Biological Activity of Some Magnesium(II) Complexes of Quinolones.

A new magnesium complex of quinolone antibacterial agent was prepared. This new complex as well as a previously isolated complex of magnesium with ciprofloxacin were tested against various Gram positive and Gram negative microorganisms. Antimicrobial activities were evaluated using the agar diffusion test. The results have shown that all magnesium complexes are significantly less active than the parent quinolone drugs. It was also found that the activity of quinolones is reduced when the solutions of quinolones are titrated with magnesium ions.

NMR Investigation of the Copper(II)-Ciprofloxacin System.

A proton NMR study was performed on the copper(ll)-ciprofloxacin system. The proton relaxation times (T(1)) were determined from the titration data in acidic and basic media. In acidic medium the H5 signal is dramatically affected and it is assumed that copper is bonded to the quinolone through carbonyl and one of the carboxyl oxygens. Such bonding is in agreement with the X-ray literature data for the complex [Cu(cf)(1)]Cl(2).6H(2)O isolated from the slightly acidic solution. There are additional significant changes in (1)T(1) of H3' and H5' atoms which suggest that the terminal nitrogen atom of the piperazine ring system-N4' also interacts with copper in the basic conditions. Thus it is plausible that more than one species are present in the solution at high pH values.

Antibacterial tests of bismuth(III)-quinolone (ciprofloxacin, cf) compounds against Helicobacter pylori and some other bacteria. Crystal structure of (cfH2)2[Bi2Cl10].4H2O.

The antibacterial tests of two bismuth(III)-ciprofloxacin (cf) compounds against Helicobacter pylori (H. pylori) and some other bacteria were performed. The results have shown that the activity of both compounds is comparable to that of ciprofloxacin hydrochloride. The crystal structure of (cfH2)2[Bi2Cl10].4H2O (cfH2 = doubly protonated molecule of cf) is presented and discussed. The compound was isolated from acidic medium where quinolone is protonated and thus no bonding between quinolone and bismuth was observed. The bismuth(III) ions are coordinated by chloride ions forming dinuclear [Bi2Cl10]4- anions. The charge of this ion is compensated with protonated quinolone molecules (ionic interactions).

Effect of Copper Acyclovir Complexes on Herpes Simplex Virus Type 1 and Type 2 (HSV-1, HSV-2) Infection in Cultured Cells.

We have found that when copper, zinc or cobalt is bound to a suitable ligand, the appropriate complex exhibited a significant anti-HSV effect (Varadinova et al., 1993; 1996). Recently published data by Sagripanti et al. (1997) also show that the inhibition of HSV by copper was enhanced by reducing agents and that mechanism of the inactivation is similar as for copper-mediated DNA damage (Aruoma, et al. 1991; Dizdaroglu, et al., 1991; Toyokuni and Sagripanti, 1994). Therefore it was interesting to study the efect of Cu(ll) coordination compounds with acyclovir (ACV) on the replication of HSV in cultured cells. The experiments on cytotoxicity as well as on the activity of three different Cu-ACV complexes [Cu(ACV)(2)Cl(2)(H(2)O)(2)] = (A); [Cu(ACV)(2)(H(2)O)(3)](NO(3))(2).H(2)O = (B) and [Cu(ACV)(2)(H(2)O)(2)](NO(3))(2)] = (C) towards virus replication, with special attention on the growth of ACV-resistant strain R-100 were performed on MDBK cells. ACV was used as a reference compound. The following results were obtained: 1) Increased cell's viability in the presence of 20-40(g/ml ACV and decreased one in the presence of Cu-ACV complexes with relative level (A) >> (B) > (C); 2) Cu-ACV complexes are more cytotoxic than the ligand - ACV and the relative level is (C)>(B)>(A); 3) The anti-HSV effect of ACV can be modulated by copper at levels depending on the specificity of the particular virus strain: (i) for the ACV sensitive strain DA (HSV-1) - ACV ((A) > (C) > (B); (ii) for the ACV sensitive strain Bja (HSV-2) (A) > ACV > (C) > (B); (iii) for strain R-100 (ACV(R), TK(a)) - (A) > ACV > (C) > (B). This findings are consistent with previously published data and undoubtedly show that Cu-ACV complexes could be useful in the treatment of HSV infections, especially when the causative agent is a resistant to ACV mutant.

Crystal structure and characterization of the bismuth(III) compound with quinolone family member (ciprofloxacin). Antibacterial study.

Two bismuth(III) compounds of ciprofloxacin (cf) were synthesized. The crystal structure of one--(cfH2) (cfH) [BiCl6].2H2O (cfH2 = doubly protonated molecule of cf, cfH = protonated molecule of cf)--is presented and discussed. The compound crystallizes in the monoclinic space group P 21/c with a = 17.758(4), b = 7.600(10), c = 31.908(6) A, beta = 101.03(2)0, Z = 4. The charge of the isolated hexachlorobismuthate(III) anions is compensated with protonated of molecules (ionic interactions). One of the cf molecules is protonated at carbonyl oxygen O(1) and nitrogen N(24) of the piperazine residue, and the other at N(24) only. Two water molecules participate in the hydrogen bond network. Antimicrobial activity of this compound was tested against different microorganisms. The results of TG and FT-IR measurements are also included.

Synthesis, crystal structure, and characterization of two metal-quinolone compounds.

Two novel metal-quinolone compounds have been synthesized and characterized by analytical, spectroscopic, and X-ray diffraction methods. The crystal structure of both, (erxH2) [FeCl4]Cl and (kinoH2)[CuCl4]. H2O, is presented and discussed (erxH2 = doubly protonated form of enrofloxacin, kinoH2 = doubly protonated form of the second quinolone). In both compounds, the hydrogen atom is bonded between the 4-keto oxygen O(1) and carboxylic oxygen O(11), thus preventing the bonding of the metal to this part of the molecule. Antimicrobial activities of metal-quinolone compounds were tested against different microorganisms.