New Hybrid Scaffolds based on Hydrazinyl Thiazole Substituted Coumarin; As Novel Leads of Dual Potential; In Vitro α-Amylase Inhibitory and Antioxidant (DPPH and ABTS Radical Scavenging) Activities

Synthesis, characterization, antioxidant and antiparasitic activities new naphthyl-thiazole derivatives

In this work, 13 thiosemicarbazones (1a - m) and 16 thiazoles (2a - p) were obtained, which were properly characterized by spectroscopic and spectrometric techniques. The pharmacokinetic properties obtained in silico revealed that the derivatives are in accordance with the parameters established by lipinski and veber, showing that such compounds have good bioavailability or permeability when administered orally. In assays of antioxidant activity, thiosemicarbazones showed moderate to high antioxidant potential when compared to thiazoles. In addition, they were able to interact with albumin and DNA. Screening assays to assess the toxicity of compounds to mammalian cells revealed that thiosemicarbazones were less toxic when compared to thiazoles. In relation to in vitro antiparasitic activity, thiosemicarbazones and thiazoles showed cytotoxic potential against the parasites Leishmania amazonensis and Trypanosoma cruzi. Among the compounds, 1b, 1j and 2l stood out, showing inhibition potential for the amastigote forms of the two parasites. As for the in vitro antimalarial activity, thiosemicarbazones did not inhibit Plasmodium falciparum growth. In contrast, thiazoles promoted growth inhibition. This study shows in a preliminary way that the synthesized compounds have antiparasitic potential in vitro.

4-[Bis(thiazol-2-ylamino)methyl]phenol

We have designed and synthesized novel bis-thiazole derivative. A 4-[bis(thiazol-2-ylamino)methyl]phenol was efficiently prepared in 71% yield by the reaction of 2-aminothiazole with 4-hydroxybenzaldehyde in ethanol for 24 h. The structure of newly obtained compound was characterized by 1H, 13C NMR and mass spectrometry. Bis-thiazole derivative exhibits high tyrosinase inhibitory activity with an IC50 value of 29.71 μM. This inhibitory activity is 2.4 times higher than that of activity of kojic acid (IC50 72.27 µM) and almost 13 times higher than that of ascorbic acid (IC50 385.6 µM). Obtained data suggest that the presented compound may be a leading candidate for a tyrosinase inhibitor.

Synthetic benzofuran-linked chalcones with dual actions: a potential therapeutic approach to manage diabetes mellitus

Background: Identification of molecules having dual capabilities to reduce postprandial hyperglycemia and oxidative stress is one of the therapeutic approaches to treat diabetes mellitus. In this connection, a library of benzofuran-linked chalcone derivatives were evaluated for their dual action. Methods: A series of substituted benzofuran-linked chalcones (2-33) were synthesized and tested for α-amylase inhibitory as well as 2,2-diphenylpicrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities. Results: All compounds showed α-amylase inhibitory activity ranging from IC₅₀ = 12.81 ± 0.03 to 87.17 ± 0.15 μM, compared with the standard acarbose (IC₅₀ = 13.98 ± 0.03 μM). Compounds also demonstrated radical scavenging potential against DPPH and ABTS radicals. Conclusion: The identified compounds may serve as potential leads for further advanced research.

Syntheses, in vitro, and in silico studies of rhodanine-based schiff bases as potential α-amylase inhibitors and radicals (DPPH and ABTS) scavengers

A two-step reaction method was used to synthesize a series of rhodanine-based Schiff bases (2-33) that were characterized using spectroscopic techniques. All compounds were assessed for α-amylase inhibitory and radical scavenging (DPPH and ABTS) activities. In comparison to the standard acarbose (IC₅₀ = 9.08 ± 0.07 µM), all compounds demonstrated good to moderate α-amylase inhibitory activity (IC₅₀ = 10.91 ± 0.08-61.89 ± 0.102 µM). Compounds also demonstrated significantly higher DPPH (IC₅₀ = 10.33 ± 0.02-96.65 ± 0.03 µM) and ABTS (IC₅₀ = 12.01 ± 0.12-97.47 ± 0.13 µM) radical scavenging activities than ascorbic acid (DPPH, IC₅₀ = 15.08 ± 0.03 µM; ABTS, IC₅₀ = 16.09 ± 0.17 µM). The limited structure-activity relationship (SAR) suggests that the position and nature of the substituted groups on the phenyl ring have a vital role in varying inhibitory potential. Among the series, compounds with an electron-withdrawing group at the para position showed the highest potency. Kinetic studies revealed that the compounds followed a competitive mode of inhibition. Molecular docking results are found to agree with experimental findings, showing that compounds reside in the active pocket due to the main rhodanine moiety.

