Moringa (Moringa oleifera Lam.) is a tree that grows in tropical and subtropical regions. In this study, the plants were grown in a temperate climate zone from seeds collected at the Island of St. Lucia. Cultivation was carried out in the field and in a greenhouse in Prešov, East Slovakia. Leaf samples were taken from young plants and dried naturally. In the ethanol and hot water extracts of the leaves, the dry matter, total phenolic substances, and antioxidant activity were determined using three methods: superoxide anion radical scavenging activity, hydroxyl radical scavenging activity, and ferric reducing ability of plasma (FRAP) assay. The highest amount of total phenols was detected in the ethanolic extract of the leaves from the field 911.14 mg GAE L−1, resp. 69.70 mg GAE g−1 DM. The lowest amount was noticed in the leaves from the greenhouse 408.88 mg GAE L−1, resp. 13.07 mg GAE g−1 DM. The amount was significantly lower in the aqueous extracts. A high antioxidant activity of the leaves from the field was detected in all ethanolic and hot water extracts. Both types of leaf extracts from the greenhouse showed statistically significant lower antioxidant activity. The obtained results indicate that outdoor cultivation in a temperate climate zone was stressful for the plants, leading to an increased formation of phenolic substances, and consequently to higher antioxidant activity.

Heracleum mantegazzianum is an invasive species in middle Europe. The mode of action of its invasiveness is still not known. Our study focuses on observation of potential allelopathic influence by the production and release of phytochemicals into its environment. Plant material was collected four times within one season (April, May, June, July 2019) at locality Lekárovce (eastern Slovakia) for comparison of differences in composition and potential allelopathy. Water extracts from collected samples were used for different biological assays. The total phenols and flavonoids were determined spectrophotometrically. The profile and content of phenolic components, including coumarins, were determined by two techniques of liquid chromatography along with in vitro evaluation of the free radical scavenging activity of extracts (DPPH, Hydroxyl, Superoxide, and FRAP). The changes in composition in extracts in different seasonal periods were evident as well as potential phytotoxic activity in some concentrations on specific model plants. The slight antioxidant activity was noted. The invasiveness of the current species could be supported by the excretion of its phytochemicals into its surroundings and by different modes of action influencing living organisms in its environment.

Moringa (Moringa oleifera Lam.) is a tree that grows in tropical and subtropical regions. In this study, the plants were grown in a temperate climate zone from seeds collected at the Island of St. Lucia. Cultivation was carried out in the field and in a greenhouse in Prešov, East Slovakia. Leaf samples were taken from young plants and dried naturally. In the ethanol and hot water extracts of the leaves, the dry matter, total phenolic substances and antioxidant activity were determined using three methods: superoxide anion radical scavenging activity, hydroxyl radical scavenging activity and ferric reducing ability of plasma (FRAP) assay. The highest amount of total phenols was detected in the ethanolic extract of the leaves from the field, the lowest amount was noticed in the leaves from the greenhouse. The amount was significantly lower in the aqueous extracts. A high antioxidant activity of the leaves from the field was detected in all ethanolic and hot wa-ter extracts. Both types of leaf extracts from the greenhouse showed statistically significant lower antioxidant activity. The obtained results indicate that outdoor cultivation in a temperate cli-mate zone was stressful for the plants, leading to an increased formation of phenolic substances, and consequently to higher antioxidant activity.

