Design, synthesis, characterization, antioxidant and in vitro cytotoxic activities of novel coumarin thiazole derivatives

Synthesis and Biological Screening of New 2-(5-Aryl-1-phenyl-1H-pyrazol-3-yl)-4-aryl Thiazole Derivatives as Potential Antimicrobial Agents

A new series of 2-(5-aryl-1-phenyl-1H-pyrazol-3-yl)-4-aryl thiazoles (10a-ab) have been synthesized by a cyclocondensation reaction of 5-aryl-1-phenyl-1H-pyrazole-3-carbothioamide (7a-d) with substituted phenacyl bromide (8a-f). The structure of newly synthesized 2-(5-aryl-1-phenyl-1H-pyrazol-3-yl)-4-aryl thiazole (10a-ab) derivatives was characterized by spectroscopic analysis. The compounds 10a-ab were evaluated for in vitro antibacterial activity against Escherichia coli (NCIM 2574), Proteus mirabilis (NCIM 2388), Bacillus subtilis (NCIM 2063), Staphylococcus aureus (NCIM 2178), and in vitro antifungal activity against Aspergillus niger (ATCC 504) and Candida albicans (NCIM 3100). Among the twenty-eight pyrazolyl-thiazole derivatives, six compounds, 10g, 10h, 10i, 10j, 10o, and 10t, showed good activity against P. mirabilis; four compounds 10q, 10u, 10y, and 10z showed good activity against S. aureus; and twenty-four derivatives showed good antifungal activity against A. niger. Compounds 10g, 10q, 10r, 10s, and 10ab showed comparable activity with respect to the reference drug Ravuconazole. Thus, the significant antimicrobial activity of 2-(5-aryl-1-phenyl-1H-pyrazol-3-yl)-4-aryl thiazole (10a-ab) derivatives prompted that these scaffolds could assist in the development of lead compounds to treat microbial infections.

The Role of Poly-Herbal Extract in Sodium Chloride-Induced Oxidative Stress and Hyperlipidemia in Male Wistar Rats

Consistent consumption of high salt diet (HSD) has been associated with increased cellular generation of free radicals, which has been implicated in the derangement of some vital organs and etiology of cardiovascular disorders. This study was designed to investigate the combined effect of some commonly employed medicinal plants on serum lipid profile and antioxidant status of aorta, kidney, and liver of high salt diet-fed animals. Out of the total fifty male Wistar rats obtained, fifteen were used for acute toxicity study, while the remaining thirty-five were divided into 5 groups of 7 animals each. Group 1 and 2 animals were fed normal rat chow (NRC) and 16% high salt diet (HSD) only, respectively. Animals in groups 3, 4 and 5 were fed 16% HSD with 800, 400, and 200 mg/kg bw poly-herbal extract (PHE), respectively, once for 28 consecutive days. Serum low-density lipoprotein (LDL), triacylglycerol (TG), total cholesterol (TC) and high-density lipoprotein (HDL), malondialdehyde, nitric oxide, catalase, superoxide dismutase, glutathione peroxidase, glutathione concentration, and activities were assessed in the aorta, kidney, and liver. Poly-herbal extract (p < 0.05) significantly reduced malondialdehyde and nitric oxide concentrations and also increased antioxidant enzymes and glutathione activity. Elevated serum TG, TC, LDL, and TC content in HSD-fed animals were significantly (p < 0.05) reduced to normal in PHE-treated rats while HDL was significantly elevated (p < 0.05) in a concentration-dependent manner in PHE treated animals. Feeding with PHE attenuated high-salt diet imposed derangement in serum lipid profile and antioxidant status in the organs of the experimental rats.

Thiazole Ring-A Biologically Active Scaffold

BACKGROUND

Thiazole is a good pharmacophore nucleus due to its various pharmaceutical applications. Its derivatives have a wide range of biological activities such as antioxidant, analgesic, and antimicrobial including antibacterial, antifungal, antimalarial, anticancer, antiallergic, antihypertensive, anti-inflammatory, and antipsychotic. Indeed, the thiazole scaffold is contained in more than 18 FDA-approved drugs as well as in numerous experimental drugs.

OBJECTIVE

To summarize recent literature on the biological activities of thiazole ring-containing compounds Methods: A literature survey regarding the topics from the year 2015 up to now was carried out. Older publications were not included, since they were previously analyzed in available peer reviews.

RESULTS

Nearly 124 research articles were found, critically analyzed, and arranged regarding the synthesis and biological activities of thiazoles derivatives in the last 5 years.

In vitro antioxidant activity of thiazolidinone derivatives of 1,3-thiazole and 1,3,4-thiadiazole

The initial steps in preclinical drug developing research concern the synthesis of new compounds for specific therapeutic use which needs to be confirmed by in vitro and then in vivo testing. Nine thiazolidinone derivatives (numerically labeled 1-9) classified as follows: 1,3-thiazole-based compounds (1 and 2); 1,3,4-thiadiazole based compounds (3 and 4); substituted 5-benzylideno-2-adamantylthiazol[3,2-b][1,2,4]triazol-6(5H)ones (5-8); and an ethylaminothiazole-based chalcone (9), were tested for antioxidant activity (AOA) by using three in vitro assays: DPPH (1,1-diphenyl-2-picrylhydrazyl scavenging capacity test); FRAP (ferric reducing antioxidant power test); and TBARS (thiobarbituric acid reactive substances test). Compounds 1-4 and 9 in particular are newly synthesized compounds. Also, traditional antioxidants Vitamins E and C and α-lipoic acid (α-LA) were tested. The results of DPPH testing: Vitamin C 94.35%, Vitamin E 2.99% and α-LA 1.57%; compounds: 4 33.98%; 2 18.73%; 1 15.62%; 5 6.59%; 3 4.99%; 6-9 demonstrated almost no AOA. The results of TBARS testing (% of LPO inhibition): Vitamin C 62.32%; Vitamin E 36.29%; α-LA 51.36%; compounds: 1 62.11%; 5 66.71%; 9 60.93%; 4, 6 and 7 demonstrated ∼50%; 3 and 8 displayed ∼38%; 2 23.51%. By FRAP method, Vitamins E and C showed equal AOA, ∼100%, unlike α-LA (no AOA), and AOA of the tested compounds (expressed as a fraction of the AOA of Vitamin C) were: 2 and 4-75%; 8, 3 and 1-45%; 5-7 and 9-27%. Different red-ox reaction principles between these assays dictate different AOA outcomes for a single compound. Vitamin C appeared to be the superior antioxidant out of the traditional antioxidants; and compound 4 was superior to other tested thiazolidinone derivatives. Vitamin C appeared to be the superior antioxidant out of the traditional antioxidants; and compound 4 was superior to other tested thiazolidinone derivatives. Phenyl-functionalized benzylidene, amino-carbonyl functional domains and chelating ligand properties of the thiazolidinone derivatives correlated with AOA.