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Assessment of antioxidative and cyto/genoprotective properties of chestnut honey against UVB radiation in vitro

Ultraviolet B (UVB) radiation causes a number of harmful effects in cells including direct DNA damage, oxidative stress, signalling pathway disorders, inflammatory response and photocancerogenesis. Along with research into the biological basis of malignant cell transformation, great efforts are being made on research into various natural and synthetic compounds that can provide protection against the harmful effects of UV radiation. Natural compounds have a number of advantages because they mostly show low toxicity and good efficacy. In addition to being able to enter the body through food, they are also components of various cosmetic products that are applied directly to the skin. Honey is a completely natural and nutritionally rich product of honey bees. Its content of minerals, vitamins, antioxidants, but also sensory properties, depend on the geographical location of the apiary in the period of active food collection. Previous findings indicate that chestnut honey is characterized with a high content of phenolic components, and consequently exerts a good antioxidant effect. Present study was undertaken to investigate potential geno- and cytoprotective effects of the chestnut honey in vitro. The experiment was conducted on the human peripheral blood lymphocytes and plasma. We proposed the hypothesis that treating cells with chestnut honey can increase the survival rate and decrease primary DNA damage as well as the oxidative stress levels after exposure to UVB irradiation. Experimental design included two exposure scenarios: (I) 2 hours of pretreatment of cells and whole blood with honey followed by exposure to UVB irradiation and an additional 1 hour incubation of cells/whole blood at 37 °C, (II) treatment including exposure to UVB irradiation and incubation of cells/whole blood with honey for 2 hours at 37 °C. The effects of the honey were assessed at concentrations that correspond to the daily acceptable honey intake dose and a 10-fold higher concentration than the daily acceptable dose. Primary damage of lymphocyte DNA, as well as the protective effect of honey, was evaluated using the alkaline comet assay, while the plasma samples were used to determine markers of oxidative stress (lipid peroxidation, levels of reactive oxygen species and glutathione). Obtained results confirmed our assumptions. Chestnut honey showed good cytoprotective and genoprotective, as well as antioxidative effect after exposure of lymphocytes and whole blood to UVB irradiation. The beneficial effect of honey was more pronounced after the treatment of irradiated samples. The optimal concentration of honey was shown to be 1 mg/mL, while the lowest (0, 2157 mg/mL) and the highest (10 mg/mL) concentrations showed a prooxidative effect in measuring oxidative stress markers. Our results suggest that chestnut honey ameliorated detrimental effects of UVB radiation, which has to be further studied on other in vitro and in vivo model systems.

Ultraviolet B radiation, chestnut honey, comet assay, oxidative stress markers

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