The impact of chemical composition on the antioxidant, antifungal and antibacterial activity of commercial Macedonian cold-pressed oils

The chemical composition and quality of four commercial cold-pressed oils (poppy seed oil, almond oil, walnut oil and wheat germ oil) from Macedonia were examined in this work. Regarding the fatty acid composition, the highest level of oleic acid was determined in almond oil (67.57±0.02%) and wheat germ oil (38.14±0.04%), whereas the poppy seed oil and walnut oil were the richest sources of linoleic acid with abundance of 72.28±0.06% and 60.73±0.01% respectively. The significant quantity of α-linoleic acid (ALA) was detected only in walnut oil (11.74±0.01%). The highest level of α-tocopherol (23.77±0.01 mg/100 g of oil) was quantified in almond oil while γ-tocopherol was the most abundant in walnut and wheat germ oils. The results from antioxidant assays showed that Vitamin-E-active compounds were the most important minor compounds responsible for antioxidant activity against DPPH radical, whereas total phenolic compounds were the most active against ABTS radical. Phytosterols, as minor compounds present in the oils, did not contribute significantly to the total antioxidant potential of the oils but, their levels in particular oils, together with fatty acids, can be useful and reliable markers for the purity of the oils and determination of the composition of blends. Regarding antimicrobial activity, the cold-pressed poppy seed oil had antibacterial activity against Listeria monocytogenes whereas, significant antifungal activity against Candida albicans indicated almond, walnut and poppy seed oils

Synthesis and properties of novel Coenzyme-Q derivatives obtained from Coenzyme Q-0

Coenzyme Q-0 is an amphiphilic compound that is involved in the biosynthesis of Coenzyme Q-10 (CoQ10). CoQ10 transfers electrons along the ETC and protons across the inner mitochondrial membrane (IMM), while taking a crucial part in the oxidative phosphorylation processes. Our goal was to study the possible reaction of CoQ-0 with NaOH, and to learn about the properties of the new derivatives. As main instrumental techniques to achieve the prevised goals we explored voltammetry, UV-vis spectrometry, electron paramagnetic resonance (EPR) nuclear magnetic resonance (NMR), and HPLC MS.1,2 We have found that NaOH can induce cleavage of C-O bond of the metoxy (O-CH3) groups located at positions 2 and 3 on the quinone ring in the structure of Coenzyme Q-0. The newly created products have much stronger antioxidant properties than the native Coenzyme Q-0. Upon reduction, the novel derivatives are strong ligands for Ca2+ and other double charged earth-alkaline cations. The new products obtained via alkaline reaction of Coenzyme Q-0 can be seen as compounds having a double role-antioxidants and metal-ligands. Experiments are in progress aimed to show the effect of the new Coenzyme Q-0 derivatives on living cells

Determination of antioxidant capacity with a cyclic voltammetry in production step in a double fermentation process during the preparation of traditional home made fruit vinegar

Cyclic voltammetry provides high potential for investigation of antioxidant compounds, assessment of antioxidant capacity and measurement of electrochemical kinetics. This method is the most commonly used technique for the characterization of antioxidant capacity in food control and other samples. The aim of this work is the evaluation of the antioxidant activity of traditional home made fruit vinegar at each production step in a double fermentation process (alcoholic and acetic); the effect of antioxidant capacity in spontaneous acetic versus inoculated alcoholic fermentation was of special interest. Antioxidant capacity has been evaluated using cyclic voltammetry (CV) measuring the speed of homogeneous redox reaction radical ABTS•+. The stable radical cation ABTS•+ electrochemically is generated on the surface of the glassy carbon electrode by electrochemical oxidation of an aqueous solution of ABTS. ABTS•+ radical cation is a mediator in the catalytic oxidation of the antioxidants present in vinegar. The calibration was made with theoretical simulation of the electrochemical analysis of potential standard substance depending on the kinetics of the electrode reaction and the anti-oxidative capacity of these samples were determined by measuring the intensity of anodic current, and was expressed in terms of the kinetics of the electrode reaction. The results from cyclic voltammetry have shown that the homemade fruit vinegars have high antioxidant properties, which is with correlation with others performed antioxidant assays

Properties of Coenzyme Q derivatives obtained via reaction from Coenzyme Q-0 in alkaline media

Novel set of coenzyme Q-like hydroxilated deriavtives have been synthesized via reaction of COenzyme Q-0 in strong alkaline media. The novel compounds show pronounced antioxidative and metal binding properties toward earth-alkaline cations. These features are completely new for this class of compounds. Many of them can be potentially applied as anticancer agents

Electrochemical behavior of capsaicin and its anti-oxidative properties studied by means of cyclic voltammetry

