Anti-cancer effect of in vivo inhibition of nitric oxide synthase in a rat model of breast cancer.

Increased expression of nitric oxide synthase (NOS) is associated with different cancers such as cervical, breast, lung, brain, and spinal cord. Inhibition of NOS activity has been suggested as potential tool to prevent breast cancer. The anti-tumor therapeutic effect of L-nitro arginine methyl ester (L-NAME), NOS inhibitor, using in vivo models is currently under investigation. We hypothesized that L-NAME will show an anti-tumor effect by delaying a progression of breast cancer via a modulation of cell death and proliferation, and angiogenesis. We used a novel model of anti-cancer treatment by the administration of L-NAME (30 mg/kg in a day, intraperitoneal) injected every third day for five weeks to rat model of 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast tumor. Concentrations of nitrite anions, polyamines, malondialdehyde, NH4+ levels, and arginase activity in the blood were decreased in DMBA + L-NAME-treated rats compared with DMBA rats. The mortality rates, tumor number, weight, and volume, as well as the histopathological grade of breast cancer were also significantly reduced. In addition, L-NAME treatment showed a delay in tumor formation, and in body weight compared with rats administrated only with DMBA. In conclusion, our data show that L-NAME is a promising anti-cancer agent to treat breast cancer, which can lead to development of anti-tumor therapeutic tools in future.

Changes in growth kinetic parameters, morphology and mitotic activity of yeasts Candida guilliermondii exposed to the low-intensity waves of 51.8-GHz frequency.

Under the influence of electromagnetic waves of millimeter range with the frequency of 51.8 GHz, changes in the morphology, growth parameters and mitotic activity of yeasts C. guilliermondii NP-4 are revealed. Filamentous and giant cells appeared in a population of exposed yeasts. The sigmoid shape of the growth curve remained but the lag phase duration was increased by 2 h in comparison with non-exposed yeasts; accordingly, the log and stationary phases followed 2 h later. The specific growth rate in the log growth phase and colony-forming ability of exposed yeasts was decreased. It is suggested that yeasts have some response mechanisms to 51.8-GHz frequency electromagnetic waves. The results can be used to understand the response mechanisms of microorganisms to non-ionizing radiation, as well as to develop approaches to protect living organisms from it. The effect of electromagnetic waves of 51.8-GHz frequency to suppress yeasts can be applied in biotechnology and medicine.

Antibacterial activity of royal jelly-mediated green synthesized silver nanoparticles.

The application of green synthesis in nanotechnology is growing day by day. It's a safe and eco-friendly alternative to conventional methods. The current research aimed to study raw royal jelly's potential in the green synthesis of silver nanoparticles and their antibacterial activity. Royal jelly served as a reducing and oxidizing agent in the green synthesis technology of colloidal silver nanoparticles. The UV-Vis maximum absorption at ~ 430 nm and fluorescence emission peaks at ~ 487 nm confirmed the presence of Ag NPs. Morphology and structural properties of Ag NPs and the effect of ultrasound studies revealed: (i) the formation of polydispersed and spherical particles with different sizes; (ii) size reduction and homogeneity increase by ultrasound treatment. Antibacterial activity of different concentrations of green synthesized Ag NPs has been assessed on Gram-negative S. typhimurium and Gram-positive S. aureus, revealing higher sensitivity on Gram-negative bacteria.

Artemisia dracunculus L. essential oil phytochemical components trigger the activity of cellular antioxidant enzymes.

Investigation of dietary biologically active phytochemicals is of interest due to the availability, low cost, and low rate of side effects of these substances. The main objective of this work was to investigate the influence of the essential oil (EO) extracted from the aerial parts of Artemisia dracunculus on the antioxidant capacity of cells as this plant is one of the most available and widely used as spice and in folk medicine. For this, BV-2 microglial wild type (WT) and acyl-CoA oxidase type 1 (ACOX1) deficient cells (Acox1-/- ) were used. Acox1-/- cells were applied as the model of cellular oxidative damage. The main component of EO of A. dracunculus was estragole, which was reaching 84.9% in plants cultivated at high altitude Armenian landscape. IC50 value of EO in 1,1-diphenyl-2-picrylhydrazyl assay was 94.2 µg/ml. Sub-cytotoxic concentration in the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test for both BV-2 WT and Acox1-/- cell lines was 5.10-1  µg/ml. Seventy-two-hours treatment with EO leads to the increased viability (up to 12% in WT and up to 14% -in BV-2 Acox1-/- cells). The 48-hr treatment increased the ACOX1 activity up to 70% in WT cells. Catalase and superoxide dismutase activities of both cell lines increased following the 24-48-hr treatment. These results indicate that A. dracunculus EO can be considered as a potential protective agent useful in preventive medicine.

