Novel anti-inflammatory and analgesic agents: synthesis, molecular docking and in vivo studies

Design, synthesis, biological assessment and molecular modeling studies of novel imidazothiazole-thiazolidinone hybrids as potential anticancer and anti-inflammatory agents

A new series of imidazothiazole derivatives bearing thiazolidinone moiety (4a-g and 5a-d) were designed, synthesized and evaluated for potential epidermal growth factor receptor (EGFR) kinase inhibition, anticancer and anti-inflammatory activity, cardiomyopathy toxicity and hepatotoxicity. Compound 4c inhibited EGFR kinase at a concentration of 18.35 ± 1.25 µM, whereas standard drug erlotinib showed IC50 value of 06.12 ± 0.92 µM. The molecular docking, dynamics simulation and MM-GBSA binding energy calculations revealed strong interaction of compound 4c with binding site of EGFR. The synthesized compounds were evaluated for their anticancer activity by MTT assay against three human cancer cell lines A549 (Lung), MCF-7 (Breast), HCT116 (Colon), one normal human embryonic kidney cell line HEK293 and also for their EGFR kinase inhibitory activity. Few compounds of the series (4a, 4b, 4c) showed promising growth inhibition against all the tested cancer cell lines and against EGFR kinase. Among these, compound 4c was found to be most active and displayed IC50 value of 10.74 ± 0.40, 18.73 ± 0.88 against cancer cell lines A549 and MCF7 respectively whereas it showed an IC50 value of 96.38 ± 1.79 against HEK293 cell line indicating lesser cytotoxicity for healthy cell. Compounds 4a, 4b and 4c were also examined for their apoptosis inducing potential through AO/EB dual staining assay and it was observed that their antiproliferative activity against A549 cells is mediated via induction of apoptosis. Cardiomyopathy studies showed normal cardiomyocytes with no marked sign of pyknotic nucleus of compounds 4b and 4c. Hepatotoxicity studies of compounds 4b and 4c also showed normal architecture of hepatocytes. Compounds 4a-g and 5a-d were also evaluated for their in-vitro anti-inflammatory activity by protein albumin denaturation assay. Among the tested compounds 4a-d and 5a-b showed promising activity and were selected for in-vivo inflammatory activity against carrageenan rat paw edema test. Among these compounds, 4b was found to be most active in the series showing 84.94% inhibition, whereas the standard drug diclofenac sodium showed 84.57% inhibition. Compound 4b also showed low ulcerogenic potential and lipid peroxidation. Thus, compounds 4c and 4b could be a promising lead compounds for developing anticancer and anti-inflammatory agents with low toxicity and selectivity.

Current Development of Thiazole-Containing Compounds as Potential Antibacterials against Methicillin-Resistant Staphylococcus aureus

The emergence of multi-drug-resistant bacteria is threatening to human health and life around the world. In particular, methicillin-resistant Staphylococcus aureus (MRSA) causes fatal injuries to human beings and serious economic losses to animal husbandry due to its easy transmission and difficult treatment. Currently, the development of novel, highly effective, and low-toxicity antimicrobials is important to combat MRSA infections. Thiazole-containing compounds with good biological activity are widely used in clinical practice, and appropriate structural modifications make it possible to develop new antimicrobials. Here, we review thiazole-containing compounds and their antibacterial effects against MRSA reported in the past two decades and discuss their structure-activity relationships as well as the corresponding antimicrobial mechanisms. Some thiazole-containing compounds exhibit potent antibacterial efficacy in vitro and in vivo after appropriate structural modifications and could be used as antibacterial candidates. This Review provides insights into the development of thiazole-containing compounds as antimicrobials to combat MRSA infections.

Discovery of novel 2-(4-(benzyloxy)-5-(hydroxyl) phenyl) benzothiazole derivatives as multifunctional MAO-B inhibitors for the treatment of Parkinson's disease

To discover novel multifunctional agents for the treatment of Parkinson's disease, a series of 2-(4-(benzyloxy)-5-(hydroxyl) phenyl) benzothiazole derivatives was designed, synthesized and evaluated. The results revealed that representative compound 3h possessed potent and selective MAO-B inhibitory activity (IC₅₀ = 0.062 µM), and its inhibitory mode was competitive and reversible. Additionally, 3h also displayed excellent anti-oxidative effect (ORAC = 2.27 Trolox equivalent), significant metal chelating ability and appropriate BBB permeability. Moreover, 3h exhibited good neuroprotective effect and anti-neuroinflammtory ability. These results indicated that compound 3h was a promising candidate for further development against PD.

N-(2-ozoazepan-3-yl)-pyrrolidine-2-carboxamide, a novel Octopus vulgaris ink-derived metabolite, exhibits a pro-apoptotic effect on A549 cancer cell line and inhibits pro-inflammatory markers

This research aimed to chemically synthesize and evaluate the antiproliferative and anti-inflammatory potential of ozopromide (OPC), a novel compound recently isolated from O. vulgaris ink. After chemical synthesis, OPC structural characterization was confirmed by COSY2D, FTIR, and C-/H-NMR. OPC inhibited the growth of human breast (MDA-MB-231), prostate (22Rv1), cervix (HeLa), and lung (A549) cancerous cells, being the highest effect on the latter (IC₅₀: 53.70 μM). As confirmed by flow cytometry, OPC induced typical apoptosis-derived morphological features on A549 cells, mostly at early and late apoptosis stages. OPC generated a dose-dependent effect inhibiting IL-6 and IL-8 on LPS-stimulated peripheral mononuclear cells (PBMCs). A major affinity of OPC to Akt-1 and Bcl-2 proteins in silico agreed with the observed pro-apoptotic mechanisms. Results suggested that OPC has the potential to alleviate inflammation and be further studied for anticancer activity. Marine-derived food products such as ink contains bioactive metabolites exhibiting potential health benefits.

