Pavlína Foltínová

Synthesis, antimicrobial activity and bleaching effect of some reaction products of 4-oxo-4H-benzopyran-3-carboxaldehydes with aminobenzothiazoles and hydrazides

The synthesis of the biologically active novel systems derived from reaction of 3-formylchromones with three types of amino derivatives, 6-R2-2-aminobenzothiazoles, 6-amino-2-R3-thiobenzothiazoles and hydrazide derivatives (derived from cyanoacetic, isonicotine, salicylic and gallic acids) was carried out. The structures of the prepared compounds have been proved by elemental analysis, 1H NMR and IR spectra. Antimicrobial activity was studied against the following microorganisms--bacteria G+ (Staphylococcus aureus 29/58, Bacillus subtilis 18/66), G- (Escherichia coli 326/71, Pseudomonas aeruginosa); yeasts: Candida albicans, Saccharomyces cerevisiae; moulds: Microsporum gypseum, Aspergillus niger, Scopulariopsis brevicaulis; and against typical and atypical mycobacteria: Mycobacterium tuberculosis (H37Rv), Mycobacterium kansasii (PFG 8), Mycobacterium avium (My 80/72), Mycobacterium fortuitum (1021). The hereditary bleaching effect on the plastid system of Euglena gracilis, a unique phenomenon of the biological activity of chromone derivatives, is reported. The bleaching test on E. gracilis is used for detecting extranuclear mutations.

Antimicrobial effects of some benzthiazol derivatives

Substitution with NO2, Cl, Br and I into position 6 of 2-benzthiazoIthiol derivatives increased their antimicrobial efficiency while the SH group is preserved. This increase affected both G+ and G-bacteria, mycobacteria and some fungi The degree of efficiency of the benzthiazol derivatives is also influenced by the substituent in position 2.

New conjugated benzothiazole-N-oxides: synthesis and biological activity.

Eleven new 2-styrylbenzothiazole-N-oxides have been prepared by aldol – type condensation reactions between 2-methylbenzothiazole–N-oxide and para-substituted benzaldehydes. Compounds with cyclic amino substituents showed typical push-pull molecule properties. Four compounds were tested against various bacterial strains as well as the protozoan Euglena gracilis as model microorganisms. Unlike previously prepared analogous benzothiazolium salts, only weak activity was recorded.

Qsar study of the toxicity of benzothiazolium salts against Euglena gracilis: the Free-Wilson approach.

The Free-Wilson QSAR model in the Fujita-Ban modification was used to calculate the quantitative substituent activity contributions to the toxicity against Euglena gracilis in a series of 91 benzothiazolium salts. An important increase of activity was found for R1 = styryl or SCH2C6H5 group and for R2 = propargyl or allyl group. The substituents on benzene ring also enhance the activity. The possible relations between structure of active groups and their electronic or physicochemical properties are discussed. By using the calculated values it is possible to predict toxicity for 1300 compounds. New compounds with assumed high or low toxicity are predicted.

Benzothiazolium salts--relationships between their structure, toxicity and effect on the plastid system of Euglena gracilis.

The effects of 41 benzothiazolium salts onEuglena gracilis were characterized with regard to the influence on growth and on chlorophyll synthesis, and to their ability to induce permanent loss of chloroplasts. Some salts induced white mutants ofE. gracilis (the first benzothiazole derivatives with this activity). The relationship between the biological effect and chemical structure was confirmed and expressed quantitatively by means of Free - Wilson and Fujita -Ban analysis.

Protective effect of ascorbic acid on bleaching activity of N-methyl-N'-nitro-N-nitrosoguanidine and furazolidone

Exposure of autotrophic cells ofEuglena gracilis to MNNG and furazolidone results in an irreversible loss of chloroplasts leading to a production of white mutants (permanent bleaching). Induction of the white mutants is significantly decreased by ascorbic acid, especially during the first stages of this mutation process.

Effect of some benzthiazol derivatives onEuglena gracilis

Abstract6-Substituted derivatives of 2-benzthiazolthiol and allyl (2-benzthiazolylthio)acetate exhibit, after an exposure to light, and inhibitory action on the division of dark-depigmentedEuglena cells, as well as the synthesis of chlorophyll. These substances also have a marked inhibitory effect on the development of plastids in nondividing cells maintained under resting conditions. No induction of heterotrophic plastidfree mutants was found under growth or resting conditions.