Anna Biernasiuk

Synthesis and Antimicrobial Activity of New 1,3-Thiazolidin-4-one Derivatives Obtained from Carboxylic Acid Hydrazides

GRAPHICAL ABSTRACT Abstract This study presents the synthesis, spectral analysis, and antimicrobial evaluation of a new series of 1,3-thiazolidin-4-one derivatives. New compounds were prepared by the reaction of N-substituted carboxylic acid hydrazide derivatives with thioglycolic acid. The structures of the obtained compounds were confirmed by means of 1H NMR and 13C NMR. All the synthesized compounds were screened for their in vitro antibacterial and antifungal activities using the broth microdilution method against a panel of reference strains of 20 microorganisms, including 10 strains of Gram-positive bacteria, 7 strains of Gram-negative bacteria, and fungi belonging to 3 yeasts of Candida spp. Our results indicate that some of the investigated compounds showed good to mild bioactivity, with bacteriostatic or fungistatic effect against reference strains of Gram-positive bacteria, mainly M. luteus and yeast belonging to Candida spp., especially C. albicans.

Novel synthesis scheme and in vitro antimicrobial evaluation of a panel of (E)-2-aryl-1-cyano-1-nitroethenes

Abstract Drug resistance has become a major concern in the field of infection management, therefore searching for new antibacterial agents is getting more challenging. Our study presents an optimized and eco-friendly synthesis scheme for a panel of nitroalkenes bearing various functional groups in the aromatic moiety and bromine or cyano substituents in 1 position of nitrovinyl moiety. The presence of nitrolefine group outside the ring minimalizes genotoxic properties while conjugation of aryl group with nitrovinyl moiety increases stability of the compounds. Then our research focused on evaluation of biological properties of such obtained (E)-2-aryl-1-cyano-1-nitroethenes. As they exhibit strong bacteriostatic and bactericidal activities against reference bacteria and yeast species with no detectable cytotoxicity towards cultured human HepG2 and HaCaT cells, they could be promising candidates for the replacement of traditional nitrofurane-containing antibacterial drugs. Nevertheless, validation of the obtained data in an in vivo model and additional safety studies on mutagenicity are still required.

Discovery and evaluation of efficient selenazoles with high antifungal activity against Candida spp.

Synthesis, characterization and investigation of antifungal and antibacterial activities of fourteen 2,4- disubstituted 1,3-selenazoles is presented. Their structures were determined using (1)H and (13)C NMR, FAB MS and HRMS analyses. Among the derivatives, compounds 5, 6, 8, 9, 12, 13 and 15 had very strong activity against reference strains of C. albicans ATCC 10231 and C. parapsilosis ATCC 22019 with MIC = 0.24-7.81 µg/ml. The compounds 5, 6, 8, 13 and 15 showed also very strong activity against clinical isolates belonging to non-albicans Candida spp. strains, i.e. C. krusei, C. inconspicua, C. famata, C. lusitaniae, C. sake, C. parapsilosis, C. dubliniensis with MIC = 0.24-7.81 µg/ml. The activity of several of these was similar to the activity of most commonly used antifungal agents fluconazole. The compounds 9 and 16 indicate also very strong antibacterial activity against S. epidermidis and M. luteus with MIC = 1.95-3.91 µg/ml. Additionally, the compound 11 is strong active against M. luteus with MIC = 3.91 µg/ml.

Synthesis, antimicrobial and anticonvulsant screening of small library of tetrahydro-2H-thiopyran-4-yl based thiazoles and selenazoles

Abstract Synthesis and investigation of antimicrobial activity of 22 novel thiazoles and selenazoles derived from dihydro-2H-thiopyran-4(3H)-one are presented. Additionally, anticonvulsant activity of six derivatives is examinated. Among the derivatives, compounds 4a–f, 4i, 4k, 4 l, 4n, 4o–s and 4v have very strong activity against Candida spp. with MIC = 1.95–15.62 μg/ml. In the case of compounds 4a–f, 4i, 4k, 4 l, 4n, 4o, 4r and 4s, the activity is very strong against some strains of Candida spp. isolated from clinical materials, with MIC = 0.98 to 15.62 μg/ml. Additionally, compounds 4n-v are found to be active against Gram-positive bacteria with MIC = 7.81–62.5 μg/ml. The results of anticonvulsant screening reveal that compounds 4a, 4b, 4m and 4n demonstrate a statistically significant anticonvulsant activity in the pentylenetetrazole model, whereas compounds 4a and 4n showed protection in 6-Hz psychomotor seizure model. Noteworthy, none of these compounds impaired animals’ motor skills in the rotarod test. We also performed quantum chemical calculation of interaction and binding energies in complex of 4a with cyclodextrin.