Characteristics of DNA polymerase I from an extreme thermophile, Thermus scotoductus strain K1.

Several native and engineered heat-stable DNA polymerases from a variety of sources are used as powerful tools in different molecular techniques, including polymerase chain reaction, medical diagnostics, DNA sequencing, biological diversity assessments, and in vitro mutagenesis. The DNA polymerase from the extreme thermophile, Thermus scotoductus strain K1, (TsK1) was expressed in Escherichia coli, purified, and characterized. This enzyme belongs to a distinct phylogenetic clade, different from the commonly used DNA polymerase I enzymes, including those from Thermus aquaticus and Thermus thermophilus. The enzyme demonstrated an optimal temperature and pH value of 72-74°C and 9.0, respectively, and could efficiently amplify 2.5 kb DNA products. TsK1 DNA polymerase did not require additional K+ ions but it did need Mg2+ at 3-5 mM for optimal activity. It was stable for at least 1 h at 80°C, and its half-life at 88 and 95°C was 30 and 15 min, respectively. Analysis of the mutation frequency in the amplified products demonstrated that the base insertion fidelity for this enzyme was significantly better than that of Taq DNA polymerase. These results suggest that TsK1 DNA polymerase could be useful in various molecular applications, including high-temperature DNA polymerization.

The effects of NO on the urea cycle pathway in short-term intermittent hypobaric hypoxia in rats.

Short-term hypoxic states can influence the health and life activities of lowlanders who travel shortly to high altitudes, in transitory situations, such as surgical ischemia-reperfusion (to one or several organs), and in some sporting activities, such as parachuting and extreme skiing, mountain rescue teams, regular commercial flight crews, in which the subject may not even notice the hypoxia. NO is an integral part of the human physiological response to hypoxia. Until recently, the urea cycle (UC) was only considered as an important mechanism for neutralizing ammonia. We are the first to reveal an interrelation in hypoxic states between the activities of NO-synthase and UC enzymes in male rats' liver, kidney and brain. In the presented work, we have shown that during short-term intermittent hypobaric hypoxia (IHH) all enzymes of UC play an important role in the maintenance of NO quantity. The results allow thinking that kidney and brain argininosuccinate synthase (ASS) and argininosuccinate lyase (ASL) and liver ASS and ASL can be different isoenzymes. It is worth mentioning that the results have revealed new sides of l-arginine metabolism in a hypoxic state in male rats.

Origanum vulgare L. extract-mediated synthesis of silver nanoparticles, their characterization and antibacterial activities.

Plant extracts serve as reducing and coating agents and are, therefore, commonly employed for the generation of silver (Ag) nanoparticles (NPs). Plant extract mediated synthesis of Ag NPs is a green, environmentally friendly and cost-effective technique which offers a new and potential alternative to chemically synthesized NPs, decreasing the utilization of hazardous and toxic chemicals and protecting the environment. Origanum vulgare L. extracts were evaluated for total flavonoid and phenol content. The free radical scavenging activity was determined employing 2,2-diphenyl-1-picrylhydrazyl assay. Ag NPs were produced exploiting ethanolic extracts of O. vulgare L. leaves. The generation of Ag NPs was carried out both in light and dark conditions. The biosynthesized Ag NPs were characterized employing microscopic and spectroscopic techniques. Antibacterial activities of Ag NPs were determined following appropriate methods. The results revealed that energy of photons was required to reduce Ag+ to Ag0. According to scanning electron microscopy reports, biologically formed Ag NPs ranged in size from 1 to 50 nmand were presented instability causing aggregation. They indicated that O. vulgare L. extracts were rich in flavonoids and phenols and exhibited strong antioxidant activity. Ag NPs exhibited good antibacterial activity immediately after production. Gram-positive strains showed higher sensitivity to Ag NPs compared to Gram-negative stains. Ag NPs can serve as an effective antibacterial agent against antibiotic-resistant strains. The kanamycin-resistant strain was more sensitive to Ag NPs than the ampicillin-resistant strain. Thus, Origanum extract-mediated synthesized Ag NPs can be recommended as alternative effective antibacterial agents, but their activity depended on bacterial species and strains.

