No abstract

UVB is a major cause of nonmelanoma skin cancer in humans. Photochemoprevention represents an important strategy in protecting the skin against the detrimental effects of ultraviolet B (UVB). We investigated the activity of Calluna vulgaris (Cv) delivered via a hydrogel on 3 main pathways (oxidative stress, inflammation, DNA damage) on skin exposed to multiple doses of UVB in SKH-1 mice. Fifty female mice were divided randomly into 5 groups: control, vehicle, UVB irradiated, Cv + UVB irradiated, and Cv + vehicle + UVB irradiated. The extract was applied topically on the skin in a dose of 4 mg polyphenols/cm2 30 minutes before each UVB (240 mJ/cm2) exposure over 10 consecutive days. Malondialdehyde, reduced glutathione, tumor necrosis factor-α, interleukin-6, cyclobutane pyrimidine dimer (CPD) levels, sunburn cell formation and epidermal thickness, and the number of epidermal cell layers in skin were evaluated 24 hours after the last treatment. UVB increased cytokine levels (P < 0.001), formation of CPDs (P < 0.001) and sunburn cells (P < 0.001), and the epidermal thickness and number of epidermal cell layers (P < 0.001) compared with the control group. The topical application of Cv protected the skin against inflammation and DNA damage, as shown by a decreased number of CPDs (P < 0.001) and sunburn cells (P < 0.001). The administration of Cv via hydrogel may be a viable method for chemoprevention..

Electron paramagnetic resonance spectroscopy and the spin trapping technique were employed in order to monitor the superoxide radical liberated from potassium superoxide in aqueous alkaline solutions; DEPMPO (5-diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide) was used as a trapping agent. Three reaction systems were prepared, varying the ratios between KO 2 , superoxide and DEPMPO. The data indicate distinct mechanisms leading to DEPMPO/spin adducts with different kinetic rates.

Antioxidant status of foods, plant, or fruit products is generally characterized by means of spectroscopic methods. Methods like HPLC, UV-VIS, or MS spectroscopy are used to understand the chemical and physical properties of different samples, and also EPR spectroscopy seems to be a valuable tool to characterize antioxidant activity of juice beverages. In this technique, certain antioxidants present in fruit juices interact with free radicals interrupting the chain reaction that can possibly damage essential molecules. Recording the EPR signal decay caused by the reaction with a natural or artificial reducing agent, it is possible to draw conclusions about the antioxidant capability of materials. IRMS is a powerful tool to distinguish between an authentic fruit juice and a juice obtained by concentrate dilution. This technique allows also the detection of commercial C4 cane or corn derived sugar syrups in C3 fruit juices. In the present study, four commercial fruit juices were investigated using stable isotope measurements (oxygen, hydrogen, and carbon) and EPR measurements in order to check the correct labeling in the Romanian markets and to compare antioxidant activity of the studied juices and the reference. It was proven that the number of paramagnetic species decreases in time with different reaction rates and this was correlated with the antioxidant activity of the studied juices. Stable isotope ratio measurements have demonstrated that the fruit juices studied were reconstructed from concentrates with tap water, according to their label.