AChE enzyme inhibition than standard drug with IC50 values of 1.88 and 1.37 µM, respectively. Molecular docking simulations for 8l possessing the most potent AChE inhibitory activities, disclosed its interesting binding templates to the active site channel of AChE enzymes. These compounds are remarkable AChE inhibitors and have potential as AD drugs.
Recent studies show that some metal ions, injure microbial cells in various ways due to membrane breakdown, protein malfunction, and oxidative stress. Metal complexes are suited for creating novel antibacterial medications due to their distinct mechanisms of action and the variety of three-dimensional geometries they can acquire. In this Perspective, the present study focused on new antibacterial strategies based on metal oleoyl amide complexes. Thus, oleoyl amides ligand (fatty hydroxamic acid and fatty hydrazide hydrate) with the transition metal ions named Ag (I), Co (II), Cu (II), Ni (II) and Sn (II) complexes were successfully synthesized in this study. The metals- oleoyl amide were characterized using elemental analysis, and fourier transforms infrared (FTIR) spectroscopy. The antibacterial effect of metals- oleoyl amide complexes was investigated for Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) by analysing minimum inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and scanning electron microscopy (SEM). The results showed that metal-oleoyl amide complexes have high antibacterial activity at low concentrations. This study inferred that metal oleoyl amide complexes could be utilised as a promising therapeutic antibacterial agent.
Novel sulfonamides having oxadiazole ring were synthesized by multistep reaction and evaluated to check in vitro β-glucuronidase inhibitory activity. Luckily, except compound 13, all compounds were found to demonstrate good inhibitory activity in the range of IC50=2.40±0.01-58.06±1.60μM when compared to the standard d-saccharic acid 1,4-lactone (IC50=48.4±1.25μM). Structure activity relationship was also presented. However, in order to ensure the SAR as well as the molecular interactions of compounds with the active site of enzyme, molecular docking studies on most active compounds 19, 16, 4 and 6 was carried out. All derivatives were fully characterized by 1H NMR, 13C NMR and EI-MS spectroscopic techniques. CHN analysis was also presented.
To discover multifunctional agents for the treatment of Alzheimer's disease, a series of hydrazide based Schiff bases were designed and synthesized based on multitarget-directed strategy. We have synthesized twenty-eight analogs of hydrazide based Schiff bases, characterized by various spectroscopic techniques and evaluated in vitro for acetylcholinesterase and butyrylcholinesterase inhibition. All compounds showed varied degree of acetylcholinesterase and butyrylcholinesterase inhibition when compared with standard Eserine. Among the series, compounds 10, 3 and 24 having IC50 values 4.12±0.01, 8.12±0.01 and 8.41±0.06μM respectively showed potent acetylcholinesterase inhibition when compared with Eserine (IC50=0.85±0.0001μM). Three compounds 13, 24 and 3 having IC50 values 6.51±0.01, 9.22±0.07 and 37.82±0.14μM respectively showed potent butyrylcholinesterase inhibition by comparing with eserine (IC50=0.04±0.0001μM). The remaining compounds also exhibited moderate to weak inhibitory potential. Structure activity relationship has been established. Through molecular docking studies the binding interaction was confirmed.
The α-amylase acts as attractive target to treat type-2 diabetes mellitus. Therefore in discovering a small molecule as α-amylase inhibitor, we have synthesized benzofuran carbohydrazide analogs (1-25), characterized through different spectroscopic techniques such as 1HNMR and EI-MS. All screened analog shows good α-amylase inhibitory potentials with IC50 value ranging between 1.078±0.19 and 2.926±0.05µM when compared with acarbose having IC50=0.62±0.22µM. Only nine analogs among the series such as analogs 3, 5, 7, 8, 10, 12, 21, 23 and 24 exhibit good inhibitory potential with IC50 values 1.644±0.128, 1.078±0.19, 1.245±0.25, 1.843±0.19, 1.350±0.24, 1.629±0.015, 1.353±0.232, 1.359±0.119 and 1.488±0.07µM when compare with standard drug acarbose. All other analogs showed good to moderate α-amylase inhibitory potentials. The SAR study was conducted on the basis of substituent difference at the phenyl ring. The binding interaction between analogs and active site of enzyme was confirmed by docking studies.