Identification of Cyclic Sulfonamides with an N-Arylacetamide Group as α-Glucosidase and α-Amylase Inhibitors: Biological Evaluation and Molecular Modeling

Diabetes mellitus (DM), a complicated metabolic disorder, is due to insensitivity to insulin function or reduction in insulin secretion, which results in postprandial hyperglycemia. α-Glucosidase inhibitors (AGIs) and α-amylase inhibitors (AAIs) block the function of digestive enzymes, which delays the carbohydrate hydrolysis process and ultimately helps to control the postprandial hyperglycemia. Diversified 2-(3-(3-methoxybenzoyl)-4-hydroxy-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl)-N-arylacetamides were synthesized and evaluated for their in vitro inhibitory potential against α-glucosidase and α-amylase enzymes. The compounds with chloro, bromo and methyl substituents demonstrated good inhibition of α-glucosidase enzymes having IC₅₀ values in the range of 25.88–46.25 μM, which are less than the standard drug, acarbose (IC₅₀ = 58.8 μM). Similarly, some derivatives having chloro, bromo and nitro substituents were observed potent inhibitors of α-amylase enzyme, with IC₅₀ values of 7.52 to 15.06 μM, lower than acarbose (IC₅₀ = 17.0 μM). In addition, the most potent compound, N-(4-bromophenyl)-2-(4-hydroxy-3-(3-methoxybenzoyl)-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl)acetamide (12i), was found to be a non-competitive and competitive inhibitor of α-glucosidase and α-amylase enzymes, respectively, during kinetic studies. The molecular docking studies provided the binding modes of active compounds and the molecular dynamics simulation studies of compound 12i in complex with α-amylase also showed that the compound is binding in a fashion similar to that predicted by molecular docking studies.

Design, Molecular Docking, Synthesis, Characterization and Biological Activities of Novel Thiazole Derivatives

Aim:

The study aims to design & synthesize novel thiazole derivatives as potent antitubercular agents with minimal side effects.

Background:

The emergence and rapid spread of multi-drug resistant infectious microbial flora embracing a variety of bacterial as well as mycobacterium strains are causing a threat to public health worldwide.

Objective:

Owing to the importance, we designed compounds with thiazole functionality coupled with Schiff base and thiosemicarbazide, predicted the molecular properties and antitubercular potency of designed compounds by the in-silico method, and synthesized fifteen novel thiazole analogs, characterized and tested in vivo antitubercular, antibacterial and antioxidant potencies.

Methods:

Molinspiration online tool was used to predict the molecular properties and molecular docking was used to predict the antitubercular potency. FT-IR, 1H-NMR, 13C-NMR, Mass spectroscopy and bases of elemental analysis are employed to confirm the structure of compounds. 10-Fold serial dilution method, agar streak dilution test and DPPH radical scavenging methods are used to estimate antitubercular, antibacterial and antioxidant potency of title analogs, respectively.

Results:

Multi-step synthesis was used to synthesize a variety of novel thiazole derivatives coupled with Schiff base and thiosemicarbazide. Synthesized title compounds displayed a varying degree of antitubercular, antibacterial and antioxidant activities (mild to good). The title compounds possessing deactivating group exhibited superior activities than activating group, while unsubstituted analogs displayed intermediate activities. In addition, para-substituted analogs showed slightly higher activity than the corresponding meta substituted analogs.

Conclusion:

Among fifteen tested title compounds, the potent compound of this series was found to be 1-(4-nitrobenzylidene)-4-(4-(4-methoxyphenyl)thiazol-2-yl)thiosemicarbazide (BTS14), which might be extended as a novel class of antitubercular and antibacterial agents.