Synthesis, antimicrobial activity and molecular docking studies of spiroquinoline-indoline-dione and spiropyrazolo-indoline-dione derivatives

Spiro[benzo[h]quinoline-7,3'-indoline]diones and spiro[indoline-3,4'-pyrazolo[3,4-b]quinoline]diones were efficiently synthesized via one-pot multi-component reactions under ultrasound-promoted conditions. Spiro[benzo[h]quinoline-7,3'-indoline]dione derivatives were successfully developed by the reaction of isatins, naphthalene-1-amine and 1,3-dicarbonyl compounds. The spiro[indoline-3,4'-pyrazolo[3,4-b]quinoline]dione derivatives were prepared by the reaction of isatins, 5-amino-1-methyl-3-pheylpyrazole, and 1,3-dicarbonyl compounds by using ( ±)-camphor-10-sulfonic acid as a catalyst in H₂O/EtOH (3:1 v/v) solvent mixture. The antibacterial activity of the synthesized compounds was evaluated against, Enterococcus faecalis, Staphylococcus aureus and Candida albicans. Compounds 4b, 4h, and 6h showed the strongest antimicrobial activity toward both bacteria. The MIC values of these compounds ranged from 375-3000 µg/mL. The effect of these compounds (4b, 4h, 6h) as a function of applied dose and time was investigated by a kinetic study, and the interaction with these antimicrobial results was simulated by a molecular docking study. We also used the docking approach with Covid-19 since secondary bacterial infections. Docking showed that indoline-quinoline hybrid compounds 4b and 4h exerted the strongest docking binding value against the active sites of 6LU7. In addition, the synthesized compounds had a moderate to good free radical scavenging activity.

Synthesis, Computational Study, and Anticonvulsant Activity of Newly Synthesized 2-aminobenzothiazole Derivatives

Background:

Despite the fact that anticonvulsant drugs targeting multiple targets have been used in the health center, their effectiveness and tolerability in the treatment of seizures have not improved much. As a result, innovative anticonvulsant medicines are still needed urgently to overcome the significant toxicity of currently existing medications.

Objective:

This study aimed to synthesize 2-aminobenzothiazole derivatives as anticonvulsant agents, compute physicochemical parameters, and conduct a docking investigation.

Methods:

Condensing 4-(2-(benzo[d]thiazole-2-ylamino) acetamido) benzoyl chloride with substituted phenols in acetone in anhydrous potassium carbonate in the presence of potassium iodide in dry acetone yielded benzothiazole derivatives. IR and NMR spectroscopy were used to characterize the structures of freshly synthesized substances. To estimate their drug-like candidates, a number of molecular attributes of these derivatives were computed. The carbonic anhydrase enzyme was used to perform molecular docking on these synthesized compounds. The synthetic compounds were tested for biological activity, such as anticonvulsant activity and enzyme inhibitor activity for carbonic anhydrase.

Results:

The findings showed that V-5 (4-chlorophenyl 4-(2-(benzo[d]thiazol-2-ylamino)acetamido)benzoate) had the strongest anticonvulsant effect out of all the eight target compounds.

Conclusion:

The outcome of this research was that V-5 could be a promising new lead molecule for the development of anticonvulsant drugs.

Experimental and In Silico Evaluation of New Heteroaryl Benzothiazole Derivatives as Antimicrobial Agents

In this manuscript, we describe the design, preparation, and studies of antimicrobial activity of a series of novel heteroarylated benzothiazoles. A molecular hybridization approach was used for the designing compounds. The in vitro evaluation exposed that these compounds showed moderate antibacterial activity. Compound 2j was found to be the most potent (MIC/MBC at 0.23–0.94 mg/mL and 0.47–1.88 mg/mL) On the other hand, compounds showed good antifungal activity (MIC/MFC at 0.06–0.47 and 0.11–0.94 mg/mL respectively) with 2d being the most active one. The docking studies revealed that inhibition of E. coli MurB and 14-lanosterol demethylase probably represent the mechanism of antibacterial and antifungal activities.

Structure and Computational Studies of New Sulfonamide Compound: {(4-nitrophenyl)sulfonyl}tryptophan

Synthesis of sulfonamide through an indirect method that avoids contamination of the product with no need for purification has been carried out using the indirect process. Here, we report the synthesis of a novel sulfonamide compound, ({4-nitrophenyl}sulfonyl)tryptophan (DNSPA) from 4-nitrobenzenesulphonylchloride and L-tryptophan precursors. The slow evaporation method was used to form single crystals of the named compound from methanolic solution. The compound was characterized by X-ray crystallographic analysis and spectroscopic methods (NMR, IR, mass spectrometry, and UV-vis). The sulfonamide N-H NMR signal at 8.07–8.09 ppm and S-N stretching vibration at 931 cm−1 indicate the formation of the target compound. The compound crystallized in the monoclinic crystal system and P21 space group with four molecules of the compound in the asymmetric unit. Molecular aggregation in the crystal structure revealed a 12-molecule aggregate synthon sustained by O-H⋯O hydrogen bonds and stabilised by N-H⋯O intermolecular contacts. Experimental studies were complemented by DFT calculations at the B3LYP/6-311++G(d,p) level of theory. The computed structural and spectroscopic data are in good agreement with those obtained experimentally. The energies of interactions between the units making up the molecule were calculated. Molecular docking studies showed that DNSPA has a binding energy of −6.37 kcal/mol for E. coli DNA gyrase (5MMN) and −6.35 kcal/mol for COVID-19 main protease (6LU7).