In the present study, the seasonal variability of the in vitro ferric reducing ability of plasma (FRAP), total phenols, and terpene hydrocarbon content in 70% ethanol extracts were evaluated. The samples of crushed (CBs) and non-crushed ripe juniper berries (NCBs) collected at five localities in North-East Slovakia during the years 2012–2014 were compared. The method of preparation of the extract influenced the amount of dry matter (DM) in the extracts. In the CB extracts were statistically higher contents of DM (from 13.91 ± 0.11 g·L−1 to 23.84 ± 0.14 g·L−1) compared to NCB extracts (from 1.39 ± 0.01 g·L−1 to 16.55 ± 0.09 g·L−1). The differences in antioxidant activity between the investigated localities were statistically significant for both types of extract. For example, in 2013 in the locality of Zbojné, the FRAP in NCBs was 76.62 µmol·L−1·g−1 DM and in CBs was 138.27 µmol·L−1·g−1 DM, while in the Miľpoš locality, in NCBs there was 232.66 µmol·L−1·g−1 DM and in CBs there was 1178.98 µmol·L−1·g−1 DM. The differences in the antioxidant activity between the studied years in the case of NCB extracts were not statistically significant. In the case of CB extracts, significant differences between the evaluated years were found. Statistics by ANOVA confirmed that CB extracts prepared from berries in the year 2013 showed significantly higher activity compared to CB extracts from berries from the years 2012 and 2014. Based on the Pearson we found a negative correlation coefficient between the FRAP assay and the content of total polyphenols in NCB extracts (−0.531 in 2012; −0.349 in 2013; and −0.224 in 2014). In contrast, CB extracts showed a positive correlation coefficient (0.843 in 2012; 0.742 in 2013; 0.617 in 2014).

Amaranth species represent a diverse group of plants. Many of them are a rich source of secondary metabolites with many positive biological effects. Total phenolic, total flavonoid and rutin content, antioxidant activity against superoxide and hydroxyl radicals, FRAP (Ferric-reducing ability of plasma) assay and DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical scavenging assay were determined in ethanol extracts of dried leaves of the new Slovak amaranth varieties ‘Pribina’ and ‘Zobor’. The amount of total phenolic substances (‘Pribina’ GAE 38.3 mg.g−1 DM and ‘Zobor’ GAE 26.1 mg.g−1 DM), content of total flavonoids (‘Pribina’ QE 26.5 mg.g−1 DM and ‘Zobor’ QE 20.3 mg.g−1 DM) and rutin (‘Pribina’ 50.8 mg.g−1 DM and ‘Zobor’ 15.2 mg.g−1 DM) were higher in the variety ‘Pribina’, compared to the variety ‘Zobor’. A statistically higher antioxidant activity against superoxide radical (1.63%·mg−1g−1 DM), hydroxyl radical (3.20%.mg−1g−1 DM), FRAP assay (292.80 µmol.L−1·mg−1.g−1 DM) and DPPH (54.2 ± 1.78 µg.mL−1 DM) were detected in the ‘Pribina’ variety. Antiradical and antioxidant activities of both extracts showed high positive correlations in relation to the content of total phenolic substances, total flavonoids and rutin. Amaranth is an undemanding crop on specific environmental conditions and is resistant to abiotic and biotic stress.

In this study we evaluated ethanol and hot water extracts from young leaves of moringa plants growing on the island of St. Lucia. The dry matter, total phenol content, antioxidant activity against superoxide radicals, hydroxyl radicals and FRAP were evaluated. Content of dry matter (DM), total phenols (mg GAE L-1) and total phenols calculated to DM (mg GAE g(-1) DM) were statistically significantly higher in the ethanol extract in comparison to the hot water extract. Antioxidant activity against superoxide and hydroxyl radical were comparable for both extracts, but the antioxidant activity calculated on the dry matter was significantly higher for the hot water extract. Ferric reducing ability of plasma (FRAP) assay was in both cases (determined in mu mol L-1 and recalculated in mu mol L-1 g(-1) DM) statistically significantly higher for the hot water extract in comparison to the ethanol extract. Finally, secondary metabolites extracted by hot water (probably phenolic acids) have (relatively) higher antioxidant activity than polyphenols in the 70% ethanol extract.