Growth properties and hydrogen yield in green microalga Parachlorella kessleri: Effects of low-intensity electromagnetic irradiation at the frequencies of 51.8 GHz and 53.0 GHz.

The current research reports the effects of low-intensity extremely high frequency electromagnetic irradiation (EMI) of 51.8 GHz and 53.0 GHz on green microalga Parachlorella kessleri RA-002 isolated in Armenia. EMI demonstrated different effects on the growth properties of microalgae under various conditions. Under aerobic conditions a positive effect of EMI on the growth rate of P. kessleri and the content of photosynthetic pigments were observed. The data obtained indicates a significant role of O2, since the enhancing effect of EMI was determined only under aerobic conditions. Meanwhile under anaerobic conditions EMI with both frequencies caused inhibition of algal growth and a decrease in the amount of photosynthetic pigments. EMI also inhibited the yield of H2 production in P. kessleri, which was partially restored after 5-day cultivation due to the existence of protective mechanisms in this alga. The results might indicate membrane-bound mechanisms of EMI action on algae, which can be associated with the effects on photosynthetic pigments and membrane-associated enzymes responsible for H2 production. The results are useful for the development of algae biotechnology and the possibility of using EMI as a factor which regulates the production of biomass and biohydrogen by green microalgae.

Comparable antibacterial effects and action mechanisms of silver and iron oxide nanoparticles on Escherichia coli and Salmonella typhimurium.

The current research reports the antibacterial effects of silver (Ag) and citric acid coated iron oxide (Fe3O4) NPs on Escherichia coli wild type and kanamycin-resistant strains, as well as on Salmonella typhimurium MDC1759. NPs demonstrated significant antibacterial activity against these bacteria, but antibacterial effect of Ag NPs is more pronounced at low concentrations. Ag NPs inhibited 60-90% of S. typhimurium and drug-resistant E. coli. The latter is more sensitive to Fe3O4 NPs than wild type strain: the number of bacterial colonies is decreased ~ 4-fold. To explain possible mechanisms of NPs action, H+-fluxes through the bacterial membrane and the H+-translocating FOF1-ATPase activity of bacterial membrane vesicles were studied. N,N'-Dicyclohexylcarbodiimide (DCCD)-sensitive ATPase activity was increased up to ~ 1.5-fold in the presence of Fe3O4 NPs. ATPase activity was not detected by Ag NPs even in the presence of DCCD, which confirms the bactericidal effect of these NPs. The H+-fluxes were changed by NPs and by addition of DCCD. H2 yield was inhibited by NPs; the inhibition by Ag NPs is stronger than by Fe3O4 NPs. NPs showed antibacterial effect in bacteria studied in concentration-dependent manner by changing in membrane permeability and membrane-bound enzyme activity. The FOF1-ATPase is suggested might be a target for NPs.

Roasted coffee wastes as a substrate for Escherichia coli to grow and produce hydrogen.

After brewing roasted coffee, spent coffee grounds (SCGs) are generated being one of the daily wastes emerging in dominant countries with high rate and big quantity. Escherichia coli BW25113 wild-type strain, mutants with defects in hydrogen (H2)-producing/oxidizing four hydrogenases (Hyd) (ΔhyaB ΔhybC, ΔhycE, ΔhyfG) and septuple mutant (ΔhyaB ΔhybC ΔhycA ΔfdoG ΔldhA ΔfrdC ΔaceE) were investigated by measuring change of external pH, bacterial growth and H2 production during the utilization of SCG hydrolysate. In wild type, H2 was produced with rate of 1.28 mL H2 (g sugar)-1 h-1 yielding 30.7 mL H2 (g sugar)-1 or 2.75 L (kg SCG)-1 during 24 h. In septuple mutant, H2 production yield was 72 mL H2 (g sugar)-1 with rate of 3 mL H2 (g sugar)-1 h-1. H2 generation was absent in hycE single mutant showing the main role of Hyd-3 in H2 production. During utilization of SCG wild type, specific growth rate was 0.72 ± 0.01 h-1 with biomass yield of 0.3 g L-1. Genetic modifications and control of external parameters during growth could lead to prolonged and enhanced microbiological H2 production by organic wastes, which will aid more efficiently global sustainable energy needs resulting in diversification of mobile and fixed energy sources.