Discovery of Novel HIV Protease Inhibitors Using Modern Computational Techniques

The human immunodeficiency virus type 1 (HIV-1) has continued to be a global concern. With the new HIV incidence, the emergence of multi-drug resistance and the untoward side effects of currently used anti-HIV drugs, there is an urgent need to discover more efficient anti-HIV drugs. Modern computational tools have played vital roles in facilitating the drug discovery process. This research focuses on a pharmacophore-based similarity search to screen 111,566,735 unique compounds in the PubChem database to discover novel HIV-1 protease inhibitors (PIs). We used an in silico approach involving a 3D-similarity search, physicochemical and ADMET evaluations, HIV protease-inhibitor prediction (IC50/percent inhibition), rigid receptor-molecular docking studies, binding free energy calculations and molecular dynamics (MD) simulations. The 10 FDA-approved HIV PIs (saquinavir, lopinavir, ritonavir, amprenavir, fosamprenavir, atazanavir, nelfinavir, darunavir, tipranavir and indinavir) were used as reference. The in silico analysis revealed that fourteen out of the twenty-eight selected optimized hit molecules were within the acceptable range of all the parameters investigated. The hit molecules demonstrated significant binding affinity to the HIV protease (PR) when compared to the reference drugs. The important amino acid residues involved in hydrogen bonding and п-п stacked interactions include ASP25, GLY27, ASP29, ASP30 and ILE50. These interactions help to stabilize the optimized hit molecules in the active binding site of the HIV-1 PR (PDB ID: 2Q5K). HPS/002 and HPS/004 have been found to be most promising in terms of IC50/percent inhibition (90.15%) of HIV-1 PR, in addition to their drug metabolism and safety profile. These hit candidates should be investigated further as possible HIV-1 PIs with improved efficacy and low toxicity through in vitro experiments and clinical trial investigations.

Benzothiazole and Chromone Derivatives as Potential ATR Kinase Inhibitors and Anticancer Agents

Despite extensive studies and the great variety of existing anticancer agents, cancer treatment remains an aggravating and challenging problem. Therefore, the development of novel anticancer drugs with a better therapeutic profile and fewer side effects to combat this persistent disease is still necessary. In this study, we report a novel series of benzothiazole and chromone derivatives that were synthesized and evaluated for their anticancer activity as an inhibitor of ATR kinase, a master regulator of the DDR pathway. The cell viability of a set of 25 compounds was performed using MTT assay in HCT116 and HeLa cell lines, involving 72 h incubation of the compounds at a final concentration of 10 µM. Cells incubated with compounds 2c, 7h and 7l were found to show viability ≤50%, and were taken forward for dose–response studies. Among the tested compounds, three of them (2c, 7h and 7l) showed higher potency, with compound 7l exhibiting the best IC₅₀ values in both the cell lines. Compounds 2c and 7l were found to be equally cytotoxic towards both the cell lines, namely, HCT116 and HeLa, while compound 7h showed better cytotoxicity towards HeLa cell line. For these three compounds, an immunoblot assay was carried out in order to analyze the inhibition of phosphorylation of Chk1 at Ser 317 in HeLa and HCT116 cells. Compound 7h showed inhibition of pChk1 at Ser 317 in HeLa cells at a concentration of 3.995 µM. Further analysis for Chk1 and pChk1 expression was carried out in Hela cells by treatment against all the three compounds at a range of concentrations of 2, 5 and 10 µM, wherein compound 7h showed Chk1 inhibition at 2 and 5 µM, while pChk1 expression was observed for compound 7l at a concentration of 5 µM. To support the results, the binding interactions of the compounds with the ATR kinase domain was studied through molecular docking, wherein compounds 2c, 7h and 7l showed binding interactions similar to those of Torin2, a known mTOR/ATR inhibitor. Further studies on this set of molecules is in progress for their specificity towards the ATR pathway.

Discovery of benzothiazole-based thiazolidinones as potential anti-inflammatory agents: anti-inflammatory activity, soybean lipoxygenase inhibition effect and molecular docking studies

Despite the greatest achievement in the development of anti-inflammatory agents in the last two decades, the current clinical drugs suffer from a variety of complications in community settings and hospital. There is still an urgent need to design novel molecules with better safety profile and with different molecular targets from those in current clinical use. The aim of this research was to discover a series of benzothiazole-based thiazolidinones with lipoxygenase (LOX) inhibitory activity as a mechanism of anti-inflammatory action. Carrageenan-induced mouse foot paw oedema assay was carried out to determine the anti-inflammatory activity, while LOX inhibition was examined through the conversion of sodium linoleate to 13-hydroperoxylinoleic acid. Molecular docking studies were performed using AutoDock 4.2 software. The anti-inflammatory activity of the title compounds was determined in a range of 18.4%-69.57%, where compound #3 was found to be the most potent (69.57%) and also to be more active than the reference drug indomethacin (47%). Moreover, compound #3 showed the highest LOX inhibitory activity with IC50 of 13 μM being less potent to that of the reference NDGA (IC50 = 1.3 μM). Compound #3 has been identified as lead compound for further modification in an attempt to improve anti-inflammatory and LOX inhibitory activities.

Oxy210, a Semi-Synthetic Oxysterol, Exerts Anti-Inflammatory Effects in Macrophages via Inhibition of Toll-like Receptor (TLR) 4 and TLR2 Signaling and Modulation of Macrophage Polarization

Inflammatory responses by the innate and adaptive immune systems protect against infections and are essential to health and survival. Many diseases including atherosclerosis, osteoarthritis, rheumatoid arthritis, psoriasis, and obesity involve persistent chronic inflammation. Currently available anti-inflammatory agents, including non-steroidal anti-inflammatory drugs, steroids, and biologics, are often unsafe for chronic use due to adverse effects. The development of effective non-toxic anti-inflammatory agents for chronic use remains an important research arena. We previously reported that oral administration of Oxy210, a semi-synthetic oxysterol, ameliorates non-alcoholic steatohepatitis (NASH) induced by a high-fat diet in APOE*3-Leiden.CETP humanized mouse model of NASH and inhibits expression of hepatic and circulating levels of inflammatory cytokines. Here, we show that Oxy210 also inhibits diet-induced white adipose tissue inflammation in APOE*3-Leiden.CETP mice, evidenced by the inhibition of adipose tissue expression of IL-6, MCP-1, and CD68 macrophage marker. Oxy210 and related analogs exhibit anti-inflammatory effects in macrophages treated with lipopolysaccharide in vitro, mediated through inhibition of toll-like receptor 4 (TLR4), TLR2, and AP-1 signaling, independent of cyclooxygenase enzymes or steroid receptors. The anti-inflammatory effects of Oxy210 are correlated with the inhibition of macrophage polarization. We propose that Oxy210 and its structural analogs may be attractive candidates for future therapeutic development for targeting inflammatory diseases.