In the present study, in vitro hydroxyl radical scavenging activities, total phenols and terpene contents in 70% ethanol extracts were evaluated. Samples of crushed (CB) and non-crushed ripe juniper berries (NCB) collected at five localities in North-East Slovakia during the years 2012–2014 were compared. Standard or modified methods for determining phytochemical and antioxidant activity were used together with a novel method for the evaluation of the results after the correction of the measured values per gram of dry matter (DM). Statistically significantly higher DM contents (average values for three years) were found in the CB extracts (ranging from 18.86 to 21.91 mg/mL) in comparison to those for NCB (ranging from 2.59 to 9.90 mg/mL). Depending on the localities and years, the hydroxyl radical scavenging activity ranged from 15.52 to 32.85% for NCB and from 65.59 to 88.12% for CB, respectively. The contents of total phenols ranged from 43.75 to 246.75 mg gallic acid equivalents (GAE)/L (NCB) and from 151.84 to 278.19 mg GAE/L (CB), respectively. However, the higher content of total phenols per gram of DM was found in the NCB extracts (8.49–42.23 mg GAE/g DM) and then in CB (6.87–18.77 GAE/g DM). The results obtained in this study showed a higher efficiency for extraction from juniper berries in 70% ethanol if the pericarp was disrupted in comparison to that achieved with the maceration of intact berries.

Moringa oleifera Lam. has been considered as a multipurpose tree. The studies on it focus on its variable nutritional benefits. It is growing in many regions, but information about nutritional properties of those growing in the Caribbean is missing. The present study focused on biochemical analysis of main nutritional and antioxidant properties in plant material-dried leaves and seeds-of Moringa oleifera. The composition of lipids, proteins, and vitamin E was evaluated in powdered dried leaves and seeds. Fatty acids were evaluated in oil extracted from the moringa seeds. Potential antioxidant properties of the moringa were evaluated in extract from crushed and powdered leaves, as well as from the powdered seeds. The total amounts of lipids, proteins, and vitamin E were higher in powdered seeds (31.85%, 35.13%, and 220.61 mg/kg) than in powdered leaves (12.48%, 20.54%, and 178.10 mg/kg). The main compound of fatty acids presented oleic acid (76.78%) in seeds' oil and oleic (25.01%), palmitic (24.84%), and linolenic (24.71%) acids in leaves. Neohesperidin (126.8 mg/kg), followed by chlorogenic acid (99.96 mg/kg) and quercetin (43.44 and 21.44 mg/kg) were main phenolic compounds identified. Total phenols in powdered leaves' extract (635.6 mg GAE/L) was higher than in powdered seeds' extract (229.5 mg GAE/L). The activity against superoxide radical and hydroxyl radical was 92.4% and 73.1% by leaves' powder extract and 83.6% and 60.7% by crushed-leaf extract; seed-powder extract exhibited a pro-oxidation activity (-68.4%) against superoxide radical and the lowest antioxidant effect against the hydroxyl radical (55.0%).

The present study evaluated the influence of some environmental factors on the quantity and composition of essential oil (EO) in ripe berry cones of Juniperus communis L. The berry cones were collected from juniper shrubs growing wild at five localities of north-east Slovakia during the years 2012-2014. The EO yield ranged from 0.4 to 1.9

Carbon monoxide (CO) reversibly binds to hemoglobin forming carboxyhemoglobin (COHb). CO competes with O2 for binding place in hemoglobin leading to tissue hypoxia. Already 30 % saturation of COHb can be deadly. Medical oxygen at atmospheric pressure as a therapy is not enough effective. Therefore hyperbaric oxygen O2 inhalation is recommended. There was a question if partially ionized oxygen can be a better treatment at atmospheric pressure. In present study we evaluated effect of partially ionized oxygen produced by device Oxygen Ion 3000 by Dr. Engler in elimination of COHb in vitro experiments and in smokers. Diluted blood with different content of CO was purged with 5 l/min of either medicinal oxygen O2, negatively ionized O2 or positively ionized O2 for 15 min, then the COHb content was checked. In vivo study, 15 smokers inhaled of either medicinal oxygen O2 or negatively ionized O2, than we compared CO levels in expired air before and after inhalation. In both studies we found the highest elimination of CO when we used negatively ionized O2. These results confirmed the benefit of short inhalation of negatively ionized O2, in frame of Ionized Oxygen Therapy (IO2Th/Engler) which could be used in smokers for decreasing of COHb in blood.