Synthesis of indole derivatives as diabetics II inhibitors and enzymatic kinetics study of α-glucosidase and α-amylase along with their in-silico study

In this study, we have investigated a series of indole-based compounds for their inhibitory study against pancreatic α-amylase and intestinal α-glucosidase activity. Inhibitors of carbohydrate degrading enzymes appear to have an essential role as antidiabetic drugs. All analogous exhibited good to moderate α-amylase (IC₅₀ = 3.80 to 47.50 μM), and α-glucosidase inhibitory interactions (IC₅₀ = 3.10-52.20 μM) in comparison with standard acarbose (IC₅₀ = 12.28 μM and 11.29 μM). The analogues 4, 11, 12, 15, 14 and 17 had good activity potential both for enzymes inhibitory interactions. Structure activity relationships were deliberated to propose the influence of substituents on the inhibitory potential of analogues. Docking studies revealed the interaction of more potential analogues and enzyme active site. Further, we studied their kinetic study of most active compounds showed that compounds 15, 14, 12, 17 and 11 are competitive for α-amylase and non- competitive for α-glucosidase.

Substituted Benzimidazole Analogues as Potential α-Amylase Inhibitors and Radical Scavengers

Benzimidazole scaffolds are known to have a diverse range of biological activities and found to be antidiabetic and antioxidant. In this study, a variety of arylated benzimidazoles 1-31 were synthesized. Except for compounds 1, 6, 7, and 8, all are new derivatives. All compounds were screened for α-amylase inhibitory, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities. In vitro screening results revealed that all molecules demonstrated significant α-amylase inhibition with IC50 values of 1.86 ± 0.08 to 3.16 ± 0.31 μM as compared to standard acarbose (IC50 = 1.46 ± 0.26 μM). However, compounds showed significant ABTS and DPPH radical scavenging potentials with IC50 values in the range of 1.37 ± 0.21 to 4.00 ± 0.10 μM for ABTS and 1.36 ± 0.09 to 3.60 ± 0.20 μM for DPPH radical scavenging activities when compared to ascorbic acid with IC50 values of 0.72 ± 0.21 and 0.73 ± 0.05 μM for ABTS and DPPH radical scavenging potentials, respectively. Structure-activity relationship (SAR) was established after critical analysis of varying substitution effects on α-amylase inhibitory and radical scavenging (ABTS and DPPH) potentials. However, molecular docking was also performed to figure out the active participation of different groups of synthetic molecules during binding with the active pocket of the α-amylase enzyme.

In vitro and in silico studies of bis (indol-3-yl) methane derivatives as potential α-glucosidase and α-amylase inhibitors

In this paper, bis (indol-3-yl) methanes (BIMs) were synthesised and evaluated for their inhibitory activity against α-glucosidase and α-amylase. All synthesised compounds showed potential α-glucosidase and α-amylase inhibitory activities. Compounds 5 g (IC₅₀: 7.54 ± 1.10 μM), 5e (IC₅₀: 9.00 ± 0.97 μM), and 5 h (IC₅₀: 9.57 ± 0.62 μM) presented strongest inhibitory activities against α-glucosidase, that were ∼ 30 times stronger than acarbose. Compounds 5 g (IC₅₀: 32.18 ± 1.66 µM), 5 h (IC₅₀: 31.47 ± 1.42 µM), and 5 s (IC₅₀: 30.91 ± 0.86 µM) showed strongest inhibitory activities towards α-amylase, ∼ 2.5 times stronger than acarbose. The mechanisms and docking simulation of the compounds were also studied. Compounds 5 g and 5 h exhibited bifunctional inhibitory activity against these two enzymes. Furthermore, compounds showed no toxicity against 3T3-L1 cells and HepG2 cells.

Highlights

A series of bis (indol-3-yl) methanes (BIMs) were synthesised and evaluated inhibitory activities against α-glucosidase and α-amylase.

Compound 5g exhibited promising activity (IC₅₀ = 7.54 ± 1.10 μM) against α-glucosidase.