Synthetic Approaches to Biologically Active C-2-Substituted Benzothiazoles

Numerous benzothiazole derivatives are used in organic synthesis, in various industrial and consumer products, and in drugs, with a wide spectrum of biological activity. As the properties of the benzothiazole moiety are strongly affected by the nature and position of substitutions, in this review, covering the literature from 2016, we focus on C-2-substituted benzothiazoles, including the methods of their synthesis, structural modification, reaction mechanisms, and possible pharmacological activity. The synthetic approaches to these heterocycles include both traditional multistep reactions and one-pot atom economy processes using green chemistry principles and easily available reagents. Special attention is paid to the methods of the thiazole ring closure and chemical modification by the introduction of pharmacophore groups.

Thiazolidin-4-Ones as Potential Antimicrobial Agents: Experimental and In Silico Evaluation

Herein, we report computational and experimental evaluations of the antimicrobial activity of twenty one 2,3-diaryl-thiazolidin-4-ones. All synthesized compounds exhibited an antibacterial activity against six Gram-positive and Gram-negative bacteria to different extents. Thus, the MIC was in the range of 0.008-0.24 mg/mL, while the MBC was 0.0016-0.48 mg/mL. The most sensitive bacterium was S. Typhimurium, whereas S. aureus was the most resistant. The best antibacterial activity was observed for compound 5 (MIC at 0.008-0.06 mg/mL). The three most active compounds 5, 8, and 15, as well as compound 6, which were evaluated against three resistant strains, MRSA, P. aeruginosa, and E. coli, were more potent against all bacterial strains used than ampicillin. The antifungal activity of some compounds exceeded or were equipotent with those of the reference antifungal agents bifonazole and ketoconazole. The best activity was expressed by compound 5. All compounds exhibited moderate to good drug-likeness scores ranging from -0.39 to 0.39. The docking studies indicated a probable involvement of E. coli Mur B inhibition in the antibacterial action, while CYP51 inhibition is likely responsible for the antifungal activity of the tested compounds. Finally, the assessment of cellular cytotoxicity of the compounds in normal human MRC-5 cells revealed that the compounds were not toxic.

Acridinium-conjugated aromatic heterocycles as highly potent FtsZ inhibitors: Design, synthesis, and biological evaluation

The epidemic of multidrug resistance (MDR) is a serious threat to public health, and new classes of antibiotics with novel mechanisms of action are in critical need. We rationally designed and efficiently synthesized three series of new chemical entities with potential antibacterial activity targeting filamenting temperature-sensitive mutant Z (FtsZ). Evaluation of these compounds against a panel of Gram-positive bacteria including MDR and vancomycin-resistant Enterococcus strains indicated that most compounds showed enhanced antibacterial efficacy, comparable or even superior to the reference drugs. The newly synthesized compounds proved to be substrates of the Escherichia coli efflux pump AcrB, thus affecting the activity. Their structure-activity relationships were summarized in detail. The most potent compound 10f quickly eliminated bacteria in a bactericidal mode, with low susceptibility to induce bacterial resistance. Further mechanistic studies with the BsFtsZ protein revealed that 10f functioned as an effective FtsZ inhibitor through altering the dynamics of FtsZ self-polymerization via a stimulatory mechanism, which leads to inhibition of cell division and cell death. Besides, 10f not only displayed no obvious cytotoxicity to mammalian cells but also had a high efficacy in a murine model of bacteremia in vivo. Regarded as a whole, our findings highlight 10f as a promising new FtsZ-targeting bactericidal agent.

Current Perspective of Synthesis of Medicinally Relevant Benzothiazole Based Molecules: Potential for Antimicrobial and Anti-Inflammatory Activities

The therapeutic potential of the majority of the marketed drugs is due to the presence of a heterocyclic nucleus, which constitutes a huge role in the field of medicinal chemistry. These heterocyclic scaffolds could act as a template in order to design potential therapeutic agents against several diseases. Benzothiazole scaffold is one of the influential heteroaromatic rings in the field of medicinal chemistry owing to its extensive pharmacological features. Herein, we have focused on the synthesis of benzothiazole based medicinal molecules, which possess antimicrobial and anti-inflammatory activities. This review covers a systematic description of synthetic routes for biologically relevant benzothiazole derivatives in the last five years. The main aim of this study is to show the diversification of benzothiazole based molecules into their pharmacologically more active derivatives. This review's synthetic protocols include metal-free, metal-catalyzed, and metal precursor azo dyes strategies for the development of benzothiazole derived bioactive compounds. The discussion under the various headings covers synthetic schemes and biological activities of the most potent molecules in the form of minimum inhibitory concentration.

Synthesis, structural insights, and biological screening of DNA targeted Ru(ii)(η6-p-cymene) complexes containing bioactive amino-benzothiazole ligand scaffolds

Two new drug candidates [Ru(p-cymene)(C7H4ClN2S)Cl2] and [Ru(p-cymene)(C7H5FN2S)Cl2] were synthesized and characterised. The in vitro cytotoxic activity of the complexes was assessed against five human cancer cell lines and anthelmintic activity was also investigated.

Synthesis, characteristic fragmentation patterns, and antibacterial activity of new azo compounds from the coupling reaction of diazobenzothiazole ions and acetaminophen

In this study, a series of azobenzothiazole dyes 4 were synthesized via diazotization of substituted benzothiazole derivatives followed by azo coupling with acetaminophen. The chemical structures of all synthesized compounds were confirmed using analytical data and spectroscopic techniques, including UV-visible, IR, mass spectra, and 1H- and 13C-NMR. The in situ formed diazobenzothiazole ions regiospecifically react with acetaminophen derivatives in the Hollemann-guided electrophilic aromatic substitution mechanism. The regio-orientations were established, on the one hand, by a rigorous interpretation of 1H-NMR spectra and, on the other hand, by the characteristic fragmentation patterns observed on the electrospray mass spectra. In the cases of 4a and 4b, multisubstitutions occurred. The antimicrobial activity of compound 4, along with all the starting materials, was investigated on Pseudomonas aeruginosa PA01, Staphylococcus aureus 18, Escherichia coli 64R, and S. aureus ATCC 25923. The results showed that this skeletal framework exhibited marked potency as antibacterial agents. The most active antibacterial agent against both targeted organisms was compound 4a′.

