Design, synthesis, anticonvulsant evaluation and docking study of 2-[(6-substituted benzo[d]thiazol-2-ylcarbamoyl)methyl]-1-(4-substituted phenyl)isothioureas

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.

Proapoptotic effects of halogenated bis-phenylthiourea derivatives in cancer cells

New halogenated thiourea derivatives were synthesized via the reaction of substituted phenylisothiocyanates with aromatic amines. Their cytotoxic activity was examined in in vitro studies against solid tumors (SW480, SW620, PC3), a hematological malignance (K-562), and normal keratinocytes (HaCaT). Most of the compounds were more effective against SW480 (1a, 3a, 3b, 5j), K-562 (2b, 3a, 4a), or PC3 (5d) cells than cisplatin, with favorable selectivity. Their anticancer mechanisms were studied by Annexin V-fluorescein-5-isothiocyanate apoptosis, caspase-3/caspase-7 assessment, cell cycle analysis, interleukin-6 (IL-6) release inhibition, and reactive oxygen species (ROS) generation assay. Thioureas 1a, 2b, 3a, and 4a were the most potent activators of early apoptosis in K-562 cells, and substances 1a, 3b, 5j triggered late-apoptosis or necrosis in SW480 cells. This proapoptotic effect was proved by the significant increase of caspase-3/caspase-7 activation. Cell cycle analysis revealed that derivatives 1a, 3a, 5j increased the number of SW480 and K-562 cells in the sub-G1 and/or G0/G1 phases, and one evoked cycle arrest at the G2 phase. The most potent thioureas inhibited IL-6 cytokine secretion from PC3 cells and both colon cancer cell lines. Apoptosis-inducing compounds also increased ROS production in all tumor cell cultures, which may enhance their anticancer properties.

Thiazolidinedione derivatives as novel GPR120 agonists for the treatment of type 2 diabetes

GPR120, also called FFAR4, is preferentially expressed in the intestines, and can be stimulated by long-chain free fatty acids to increase the secretion of glucagon-like peptide-1 (GLP-1) from intestinal endocrine cells. It is known that GLP-1, as an incretin, can promote the insulin secretion from pancreatic cells in a glucose-dependent manner. Therefore, GPR120 is a potential drug target to treat type 2 diabetes. In this study, thiazolidinedione derivatives were found to be novel potent GPR120 agonists. Compound 5g, with excellent agonistic activity, selectivity, and metabolic stability, improved oral glucose tolerance in normal C57BL/6 mice in a dose-dependent manner. Moreover, compound 5g exhibited anti-diabetic activity by promoting insulin secretion in diet-induced obese mice. In summary, compound 5g might be a promising drug candidate for the treatment of type 2 diabetes.

GPR120 has emerged as an attractive target for the treatment of type 2 diabetes and obesity. Thiazolidinedione derivatives were found to be novel potent GPR120 agonists.

Recent Development in Substituted Benzothiazole as an Anticonvulsant Agent

Heterocyclic compounds and their derivatives gained more attention due to their valuable biological and pharmacological properties. Benzothiazole is a heterocyclic structure containing a bicyclic ring system with a large panel of applications. The benzothiazole is present in many new products undergoing research hoping that it possesses various biological activities. Epilepsy is a diverse group of diseases marked by neuronal excitability and hypersynchronous neuronal activity of motor, sensory or autonomic events with or without loss of consciousness. Presently, many antiepileptic drugs like lamotrigine, stiripentol tiagabine, pregabalin, felbamate, and topiramate are available and effective towards 60-80% of patients only, along with undesirable side effects, such as hepatotoxicity, gastrointestinal disturbance, drowsiness, gingival hyperplasia, and hirsutism. Thus, many attempts are still on-going to develop antiepileptic drugs with a safer profile. This review is mainly focused on the compilation of reported scientific literature data in the recent one-decade on the anticonvulsant activity of benzothiazole compounds.

Raloxifene potentiates the effect of fluoxetine against maximal electroshock induced seizures in mice

The evidence to guide clinicians regarding rationale polytherapy with current antiepileptic drugs (AEDs) is lacking, and current practice recommendations are largely empirical.  The excessive drug loading with combinatorial therapies of existing AEDs are associated with escalated neurotoxicity, and that emergence of pharmacoresistant seizures couldn't be averted. In pursuit of judicious selection of novel AEDs in combinatorial therapies with mechanism based evidences, standardized dose of raloxifene, fluoxetine, bromocriptine and their low dose combinations, were experimentally tested for their impact on maximal electroshock (MES) induced tonic hind limb extension (THLE) in mice. Hippocampal neuropeptide Y (NPY) levels, oxidative stress and histopathological studies were undertaken. The results suggest the potentiating effect of 4 mg/kg raloxifene on 14 mg/kg fluoxetine against MES induced THLE, as otherwise monotherapy with 4 mg/kg raloxifene was unable to produce an effect. The results also depicted better efficacy than carbamazepine (20 mg/kg), standard AED. Most profoundly, MES-induced significant (P < 0.001) reduction in hippocampal NPY levels, that were escalated insignificantly with the duo-drug combination, suggesting some other mechanism in mitigation of electroshock induced seizures. These results were later corroborated with assays to assess oxidative stress and neuronal damage. In conclusion, the results demonstrated the propitious therapeutic benefit of duo-drug low dose combination of drugs; raloxifene and fluoxetine, with diverse mode of actions fetching greater effectiveness in the management of generalized tonic clonic seizures (GTCS).

