Ultraviolet (UV) radiation can result in DNA damage, mainly through direct formation of pyrimidine dimers and generation of reactive oxygen species, which can lead to the skin disorders including cancer. In accordance with this, the use of natural antigenotoxins and/or antioxidants could contribute to human health protection. Considering that plants are rich in both, the aim of this study was to investigate UV-protective and antioxidative properties of yellow gentian (Gentiana lutea), being well established in pharmacopeias and traditional medicine. Tested extracts were derived from root and shoot of the in vitro cultivated plants. Prescreening of the genotoxic properties of UVC, UVA, and the extracts, as well as the extracts’ antigenotoxicity were estimated by applying alkaline comet assay on normal fetal lung fibroblast (MRC-5) and human melanoma cells (Hs 294T). Antioxidant potential was tested in ferrous ions chelating ferric reducing antioxidant power and cupric reducing antioxidant capacity assays. Genotoxicity testing, which revealed moderate DNA-damaging potential of root extract on MRC-5 cells and high genotoxicity of shoot extract on both cell lines, pointed out nongenotoxic concentrations that could be used in antigenotoxicity assay. Doses of 63 and 3 J/cm2 for UVC and UVA, respectively, were established for antigenotoxicity study, since they induced sufficient DNA damage without notable cytotoxicity. Results of antigenotoxicity revealed strong protective effect of both extracts against UVC (the highest inhibitions 58% and 47%) and UVA (the highest inhibitions 69% and 60%), in Hs 294T and MRC-5 cells, respectively. Study of the antioxidative properties demonstrated stronger activity of shoot extract. Results obtained proved to be encouraging but further research of the UV-protective role of Gentiana lutea extracts and underlying molecular mechanisms is recommended.
Acinetobacter baumannii is an emerging nosocomial pathogen resistant to a wide spectrum of antibiotics, with great potential to form a biofilm, which further aggravates treatment of infections caused by it. Therefore, searching for new potent agents that are efficient against A. baumannii seems to be a necessity. One of them, which has already been proven to possess a wide spectrum of biological activities, including antimicrobial effect, is cinnamon essential oil. Still, further increase of antibacterial efficacy and improvement of bioavailability of cinnamon oil is possible by emulsification process. The aim of this study was comparative analysis of cinnamon essential oil and its emulsion against biofilm forming A. baumannii clinical isolates. Furthermore, the investigation of toxicological aspects of possible applications of essential oil and emulsion was done as well. Gas chromatography–mass spectrometry of essential oil indicated trans-cinnamaldehyde as the most abundant component. The cinnamon emulsion was synthesized from cinnamon essential oil by combining modified low- and high- energy methods. Synthesized emulsion was characterized with Fourier-transform infrared spectroscopy and photon correlation spectroscopy. Both substances exhibited significant antibacterial (minimal inhibitory concentrations in the range 0.125–0.5 mg/ml) and antibiofilm effects (inhibitions of formation and reduction of pre-formed biofilm were 47–81 and 30–62%, respectively). Compared to essential oil, the efficacy of emulsion was even stronger considering the small share of pure oil (20%) in the emulsion. The result of biofilm eradication assay was confirmed by scanning electron microscopy. Even though the cytotoxicity was high especially for the emulsion, genotoxicity was not determined. In conclusion, strong antibacterial/antibiofilm effect against A. baumannii of the cinnamon essential oil and the fact that emulsification even potentiated the activity, seems to be of great significance. Observed cytotoxicity implicated that further analysis is needed in order to clearly determine active principles being responsible for obtained antibacterial/antibiofilm and cytotoxic properties.
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