Compound 5s exhibited promising activity (IC₅₀ = 30.91 ± 0.86 μM) against α-amylase.

In silico studies were performed to confirm the binding interactions of synthetic compounds with the enzyme active site.

Novel cinnamic acid magnolol derivatives as potent α-glucosidase and α-amylase inhibitors: Synthesis, in vitro and in silico studies

In this study, twenty novel cinnamic acid magnolol derivatives were synthesized, and screened for their anti-hyperglycemic potential. All synthesized compounds exhibited good to moderate α-glucosidase and α-amylase inhibitory activities with IC₅₀ values: 5.11 ± 1.46-90.26 ± 1.85 µM and 4.27 ± 1.51-49.28 ± 2.54 µM as compared to the standard acarbose (IC₅₀: 255.44 ± 1.89 μM and 80.33 ± 2.95 μM, respectively). Compound 6j showed the strongest inhibitory activity against α-glucosidase (IC₅₀ = 5.11 ± 1.46 µM) and α-amylase (IC₅₀ = 4.27 ± 1.51 µM). Kinetic study indicated that compound 6j was reversible and a mixed type inhibitor against α-glucosidase and α-amylase. In silico studies revealed the binding interaction between 6j and two enzymes, respectively. Finally, cells cytotoxicity assay revealed that compound 6j showed low toxicity against 3 T3-L1 cells and HepG2 cells.

The newly synthesized thiazole derivatives as potential antifungal compounds against Candida albicans

Abstract

Recently, the occurrence of candidiasis has increased dramatically, especially in immunocompromised patients. Additionally, their treatment is often ineffective due to the resistance of yeasts to antimycotics. Therefore, there is a need to search for new antifungals. A series of nine newly synthesized thiazole derivatives containing the cyclopropane system, showing promising activity against Candida spp., has been further investigated. We decided to verify their antifungal activity towards clinical Candida albicans isolated from the oral cavity of patients with hematological malignancies and investigate the mode of action on fungal cell, the effect of combination with the selected antimycotics, toxicity to erythrocytes, and lipophilicity. These studies were performed by the broth microdilution method, test with sorbitol and ergosterol, checkerboard technique, erythrocyte lysis assay, and reversed phase thin-layer chromatography, respectively. All derivatives showed very strong activity (similar and even higher than nystatin) against all C. albicans isolates with minimal inhibitory concentration (MIC) = 0.008–7.81 µg/mL Their mechanism of action may be related to action within the fungal cell wall structure and/or within the cell membrane. The interactions between the derivatives and the selected antimycotics (nystatin, chlorhexidine, and thymol) showed additive effect only in the case of combination some of them and thymol. The erythrocyte lysis assay confirmed the low cytotoxicity of these compounds as compared to nystatin. The high lipophilicity of the derivatives was related with their high antifungal activity. The present studies confirm that the studied thiazole derivatives containing the cyclopropane system appear to be a very promising group of compounds in treatment of infections caused by C. albicans. However, this requires further studies in vivo.

Key points

• The newly thiazoles showed high antifungal activity and some of them — additive effect in combination with thymol.

• Their mode of action may be related with the influence on the structure of the fungal cell wall and/or the cell membrane.

• The low cytotoxicity against erythrocytes and high lipophilicity of these derivatives are their additional good properties.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-021-11477-7.

Synthesis and Physicochemical Characterization of Novel Dicyclopropyl-Thiazole Compounds as Nontoxic and Promising Antifungals