Hydroxybenzoic acids are effective radical scavengers. Gallic, 2,4-di-hydroxybenzoic, 3,5-dihydroxybenzoic, and caffeic acids gave the best results.

UV-VIS spectroscopic investigations of interaction of bovine and human serum albumin with selected chalcones (1) and their cyclic chalcone analogues: (E)-2-(4’-X-benzylidene-1-tetralones (3), benzosuberones (4) with dimethylamino and methoxy substituents and (E)-2-(2’,4’-dimethox- ybenzylidene)-1-indanone (2) were performed in polar respiration medium. Absorption maxima of the tested compounds were investigated in the presence of bovine and human serum albumin at the 0, 10, 30 and 60 minute timepoints of the interaction. The absorbance of all studied compounds in the presence of proteins decreased after one hour of the reaction. Molecule 4a showed the strongest and fastest kinet initial interaction with both albumins.

Chalcones and their synthetic cyclic analogues have been shown to possess a full scale of biological activities in a variety of experimental systems. They were assessed to be mostly effective in defense against free radicals in the organism, but several compounds exhibited cytotoxic pro-oxidant activities. The respiratory response and antioxidant status in mitochondria were investigated upon addition of 4'-dimethylaminochalcone (1a) and its cyclic analogues, (E)-2-(4'-((CH3)2 N)-benzylidene)-1-indanone (1b), -1-tetralone (1c), and -1-benzosuberone (1d). Selected structures were able to change the respiratory response of mitochondria and showed an ability to modify mitochondrial metabolic and redox efficiency, though they did not indicate redox reactivity towards glutathione in adduct-free incubations. The results of the study indicate that -chalcone and -tetralone derivatives cause suppression of reactive oxygen species affecting mitochondrial respiration by mild uncoupling. In addition, (E)-2-(4'-((CH3)2 N)-indanone (1b), and to a greater extent, -benzosuberone (1d), showed pro-oxidant effects, which partially explain their cytotoxicity.

The antioxidant properties of pyrocatechol, resorcinol, hydroquinone and pyrogallol against superoxide radicals were determined in a stepwise kinetic manner. The best and most stable antioxidant properties were recorded for pyrocatechol, followed by hydroquinone. Antioxidant and pro-oxidant properties were found for resorcinol and pyrogallol, especially at higher concentrations (greater than 50 μg/cm3) and longer irradiation times (15 and 20 min). The positions of the hydroxy groups were crucial for antioxidant and pro-oxidant properties. Ortho and para were more effective in taking electrons from superoxide radicals than meta and vicinal phenols. However, phenols generally lose the electrons slowly and so are changed to pro-oxidants. This phenomenon could explain the leaking of electrons in the respiratory chain, formation of oxygen radicals in the mitochondria and the lower than theoretically possible production of adenosine triphosphate.

Whey protein isolate (WPI) was hydrolysed for 0.5–8 h using Alcalase, and the 5-h hydrolysate, identified to possess the strongest reducing ability, was subjected to column fractionation and antioxidant activity assays. Sephadex G-10 gel filtration chromatography of the 5-h hydrolysate yielded four fractions (I, II, III and IV) that were composed of peptides of >40k, 2.8–40k, 0.1–2.8k, and <0.1k, respectively. Fraction III exhibited the strongest free radical scavenging effects, which was evidenced by the electron spin resonance (ESR) of 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH) and of trapped hydroxyl (OH) and superoxide (O2-) radicals. The results indicated that antioxidant activity of whey protein hydrolysates depended on peptide molecular weight, with peptides of 0.1–2.8k possessing the strongest radical scavenging activity.