Keeping in mind the pharmacological importance of 2-aminothiazole and 1,2,4-triazole heterocyclic moieties, a series of novel ethylated bi-heterocyclic acetamide hybrids, 9a-p, was synthesized in a multi-step protocol. The structures of newly synthesized compounds were characterized by 1H NMR, 13C NMR, IR and EI-MS spectral studies. The inhibitory effects of these bi-heterocyclic acetamides (9a-n) were evaluated against elastase and all these molecules were identified as potent inhibitors relative to the standard used. The Kinetics mechanism was analyzed by Lineweaver-Burk plots which revealed that, 9h, inhibited elastase competitively by forming an enzyme-inhibitor complex. The inhibition constants Ki calculated from Dixon plots for this compound was 0.9 µM. The computational study was articulate with the experimental results and these ligands unveiled good binding energy values (kcal/mol). So, these molecules can be considered as promising medicinal scaffolds for the treatment of skin melanoma, wrinkle formation, uneven pigmentation, and solar elastosis.
The present research was designed for the selective synthesis of novel bi-heterocyclic acetamides, 9a-n, and their tyrosinase inhibition to overwhelm the problem of melanogenesis. The structures of newly synthesized compounds were confirmed by spectral techniques such as 1H NMR, 13C NMR, and EI-MS along with elemental analysis. The inhibitory effects of these bi-heterocyclic acetamides (9a-n) were evaluated against tyrosinase and all these molecules were recognized as potent inhibitors relative to the standard used. The Kinetics mechanism was analyzed by Lineweaver-Burk plots which explored that compound, 9h, inhibited tyrosinase competitively by forming an enzyme-inhibitor complex. The inhibition constants Ki calculated from Dixon plots for this compound was 0.0027 µM. The computational study was coherent with the experimental records and these ligands exhibited good binding energy values (kcal/mol). The hemolytic analysis revealed their mild cytotoxicity towards red blood cell membranes and hence, these molecules can be pondered as nontoxic medicinal scaffolds for skin pigmentation and related disorders.
In the present study, a series of fourteen 5-benzoyl-4-methyl-1,3,4,5-tetrahydro-2H-1,5-benzodiazepin-2-one derivatives were designed, synthesized and characterized by appropriate spectral analysis. Further, titled compounds were in-vitro screened against wild HIV-1 RT enzyme using ELISA based colorimetric assay, in which four compounds significantly inhibited the RT activity with IC50≤25µM. Moreover, two significantly active compounds of the series, A10 and A11 exhibited IC50 values 8.62 and 6.87µM respectively, during the in-vitro assay. Structure Activity Relationship (SAR) studies were performed for the synthesized compounds in order to estimate the effect of substitution pattern on the RT inhibitory potency. The cytotoxicity of the synthesized compounds was evaluated against T lymphocytes. Further, putative binding modes of the significantly active (A11) and the least active (A4) compounds with wild HIV-1 RT were also investigated using docking studies.
α-Amylase is a target for type-2 diabetes mellitus treatment. However, small molecule inhibitors of α-amylase are currently scarce. In the course of developing small molecule α-amylase inhibitors, we designed and synthesized thiadiazole quinoline analogs (1-30), characterized by different spectroscopic techniques such as 1HNMR and EI-MS and screened for α-amylase inhibitory potential. Thirteen analogs 1, 2, 3, 4, 5, 6, 22, 23, 25, 26, 27, 28 and 30 showed outstanding α-amylase inhibitory potential with IC50 values ranges between 0.002±0.60 and 42.31±0.17μM which is many folds better than standard acarbose having IC50 value 53.02±0.12μM. Eleven analogs 7, 9, 10, 11, 12, 14, 15, 17, 18, 19 and 24 showed good to moderate inhibitory potential while seven analogs 8, 13, 16, 20, 21 and 29 were found inactive. Our study identifies novel series of potent α-amylase inhibitors for further investigation. Structure activity relationship has been established.