Hydrazide-hydrazones of 3-methoxybenzoic acid and 4-tert-butylbenzoic acid with promising antibacterial activity against Bacillus spp.

Abstract A series of 28 hydrazide-hydrazones of 3-methoxybenzoic and 4-tert-butylbenzoic acid were synthesized and screened in vitro against the panel of reference strains of bacteria and fungi with the use of the broth microdilution method according to EUCAST and CLSI guidelines. Five of the synthesized compounds were found to exhibit high bacteriostatic or bactericidal activity against Gram-positive bacteria. The antimicrobial activity of compounds 13, 14, and 16 against Bacillus spp. was higher than that of commonly used antibiotics, like cefuroxime or ampicillin.

Design, synthesis, and in vitro antimicrobial activity of hydrazide-hydrazones of 2-substituted acetic acid.

In this study, 30 hydrazide–hydrazones of phenylacetic (3–10) and hydroxyacetic acid (11–32) were synthesized by the condensation reaction of appropriate 2‐substituted acetic acid hydrazide with different aromatic aldehydes. The obtained compounds were characterized by spectral data and evaluated in vitro for their potential antimicrobial activities against a panel of reference strains of micro‐organisms, including Gram‐positive bacteria, Gram‐negative bacteria, and fungi belonging to the Candida spp. The results from our antimicrobial assays indicated that among synthesized compounds 3–32, especially compounds 6, 14, and 26 showed high bactericidal activity (MIC = 0.488–7.81 μg/ml) against reference Gram‐positive bacteria, and in some cases, their activity was even better than that of commonly used antibiotics, such as cefuroxime or ampicillin.

Chemical compositions and antibacterial activity of extracts obtained from the inflorescences of Cirsium canum (L.) all

The aim of this study was to investigate phenolic acids and flavonoids in methanolic, dichloromethane, acetone and ethyl acetate extracts and fractions from inflorescences of Cirsium canum (L.). RP-HPLC analysis enabled identification of the following: chlorogenic acid, caffeic acid, p-coumaric acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, syringic acid, trans-cinnamic acid, luteolin-7-glucoside, apigenin-7-glucoside, kaempferol-3-glucoside, linarin, apigenin, rutoside, luteolin and kaempferol. The antimicrobial activity of tested extracts was determined in vitro against reference microorganisms, including bacteria or fungi, belonging to yeasts. Our data showed that the tested extracts had no influence on the growth of the reference strains of Gram-negative bacteria and yeasts belonging to Candida spp. Among them, the fractions possessed the highest activity against Gram-positive bacteria, especially Streptococcus aureus and Streptococcus pneumoniae belonging to pathogens and Streptococcus epidermidis, Bacillus cereus and Bacillus subtilis belonging to opportunistic microorganisms.

Synthesis and investigation of antimicrobial activities of nitrofurazone analogues containing hydrazide-hydrazone moiety

Graphical abstract

New 3-hydroxy-2-naphthoic hydrazide derivatives: thiosemicarbazides and 1,2,4-triazole-3-thiones, their synthesis and in vitro antimicrobial evaluation

In this paper, we describe twelve 3-hydroxy-2-naphthoic hydrazide derivatives (six thiosemicarbazides and six 1,2,4-triazole-3-thiones) which we have synthesized. Thiosemicarbazide derivatives were prepared by condensation reaction of 3-hydroxy-2-naphthoic hydrazide with appropriate isothiocyanates. The 1,2,4-triazole-3-thiones were synthesized by the cyclization reaction of corresponding thiosemicarbazide derivatives in alkaline media. All obtained compounds have been analyzed by 1H NMR and 13C NMR spectra and evaluated for in vitro antimicrobial activity against a panel of reference strains of microorganisms, including Gram-positive bacteria, Gram-negative bacteria and fungi belonging to yeasts Candida spp. Our antimicrobial screening results indicated that some of the newly obtained compounds showed high antibacterial activity, especially against Gram-positive bacteria. Among them, the activity of compounds 1, 2 and 4 was moderate to strong against staphylococci. In addition to this, compounds 1 and 2 showed two times higher activity than cefuroxime and four times higher activity than ampicillin against Bacillus cereus ATCC 10876.Graphical Abstract

Synthesis and antimicrobial activities of novel 6-(1,3-thiazol-4-yl)-1,3-benzoxazol-2(3H)-one derivatives

Abstract Synthesis, characterization and investigation of antimicrobial activities of seven new 6-(1,3-thiazol-4-yl)-1,3-benzoxazol-2(3H)-ones are presented. Their structures were determined using 1H NMR, 13C NMR and elemental analyses. The compounds possess some biological activity against Gram-positive bacteria, especially against Micrococcus luteus belonging to opportunistic pathogens, with an MIC of 31.25 μg/mL.