Influence of C4 -Dcu transporters on hydrogenase and formate dehydrogenase activities in stationary phase-grown fermenting Escherichia coli.

During mixed-acid fermentation, Escherichia coli transports succinate mainly via transporters of the Dcu family. Here, we analyze the influence of Dcu transporters on hydrogenase (Hyd) and fermentative formate dehydrogenase (FDH-H) activities and how this is affected by external pH and carbon source. Using selected dcu mutations, it was shown that Dcu carriers mainly affect Hyd and FDH-H activities during glycerol but not glucose fermentation at acidic pH. During glycerol fermentation at pH 5.5, inactivation of either one or all Dcu carriers increased total Hyd activity by 60% compared with wild type. Under the same growth conditions, a dcuACBD mutant had a twofold higher FDH-H activity. When glucose was fermented in dcuD single mutant at pH 5.5, the FDH-H activity was also increased twofold compared with wild type. Interestingly, in dcuD or dcuACBD mutants at pH 7.5, Hyd activity was lowered by 20%. Taken together, it can be concluded that during glucose fermentation at pH 7.5, lack of DcuD affects Hyd enzyme activity, but at pH 5.5, it has a stronger effect on FDH-H activity. During glycerol fermentation, lack of Dcu carriers increased Hyd and FDH-H activities as revealed at pH 5.5. The results suggest that impairing Dcu transport function increases intracellular formate levels and thus affects H2 cycling and proton-motive force generation.

Silver ion bioreduction in nanoparticles using Artemisia annua L. extract: characterization and application as antibacterial agents.

The biological synthesis of metal nanoparticles using plant extracts with defined size and morphology is a simple, nontoxic and environmentally friendly method. The present study focused on the synthesis of silver nanoparticles (Ag NPs) by Artemisia annua L. extract as reducing and stabilising agent. The Ag NPs function, as antibacterial agents, is with that they are further used in human therapy. The effects of pH and temperature on the synthesis of NPs were characterized by UV-absorption spectroscopy and shown by surface plasmon resonance (SPR) band at 410 nm. NPs' size and morphology were measured by transmission electron microscopy (TEM) and dynamic light scattering (DLS). TEM images showed that Ag NPs were in a nano-sized range (20-90 nm) and had spherical shape. Our findings demonstrated that lower concentration (100 µg mL-1) of the biogenic Ag NPs exhibited antibacterial activity against Gram-negative Escherichia coli BW 25113 and Gram-positive Enterococcus hirae ATCC 9790.

Phytochemical Screening and Detection of Antibacterial Components from Crude Extracts of Some Armenian Herbs Using TLC-Bioautographic Technique.

The aim of the research was to explore qualitative and quantitative phytochemical constituents of different extracts from Agrimonia eupatoria L., Hypericum alpestre subsp. polygonifolium (Rupr.) Avet. & Takht., Rumex obtusifolius Willd and Sanguisorba officinalis L. and analyze their bioactive constituents using TLC-bioautography technique. In TLC analysis different solvent systems as mobile phases were used in order to make assumptions about the nature of active antibacterial compounds. The highest total phenolic, flavonoid and tannin content was detected in methanol extract of A. eupatoria (358.9 µg Gallic acid equivalent per mg dry weight), acetone extract of H. alpestre (216.75 µg Quercetin equivalent per mg dry weight) and acetone extract of R. obtusifolius (76.24 µg Catechin equivalent per mg dry weight), respectively. TLC-bioautography analysis using mobile phases with different polarity allowed to separate different bands from tested plants methanol and acetone extracts possessing antibacterial activity against Staphylococcus aureus MDC 5233. Thus, it was revealed, that polar compounds could have considerable contribution to the antibacterial activity of acetone and methanol extracts of H. alpestre and R. obtusifolius. It was hypothesized, that complex compounds can be responsible for the antibacterial action of extracts of A. eupatoria and S. officinalis. Based on obtained data, A. eupatoria, H. alpestre, R. obtusifolius and S. officinalis plants can be recommended as sources of new antibacterial agents.

Antifungal Activity of Lactic Acid Bacteria Isolates and Their Associations: The Effects of Ca and Mg Divalent Cations.

