Antimutagenic activity and radical scavenging activity of water infusions and phenolics from ligustrum plants leaves.

Water infusions of Ligustrum delavayanum and Ligustrum vulgare leaves and eight phenolics isolated therefrom have been assayed in vitro on ofloxacin-induced genotoxicity in the unicellular flagellate Euglena gracilis. The tested compounds luteolin, quercetin, luteolin-7-glucoside, luteolin-7-rutinoside, quercetin-3-rutinoside, apigenin-7-rutinoside, tyrosol and esculetin inhibited the mutagenic activity of ofloxacin (43 microM) in E. gracilis. Water infusions from leaves of L. delavayanum and L. vulgare showed higher antimutagenic effect (p(t) < 0.001). The activity of these samples against ofloxacin (86 microM)-induced genotoxicity was lower, but statistically significant (p(t) < 0.05), excluding the water infusion of L. delavayanum leaves (p(t) < 0.01). Efficacy of quercetin, luteolin-7-rutinoside, apigenin-7-rutinoside was insignificant. The antimutagenic effect of most phenolics we studied could be clearly ascribed to their DPPH scavenging activity, substitution patterns and lipophilicity.

Antimutagenic in vitro activity of plant polyphenols: Pycnogenol and Ginkgo biloba extract (EGb 761).

Ofloxacin (15 microg/mL) and acridine orange (5 microg/mL) induce mutagenicity by different mechanisms in the photosynthetic flagellate Euglena gracilis. The present study examined whether Pycnogenol (PYC; 5-100 microg/mL) or Ginkgo biloba extract (EGb 761; 5-100 microg/mL) could protect against the mutagenic effects of each of the mutagens and the potential mechanisms underlying such protection. The highest concentration of PYC and EGb 761 effectively reduced the mutagenic activity of both ofloxacin and acridine orange by more than 99% (p < 0.001). Using luminol-dependent photochemical methodology it was demonstrated that EGb 761 and PYC were effective antioxidants. In addition, as determined by spectrophotometry, PYC and EGb 761 bound acridine orange. Both PYC and EGb 761 have been shown to produce dual antimutagenic effects, as evidenced by both antioxidant and physicochemical properties. The findings suggest that EGb 761 and PYC would thus be suitable for future study, not only as antioxidants, but also as antimutagenic agents.

Antioxidant and antimutagenic activity of mannan neoglycoconjugates: mannan-human serum albumin and mannan-penicillin G acylase.

The antioxidant and antimutagenic activity of the yeast cell-wall mannan and mannan conjugates--in particular the mannan of Saccharomyces cerevisiae (M-S.c.) and conjugates of mannan S. cerevisiae with human serum albumin (M-HSA1, M-HSA2) and the microbial enzyme penicillin G acylase (M-PGA)--were evaluated in vitro in the unicellular flagellate Euglena gracilis exposed to the genotoxic agents ofloxacin and acridine orange (AO). M-S.c., M-HSA1, M-HSA2 and M-PGA show a statistically significant, concentration-dependent protective antigenotoxic activity against both compounds. M-PGA was the most efficient inhibitor of ofloxacin- and AO-induced chloroplast DNA damage, whereas M-HSA2 and M-HSA1 were less effective and M-S.c. had the lowest antigenotoxic activity. It is suggested that different mechanisms may be involved in their protective effect--antioxidant activity in the case of ofloxacin-induced DNA damage and direct adsorption of AO on mannan conjugates as possible mechanisms of protection, based on spectrophotometric measurements. The important characteristics of yeast cell-wall mannans and mannan conjugates, such as their high water solubility, their broad spectrum of biological activity, low toxicity, stability and their antimutagenic effects via different modes of action, appear to be promising features for their practical application as antioxidants and antimutagenic agents.

Molecular identification and diversity of enterococci isolated from Slovak Bryndza cheese.

Three hundred and eight presumed enterococcal isolates were recovered from Bryndza, a soft sheep milk cheese. The cheese samples were obtained from five different commercial distributors in Slovakia and were taken at three different seasonal intervals. All isolates were identified to the species level using genotypic tools. Species-specific PCR using ddl genes highlighted the predominance of Enterococcus faecium (176 isolates) and assigned 50 isolates to the species Enterococcus faecalis. The remaining 82 isolates were classified using repetitive element sequence-based polymerase chain reaction (PCR) with primer (GTG)(5)-(GTG)(5)-PCR, in combination with phenylalanyl-tRNA synthase gene (pheS) sequence analysis and by whole-cell protein analysis (SDS-PAGE). These strains were identified as Enterococcus durans (59 strains), Enterococcus italicus (8 strains), Enterococcus casseliflavus (3 strains), Enterococcus gallinarum (3 strains), Enterococcus hirae (1 strain), and 8 strains were members of the species Lactococcus lactis. Of the seven enterococcal species isolated, three of them, E. durans, E. faecalis and E. faecium were present in all samples studied, with E. faecium as the predominant one. The precise identification of enterococci in Bryndza cheese is an essential step in the process of evaluation of their functional properties which will be further studied and assessed.