Sixteen 4-hydroxycoumarin derivatives were synthesized, characterized through EI-MS and (1)H NMR and screened for urease inhibitory potential. Three compounds exhibited better urease inhibition than the standard inhibitor thiourea (IC50=21±0.11μM) while other four compounds exhibited good to moderate inhibition with IC50 values between 29.45±1.1μM and 69.53±0.9μM. Structure activity relationship was established on the basis of molecular docking studies, which helped to predict the binding interactions of the most active compounds.
4-Thiazolidinone analogs 1-20 were synthesized, characterized by (1)H NMR and EI-MS and investigated for urease inhibitory activity. All twenty (20) analogs exhibited varied degree of urease inhibitory potential with IC50 values 1.73-69.65μM, if compared with standard thiourea having IC50 value of 21.25±0.15μM. Among the series, eight derivatives 3, 6, 8, 10, 15, 17, 19, and 20 showed outstanding urease inhibitory potential with IC50 values of 9.34±0.02, 14.62±0.03, 8.43±0.01, 7.3±0.04, 2.31±0.002, 5.75±0.003, 8.81±0.005, and 1.73±0.001μM, respectively, which is better than the standard thiourea. The remaining analogs showed good to excellent urease inhibition. The binding interactions of these compounds were confirmed through molecular docking studies.
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.
In search of better α-glucosidase inhibitors, a series of bis-indolylmethane sulfonohydrazides derivatives (1-14) were synthesized and evaluated for their α-glucosidase inhibitory potential. All derivatives exhibited outstanding α-glucosidase inhibition with IC50 values ranging between 0.10 ± 0.05 to 5.1 ± 0.05 μM when compared with standard drug acarbose having IC50 value 856.28 ± 3.15 μM. Among the series, analog 7 (0.10 ± 0.05 μM) with tri-chloro substitution on phenyl ring was identified as the most potent inhibitor of α-glucosidase (∼ 8500 times). The structure activity relationship has been also established. Molecular docking studies were also performed to help understand the binding interaction of the most active analogs with receptors. From the docking studies, it was observed that all the active bis-indolylmethane sulfonohydrazides derivatives showed considerable binding interactions within the active site (acarbose inhibition site) of α-glucosidase. We also evaluated toxicity of all derivatives and found none of them are toxic.
Twenty five derivatives of indole carbohydrazide (1-25) had been synthesized. These compounds were characterized using 1H NMR and EI-MS, and further evaluated for their α-amylase inhibitory potential. The analogs (1-25) showed varying degree of α-amylase inhibitory potential. ranging between 9.28 and 599.0µM when compared with standard acarbose having IC50 value 8.78±0.16µM. Six analogs, 25 (IC50=9.28±0.153µM), 22 (IC50=9.79±0.43µM), 4 (IC50=11.08±0.357µM), 1 (IC50=12.65±0.169µM), 8 (IC50=21.37±0.07µM) and 14 (IC50=43.21±0.14µM) showed potent α-amylase inhibition as compared to the standard acarbose (IC50=8.78±0.16µM). All other analogs displayed good to moderate inhibitory potential. Structure-activity relationship was established through the interaction of the active compounds with enzyme active site with the help of docking studies.
Diabetes being a chronic metabolic disorder have attracted the attention of medicinal chemists and biologists. The introduction of new and potential drug candidates for the cure and treatment of diabetes has become a major concern due to its increased prevelance worldwide. In the current study, twenty-seven azachalcone derivatives 3-29 were synthesized and evaluated for their antihyperglycemic activities by inhibiting α-amylase and α-glucosidase enzymes. Five compounds 3 (IC50 = 23.08 ± 0.03 µM), (IC50 = 26.08 ± 0.43 µM), 5 (IC50 = 24.57 ± 0.07 µM), (IC50 = 27.57 ± 0.07 µM), 6 (IC50 = 24.94 ± 0.12 µM), (IC50 = 27.13 ± 0.08 µM), 16 (IC50 = 27.57 ± 0.07 µM), (IC50 = 29.13 ± 0.18 µM), and 28 (IC50 = 26.94 ± 0.12 µM) (IC50 = 27.99 ± 0.09 µM) demonstrated good inhibitory activities against α-amylase and α-glucosidase enzymes, respectively. Acarbose was used as the standard in this study. Structure-activity relationship was established by considering the parent skeleton and different substitutions on aryl ring. The compounds were also subjected for kinetic studies to study their mechanism of action and they showed competitive mode of inhibition against both enzymes. The molecular docking studies have supported the results and showed that these compounds have been involved in various binding interactions within the active site of enzyme.