Developing a scaffold for urease inhibition based on benzothiazoles: Synthesis, docking analysis, and therapeutic potential

The synthesis, in silico molecular docking, and in vitro urease inhibition studies of a novel series of benzothiazole derivatives are reported. The title compounds in the two series, namely, 2-({5-[(benzothiazol-2-ylthio)methyl]-1,3,4-oxadiazol-2-yl}thio)-1-(4-substituted-phenyl)ethan-1-one and 2-(benzothiazol-2-ylthio)-1-(4-substituted-phenyl)ethan-1-one oxime, were synthesized by the reaction of benzo[d]thiazole-2-thiol with different kinds of intermediates in several steps using both conventional and microwave techniques. All compounds were found to have an excellent degree of urease-inhibitory potential ranging between 16.16 ± 0.54 and 105.32 ± 2.10 µM when compared with the standard inhibitor acetohydroxamic acid with IC₅₀  = 320.70 ± 4.24 µM. The structure-activity relationship was established in detail. The binding interactions of the compounds with the enzyme were confirmed through molecular docking. Further, 100 -ns molecular dynamics simulations were performed to investigate the stability and structural perturbations experienced by the most potent compound over the urease active site.

Synthesis, structural, pharmacological and molecular docking simulations studies of Schiff base transition metal complexes procured from acetylacetonyl-4-iminoantipyrine and tyrosine

Schiff base complexes of Cu(II), Ni(II), Co(II), VO(II) and Zn(II) ions have been synthesized by condensation of acetylaceto-4-iminoantipyrine and tyrosine. The structural characterization of compounds has been investigated using elemental analysis, molar conductance and magnetic susceptibility measurements, UV-Vis., FT-IR, ESI-mass, ¹H-NMR, ¹³C-NMR, ESR spectroscopy, cyclic voltammetry, XRD and SEM techniques. The observed analytical data indicate that the metal chelates have the general formula of [ML] type. Powder XRD pattern of Schiff base and its complexes authenticate their crystalline nature. From SEM morphology studies, the reduction grain size of Schiff base in metal chelates was observed which is due to the chelation of the Schiff base. From the IR, electronic absorption spectra and magnetic measurement data, square planar geometry was proposed for the metal complexes except for the [VOL] complex which exhibits square pyramidal geometry. The X-band ESR spectra of [CuL] and [VOL] complexes in DMSO solution were recorded at 77 & 300 K and their spin Hamiltonian parameter values support the proposed geometry. The interactions of the [CuL] complex with CT-DNA were investigated by UV-Vis and absorption titrations. DNA binding interaction studies reveal the hydrophobic interaction between CT-DNA and complexes. Furthermore, analgesic, anti-inflammatory, CNS and antimicrobial studies of the Schiff base and its transition metal complexes were examined and resolved metal complexes have enhanced pharmacological and biological activity when compared to free Schiff base. Molecular docking studies of the complex with DNA and (PDB ID: 6COX) protein were investigated.

Exploration of the Antimicrobial Effects of Benzothiazolylthiazolidin-4-One and In Silico Mechanistic Investigation

BACKGROUND

Infectious diseases still affect large populations causing significant morbidity and mortality. Bacterial and fungal infections for centuries were the main factors of death and disability of millions of humans. Despite the progress in the control of infectious diseases, the appearance of resistance of microbes to existing drugs creates the need for the development of new effective antimicrobial agents. In an attempt to improve the antibacterial activity of previously synthesized compounds modifications to their structures were performed.

METHODS

Nineteen thiazolidinone derivatives with 6-Cl, 4-OMe, 6-CN, 6-adamantan, 4-Me, 6-adamantan substituents at benzothiazole ring were synthesized and evaluated against panel of four bacterial strains S. aureus, L. monocytogenes, E. coli and S. typhimirium and three resistant strains MRSA, E. coli and P. aeruginosa in order to improve activity of previously evaluated 6-OCF₃-benzothiazole-based thiazolidinones. The evaluation of minimum inhibitory and minimum bactericidal concentration was determined by microdilution method. As reference compounds ampicillin and streptomycin were used.

RESULTS

All compounds showed antibacterial activity with MIC in range of 0.12-0.75 mg/mL and MBC at 0.25->1.00 mg/mL The most active compound among all tested appeared to be compound 18, with MIC at 0.10 mg/mL and MBC at 0.12 mg/mL against P. aeruginosa. as well as against resistant strain P. aeruginosa with MIC at 0.06 mg/mL and MBC at 0.12 mg/mL almost equipotent with streptomycin and better than ampicillin. Docking studies predicted that the inhibition of LD-carboxypeptidase is probably the possible mechanism of antibacterial activity of tested compounds.

CONCLUSION

The best improvement of antibacterial activity after modifications was achieved by replacement of 6-OCF₃ substituent in benzothiazole moiety by 6-Cl against S. aureus, MRSA and resistant strain of E. coli by 2.5 folds, while against L. monocytogenes and S. typhimirium from 4 to 5 folds.

Synthesis of biologically active derivatives of 2-aminobenzothiazole

The minireview considers the current trends in the synthesis of some biologically active compounds based on 2-aminobenzothiazole. The presented information covers publications of the last five years.

Contemporary advances of cyclic molecules proposed for inflammation

This review stretches insight about the advancement (2011-2021) of synthesized non-heterocyclic, heterocyclic and natural occurring cyclic molecules for inflammation. While inflammation is very significant in the abolition of pathogens and other causes of soreness, a protracted inflammatory procedure takes to outcomes in chronic disease that might finally affect in organ failure or damage. Thus, restraining the provocative process by the use of anti-inflammatory agents is chief in controlling this damage. It also reveals other pursuit along with their anti-inflammatory activity. Molecular docking studies represent most suitable PDB (Protein Data Bank) ID for the synthesized heterocyclic molecules with their selective inhibitor. It discusses the findings presented in recent research papers and provides understanding to researchers intended for the growth of newer combinations/molecules having littler side things.

