The Action Mechanisms, Anti-Cancer and Antibiotic-Modulation Potential of Vaccinium myrtillus L. Extract.

BACKGROUND: Herbal medicinal products containing Vaccinium myrtillus L. (bilberry) fruits and fruit extracts are widely available in the market. Although bilberry leaves and stems are considered as bio-waste, they contain much higher levels of phenolic compounds than fruits. The study aimed to investigate the antimicrobial and anticancer potential of aerial part extracts from Vaccinium myrtillus L. (V. myrtillus, VM) plants harvested at high altitudes in Armenian landscape and characterize the bioactive phytochemicals. MATERIAL AND METHODS: For evaluation of antioxidant properties, chemical-based tests (total phenolic and flavonoid content, and antiradical activity in 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) tests) and cellular antioxidant activity (CAA) assay were applied. Genotoxicity and anticancer properties of the extract alone and in combination with fluorouracil were explored in human cancer and normal cell lines. Antibacterial properties of V. myrtillus extract alone and in combination with antibiotics, as well as their effect on proton-flux rate through cell membrane were explored on bacterial strains. The characterization of active phytochemicals was done using Liquid Chromatography-Quadrupole-Orbitrap High-Resolution Mass Spectrometry (LC-Q-Orbitrap HRMS). RESULTS: The V. myrtillus aerial part extract demonstrated promising antioxidant properties in all tests. The selective cytotoxic activity was documented against various cancer cell lines (human colon adenocarcinoma (HT29), human breast cancer (MCF-7) and human cervical carcinoma (HeLa)), while it did not inhibit the growth of tested human normal primary renal mixed epithelial cells (HREC) even at 10-fold higher concentrations. The extract did not have genotoxic properties in comet assay making it a potential source for the development of anticancer preparations. The investigated extract did not directly inhibit the growth of Escherichia coli (E. coli) and Salmonella typhimurium (S. typhimurium) strains at up to 1 mg/mL concentration. However, V. myrtillus extract enhanced the kanamycin intake and increased its efficiency against E. coli strain. The phytochemical characterization of the extract showed the presence of different groups of phenolics. CONCLUSIONS: Based on obtained data, we suggest the aerial parts of the V. myrtillus plant as an alternative source of bioactive natural products for food supplements, nutraceuticals, functional foods and medicine.

Osmotic stress as a factor for regulating E. coli hydrogenase activity and enhancing H2 production during mixed carbon sources fermentation.

Escherichia coli performs mixed-acid fermentation and produces molecular hydrogen (H2) via reversible hydrogenases (Hyd). H2 producing activity was investigated during hyper- and hypo-osmotic stress conditions when a mixture of carbon sources (glucose and glycerol) was fermented at different pHs. Hyper-osmotic stress decreased H2 production rate (VH2) ~30 % in wild type at pH 7.5 when glucose was supplemented, while addition of formate stimulated VH2 ~45% compared to hypo-stress conditions. Only in hyfG in formate assays was VH2 inhibited ~25% compared to hypo-stress conditions. In hypo-stress conditions addition of glycerol increased VH2 ~2 and 3 fold in hybC and hyfG mutants, respectively, compared to wild type. At pH 6.5 hyper-osmotic stress stimulated VH2 ~2 fold in all strains except hyaB mutant when glucose was supplemented, while in formate assays significant stimulation (~3 fold) was determined in hybC mutant. At pH 5.5 hyper-osmotic stress inhibited VH2 ~30% in wild type when glucose was supplemented, but in formate assays it was stimulated in all strains except hyfG. Taken together, it can be concluded that, depending on external pH and absence of Hyd enzymes in stationary-phase-grown osmotically stressed E. coli cells, H2 production can be stimulated significantly which can be applied in developing H2 production biotechnology.

Essential Oil and Ethanol Extract of Oregano (Origanum vulgare L.) from Armenian Flora as a Natural Source of Terpenes, Flavonoids and other Phytochemicals with Antiradical, Antioxidant, Metal Chelating, Tyrosinase Inhibitory and Antibacterial Activity.

BACKGROUND: Origanum vulgare is used in Armenian cuisine as well as in folk medicine. The aim of this investigation was to determine the peculiarities of the chemical composition of Armenian flora's oregano essential oil (EO) and ethanol extract (EE) and to characterize mainly antioxidant and antibacterial properties in vitro. METHODS: EO of plant aerial parts was extracted by the hydro-distillation method, and the composition was analyzed by gas-chromatography (GC). EE was prepared using ethanol as a solvent. Antioxidant, antibacterial and other biological activity of EO and EE was determined using appropriate methods. RESULTS: The terpenes were found to be the greatest part of oregano EO (ß-caryophyllene epoxide - 13.3 %; ß- caryophyllene -8.2 %; ο-cymene - 5.2 %). The flavonoid content of EE was 3.9±0.7 mg g-1 catechin equivalents. Antiradical activities of EO and EE expressed with half-maximum inhibitory concentrations were 1057 µg mL-1 and 19.97 µg mL-1. The antioxidant index in the case of using extract (1000 µg mL-1) was 77.3±1.5 %. The metal chelating activity of EE was 74.5±0.2 %. The tyrosinase inhibitory activities of EO, EE and arbutin were 26.5±0.3 %, 6.5±0.2 % and 50±0.1 %, respectively. Both EO and EE of oregano were able to suppress the growth of testmicroorganisms including clinical pathogen isolates, but have moderate antimicrobial activity. EO antibacterial activity against ampicillin-resistant Escherichia coli was similar to the activity against non-resistant strain. EE was not active against ampicillin-resistant E. coli in contrast to non-resistant one. CONCLUSION: The results indicate high antioxidant and moderate antibacterial as well as high antiradical, metal chelating, tyrosinase inhibitory activity of oregano EO and EE, which can be used as a natural source of terpenes, flavonoids and other phytochemicals in medicine, pharmaceutics, cosmetics and food industry. EO has antibacterial activity also against ampicillin-resistant E. coli.

Chemical composition and some biological activities of the essential oils from basil Ocimum different cultivars.

BACKGROUND: The plants belonging to the Ocimum genus of the Lamiaceae family are considered to be a rich source of essential oils which have expressed biological activity and use in different area of human activity. There is a great variety of chemotypes within the same basil species. Essential oils from three different cultivars of basil, O. basilicum var. purpureum, O. basilicum var. thyrsiflora, and O. citriodorum Vis. were the subjects of our investigations. METHODS: The oils were obtained by steam distillation in a Clevenger-type apparatus. The gas chromatography mass selective analysis was used to determine their chemical composition. The antioxidant activities of these essential oils were measured using 1,1-diphenyl-2-picrylhydrazyl assays; the tyrosinase inhibition abilities of the given group of oils were also assessed spectophotometrically, and the antimicrobial activity of the essential oils was determined by the agar diffusion method, minimal inhibitory concentrations were expressed. RESULTS: According to the results, the qualitative and quantitative composition of essential oils was quite different: O. basilicum var. purpureum essential oil contained 57.3% methyl-chavicol (estragol); O. basilicum var. thyrsiflora oil had 68.0% linalool. The main constituents of O. citriodorum oil were nerol (23.0%) and citral (20.7%). The highest antioxidant activity was demonstrated by O. basilicum var. thyrsiflora essential oil. This oil has also exhibited the highest tyrosinase inhibition level, whereas the oil from O. citriodorum cultivar demonstrated the highest antimicrobial activity. CONCLUSIONS: The results obtained indicate that these essential oils have antioxidant, antibacterial and antifungal activity and can be used as natural antioxidant and antimicrobial agents in medicine, food industry and cosmetics.