The study of effects of Ca2+ and Mg2+ on antifungal activity of lactic acid bacteria (LAB) isolates and their associations revealed inducing and inhibiting effects on antifungal activity. The addition of Ca2+ essentially inhibited the antifungal effect of L. rhamnosus MDC9661 but stimulated the activity of RIN-2003-Ls, MDC9632 and MDC9633 strains, as well as their associations. Mg2+ partly increased the inhibitory activity of LAB isolates, while the addition of ions combination did not cause changes of their antifungal activity. The supplementation of Ca2+ stimulated the antifungal effect of most associations against Penicillium sp., Trichoderma viride, Geotrichum candidum, and Aspergillus flavus compared with the native conditions. The addition of Mg2+ induced the antifungal activity of RIN-2003-Ls, MDC9632, MDC9633, and INR-2010-Tsov-G-St combinations. The antifungal effects of most associations were increased in the presence of ions mixture. The natural LAB associations including VKPM B-3386, MDC9632, and MDC9633 could not suppress the growth of any tested mold; however, the supplementation of ions combination revealed their antifungal effect against all kinds of molds. The finding of substantial stimulation of the most LAB associations antifungal effect by metal ions can be basis for creation of new effective antifungal preparations by the supplementation of ions combined mixture.

Formate and potassium ions affect Escherichia coli proton ATPase activity at low pH during mixed carbon fermentation.

Escherichia coli is able to ferment not only single but also mixtures of carbon sources. The formate metabolism and effect of formate on various enzymes have been extensively studied during sole glucose but not mixed carbon sources utilization. It was revealed that in membrane vesicles (MV) of wild type cells grown at pH 7.5 during fermentation of the mixture of glucose (2 g/L), glycerol (10 g/L), and formate (0.68 g/L), in the assays, the addition of formate (10 mM) increased the N,N'-dicyclohexylcarbodiimide (DCCD)-inhibited ATPase activity on ~30% but no effect of potassium ions (100 mM) had been detected. In selC (coding formate dehydrogenases) and fdhF (coding formate dehydrogenase H) single mutants, formate increased DCCD-inhibited ATPase activity on ~40 and ~70%, respectively. At pH 5.5, in wild type cells MV, formate decreased the DCCD-inhibited ATPase activity ~60% but unexpectedly in the presence of potassium ions, it was stimulated ~5.8 fold. The accessible SH or thiol groups number in fdhF mutant was less by 28% compared with wild type. In formate assays, the available SH groups number was less ~10% in wild type but not in fdhF mutant. Taken together, the data suggest that proton ATPase activity depends on externally added formate in the presence of potassium ions at low pH. This effect might be regulated by the changes in the number of redox-active thiol groups via formate dehydrogenase H, which might be directly related to proton ATPase FO subunit.

Growth of the facultative chemolithoautotroph Ralstonia eutropha on organic waste materials: growth characteristics, redox regulation and hydrogenase activity.

BACKGROUND: The chemolithoautotrophic ß-proteobacterium Ralstonia eutropha H16 (Cupriavidus necator) is one of the most studied model organisms for growth on H2 and CO2. R. eutropha H16 is also a biologically significant bacterium capable of synthesizing O2-tolerant [NiFe]-hydrogenases (Hyds), which can be used as anode biocatalysts in enzyme fuel cells. For heterotrophic growth of R. eutropha, various sources of organic carbon and energy can be used. RESULTS: Growth, bioenergetic properties, and oxidation-reduction potential (ORP) kinetics were investigated during cultivation of R. eutropha H16 on fructose and glycerol or lignocellulose-containing brewery spent grain hydrolysate (BSGH). BSGH was used as carbon and energy source by R. eutropha H16, and the activities of the membrane-bound hydrogenase (MBH) and cytoplasmic, soluble hydrogenase (SH) were measured in different growth phases. Growth of R. eutropha H16 on optimized BSGH medium yielded ~ 0.7 g cell dry weight L-1 with 3.50 ± 0.02 (SH) and 2.3 ± 0.03 (MBH) U (mg protein)-1 activities. Upon growth on fructose and glycerol, a pH drop from 7.0 to 6.7 and a concomitant decrease of ORP was observed. During growth on BSGH, in contrast, the pH and ORP stayed constant. The growth rate was slightly stimulated through addition of 1 mM K3[Fe(CN)6], whereas temporarily reduced growth was observed upon addition of 3 mM dithiothreitol. The overall and N,N'-dicyclohexylcarbodiimide-sensitive ATPase activities of membrane vesicles were ~ 4- and ~ 2.5-fold lower, respectively, upon growth on fructose and glycerol (FGN) compared with only fructose utilization (FN). Compared to FN, ORP was lower upon bacterial growth on FGN, GFN, and BSGH. CONCLUSIONS: Our results suggest that reductive conditions and low ATPase activity might be signals for energy depletion, which, in turn, leads to increased hydrogenase biosynthesis to overcome this unfavorable situation. Addition of fructose or microelements have no, or a negative, influence on hydrogenase activity. Organic wastes (glycerol, BSGH) are promising carbon and energy sources for the formation of biomass harboring significant amounts of the biotechnologically relevant hydrogenases MBH and SH. The results are valuable for using microbial cells as producers of hydrogenase enzymes as catalysts in enzymatic fuel cells.