Modern Approaches to the Synthesis and Transformations of Practically Valuable Benzothiazole Derivatives

The review is devoted to modern trends in the chemistry of 2-amino and 2-mercapto substituted benzothiazoles covering the literature since 2015. The reviewed heterocycles belong to biologically active and industrially demanded compounds. Newly developed synthesis methods can be divided into conventional multistep processes and one-pot, atom economy procedures, realized using green chemistry principles and simple reagents. The easy functionalization of the 2-NH2 and 2-SH groups and the benzene ring of the benzothiazole moiety allows considering them as highly reactive building blocks for organic and organoelement synthesis, including the synthesis of pharmacologically active heterocycles. The review provides a summary of findings, which may be useful for developing new drugs and materials and new synthetic approaches and patterns of reactivity.

Novel Thiazole-Based Thiazolidinones as Potent Anti-infective Agents: In silico PASS and Toxicity Prediction, Synthesis, Biological Evaluation and Molecular Modelling

AIMS AND OBJECTIVE

The infectious disease treatment remains a challenging concern owing to the increasing number of pathogenic microorganisms associated with resistance to multiple drugs. A promising approach for combating microbial infection is to combine two or more known bioactive heterocyclic pharmacophores in one molecular platform. Herein, the synthesis and biological evaluation of novel thiazole-thiazolidinone hybrids as potential antimicrobial agents were dissimilated.

MATERIALS AND METHODS

The preparation of the substituted 5-benzylidene-2-thiazolyimino-4- thiazolidinones was achieved in three steps from 2-amino-5-methylthiazoline. All the compounds have been screened in PASS antibacterial activity prediction and in a panel of bacteria and fungi strains. Minimum inhibitory concentration and minimum bacterial concentration were both determined by microdilution assays. Molecular modeling was conducted using Accelrys Discovery Studio 4.0 client. ToxPredict (OPEN TOX) and ProTox were used to estimate the toxicity of the title compounds.

RESULTS

PASS prediction revealed the potentiality antibacterial property of the designed thiazolethiazolidinone hybrids. All tested compounds were found to kill and to inhibit the growth of a vast variety of bacteria and fungi, and were more potent than the commercial drugs, streptomycin, ampicillin, bifomazole and ketoconazole. Further, in silico study was carried out for prospective molecular target identification and revealed favorable interaction with the target enzymes E. coli MurB and CYP51B of Aspergillus fumigatus. Toxicity prediction revealed that none of the active compounds was found toxic.

CONCLUSION

Substituted 5-benzylidene-2-thiazolyimino-4-thiazolidinones, endowing remarkable antibacterial and antifungal properties, were identified as a novel class of antimicrobial agents and may find a potential therapeutic use to eradicate infectious diseases.

New Substituted 5-Benzylideno-2-Adamantylthiazol[3,2-b][1,2,4]Triazol-6(5H)ones as Possible Anti-Inflammatory Agents

Background: Inflammation is a complex response to noxious stimuli promoted by the release of chemical mediators from the damaged cells. Metabolic products of arachidonic acid, produced by the action of cyclooxygenase and lipoxygenase, play important roles in this process. Several non-steroidal anti-inflammatory drugs act as cyclooxygenase inhibitors. However, almost all of them have undesired side effects. Methods: Prediction of the anti-inflammatory action of the compounds was performed using PASS Program. The anti-inflammatory activity was evaluated by the carrageenan paw edema test. COX and LOX inhibitory actions were tested using ovine COX-1, human recombinant COX-2 and soybean LOX-1, respectively. Docking analysis was performed using Autodock. Results: All designed derivatives had good prediction results according to PASS and were synthesized and experimentally evaluated. The compounds exhibited in vivo anti-inflammatory action with eleven being equal or better than indomethacin. Although, some of them had no or low inhibitory effect on COX-1/2 or LOX, certain compounds exhibited COX-1 inhibition much higher than naproxen and COX-2 inhibition, well explained by Docking analysis. Conclusions: A number of compounds with good anti-inflammatory action were obtained. Although, some exhibited remarkable COX inhibitory action this activity did not follow the anti-inflammatory results, indicating the implication of other mechanisms.

Synthesis, anti-inflammatory and analgesic evaluation of thiazole/oxazole substituted benzothiazole derivatives

Non-Steroidal biologically active heterocyclic compounds 4-(2-(4-chlorophenyl) benzo[d]thiazol-3(2H)-yl)-N-((3-substituted-2-hydrobenzo[d]thiazol-2-yl)methylene) thiazol-2-amine (3a-3d), 4-(2-(4-chlorophenyl)benzo[d]thiazol-3(2H)-yl)-N-((3-substituted - 2-hydrobenzo [d]thiazol-2-yl)methylene)oxazol-2-amine (3a'-3d'), (Z)-N'-(4-(2-(4-chlorophenyl)benzo[d]thiazol-3(2H)-yl)thiaol-2-yl)-N-(4-substituted phenylimino)-3-substituted-2-hydrobenzo[d]thiazole-2-carboxamidine (4a-4 h) and (Z)-N'-(4-(2-(4-chlorophenyl)benzo[d]thiazol-3(2H)-yl)oxazol-2-yl)-N-(4-substituted phenylimino) - 3-substituted-2-hydrobenzo[d]thiazole-2-carboxamidine (4a'-4h') were synthesized starting from 2-chloro-1-(2-(4-chlorophenyl)benzo[d]thiazol-3(2H)-yl) ethanone (1). The structure configuration of newly synthesized compounds has been determined by elemental analysis and various spectroscopic (IR, ¹HNMR and GCMS) techniques. These compounds were tested for their anti-inflammation, analgesic, ulcerogenic, acute toxicity and free radical scavenging action and compared with reference drugs in albino rats. Compound 4-(2-(4-chlorophenyl)benzo[d]thiazol-3(2H)-yl)-N-((3-substituted-2-hydrobenzo [d]thiazol-2-yl)methylene)thiazol-2-amine (3c) was the most active compound than reference drug at a dose of 50 mg/kg p.o.