There is a need to search for new antifungals, especially for the treatment of the invasive Candida infections, caused mainly by C. albicans. These infections are steadily increasing at an alarming rate, mostly among immunocompromised patients. The newly synthesized compounds (3a-3k) were characterized by physicochemical parameters and investigated for antimicrobial activity using the microdilution broth method to estimate minimal inhibitory concentration (MIC). Additionally, their antibiofilm activity and mode of action together with the effect on the membrane permeability in C. albicans were investigated. Biofilm biomass and its metabolic activity were quantitatively measured using crystal violet (CV) staining and tetrazolium salt (XTT) reduction assay. The cytotoxic effect on normal human lung fibroblasts and haemolytic effect were also evaluated. The results showed differential activity of the compounds against yeasts (MIC = 0.24-500 µg/mL) and bacteria (MIC = 125-1000 µg/mL). Most compounds possessed strong antifungal activity (MIC = 0.24-7.81 µg/mL). The compounds 3b, 3c and 3e, showed no inhibitory (at 1/2 × MIC) and eradication (at 8 × MIC) effect on C. albicans biofilm. Only slight decrease in the biofilm metabolic activity was observed for compound 3b. Moreover, the studied compounds increased the permeability of the membrane/cell wall of C. albicans and their mode of action may be related to action within the fungal cell wall structure and/or within the cell membrane. It is worth noting that the compounds had no cytotoxicity effect on pulmonary fibroblasts and erythrocytes at concentrations showing anticandidal activity. The present studies in vitro confirm that these derivatives appear to be a very promising group of antifungals for further preclinical studies.

A facile approach synthesis of benzoylaryl benzimidazole as potential α-amylase and α-glucosidase inhibitor with antioxidant activity

Synthetic routes to a series of benzoylarylbenzimidazol 3a-h have been derived from 3,4-diaminobenzophenone and an appropriate arylaldehyde in the presence of ammonium chloride or a mixture of ammonium chloride and sodium metabisulfite as catalyst. The antioxidant activity of targeted compounds 3a-h has been measured by four different methods and the overall antioxidant evaluation of the compounds indicated the significant MCA, FRAP, and (DPPH-SA) of the compounds except for the compound 3h. In vitro antidiabetic assay of α-amylase and α-glucosidase suggest a good to excellent activity for most tested compounds. The target benzimidazole 3f containing hydroxyl motif at para-position of phenyl revealed an important activity inhibitor against α- amylase (IC₅₀ = 12.09 ± 0.38 µM) and α-glucosidase (IC₅₀ = 11.02 ± 0.04 µM) comparable to the reference drug acarbose. The results of the anti hyperglycemic activity were supported by means of in silico molecular docking calculations showing strong binding affinity of compounds 3a-h with human pancreatic α-amylase (HPA) and human lysosomal acid-α-glucosidase (HLAG) active sites that confirm a good to excellent activity for most of tested compounds.

Chalcones and Bis-Chalcones Analogs as DPPH and ABTS Radical Scavengers

Background:

A number of synthetic scaffolds, along with natural products, have been identified as potent antioxidants. The present study deals with the evaluation of varyingly substituted, medicinally distinct class of compounds “chalcones and bis-chalcones” for their antioxidant potential.

Methods:

In vitro radical scavenging activities were performed on a series of synthetic chalcones 1- 13 and bis-chalcones 14-18.

Results:

All molecules 1-18 revealed a pronounced 2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2ʹ- azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals scavenging potential in the ranges of IC50s = 0.58 ± 0.14 - 1.72 ± 0.03 and 0.49 ± 0.3 - 1.48 ± 0.06 μM, respectively. Ascorbic acid (IC50s = 0.5 ± 0.1 and 0.46 ± 0.17 μM for DPPH and ABTS, respectively) was used as a standard radical scavenger.

Conclusion:

Structure-activity relationship (SAR) revealed an active participation of various groups, including -SMe and -OMe in scavenging activity.

Structural elucidation, molecular docking, α-amylase and α-glucosidase inhibition studies of 5-amino-nicotinic acid derivatives

In this study, 5-amino-nicotinic acid derivatives (1-13) have been designed and synthesized to evaluate their inhibitory potential against α-amylase and α-glucosidase enzymes. The synthesized compounds (1-13) exhibited promising α-amylase and α-glucosidase activities. IC50 values for α-amylase activity ranged between 12.17 ± 0.14 to 37.33 ± 0.02 µg/mL ± SEM while for α-glucosidase activity the IC50 values were ranged between 12.01 ± 0.09 to 38.01 ± 0.12 µg/mL ± SEM. In particular, compounds 2 and 4-8 demonstrated significant inhibitory activities against α-amylase and α-glucosidase and the inhibitory potential of these compounds was comparable to the standard acarbose (10.98 ± 0.03 and 10.79 ± 0.17 µg/mL ± SEM, respectively). In addition, the impact of substituent on the inhibitory potential of these compounds was assessed to establish structure activity relationships. Studies in molecular simulations were conducted to better comprehend the binding properties of the compounds. All the synthesized compounds were extensively characterized with modern spectroscopic methods including 1H-NMR, 13C-NMR, FTIR, HR-MS and elemental analysis.