Antibacterial activities of transient metals nanoparticles and membranous mechanisms of action.

Various transient metal and metal oxide nanoparticles (NPs) have shown pronounced biological activity, including antibacterial action against different Gram-negative and Gram-positive bacteria including pathogens and drug-resistant ones. Thus, NPs can be applied in nanotechnology for controlling bacterial growth as well as in biomedicine for the treatment of various diseases. However, the mechanisms of these effects are not clear yet. This review is focused on the antibacterial effects of transient metal NPs, especially iron oxide (Fe3O4) and Ag NPs on Escherichia coli wild type and antibiotic-resistant strains. Ag NPs show more pronounced bactericidal effect than Fe3O4 NPs. Moreover, Ag NPs display more expressed antibacterial effect at low concentrations. Interestingly, kanamycin-resistant strain is more susceptible to Fe3O4 NPs than wild type strain. In order to explain the possible mechanisms of NP effects, in addition to the production of reactive oxygen species causing damage in cells, particularly, their membranes, the changes in the membrane-associated H+-translocating FOF1-ATPase activity, H+-fluxes through the bacterial membrane, redox potential and hydrogen yield by membrane-associated enzymes-hydrogenases, are discussed. We observed from the results that FOF1-ATPase could be a main target for NPs. A scheme of possible action mechanism is proposed.

The potential therapeutic effect of NG-hydroxy-nor-L-arginine in 7,12-dimethylbenz(a)anthracene-induced breast cancer in rats.

Advances in our understanding of the metabolism and molecular functions of arginine and their alterations in cancer have led to resurgence in the interest of targeting arginine catabolism as an anticancer strategy. Therefore, arginase inhibitors have been proposed as a way to treat cancer. In this study, the anti-tumor potential of the arginase inhibition by NG-hydroxy-nor-L-arginine (nor-NOHA) (3 mg/kg/day, i.p.), administered for 5 weeks (parallel tumors development, every 3th day) against 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis in rats has been investigated. Treatment by nor-NOHA has obvious inhibition effects on development of carcinogenesis in rats was shown. That was seen in downregulation of rats' tumors size and number, mortality rate, in stopped alteration of tissue histopathology, in decrease of polyamines, NO and MDA (malondialdeide) concentrations (in blood). Results have shown arginase and NO-synthase can cooperate to restrain quantities of polyamines and NO for cancer progression. The results obtained can serve as a base to use this model for determination of productive, noncytotoxic antitumor and immune modulating concentration of anticancer agents. Perspectives of targeting arginase and NOS in cancer management can ground application in clinical medicine.

The Caucasian flora: a still-to-be-discovered rich source of antioxidants.

Cellular redox homeostasis is a state of balance between the formation of Usually Reactive Oxygen and / or Nitrogen Species (ROS/RNS), endogenous antioxidant defence systems, and exogenous dietary antioxidants. The disturbance of redox homeostasis, by the overproduction of endogenous ROS/RNS, may increase the risk of development of so-called civilisation diseases. The solution seems to be either the increased production of endogenous or consumption of exogenous antioxidants. Plant-borne antioxidants act via different chemical and molecular mechanisms, such as decreasing the level of oxidative damage in cells directly by reacting with ROS/RNS or indirectly - by inhibition of the activity and expression of free radical generating enzymes or by enhancing the activity or expression of intracellular antioxidant defence enzymes. Despite the fact that the Caucasian flora is rich of health promoting edible/medicinal plants, recent studies concerning the biological activity of these plants are very scarce. This review is summarising the state-of-art on the health-promoting potential of plants representing the Caucasian flora, whose antioxidant capacity have been investigated in various in vitro models.