Novel Leu-Val Based Dipeptide as Antimicrobial and Antimalarial Agents: Synthesis and Molecular Docking

The increase of antimicrobial resistance (AMR) and antimalarial resistance are complex and severe health issues today, as many microbial strains have become resistant to market drugs. The choice for the synthesis of new dipeptide-carboxamide derivatives is as a result of their wide biological properties such as antimicrobial, anti-inflammatory, and antioxidant activities. The condensation reaction of substituted benzenesulphonamoyl pentanamides with the carboxamide derivatives using peptide coupling reagents gave targeted products (8a-j). The in silico antimalarial and antibacterial studies showed good interactions of the compounds with target protein residues and a higher dock score in comparison with standard drugs. In the in vivo study, compound 8j was the most potent antimalarial agent with 61.90% inhibition comparable with 67% inhibition for Artemisinin. In the in vitro antimicrobial activity, compounds 8a and 8b (MIC 1.2 × 10⁻³ M and 1.1 × 10⁻³ M) were most potent against S. aureus; compound 8a, 8b, and 8j with MIC 6.0 × 10⁻³ M, 5.7 × 10⁻⁴ M, and 6.5 × 10⁻⁴ M, respectively, were the most active against B. subtilis; compound 8b (MIC 9.5 × 10⁻⁴ M) was most active against E.coli while 8a, 8b and 8d were the most active against S. typhi. Compounds 8c and 8h (MIC 1.3 × 10⁻³ M) each were the most active against C. albicans, while compound 8b (MIC 1.3 × 10⁻⁴ M) was most active against A. niger.

A brief review of the biological potential of indole derivatives

Background

Various bioactive aromatic compounds containing the indole nucleus showed clinical and biological applications. Indole scaffold has been found in many of the important synthetic drug molecules which gave a valuable idea for treatment and binds with high affinity to the multiple receptors helpful in developing new useful derivatives.

Main text

Indole derivatives possess various biological activities, i.e., antiviral, anti-inflammatory, anticancer, anti-HIV, antioxidant, antimicrobial, antitubercular, antidiabetic, antimalarial, anticholinesterase activities, etc. which created interest among researchers to synthesize a variety of indole derivatives.

Conclusion

From the literature, it is revealed that indole derivatives have diverse biological activities and also have an immeasurable potential to be explored for newer therapeutic possibilities.

2-Aryl-3-(6-trifluoromethoxy)benzo[d]thiazole-based thiazolidinone hybrids as potential anti-infective agents: Synthesis, biological evaluation and molecular docking studies

The search for new antimicrobial agents is greater than ever due to the perpetual threat of multidrug resistance in known pathogens and the relentless emergence of new infections. In this manuscript, ten thiazole-based thiazolidinone hybrids bearing a 6-trifluoromethoxy substituent on the benzothiazole core were synthesized and evaluated against a panel of four bacterial strains Salmonella typhimurium, Staphylococcus aureus, Escherichia coli and Listeria monocytogenes and three resistant strains Pseudomonas aeruginosa, E. coli and MRSA. The evaluation of minimum bactericidal and minimum inhibitory concentrations was accomplished by microdilution assay. As reference compounds ampicillin and streptomycin were employed. All compounds displayed antibacterial efficiencies with MBCs/MICs at 0.25-1 mg/mL and 0.12-1 mg/mL respectively while ampicillin displayed MBCs/MICs at 0.15-0.3 mg/mL and at 0.1-0.2 mg/mL respectively. MICs/MBC of streptomycin varied from 0.05 to 0.15 mg/mL and from 0.1 to 0.3 mg/mL respectively. The best overall effect was observed for compound h4, while compound h1 exhibited the highest effective action against E. coli (MIC/MBC 0.12/0.25 mg/ml) among all tested compounds.

Synergy Screening Identifies a Compound That Selectively Enhances the Antibacterial Activity of Nitric Oxide

Antibiotic resistance poses a serious threat to global health. To reinforce the anti-infective arsenal, many novel therapeutic strategies to fight bacterial infections are being explored. Among them, anti-virulence therapies, which target pathways important for virulence, have attracted much attention. Nitric oxide (NO) defense systems have been identified as critical for the pathogenesis of various bacteria, making them an appealing therapeutic target. In this study, we performed chemical screens to identify inhibitors of NO detoxification in Escherichia coli. We found that 2-mercaptobenzothiazole (2-MBT) can potently inhibit cellular detoxification of NO, achieving a level of inhibition that resembled the effect of genetically removing Hmp, the dominant detoxification enzyme under oxygenated conditions. Further analysis revealed that in the presence of NO, 2-MBT impaired the catalysis of Hmp and synthesis of Hmp and other proteins, whereas in its absence there were minimal perturbations to growth and protein synthesis. In addition, by studying the structure-activity relationship of 2-MBT, we found that both sulfur atoms in 2-MBT were vital for its inhibition of NO detoxification. Interestingly, when 2-mercaptothiazole (2-MT), which lacked the benzene ring, was used, differing biological activities were observed, although they too were NO dependent. Specifically, 2-MT could still prohibit NO detoxification, though it did not interfere with Hmp catalysis; rather, it was a stronger inhibitor of protein synthesis and it reduced the transcript levels of hmp, which was not observed with 2-MBT. Overall, these results provide a strong foundation for further exploration of 2-MBT and 2-MT for therapeutic applications.

Synthesis and Hypoglycemic and Anti-inflammatory Activity Screening of Novel Substituted 5-[Morpholino(Phenyl)Methyl]-Thiazolidine-2,4-Diones and Their Molecular Docking Studies

Objectives

The aim was the synthesis of novel substituted 5-[morpholino(phenyl)methyl]-thiazolidine-2,4-diones and screening for their in vivo hypoglycemic activity and in vitro anti-inflammatory activity, as well as molecular docking studies to find out active potential lead molecules.

