Synthesis, antimicrobial and antioxidant activities of pyridyl substituted thiazolyl triazole derivatives

In this present study, 63 different 5-[4-methyl-2-(pyridin-3/4-yl)thiazole-5-yl]-4-substituted-3-substituted benzylthio-4H-1,2,4-triazole derivatives were synthesized, and evaluated for their in vitro antimicrobial activity against various human pathogenic microorganisms and antioxidant activity. The derivatives were synthesized in a multi-step synthesis procedure including triazole and thiazole ring closure reactions, respectively. The synthesized derivatives (A1-24; B1-39) were screened for their antibacterial, antifungal, and antioxidant activities compared to standard agents. The derivatives possessing 3-pyridyl moiety particularly exhibited relatively high antibacterial activity (MIC= < 3.09-500 µg/mL) against Gram-positive bacteria, and compounds possessing 4-pyridyl moiety showed remarkable antioxidant activity

Synthesis of New Thiazole Derivatives Bearing Thiazolidin-4(5H)-One Structure and Evaluation of Their Antimicrobial Activity

The first report about antimicrobial resistance was published in the 1940s. And today, the antimicrobial resistance has become a worldwide problem. Because of this problem, there is a need to develop new drugs. That's why we synthesized some novel thiazolidine-4-one derivatives and evaluated their antimicrobial activity. The final compounds were obtained by reacting 2-[(4,5-diphenylthiazol-2-yl)imino]thiazolidin-4-one with some aryl aldehydes. The synthesized compounds were investigated for their antimicrobial activity against four Candida species, five gram-negative and four gram-positive bacterial species. The lead compounds (4a- h) were obtained with a yield of at least 70%. All compounds showed antimicrobial activity. Compound 4f (MIC: 31.25 µg/ml) exhibited more efficacy than the other compounds against C. glabrata (ATCC 24433). Compound 4b (MIC: 62.5 µg/ml) was the most active compound against all bacterial species, particularly K. pneumoniae (NCTC 9633). Whereas, compound 4c (MIC: <31.25 µg/ml) was observed as the most active compound against E. coli (ATCC 25922). In general, all compounds (4a-4h) showed antimicrobial activity against all fungi and bacterial species. Compounds 4b (2,6-dichlorobenzylidene), 4c (2,6-dihydroxybenzylidene), 4f (1H-pyrrol-2- yl)methylene), 4g (4-triflouromethylbenzylidene) and 4h (2,3,4-trimethoxybenzylidene) were determined as the most active compounds

High rate of sensitization to Kathon CG, detected by patch tests in patients with suspected allergic contact dermatitis

Abstract Background: Kathon CG, a combination of methylchloroisothiazolinone and methylisothiazolinone, is widely used as preservative in cosmetics, as well in household cleaning products, industrial products such as paints and glues. It has emerged as an important sensitizing agent in allergic contact dermatitis. Objectives: This study evaluated the reactivity to this substance in patients subjected to patch tests at the Dermatology Institute in Bauru, São Paulo from 2015 to 2017 and its correlation with other preservatives, the professional activity and location of the lesions. Methods: The patients were submitted to standard series of epicutaneous tests, standardized by the Brazilian Group Studies on Contact Dermatitis. Results: Out the 267 patients tested, 192 presented positivity to at least one substance and 29 of the patients (15.10%) presented reaction to Kathon CG, with predominance of the female gender (n = 27); main professional activity associated with Kathon CG sensibilization was cleaning (17.24%), followed by aesthetic areas (13.79%) and health care (10.34%). The most prevalent sensitizations among the substances tested were nickel sulphate (56.3%), followed by cobalt chloride (23.4%), neomycin (18.2%), potassium dichromate (17.7%), thimerosal (14.5%), formaldehyde (13.2%), paraphenylenediamine (9.3%), and fragrance mix (8.3%). Study limitations: We do not have data from patients that were submitted to patch test a decade ago in order to confront to current data and establish whether or no sensitization to Kathon CG has increased. Conclusion: High positivity to Kathon CG corroborates the recent findings in the literature, suggesting more attention to concentration of this substance, used in cosmetics and products for domestic use.

Assessment of anti-diabetic activity of a novel hydrazine-thiazole derivative: in vitro and in vivo method

Diabetes mellitus is a chronic disease resulting in oxidative stress that promotes tissue damage. The appearance of this disease is highly related to lifestyle and food of the population, being of great interest to search for a dietary supplement that can also act by reducing oxidative alterations. Based on the broad range of biological activity of thiazole derivatives, this work aimed to evaluate the in vitro antioxidant activity of a novel hydrazine-thiazole derivative and studies in vivo. In in vivo experiments, the liver extracts of healthy and diabetic Wistar rats were used, with analysis to determine the enzymatic activity of SOD, CAT, GPx, and GR, and determination of lipid peroxidation. Finally, in the blood of these animals, biochemical parameters were evaluated. Statistical evidence of changes caused in liver enzymes and liquid peroxidation was not detected; however, these parameters were also not changed between control groups with and without diabetes. On the other hand, concerning biochemical parameters, significant differences were detected in uric acid, alkaline phosphatase, ALT, and urea, indicating a possible antioxidant protective role of such substances in the liver and kidney of diabetic animals that could be acting by means other than that commonly reported in the literature.

Melanins and lens pigments: a comparative study

Based on previous findings that lens pigments and melanins share many physicochemical properties, human lens pigments and natural (hair) and synthetic melanins were submitted to oxidation with permanganate under strong acidic conditions. This procedure has been utilized for the characterization of melanins and results in the well defined products, thiazole-4,5-dicarboxylic acid (TDCA) and pyrrole-2,3,5-tricarboxylic acid (PTCA), which can be quantitated by high performance liquid chromatography (HPLC). PTCA is regarded as a marker of black eumelanins and was therefore a main component of synthetic DOPA-eumelanin and dark hair. Its identity was established by synthesis from 5-hydroxyindole-2-carboxylic acid. TDCA derives from pheomelanins and was therefore an important component of red hair and synthetic GSH-pheomelanin. TDCA was identified by its retention time relative to PTCA. The analysis of a series of cataract digests of increasing pigmentation (type I < type IV < type V) and a purified fraction of lens pigments (DE52 pigment) revealed the presence in these preparations of both PTCA and TDCA. The concentration of TDCA significantly increased with the degree of pigmentation of the digests and reached a maximum in the DE52 pigment. The TDCA/PTCA ratio was high in the lens preparations and comparable to that given by hair pheomelanin. These findings support that pheomelanin is an integral part of lens pigments. By comparing the yields of TDCA in GSH-pheomelanin and in the purified lens pigment, a 9 per cent contribution of pheomelanin to the lens pigment was estimated