Virucidal action of sore throat lozenges against respiratory viruses parainfluenza type 3 and cytomegalovirus.

Most respiratory tract infections are self-limiting and caused by viruses, and do not warrant antibiotic treatment. Despite this, patients with respiratory tract infections often receive antibiotics, fuelling the rise of antibiotic resistance. Therefore, there is a need to encourage patients to try alternative non-antibiotic therapies, which ideally treat the symptoms and the cause. Lozenges containing amylmetacresol and 2,4-dichlorobenzyl alcohol (AMC/DCBA lozenges) as well as lozenges containing hexylresorcinol have been shown to provide effective symptomatic relief for sore throat. In this study, we investigated whether these lozenges also have virucidal effects in vitro against two viruses associated with respiratory tract infections, parainfluenza virus type 3 and cytomegalovirus. Both viruses were incubated with AMC/DCBA lozenge, placebo lozenge or the active ingredients (AMC/DCBA) as free substances, and parainfluenza virus type 3 was incubated with hexylresorcinol lozenge, placebo lozenge or hexylresorcinol as a free substance. Virucidal effects were observed with the active lozenges and the active ingredients as free substances against both parainfluenza virus type 3 and cytomegalovirus. Mean reductions in viral titre were significantly greater compared with placebo lozenge and peak effects were observed for the shortest incubation time, 1min. These findings suggest that AMC/DCBA lozenge and hexylresorcinol lozenge have the potential to have local antiviral effects in patients with sore throat due to viral respiratory tract infections. Use of such over-the-counter treatments for self-limiting respiratory tract infections may satisfy patients' desire for an anti-infective medication and reduce the demand for antibiotics.

Effects of known phenoloxidase inhibitors on hemocyanin-derived phenoloxidase from Limulus polyphemus.

Inhibitors of phenoloxidase are used routinely to characterise the structural and functional properties of phenoloxidases. Hemocyanin-derived phenoloxidase activity is also sensitive to standard phenoloxidase inhibitors. In this study, we characterise the effects of a number of phenoloxidase inhibitors on hemocyanin-derived phenoloxidase activity from the chelicerate, Limulus polyphemus. Both inhibition type and K(i) values were similar to those observed for hemocyanin-derived phenoloxidase from another chelicerate, Eurypelma californicum. In addition, substrate inhibition was observed at concentrations above 2mM dopamine. The conformation in which two of the inhibitors, namely tropolone and kojic acid, would bind near the Cu(II) centre of hemocyanin is proposed.

[Mechanisms of interaction between DNA and chemical analogues of microbial anabiosis autoinducers].

The alkylhydroxybenzene (AHB) autoregulatory factors d1 (fd1) of microorganisms have been found to directly interact with highly polymeric DNA. This circumstance results in changes, related to alterations in the topology of this macromolecule, in DNA physicochemical properties. The physicochemical properties of DNA in the presence of chemical analogues of microbial AHBs (methylresorcinol; hexylresorcinol; and 2-(4-hydroxyphenyl)ethane-1-ol, also known as tyrosol) were investigated using adsorption spectrophotometry, fluorometry, heat denaturation, viscosimetry, and electrophoresis in agarose gel. A number of concordant effects pointing to DNA-AHB interactions were revealed that manifesed themselves in the hypochromic properties of the resulting complexes, an increase in their melting temperature and viscosity, a decrease in their electrophoretic mobility, and a change in the fluorescent properties of AHBs upon complexation with DNA. Such alterations were particularly significant in the presence of hexylresorcinol, which possessed the maximum alkyl radical length among the fd1 analogues tested. Using atomic force microscopy, we visualized the micelle-like DNA nanostructures forming in the presence of AHBs. The results obtained provided the basis for developing a hypothetical model of the interaction between the biopolymer macromolecule and low-molecular-weight AHBs that takes into account the differences in the hydrophobicity of individual AHB homologues functioning as ligands. In terms of our model, we discuss AHB involvement in the stabilization of DNA and alteration of its topology, i.e., in the process related to intragenomic rearrangements, which account for the intrapopulational variability of bacteria, including dissociation processes.

[Hexylresorcinol induces chromosome aberrations in mouse peripheral blood cells].

Hexylresorcinol has been demonstrated to induce chromosome aberrations in eukaryotic cells at doses of 0.5, 0.05, and 0.005 mg/g body weight. The metabolic transformation of hexylresorcinol in mice decreases its genotoxic effect. The mutagenic effect is retained for three days only after the administration of the highest dose of hexylresorcinol (0.5 mg/g); during the first two days, lower doses are also genotoxic. Therefore, hexylresorcinol doses lower than 0.5 mg/g body weight are metabolized within two days to the extent precluding the expression of the cytotoxic effect. After a single administration to mice, exogenous hexylresorcinol is transformed at a rate of 0.0025-0.025 mg/day.