Materials and Methods

Substituted aromatic aldehydes, thiazolidine-2,4-dione, and morpholine on Mannich reaction gave the title compounds. They were characterized by physical and spectral methods. In vivo hypoglycemic activity was examined in alloxan induced Wistar albino rats by tail tipping method. In vitro anti-inflammatory activity was tested by human red blood cell (HRBC) membrane stabilization and protein denaturation. Using AutoDock, molecular docking studies were carried out to find out the best fit ligands.

Results

Series of substituted 5-[morpholino(phenyl)methyl]-thiazolidine-2,4-diones were synthesized and chemically they were confirmed by spectral techniques. Acute toxic studies of in vivo hypoglycemic activity results revealed that compounds 4c, 4h, and 4n exhibited good activity at 35 mg/kg body weight. Chronic toxic study results indicated that compounds 4h and 4n exhibited good activity at 70 mg/kg body weight. Anti-inflammatory activity results indicated the highest inhibition was shown by compounds 4k and 4f at 500 μg/mL in HRBC membrane stabilization. In protein denaturation, the highest inhibition was shown by compound 4k at 500 μg/mL. In molecular docking studies, compounds 4h and 4n exhibited higher binding affinity at PPARγ receptor protein and compound 4k exhibited higher binding affinity at COX-1 and COX-2 actives sites.

Conclusion

Microwave irradiation produced high yield in short reaction times. The presence of electron releasing groups at the para position of the phenyl ring may give the ability to produce hypoglycemic activity and the presence of electron withdrawing groups at the para position of the phenyl ring causes anti-inflammatory activity. The results showed that some compounds exhibited good hypoglycemic and anti-inflammatory activities. Compounds 4h and 4n exhibited higher binding affinity at PPARγ receptor protein and compound 4k exhibited higher binding affinity at COX isoenzymes' active sites in molecular docking studies.

Green synthesis and biological evaluation of 6-substituted-2-(2-hydroxy/methoxy phenyl)benzothiazole derivatives as potential antioxidant, antibacterial and antitumor agents

We present a new efficient green synthetic protocol for introduction of substituents to the C-6 position of 2-arylbenzothiazole nuclei. Newly synthesized compounds were designed to study the influence of the hydroxy and methoxy groups on the 2-arylbenzothiazole scaffold, as well as the influence of the type of substituents placed on the C-6 position of benzothiazole moiety on biological activity, including antibacterial, antitumor and antioxidant activity. Modest activity was observed against the tested Gram-positive and Gram-negative bacterial strains for only amidino derivatives 5d and 6d. The tested compounds exhibited moderate to strong antiproliferative activity towards the tumor cell lines tested. The SAR study revealed that the introduction of substituents into the benzene ring of the benzothiazole nuclei is essential for antiproliferative activity, while introduction of the hydroxy group into the 2-aryl moiety of the 2-arybenzothiazole scaffold significantly improved selectivity against tumor cell lines. The observed results revealed several novel 6-substituted-2-arylbenzothiazole compounds, 5b, 5c, 5f and 6f, with strong and selective antiproliferative activity towards HeLa cells in micro and submicromolar concentrations, with the most selective compounds being 6-ammonium-2-(2-hydroxy/methoxyphenyl)benzothiazoles 5f and 6f. The compound 5f bearing the hydroxy group on the 2-arylbenzothiazole core showed the most promising antioxidative activity evaluated by DPPH, ABTS and FRAP in vitro assays. The presence of the amino protonated group attached at the benzothiazole moiety was essential for the antiproliferative and antioxidant activity observed, exerted through a change in the levels of the reactive oxygen species-modulated HIF-1 protein.

New peptide derived antimalaria and antimicrobial agents bearing sulphonamide moiety

Fourteen novel dipeptide carboxamide derivatives bearing benzensulphonamoyl propanamide were synthesized and characterized using 1H NMR, 13C NMR, FTIR and MS spectroscopic techniques. In vivo antimalarial and in vitro antimicrobial studies were carried out on these synthesized compounds. Molecular docking, haematological analysis, liver and kidney function tests were also evaluated to assess the effect of the compounds on the organs. At 200 mg/kg body weight, 7i inhibited the multiplication of the parasite by 81.38% on day 12 of post-treatment exposure. This was comparable to the 82.34% reduction with artemisinin. The minimum inhibitory concentration (MIC) in µM ranged from 0.03 to 2.34 with 7h having MIC of 0.03 µM against Plasmodium falciparium. The in vitro antibacterial activity of the compounds against some clinically isolated bacteria strains showed varied activities with some of the new compounds showing better activities against the bacteria and the fungi more than the reference drug ciprofloxacin and fluconazole.

Visnagin and benzofuran scaffold-based molecules as selective cyclooxygenase-2 inhibitors with anti-inflammatory and analgesic properties: design, synthesis and molecular docking

A series of new visnagin and benzofuran scaffold-based molecules was designed and synthesized as anti-inflammatory and analgesic agents. Biological screening of these compounds showed that they exhibit potent anti-inflammatory/analgesic activity with a safer side effect profile in in vivo mouse models. In vitro cyclooxygenase (COX) inhibition assay showed that the compounds elicit their function through selective COX-2 inhibition. Molecular docking study also revealed the ability of the compounds to correctly recognize the active site and achieve noncovalent binding interactions with key residues therein. The best combined profile of anti-inflammatory, analgesic and COX-2 selective inhibition properties in association with low gastrotoxicity was displayed by the analogs 8, 11b and 19d, which can be considered as promising leads for further future optimization.

Therapeutic advancement of benzothiazole derivatives in the last decennial period

Benzothiazole, a fused heterocyclic moiety, has attracted synthetic and medicinal chemists for good reasons. It is a valuable scaffold that possesses diverse biological activities, such as anticancer, anti-inflammatory, antimicrobial, antiviral, antimalarial, and anticonvulsant effects. This review mainly focusses on the recent research work on the different biological activities of benzothiazole-based compounds.