Synthesis of azachalcones, their α-amylase, α-glucosidase inhibitory activities, kinetics, and molecular 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.

Synthesis of arylidene hydrazinylpyrido[2,3-d]pyrimidin-4-ones as potent anti-microbial agents

Combination of arylidene hydrazinyl moiety with pyrido[2,3-d]pyrimidin-4-one skeleton in compounds 7‒26 results in the output of unprecedented anti-microbial agents. Arylidene hydrazinyl based on Pyrido[2,3-d]pyrimidin-4-one analoges 7‒26 prepared by the treatment of [2,3-d]pyrimidin-4-ones 6a,b with various aromatic aldehydes. The antimicrobial action for recently synthesized compounds was considered towards gram positive bacterial species (Staphylococcus aurous ATCC- 47077; Bacillus cereus ATCC-12228), gram negative bacterial species (Escherichia coli ATCC-25922; Salmonella typhi ATCC-15566) and Candida albicans ATCC-10231 as fungal strains. The antimicrobial action expanded by expanding the electron donating group in position 2 and 5 for Pyrido[2,3-d]pyrimidin-4-one core. Derivatives 13, 14, 15, 16 and 12; individually appeared hopeful anti-microbial action towards all strains utilized with inhibition zone higher than that of standard reference drug with lowest MIC.

Synthesis and screening of (E)-3-(2-benzylidenehydrazinyl)-5,6-diphenyl-1,2,4-triazine analogs as novel dual inhibitors of α-amylase and α-glucosidase

(E)-3-(2-Benzylidenehydrazinyl)-5,6-diphenyl-1,2,4-triazines analogs 1-27 were synthesized by multi-step reaction scheme and subjected to in vitro inhibitory screening against α-amylase and α-glucosidase enzymes. Out of these twenty-seven synthetic analogs, ten compounds 14-17, 19, and 21-25 are structurally new. All compounds exhibited good to moderate inhibitory potential in terms of IC₅₀ values ranging (IC₅₀ = 13.02 ± 0.04-46.90 ± 0.05 µM) and (IC₅₀ = 13.09 ± 0.08-46.44 ± 0.24 µM) in comparison to standard acarbose (IC₅₀ = 12.94 ± 0.27 µM and 10.95 ± 0.08 µM), for α-amylase and α-glucosidase, respectively. Structure-activity relationship indicated that analogs with halogen substitution(s) were found more active as compared to compounds bearing other substituents. Kinetic studies on most active α-amylase and α-glucosidase inhibitors 5, 7, 9, 15, 24, and 27, suggested non-competitive and competitive types of inhibition mechanism for α-amylase and α-glucosidase, respectively. Molecular docking studies predicted the good protein-ligand interaction (PLI) profile with key interactions such as arene-arene, H-<, <-<, and <-H etc., against the corresponding targets.

Diversified Thiazole Substituted Coumarins and Chromones as Non- Cytotoxic ROS and NO Inhibitors

Background:

Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, aspirin, indomethacin, flufenamic acid and phenylbutazone are used to treat most of the inflammatory disorders. These NSAIDs are also associated with serious side effects including gastric ulceration, nephrotoxicity, and bleeding, mainly due to acidic nature. Hence, there is a need to identify highly potent and safer treatment for inflammatory disorders.

Methods:

Herein, synthetic hydrazinyl thiazole substituted coumarins and chromones 1-48 were evaluated for ROS inhibitory activity. ROS were generated from zymosan activated whole blood phagocytes.

