Milan Nagy

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 µM) in E. gracilis. Water infusions from leaves of L. delavayanum and L. vulgare showed higher antimutagenic effect (pt < 0.001). The activity of these samples against ofloxacin (86 µM)-induced genotoxicity was lower, but statistically significant (pt < 0.05), excluding the water infusion of L. delavayanum leaves (pt < 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.

Amyloid aggregation of lysozyme: The synergy study of red wine polyphenols

The amyloidoses are diseases associated with nonnative folding of proteins and characterized by the presence of protein amyloid aggregates. The ability of quercetin, resveratrol, caffeic acid, and their equimolar mixtures to affect amyloid aggregation of hen egg white lysozyme in vitro was detected by Thioflavin T fluorescence assay. The anti‐amyloid activities of tested polyphenols were evaluated by the median depolymerization concentrations DC50 and median inhibition concentrations IC50. Single substances are more efficient (by at least one order) in the depolymerization of amyloid aggregates assay than in the inhibition of the amyloid formation with IC50 in 10−4 to 10−5M range. Analyzed mixture samples showed synergic or antagonistic effects in both assays. DC50 values ranged from 10−5 to 10−8M and IC50 from 10−5 to 10−9M, respectively. We observed that certain mixtures of studied polyphenols can synergistically inhibit production of amyloids aggregates and are also effective in depolymerization of the aggregates. Synergic or antagonistic effects of studied mixtures were correlated with protein–small ligand docking studies and AFM results. Differences in these activities could be explained by binding of each polyphenol to a different amino acid sequence within the protein. Our results indicate that synergic/antagonistic anti‐amyloid effects of studied mixtures depend on the selective binding of polyphenols to the known amyloidogenic sequences in the lysozyme chain. Our findings of the effective reduction of amyloid aggregation of lysozyme by polyphenol mixtures in vitro are of the utter physiological relevance considering the bioavailability and low toxicity of tested phenols. Proteins 2013;

Phenolic acids inhibit chloroplast mutagenesis in Euglena gracilis

The mutagenicity (bleaching activity) of ofloxacin (43 microM) and acridine orange (AO) (13.5 microM) in Euglena gracilis is inhibited by plant phenolics. Caffeic acid (CA), p-coumaric acid (PCA), ferulic acid (FA) and gentisic acid (GA) (25, 50, 100 and 250 microM) exhibited a significant concentration-dependent inhibitory effect against ofloxacin-induced mutagenicity, which was very effectively eliminated by the highest concentration of all four of those phenolic acids. The mutagenicity of AO was also significantly reduced in the presence of CA, PCA and FA (25, 50, 100 and 250 microM). However, GA exhibited no significant activity, even at the concentration of 250 microM. Based on the UV spectrophotometric measurements, we suggest that the antimutagenic effect of CA, PCA, FA and GA resulted from the scavenging of reactive oxygen species (ROS) produced by ofloxacin. On the other hand, the reduction of AO-induced mutagenicity correlates with the binding capabilities of CA, PCA and FA, with the exception of GA.

Synergy Study of the Inhibitory Potential of Red Wine Polyphenols on Vascular Smooth Muscle Cell Proliferation

Vascular smooth muscle cell (VSMC) proliferation contributes to the development of atherosclerosis. Red wine consumption due to the polyphenol content has been reported to counteract atherosclerosis progression possibly through inhibition of VSMC proliferation, among other mechanisms. In this study we investigate the antiproliferative activity of four wine polyphenols: resveratrol, quercetin, ethyl gallate, and (+)-catechin in rat aortic VSMC. All four polyphenols inhibited serum-induced VSMC proliferation when applied as a single treatment. To further address a potential synergistic action of the investigated polyphenols, the antiproliferative effect of different combinations in equimolar, as well as equipotent ratios were quantified. The IC₅₀ values of single polyphenols regarding the inhibition of VSMC proliferation ranged from 49.58 µM to 86.06 µM. However, apparent inhibitory efficacy of each compound increased by a factor of 10.4 in the quadruple equipotent mixture, as calculated from the dose-reduction index. Thus, the effective IC₅₀ values of each of the four mixture constituents ranged from 4.76 µM to 8.27 µM. The calculated combination index (CI, where CI <, =, or > 1 indicate synergy, additivity, or antagonism, respectively) values of equimolar combinations of the polyphenols indeed indicated mainly synergy (CI ranging from 0.24 ± 0.01 to 1.51 ± 0.13). Optimized equipotent mixture showed enhanced synergy (CI ranging from 0.18 ± 0.04 to 1.36 ± 0.26). In conclusion, we show for the first time that four major polyphenols from wine synergistically inhibit VSMC proliferation.

Antibacterial activity of plant extracts from the families Fabaceae, Oleaceae, Philadelphaceae, Rosaceae and Staphyleaceae.

The selected plant extracts exhibited antibacterial activity. The strongest effect was manifested by extracts prepared from Gymnocladus dioicus, Amelanchier ovalis, Exochorda racemosa, Holodiscus discolor, Philadelphus microphyllus, Philadelphus coronarius and Pelargonium tabulare. The percentage inhibition of bacterial growth was 0–41.8%. In addition it was found that extracts isolated from Amelanchier ovalis, Exochorda racemosa and Pelargonium tabulare were specifically effective only against the bacterial strains tested. Copyright

Comparison of Essential Oils from Marrubium vulgare L. and M. peregrinum L.