Synthesis carbonic anhydrase enzyme inhibition and antioxidant activity of novel benzothiazole derivatives incorporating glycine, methionine, alanine, and phenylalanine moieties

Thirteen novel benzothiazole derivatives incorporating glycine, methionine, alanine, and phenylalanine were synthesised by facile acylation reactions through benzotriazole or DCC mediated reactions and their structures were identified by 1H-NMR, 13C-NMR, and FT-IR spectroscopic techniques and elemental analysis. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against four human (h) isoforms, hCA I, hCA II, hCA V, and hCA XIII. Some of the synthesised compounds showed good in vitro carbonic anhydrase inhibitory properties, with inhibition constants in the micromolar level. The new amino acid benzothiazole conjugates found to be more effective against hCA V and hCA II inhibition. In vitro antioxidant activities of the novel compounds were determined by DPPH method. Most of the synthesised compounds showed moderate to low antioxidant activities compared to the control antioxidant compounds (BHA and α-tocopherol).

Novel benzothiazole hydrazine carboxamide hybrid scaffolds as potential in vitro GABA AT enzyme inhibitors: Synthesis, molecular docking and antiepileptic evaluation

In the present study, a series of newer benzothiazole derivatives containing thiazolidin-4-one (5a-g) and azetidin-2-one (6a-g), were synthesized by the cyclization of benzothiazolyl arylidene hydrazine carboxamide derivatives with thioglycolic acid and chloroacetyl chloride, respectively. Results of in vivo anticonvulsant screening revealed that compounds having 2,4-dicholoro (5c and 6c) and 4-nitro substituent (5g) at the phenyl ring have promising anticonvulsant activities without any neurotoxicity. Selected compounds were also evaluated for their in vitro GABA AT inhibition. The results indicated that compound 5c (IC₅₀ 15.26 μM) exhibited excellent activity as compared to the standard drug vigabatrin (IC₅₀ 39.72 μM) suggesting the potential of these benzothiazole analogues as new anticonvulsant agents.

Synthesis, in vivo and in silico evaluation of novel 2,3-dihydroquinazolin-4(1H)-one derivatives as potential anticonvulsant agents

In light of the pharmacophoric structural requirements for achieving anticonvulsant activity, a series of N-(1-methyl-4-oxo-2-un/substituted-1,2-dihydroquinazolin-3[4H]-yl)benzamide (4a-g) and N-(1-methyl-4-oxo-2-un/substituted-1,2-dihydroquinazolin-3[4H]-yl)-2-phenylacetamide (4h-n) derivatives were synthesized in two steps starting from the reaction of N-methyl isatoic anhydride with the appropriate hydrazide and followed by condensation with the appropriate aldehyde. The anticonvulsant activities of the synthesized compounds were evaluated according to the anticonvulsant drug development (ADD) programme protocol. Among the synthesized compounds, 4n showed promising activity in both the maximal electroshock (MES) and pentylenetetrazole (PTZ) tests with median effective dose (ED₅₀ ) values of 40.7 and 6 mg/kg, respectively. The six most promising derivatives, 4b, 4a, 4c, 4f, 4j, and 4i, showed very low ED₅₀ values in the PTZ test (3.1, 4.96, 8.68, 9.89, 12, and 13.53 mg/kg, respectively). All the tested compounds showed no to low neurotoxicity in the rotarod test with a wide therapeutic index. Docking studies of compound 4n suggested that GABA_A binding could be the mechanism of action of these derivatives. The in silico drug likeliness parameters indicated that none of the designed compounds violate Lipinski's rule of five and that they are able to cross the blood-brain barrier. Hit, Lead & Candidate Discovery.

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.

Novel Hybrid Formulations Based on Thiourea Derivatives and Core@Shell Fe₃O₄@C18 Nanostructures for the Development of Antifungal Strategies

The continuously increasing global impact of fungal infections is requiring the rapid development of novel antifungal agents. Due to their multiple pharmacological activities, thiourea derivatives represent privileged candidates for shaping new drugs. We report here the preparation, physico-chemical characterization and bioevaluation of hybrid nanosystems based on new 2-((4-chlorophenoxy)methyl)-N-(substituted phenylcarbamo-thioyl)benzamides and Fe₃O₄@C₁₈ core@shell nanoparticles. The new benzamides were prepared by an efficient method, then their structure was confirmed by spectral studies and elemental analysis and they were further loaded on Fe₃O₄@C₁₈ nanostructures. Both the obtained benzamides and the resulting hybrid nanosystems were tested for their efficiency against planktonic and adherent fungal cells, as well as for their in vitro biocompatibility, using mesenchymal cells. The antibiofilm activity of the obtained benzamides was dependent on the position and nature of substituents, demonstrating that structure modulation could be a very useful approach to enhance their antimicrobial properties. The hybrid nanosystems have shown an increased efficiency in preventing the development of Candida albicans (C. albicans) biofilms and moreover, they exhibited a good biocompatibility, suggesting that Fe₃O₄@C₁₈core@shell nanoparticles could represent promising nanocarriers for antifungal substances, paving the way to the development of novel effective strategies with prophylactic and therapeutic value for fighting biofilm associated C. albicans infections.