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Synteza i aktywność biologiczna pochodnych salinomycyny

Antoszczak M., Huczyński A., Brzezinski B.

Wiadomości Chemiczne

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2017

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[Z] 71, 7-8

629--661

EN

Polyether ionophore antibiotics (ionophores) represent a large group of naturally- occurring lipid-soluble compounds isolated from actinomycetes strains of Streptomyces genus. Ionophores are able to form complexes with the metal cations, especially sodium and potassium, and transport them across the lipid membranes according to electroneutral or electrogenic transport mechanism. This process disturbs the intercellular Na+/K+ concentration gradient and intracellular pH, leads to the mitochondrial injuries, cell swelling, vacuolization and finally to programmed cell death (apoptosis). For this reason, ionophore antibiotics found commercial use in veterinary medicine as coccidiostatic agents and non-hormonal growth promoters. In addition to the industrial use of ionophores, some of them effectively and selectively inhibit properties of different cancer cells as well as enhance the anti-cancer effects of radio- and/or chemotherapy. In this group, particularly interesting is salinomycin because of its potent anti-microbial and anti-cancer activity, including efficiency against multi-drug resistant cancer cells and cancer stem cells. A very interesting direction of research is the chemical modification of ionophore antibiotics, which can lead to obtaining various derivatives with better biological activity and lower toxicity than those of the starting substances. Because biological activity of ionophore antibiotics and their derivatives is strictly connected with the ability to form characteristic pseudocyclic structures around the complexed cations (host-guest complex), it is also important to establish the detailed information on these structures. In this context, our review article is focused on the possible role of salinomycin and its derivatives in anti-microbial as well as anti-cancer therapy, and gives an overview of the properties of this antibiotic.

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Structure of a New Schiff Base of Gossypol with Ethyl 4-Amino-1-piperidine Carboxylate in the Solid and in the Solution

Przybylski P., Pyta K., Ratajczak-Sitarz M., Katrusiak A., Brzezinski B.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 5

747-759

EN

Crystals of the Schiff base derivative of gossypol with ethyl 4-amino-1-piperidine carboxylate (GSPC) have been grown and subsequently examined by X-ray diffraction, FT-IR and NMR methods. The crystal space group is P21/n with a = 11.869(1) A, b = 13.540(1) capital A, ring c = 28.119(1) capital A, ring, beta = 91.22(1)° and Z = 4. In the crystal GSPC exists in the enamine-enamine tautomeric form. The intramolecular N(16)–H(16)źźźO(2), N(16’)–H(16’)źźźO(2’) hydrogen bonds assisted by the resonance of the pi-electrons in the aromatic system are the strongest. The FT-IR spectral features of the crystals are in agree - ment with the X-ray data indicating that both parts of the molecule are similarly intramolecular hydrogen-bonded but different intermolecular hydrogen-bonded, al - though the molecule is symmetrically substituted. The FT-IR as well as 1H and 13C NMR spectra have shown that in chloroform solution the enamine-enamine tautomeric form is preserved and the whole structure of GSPC be comes more symmetrical.

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Hydrogen-bonded chains with large proton polarizability due to collective proton motion - pathways for protons in biological membranes

Zundel G., Brzezinski B.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 2

172-192

EN

Hydrogen-bonded chains may show very large proton polarizability due to collective proton motion if they are largely symmetrical. This result was first obtained with polylysine + dihydrogenphosphate and with polyglutamic acid + dihydrogenphosphate systems, respectively. These systems cause intense IR continua, demonstrating their large proton polarizability. This proton polarizability was studied in detail with intramolecular hydrogen-bonded systems and results of these studies are extensively discussed in this paper. Such hydrogen-bonded chains are very effective proton pathways in biology. They can easily be regulated by local electrical fields and by specific interactions. Two such pathways are discussed, the one in the L550 intermediate in the bacteriorhodopsin molecule and the pathway in the F0 subunit of the ATP synthase.

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FT-IR and NMR stedies of proton sponge character of Cis-1,2-bis(diethylaminomethyl)cyclohexane

Brzezinski B., Grech E., Klimkiewicz J., Schroeder G., Stefaniak L., Urjasz H.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 2

284-291

EN

Cis-1,2-bis(diethylaminomethyl)cyclohexane (DEAMCH) was synthesized and its pK-a values in acetonitrile were measured. Dual behevioral of DEAMCH was observed in the reaction with various acids: HClO4, 4-tert-butylphenol, 4-cyanophenol and pentachlorophenol (PCP) in acetonitrile and acetone-d-6 solutions, respectively, when studied by FT-IR as well as (1)H, (13)C and (15)N NMR spectroscopy. An intramolecular NHN(+) hydrogen bond was found in 1:1 complex of DEAMCH with HClO4 in solution. This hydrogen bond was, however, weaker than those previously observed in other protonated proton sponges. In complexes of DEAMCH with 4-cyanophenol both NHN(+) intramolecular hydrogen bond and structurally symmetrical intermolecular homoconjugated (OHO)(-) hydrogen bonds were formed. These properties of DEAMCH demonstrate its proton sponge like character. On the other hand, in complexes of DEAMCH with more acidic phenol such as PCP intermolecular hydrogen-bonded complexes are formed, in which the OH protons are localized at the amino groups. For these O(-)...HN(+) hydrogen bonds a strongly asymmetrical double minimum proton potential with the well at the N atom is present, characteristic of complexes having no proton sponge like character.