Abstract The chemical composition of the essential oils obtained from the flowering aerial parts of Marrubium vulgare L.. and Marrubium peregrinum L. were determined by GC/MS. Twelve components were identified in M. vulgare oil with β-caryophyllene (45.8%) and germacrene D (14.4%) being the major constituents. In M. peregrinum oil, sixteen compounds were identified with β-caryophyllene (31.3%), germacrene D (28.1%) and bicyclogermacrene (15.3%) predominating.

In Vitro Antioxidant Activities of Three Red Wine Polyphenols and Their Mixtures: An Interaction Study

The well-known antioxidant activity of red wine is explained mostly by its polyphenols content, where the final effect is based on the wine components’ interaction. The aim of our work was the study of the interaction of three red wine polyphenols—quercetin, resveratrol and caffeic acid—alone and in their equimolar binary and ternary mixtures in different antioxidant/scavenging assays (inhibition of 2-deoxy-D-ribose degradation by hydroxyl radical, FRAP, Fe(III) reducing power, DPPH, ABTS and NO scavenging, respectively). Interaction analysis, based on median effect equation, was performed for the determination of synergy and/or antagonism. The obtained results indicate that the mutual interactions of tested polyphenols in their mixtures are markedly different from each other, depending on the reaction mechanism of the assay used. The measured antioxidant activity of individual polyphenols is not a constant value when other substances are present in the mixture with this polyphenol. Interactions can cause the finally observed synergy/antagonism/additive effects without any possibility of predicting them from the known activities of single compounds. This “unpredictability” claim based on in vitro assay results should be very important in multiple systems and processes in Nature, where the interactions among compounds in mixtures need to be take into account.

Phenolic acids reduce the genotoxicity of acridine orange and ofloxacin inSalmonella typhimurium

Naturally occurring plant phenolics,p-coumaric acid (PA), caffeic acid (CA), ferulic acid (FA) and gentisic acid (GA) (25–100 nmol/L) had protective effects on acridine orange (AO; 216 μmol/L)- and ofloxacin (3 μmol/L)-induced genotoxicity inSalmonella typhimurium. FA, GA and CA exhibited a significant concentration-dependent protective effect against the genotoxicity of AO and ofloxacin, with the exception of PA, which at all concentrations tested abolished the AO and ofloxacin genotoxicity. UV spectrophotometric measurements showed the interaction of PA, FA, GA and CA with AO but not with ofloxacin; this interaction is obviously responsible for the reduction of AO-inducedS. typhimurium mutagenicity. In the case of ofloxacin the antimutagenic effect of PA, FA, GA and CA is assumed to be a result of their ability to scavenge reactive oxygen species (ROS) produced by ofloxacin.

Cytotoxic effects of plant extracts from the families Fabaceae, Oleaceae, Philadelphaceae, Rosaceae and Staphyleaceae

A human transformed line of HeLa cells was treated with extracts prepared from Gymnocladus dioicus, Holodiscus discolor, Stephanandra tanakae, Ligustrum delavayanum, Ligustrum vulgare and Staphylea pinnata. The study evaluating the influence of the active extracts on HeLa cell division also reveals their acute, delayed and combined effect. A 35% degradation of HeLa cells was found after 72 h treatment with 62.5 µg/mL of the extract isolated from Stephanandra tanakae. A 100% lysis of HeLa cells was observed after 72 h treatment with a 125 µg/mL concentration of the extract prepared from Gymnocladus dioicus. The extracts from Ligustrum devayanum and Ligustrum vulgare were specifically effective only with HeLa cells. On the other hand, the extract prepared from Gymnocladus dioicus was effective on the bacteria and on the HeLa cells. Copyright

Free-radical degradation of high-molecular-weight hyaluronan induced by ascorbate plus cupric ions. Testing of bucillamine and its SA981-metabolite as antioxidants

High-molecular-weight hyaluronan (HA) samples were exposed to free-radical chain-degradation reactions induced by ascorbate in the presence of Cu(II) ions - the so-called Weissbergers oxidative system. The concentrations of both reactants [ascorbate, Cu(II)] were comparable to those that may occur during an early stage of the acute phase of joint inflammation. The time-dependent changes of the viscosity of the HA solution in the absence of the substance tested were monitored by rotational viscometry. However, when the anti- or pro-oxidative effects of the antioxidants/drugs were investigated, their dose-dependency was also examined. Additionally, the anti-oxidative activities of these substances were screened by the well-established ABTS and DPPH decolorization assays. The actions of the disease-modifying anti-rheumatic drugs, namely bucillamine and D-penicillamine, were compared to those of L-cysteine and of SA981, the oxidized metabolite of bucillamine. The results indicated that bucillamine was the most efficient scavenger of hydroxyl- and/or peroxyl-type radicals, even at the lowest drug concentration. In contrast, SA981 demonstrated no scavenging activity against the aforementioned free radicals. D-Penicillamine and L-cysteine showed a dual effect, i.e. a pronounced anti-oxidative effect was, after a given time period, followed by a significant pro-oxidative effect.