Results:

Among all tested compounds, compounds 1 (IC50 = 38.3 ± 7.1 μM), 2 (IC50 = 5.7 ± 0.2 μM), 5 (IC50 = 28.3 ± 3.5 μM), 23 (IC50 = 12.5 ± 3.1 μM), 27 (IC50 = 32.8 ± 1.1 μM), 39 (IC50 = 20.2 ± 1.6 μM), and 42 (IC50 = 43.2 ± 3.8 μM) showed potent ROS inhibition as compared to standard ibuprofen (IC50 = 54.3 ± 1.9 μM). Whereas, compounds 3 (IC50 = 134.7 ± 1.0 μM), 16 (IC50 = 75.4 ± 7.2 μM), 24 (IC50 = 102.4 ± 1.0 μM), and 31 (IC50 = 86.6 ± 1.5 μM) were found to be moderately active. Compounds 1, 2, 5, 23, 27, 39, and 42, having potent ROS inhibitory activity were also screened for their nitric oxide (NO) inhibition. Cytotoxicity was also checked for all active compounds on NIH-3T3 cell line. Cyclohexamide (IC50 = 0.13 ± 0.02 μM) was used as standard.

Conclusion:

Identified active compounds from these libraries may serve as lead candidates for future research in order to obtain a more potent, and safer anti-inflammatory agent.

Synthesis, photophysical and electrochemical properties of donor–acceptor type hydrazinyl thiazolyl coumarins

A practical green MCR strategy has been developed for the synthesis of D–A type hydrazinyl thiazolyl coumarins catalyzed by an environmentally compatible MMT K10 clay in water at RT.

Benzo[b]thiophene-thiazoles as potent anti-Toxoplasma gondii agents: Design, synthesis, tyrosinase/tyrosine hydroxylase inhibitors, molecular docking study, and antioxidant activity

Synthesis and investigation of anti-Toxoplasma gondii activity of novel thiazoles containing benzo [b]thiophene moiety are presented. Among the derivatives, compound 3k with adamantyl group shows exceptionally high potency against Me49 strain with IC₅₀ (8.74 μM) value which is significantly lower than the activity of trimethoprim (IC₅₀ 39.23 μM). In addition, compounds 3a, 3b and 3k showed significant activity against RH strain (IC₅₀ 51.88-83.49 μM). The results of the cytotoxicity evaluation showed that Toxoplasma gondii growth was inhibited at non-cytotoxic concentrations for the mammalian L929 fibroblast (CC₃₀ ∼ 880 μM). The most active compound 3k showed tyrosinase inhibition effect, with IC₅₀ value of 328.5 μM. The binding energies calculated for compounds 3a-3e, 3k are strongly correlated with the experimentally determined values of tyrosinase inhibition activity. Moreover, the binding energies corresponding to the same ligands and calculated for both tyrosinase and tyrosine hydroxylase are also correlated with each other, suggesting that tyrosinase inhibitors may also have an inhibitory effect on tyrosine hydroxylase. Compounds 3j and 3k have also very strong antioxidant activity (IC₅₀ 15.9 and 15.5 μM), respectively, which is ten times higher than well-known antioxidant BHT.

Synthesis of new indazole based dual inhibitors of α-glucosidase and α-amylase enzymes, their in vitro, in silico and kinetics studies

The current study describes the discovery of novel inhibitors of α-glucosidase and α-amylase enzymes. For that purpose, new hybrid analogs of N-hydrazinecarbothioamide substituted indazoles 4-18 were synthesized and fully characterized by EI-MS, FAB-MS, HRFAB-MS, ¹H-, and ¹³C NMR spectroscopic techniques. Stereochemistry of the imine double bond was established by NOESY measurements. All derivatives 4-18 with their intermediates 1-3, were evaluated for in vitro α-glucosidase and α-amylase enzyme inhibition. It is worth mentioning that all synthetic compounds showed good inhibition potential in the range of 1.54 ± 0.02-4.89 ± 0.02 µM for α-glucosidase and for α-amylase 1.42 ± 0.04-4.5 ± 0.18 µM in comparison with the standard acarbose (IC₅₀ value of 1.36 ± 0.01 µM). In silico studies were carried out to rationalize the mode of binding interaction of ligands with the active site of enzymes. Moreover, enzyme inhibitory kinetic characterization was also performed to understand the mechanism of enzyme inhibition.