Introduction: Reactive species play a dual deleterious and beneficial antioxidant role. Overproduction of reactive species can cause damage of cell structures, including lipids and membranes, proteins and DNA. Hydroxybenzoic acid belongs to a group of phenolic compounds. Hydroxybenzoic acids itself and its derivatives showed antioxidant properties against different type of free radicals and can prevent or decrease overproduction of reactive species. Methods: In this study we tested antioxidant properties of 14 different benzoic acid derivatives against superoxide radical. The antioxidant properties of tested compound were determined by Beauchamp and Fridovich methods (1971). We studied kinetics and relationship between structure and antioxidant activity of the compounds. Results: The monohydroxybenzoic derivatives showed the best antioxidant properties. The results showed different antioxidant properties of hydroxybenzoic acid derivatives in 5, 10, 15 and 20 minutes of the reaction. Very important is the position of -OH group to carboxylate group. The compounds with hydroxyl group in ortho and para position to the carboxylate group showed the best antioxidant properties. Derivatives with blocked -OH group showed very low antioxidant properties in comparison with derivatives with blocked -COOH group. Conclusion: The structure and position of hydroxyl group is very important for antioxidant acitivy.

UV–vis and fluorescence spectroscopic investigations of chalcones and cyclic chalcone analogues, (E)-2-(4-X-benzylidene)-1-indanones, -tetralones, and -benzosuberones with the same substitution patterns were performed in solvents with different polarity. Comparison of position of the absorption maxima of three substituted series (unsubstituted, methoxy, and dimethylamino) showed the same decreasing order indanones ≥ chalcones ≥ tetralones ≥ benzosuberones in each solvent indicating the strongest conjugation of the rigid, planar indanones. All the compounds showed positive solvatochromism, which is consistent with transitions having significant charge transfer character. The order of the observed solvent-induced bathochromic shifts of the absorption maxima was found to correlate with the donor number of the solvents. The solvent-induced shift of the emission maxima of each compound is larger than that of the absorption maxima. Recording the UV–vis spectra of the compounds in the presence of bovine and human serum albumin resulted in a slight hypsochromic shift of (E)-2-(4-methoxybenzylidene)- and (E)-2-[(4-dimethylamino)benzylidene]benzosuberone indicating changing the polar environment to a less polar one. Such an observation is in accord with an interaction of the molecules with the hydrophobic binding site(s) of the two proteins.

Humic acids are known for their overall positive health and productivity effects in animal feeding trials and, controversially, as an aetiological factor of cancer. We tried to assess the in vitro effect of humic acids from a selected source in Slovakia when used at recommended prophylactic dosage. We investigated antioxidant properties, enzymatic and non-enzymatic antioxidant defence system in liver mitochondria and cultured cancer cell lines in vitro. We observed a significant decrease in superoxide dismutase activity after humic acids treatment irrespective of dissolving in dimethyl sulphoxide or direct addition to mitochondria suspension in a respiration medium. Activities of other antioxidant enzymes measured, such as glutathione peroxidase and glutathione reductase, showed no significant differences from the control as well as the reduced glutathione content. Percentage of inhibition by humic acids of superoxide radical indicated lower efficacy compared with that of hydroxyl radical. Survival of six different cancer cells lines indicated that only the acute T lymphoblastic leukaemia cell line was sensitive to the tested humic acids. Despite relatively low solubility in aqueous solutions, humic acids from the selected source participated in redox regulation. By recapturing the radicals, humic acids reloaded the antioxidant defensive mechanism. Results from in vitro study conducted with humic acids from the natural source showed potential of these substances as promising immunity enhancing agents.

UV–Vis spectrophotometry was used to determine acid dissociation constant (pK a) values of the natural flavonoids phloretin, phlorizin, naringenin, and naringin, as well as 4′-hydroxychalcone, 4′-(dimethylamino)chalcone, and their cyclic analogues. Comparison of the results with those previously reported for the natural flavonoids showed the applied method is a relatively straightforward and easy-to-perform technique for the determination of pK a values of compounds with relatively low solubility. Comparative analysis of the pK a values of the synthetic chalcones showed a strong correlation between the degree of conjugation and the acid strength of the respective compounds with different geometry. Our results provide further evidence that modification of the three-dimensional structure of open-chain bioactive compounds is the method of choice to modify not only their stereochemistry but also their physicochemical properties.