The major aim of this work is to study the electrochemical behavior and antioxidative features of the plant derived anti-oxidant capsaicin. The antioxidant activity and the redox behavior of this compound were investigated by means of cyclic voltammetry at a glassy carbon electrode. Stock solution of capsaicin was prepared in 96% ethanol, and diluted to different concentrations (10, 100, 150, 200, 250, 300 μmol/L). The anodic oxidation behavior of capsaicin and its catalytic (regenerative) effect on the reduction of Ferric to Ferrous ion were investigated in different pH values (3,5; 5,5; 7 and 10) and different scan rates (5 to 100 mV/s). For a comparison of the anti-oxidative properties of capsaicin, voltammetric experiments with vitamin C (100, 200, 300, 400, 500 μmol/L) were also conducted in the same experimental conditions using cyclic voltammetry (CV). Results showed that in acetic buffer with pH=3,6 capsaicin is generating the highest anodic currents Ia, and shows well defined voltamograms. The electrochemical characterization under different conditions is a promising tool to understand the redox behavior of these alkaloids found in Capsicum sp. and only several studies are reported on the electrochemical properties of capsaicin. Therefore, these results can contribute to development of a new method for a rapid estimation of capsaicin and its anti-oxidative properties by fast and simple technique as cyclic voltammetry

Rapid estimation of antioxidant capacity of some medicinal plants: electrochemical and photometric approaches

Antioxidants are compounds capable to either delay or inhibit the oxidation processes which occur under the influence of reactive oxygen species. Plant phenolic compounds (phenolic acids, flavonoids, quinones, coumarins, lignans, stilbenes, and tannins), nitrogen compounds (alkaloids, amines), carotenoids and vitamins are the most important plant substances presenting antioxidant activity. The total antioxidant capacity (TAC) of some medicinal plants collected in the region of Malesevo Mountain was evaluated using cyclic voltammetry and FRAP method. Infusions samples in the present research were prepared from: Mountain tea (Origanum vulgare L.), Lemon balm (Melissa officinalis L.), St. John’s wort (Hypericum perforatum L.), Wild thyme (Thymus serpyllum L.) and Mint tea (Mentha piperita L.). In this study we present rapid and simple electrochemical voltammetric method for estimation the total antioxidant capacity of medicinal plants in an ethanol/water phase by measuring the rate of homogeneous redox reaction with ABTS•+ radical (2,2’- azinobis(3-ethylbenzothiazoline-6-sulfonic acid)) by means of cyclic voltammetry. ABTS•+ radical was electrochemically in situ generated at the surface of glassy carbon electrode by electrochemical oxidation of ABTS in ethanol electrolyte solution. The method is based on the well-known regenerative catalytic EC´ mechanism, where the ABTS•+ radical serves as a redox mediator for catalytic oxidation of antioxidants present in the plant infusion. The total antioxidant capacity of herb infusions was determined using photometric FRAP method (Ferric reducing antioxidant power) developed by Benzie and Strain. As a conclusion we can say that there were strong correlations between the results obtained with cyclic voltammetry and FRAP method and both methods can be used forevaluation of total antioxidant capacity in medicinal plants infusions

Total antioxidant capacity of certain medicinal plants assesed with FRAP method and cyclic voltammetry

Introduction: Antioxidants are substances that protect cells from damage caused by free radicals. Many of the biological properties, including antimutagenic, anticarcinogenic and antiaging, among others, may originate from antioxidant property of many substances. Plant phenolic compounds (e.g. phenolic acids, flavonoids, quinones, coumarins, lignans, stilbenes, and tannins), nitrogen compounds (alkaloids, amines), carotenoids and vitamins are the most important plant substances presenting antioxidant activity. Aim of the study: The aim of this study was to analyze the total antioxidant levels of medicinal plants collected in the region of Malesevo Mountain, by two different methods and compare the results. Material and methods: Infusions used as samples were prepared from: Origanum vulgare L. (mountain tea), Mellisa officinalis L. (lemon balm), Hypericum perforatum L. (St. John’s wort), Thymus serpyllum L. (wild thyme) and Mentha piperita L. (mint tea). The total antioxidant capacity (TAC) of herb infusions was evaluated using the FRAP method (Ferric reducing/antioxidant power; photometric method) developed by Benzie and Strain. The total antioxidant capacity of these medicinal plants has also been studied in an ethanol/water phase by means of cyclic voltammetry (electrochemical method), by measuring the rate of the homogeneous redox rection with ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)). Results: The results from the FRAP method showed that mountain tea has the highest total antioxidant capacity 27.45. Next in the line are: lemon balm, with TAC value of 19.54, St. John’s wort, 12.64, wild thyme, 9.45 and mint tea, 8.14. The results are expressed as mmol Fe2+ L-1. The results obtained with voltammetric technique confirm the same trend of descending of the TAC values in analyzed infusions. Conclusion: As a conclusion we can say that total antioxidant levels in infusions prepared from medicinal plants originated from our country exhibit strong antioxidant potential, and this fact justify their use as potent natural antioxidant agents. Both photometric and electrochemical methods can be used for assessment of total antioxidant levels in medicinal plants infusions

