Copper-polyaniline nanocomposite: Role of physicochemical properties on the antimicrobial activity and genotoxicity evaluation.

Copper nanoparticles (Cu NPs) have proven to own excellent antimicrobial efficacy, but the problems of easy oxidation and aggregation limit their practical application. Here, nanocomposite based on polyaniline (PANI) and Cu NPs solved this problem and brought additional physicochemical properties that are markedly advantageous for antimicrobial applications. Current work exploits this potential, to examine its time- and concentration-dependent antimicrobial activity, employing E. coli, S. aureus, and C. albicans as a model microbial species. Regarding the presence of polaronic charge carriers in the fibrous polyaniline network, effects of Cu NPs' size and their partially oxidized surfaces (the data were confirmed by HRTEM, FESEM, XRD, Raman and XPS analysis), as well as rapid copper ions release, Cu-PANI nanocomposite showed efficient bactericidal and fungicidal activities at the concentrations ≤1 ppm, within the incubation time of 2 h. Beside the quantitative analysis, the high levels of cellular disruption for all tested microbes were evidenced by atomic force microscopy. Moreover, the minimum inhibitory and bactericidal concentrations of the Cu-PANI nanocomposite were lower than those reported for other nanocomposites. Using such low concentrations is recognized as a good way to avoid its toxicity toward the environment. For this purpose, Cu-PANI nanocomposite is tested for its genotoxicity and influence on the oxidative status of the human cells in vitro.

Biological effects of Echinacea purpurea on human blood cells.

The aim of this study was to investigate radioprotective properties of Echinacea purpurea tablets in vivo. We analysed lymphocyte chromosome aberrations (CA), micronuclei (MN), apoptosis of leukocytes and haematological parameters in a group of radiation workers who were identified as carrying dicentric chromosomes in their lymphocytes. All radiation workers were taking two 275 mg Echinacea tablets b.i.d., according to a pharmacist's recommendation. All parameters were analysed before and after the two-week treatment. At the end of the treatment lymphocyte CA frequency dropped significantly, and the number of apoptotic cells increased. The inverse lymphocyte-to-granulocyte ratio at the beginning of the study changed to normal at its end. In conclusion, biological effects observed after administration of Echinacea purpurea preparation suggest that it may be beneficial for the prevention of adverse health effects in workers exposed to ionising radiation.

Radioprotective effects of Gentianella austriaca fractions and polyphenolic constituents in human lymphocytes.

The aim of this study was to identify active principles of Gentianella austriaca responsible for the reduction of the incidence of micronuclei in irradiated lymphocytes in vitro. The radioprotective effects of ether (EF) and methanolic (MeF) fractions, water-soluble xanthones demethylbellidifolin (1), demethylbellidifolin 8-O-glucoside (2), bellidifolin 8-O-glucoside (3), and flavonoid swertisin (4) against chromosomal damage induced by gamma-rays were determined using the micronucleus test. EF and MeF showed better protection in treatment of human lymphocytes after gamma-irradiation than did isolated compounds. Among the isolated compounds, the effectiveness in reduction of the frequency of micronuclei followed the order 4>3>2>1. The anti-lipoperoxidant activity was in the order 2>4>1, while 3 slightly increased the level of malondialdehyde. In addition, the effectiveness in induction of apoptosis followed the order, 3>2>4, while 1 had no proapoptotic effect. These results suggest that the antioxidative properties of the polyphenols tested may contribute to the radioprotective effects of G. austriaca.

Radioprotective properties of the phytochemically characterized extracts of Crataegus monogyna, Cornus mas and Gentianella austriaca on human lymphocytes in vitro.

The objective of the present study is to evaluate the radioprotective properties of extracts of Crataegus monogyna Jacq. (Rosaceae) fruit, Cornus mas L. (Cornaceae) leaves and Gentianella austriaca (A. Kern. & Jos. Kern.) Holub (Gentianaceae) aerial parts on cultured human peripheral blood lymphocytes in vitro after irradiation with 2 Gy of 60Co gamma-rays. Plants were collected at Mt. Maljen in Serbia, air-dried and powdered, and the total phenolic content was analyzed. In C. mas leaves, ellagic and gallic acid were found to be the dominant compounds, whereas C. monogyna fruit was rich in procyanidins and flavonoids. The main constituents of G. austriaca aerial parts were gamma-pyrones and secoiridoids. Cell cultures were treated with four different doses of plant extracts (0.1 mg/mL to 0.4 mg/mL). Treatment with the lowest dose gave the best protective effect. Significant radiorecovery potentials of C. mas and C. monogyna were observed, seen as a reduced incidence of radiation-induced micronuclei (19.23% and 13.24%, respectively), reduced levels of lipid peroxidation products (50.04% and 13.18%, respectively) and two-fold enhanced apoptosis. Both extracts slowed down cell proliferation gradually, enabling more time for repair. G. austriaca possesses strong antioxidant properties, significantly reducing lipid peroxidation and the incidence of micronuclei (for 30.88% and 35.56%, respectively) while enhancing apoptosis with no perturbation of the cell cycle. This study may contribute to the search for novel radioprotective agents.

Vitamin B12 reduces ribavirin-induced genotoxicity in phytohemaglutinin-stimulated human lymphocytes.

Ribavirin, an N-glycosyl nucleoside (1-beta-D-ribofuranosyl-1, 2, 4-triazole-3 carboxamide), is a synthetic purine nucleoside analogue with a broad spectrum of antiviral activity, however, its high toxicity poses a major disadvantage of its use as a therapeutic. Various studies have shown that vitamin B12 plays a significant role in maintaining the stability of the human genome. We therefore investigated the potential beneficial effect of vitamin B12 in reducing ribavirin-induced genotoxicity. To test this, we used the cytokinesis-block micronucleus (CBMN) assay. Human blood cells were treated in vitro with increasing doses of ribavirin (0.05, 0.17, 0.32, 0.47 and 0.65 micromol/ml) for three different periods of time (2, 4 and 17 hrs). Duplicate cultures were supplemented with 50 mul of vitamin B12 during the drug treatment (final concentration of 13.5 microg/ml). Micronuclei formation and cell proliferation potential were then scored in both sets of samples and the corresponding controls. The results showed that supplementation with vitamin B12 lowered the frequency of micronuclei (Z = 2.02, p < 0.04) and recovered the proliferation potential of the treated cells for each treatment period, except for the conditions with the highest concentration of ribavirin and the shortest time. These observations underscore the unique beneficial effects of vitamin B12 in reducing genotoxicity, particularly by recovering the proliferation potential of treated cells, as demonstrated by the decrease in mononucleated cells and enhancement of binucleated and polynucleated cells. The mechanism by which vitamin B12 reduces ribavirin-induced genotoxicity is related to de novo synthesis of nucleotides, and is worthy of further investigation.