Antioxidant and antimutagenic activity of N-(2-carboxyethyl)chitosan.

The antioxidant and antimutagenic activities of the novel carboxyethyl derivatives of chitosan with three different degrees of substitution have been assayed in vitro in the unicellular flagellate Euglena gracilis subjected to the action of genotoxic agents acridine orange and ofloxacin. It has been demonstrated that chitosan derivatives exhibit concentration-dependent protective antigenotoxic activity against both mutagens. It is suggested that different mechanisms may be involved in its protective action--antioxidant activity in case of ofloxacin-induced DNA damage, as well as possible interaction with the cell membrane that prevents acridine orange from reaching the genetic compartments and subsequent damaging DNA through intercalative binding. Direct adsorption of acridine orange on chitosan derivatives was ruled out as a possible mechanism of protection on the basis of spectrophotometric measurements. Dependence of the antimutagenic properties of the studied chitosan derivatives on the degree of substitution was reversed in experiments involving acridine orange and ofloxacin, which also indicated different mechanisms of protection involved in these two cases.

Protective effects of fungal (1-->3)-beta-D-glucan derivatives against oxidative DNA lesions in V79 hamster lung cells.

beta-Glucans belong to the class of substances known as biological response modifiers with a broad range of activity. We have investigated two types of glucans: (1-->3)-beta-D glucan from the baker's yeast Saccharomyces cerevisiae and beta-glucan-chitin complex from the mycelium of filamentous fungus Aspergillus niger. Since these fibrillar beta-glucans are insoluble in water, their water-soluble derivatives--carboxymethyl glucan (CM-G), sulfoethyl glucan (SE-G), and carboxymethyl chitin-glucan (CM-CG) were prepared and tested. The aim of the present work was to investigate the protective effect of the prepared glucan derivatives against oxidative DNA damage induced by H2O2 and visible light-excited Methylene Blue in V79 hamster lung cells. The level of DNA damage (DNA strand breaks) was measured using the single cell gel electrophoresis, so called comet assay. Our findings demonstrate that all three tested glucans reduce oxidative DNA damage. The ability to reduce genotoxic activity increased in the order: CM-G

Fungal beta-(1-3)-D-glucan derivatives exhibit high antioxidative and antimutagenic activity in vitro.

The antioxidative activity and antimutagenic effects of the water-soluble beta-(1-3)-D-glucan derivatives from biotechnologically important species, in particular carboxymethyl-glucan (CM-G) and sulfoethyl-glucan (SE-G) both from the baker's yeast Saccharomyces cerevisiae, and carboxymethyl-chitin-glucan (CM-CG) from filamentous fungus Aspergillus niger, were evaluated. The luminol-dependent photochemical method using trolox as a standard showed that CM-CG, SE-G and CM-G possessed high antioxidative properties. CM-CG exhibited the highest antioxidative activity (2.15 +/- 0.14 nmol exhibits the same activity as 1 nmol of trolox), followed by SE-G (2.99 +/- 0.15 nmol) and CM-G (4.59 +/- 0.14 nmol). These glucans were experimentally confirmed to exhibit different, statistically significant activity in reducing the damage of chloroplast DNA of the flagellate Euglena gracilis induced by ofloxacin and acridine orange. Our findings suggest that the antimutagenic effect of CM-CG, SE-G and CM-G against ofloxacin is based on their antioxidative capability to scavenge reactive oxygen species (p < 0.001). As far as acridine orange is concerned, the reduction of the chloroplast DNA lesion could be a result of the absorptive capacity of the glucans (p < 0.001). We found out that the water-soluble beta-(1-3)-D-glucan derivatives possess very high antioxidative activity as well as expressive antimutagenic effects, exerted through different mode of action.

Detection of damage to DNA and antioxidative activity of yeast polysaccharides at the DNA-modified screen-printed electrode.

A simple procedure for the voltammetric detection of the DNA damage and antioxidants protecting DNA from its damage using a disposable electrochemical DNA biosensor is reported. The carbon-based screen-printed electrode (SPE) modified by a surface layer of the calf thymus double stranded (ds) DNA was used as a working electrode in combination with a silver/silver chloride reference electrode and a separate platinum auxiliary electrode. The [Co(phen)(3)](3+) ion served as the dsDNA redox marker and the [Cu(phen)(2)](2+) and [Fe(EDTA)](-) complex compounds were used as the DNA cleavage agents under the reduction by a chemical reductant (ascorbic acid). Four yeast polysaccharides with different chemical structure were investigated as the antioxidants within the concentration range of 0.05-4 mg ml(-1) in the cleavage mixture. A remarkable antioxidative activity of polysaccharides in order mannan (Candida krusei)>extracellular glucomannan (Candida utilis)>mannan (Candida albicans)>glucomannan (C. utilis) was found which is in agreement with that refered to trolox (a structural derivative of alpha-tocopherol) and determined by photochemiluminescent method.