Isolation, chemical composition, antioxidant and antimicrobial potential of essential oil from Mentha Arvensis L. organically planted from Macedonia

The volatile composition, antioxidant and antimicrobial activity of essential oils from flowers, leaves and whole plant of Mentha Arvensis L. organically planed from the territory of Macedonia were object of this study. The essential oils from dried and powdered plant materials were isolated by hydro-distillation using Clevenger-type apparatus. The composition of three essential oils was identified by GC-MS and quantified by GC-FID. Thirty-seven components were identified and quantified in the three essential oils isolated from the flowers, leaves and whole Mentha plant. The most abundant component in all three oils was menthol with 35.64%, 32.47% and 52.53% respectively. The second most dominant component in the three essential oils was isomenthone with 20.38%, 15.97% and 8.42% respectively. All other components were in quantity less than 8%. The antioxidant activity of oils was determined against ABTS radical and total phenolic contet (TPC). The maximal values from both assays indicated the essential oil from flowers of Mentha arvensis L. as the oil with highest antioxidant activity. The antimicrobial activity of Mentha essential oils was determined against Escherichia coli and Candida albicans. Our results showed the highest antibacterial activity against Escherichia coli ATCC 25922 (29.3 mm) and the highest antifungal activity against Candida albicans ATCC 10231 (39.4 mm) inhibition zone for essential oil from the leaves of Mentha arvensis L

Volatile composition, antioxidant and antimicrobial activity of essential oil from Mentha Arvensis L. organically planted from Macedonia

The volatile composition, antioxidant and antimicrobial activity of essential oils from flowers, leaves and whole plant of Mentha Arvensis L. organically planed from the territory of Macedonia were object of this study. The essential oils from dried and powdered plant materials were isolated by hydro-distillation using Clevenger-type apparatus.51,51 The composition of three essential oils was identified by GC-MS and quantified by GC-FID. 51,51 Fifty-five components were identified and quantified in the three essential oils isolated from the flowers, leaves and whole Mentha plant. The most abundant component in all three oils was menthol with 35.64%, 32.47% and 52.53% respectively. The second most dominant component in the three essential oils was isomenthone with 20.38%, 15.97% and 8.42% respectively. All other components were in quantity less than 8%. The antioxidant activity of essential oil from whole Mentha plant was determined against ABTS radical with value of 1.58 TE mg/L of oil. The antimicrobial activity of essential oil isolated from whole Mentha plant was determined against Escherichia coli and Candida albicans. Our results showed significant antibacterial activity against Escherichia coli ATCC 25922 (24 mm) and significant antifungal activity against Candida albicans ATCC 10231 (32 mm)

Determination of quality and antioxidant activity of traditional homemade fruit vinegars produced with double spontaneous fermentation

The quality and antioxidant potential of six traditional homemade vinegars produced using traditional methods was object of this study. The physicochemical characterization of vinegars produced from apple (Malus domestica), raspberry (Rubus idaeus), blueberry (Vaccinium myrtillus), blackberry (Rubus fruticosus), rose hip (Rosa canina) and persimmon (Diospyros kaki), was performed by measuring the ethanol content, total acidity, pH and dry matter in different vinegar production steps throughout a double spontaneous fermentation process, i.e., without any addition of yeasts or acetic acid bacteria. А spontaneous fermentation of fruits for vinegar production encompasses initially an alcoholic fermentation for 24 days, where fructose, glucose and sucrose, as most abundant sugars, are broken down into carbon dioxide (CO2) and ethanol as main metabolic compounds, as well as other metabolic by‐products and volatile com‐ pounds in trace amounts. The highest total phenolic compounds were measured by vinegar produced from rose hip (20.2 mg of gallic acid/mL) while the lowest concentration was determined for apple vinegar (0.29 mg of gallic acid/mL). The results from total phenolic com‐ pounds were in strong correlation with the antioxidant capacity. In this way, the use of traditional processes for the production of fruit vinegars proved to be very promising in terms of producing differentiated vinegars and, concomitantly, reaching high levels of health‐promoting antioxidant capacities