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 series of furocoumarin-stilbene hybrids has been synthesized and evaluated in vitro for inhibitory effect against acetylcholinesterase (AChE), butyrylcholinestarase (BChE), β-secretase, cyclooxygenase-2 (COX-2), and lipoxygenase-5 (LOX-5) activities including free radical-scavenging properties. Among these hybrids, 8-(3,5-dimethoxyphenyl)-4-(3,5-dimethoxystyryl)furochromen-2-one 4h exhibited significant anticholinesterase activity and inhibitory effect against β-secretase, COX-2 and LOX-5 activities. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and an in vitro cell-based antioxidant activity assay involving lipopolysaccharide induced reactive oxygen species production revealed that 4h has capability of scavenging free radicals. Molecular docking into AChE, BChE, β-secretase, COX-2 and LOX-5 active sites has also been performed.
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 series of nineteen (1-19) indole-based-thiadiazole derivatives were synthesized, characterized by 1HNMR, 13C NMR, MS, and screened for α-glucosidase inhibition. All analogs showed varied α-glucosidase inhibitory potential with IC50 value ranged between 0.95 ± 0.05 to 13.60 ± 0.30 µM, when compared with the standard acarbose (IC50 = 1.70 ± 0.10). Analogs 17, 2, 1, 9, 7, 3, 15, 10, 16, and 14 with IC50 values 0.95 ± 0.05, 1.10 ± 0.10, 1.30 ± 0.10, 1.60 ± 0.10, 2.30 ± 0.10, 2.30 ± 0.10, 2.80 ± 0.10, 4.10 ± 0.20 and 4.80 ± 0.20 µM respectively showed highest α-glucosidase inhibition. All other analogs also exhibit excellent inhibitory potential. Structure activity relationships have been established for all compounds primarily based on substitution pattern on the phenyl ring. Through molecular docking study, binding interactions of the most active compounds were confirmed. We further studied the kinetics study of analogs 1, 2, 9 and 17 and found that they are Non-competitive inhibitors.
Alpha-amylase and urease enzyme over expression endorses various complications like rheumatoid arthritis, urinary tract infection, colon cancer, metabolic disorder, cardiovascular risk, and chronic kidney disease. To overcome these complications, we have synthesized new arylhydrazide bearing Schiff bases/thiazolidinone analogues as α-amylase and urease inhibitors. The analogues 1a-r were evaluated for α-amylase inhibitory potential. All analogues were found active and show IC50 value ranging between 0.8 ± 0.05 and 12.50 ± 0.5 μM as compare to standard acarbose (IC50 = 1.70 ± 0.10 μM). Among the synthesized analogs, compound 1j, 1r, 1k, 1e, 1b and 1f having IC50 values 0.8 ± 0.05, 0.9 ± 0.05, 1.00 ± 0.05, 1.10 ± 0.10, 1.20 ± 0.10 and 1.30 ± 0.10 μM respectively showed an excellent inhibitory potential. Analogs 2a-o were evaluated against urease activity. All analogues were found active and show IC50 value ranging between 4.10 ± 0.02 and 38.20 ± 1.10 μM as compare to standard thiourea (IC50 = 21.40 ± 0.21 μM). Among the synthesized analogs, compound 2k, 2a, 2h, 2j, 2f, 2e, 2g, 2b and 2l having IC50 values 4.10 ± 0.02, 4.60 ± 0.02, 4.70 ± 0.03, 5.40 ± 0.02, 6.70 ± 0.05, 8.30 ± 0.3, 11.20 ± 0.04, 16.90 ± 0.8 and 19.80 ± 0.60 μM respectively showed an excellent inhibitory potential. All compounds were characterized through 1H, 13C NMR and HR-EIMS analysis. Structure activity relationship of the synthesized analogs were recognized and confirmed through molecular docking studies.