Abstract
This study investigated the effect of a hawthorn polyphenol extract (HPE) on ultraviolet B (UVB)-induced damage in HaCaT cells and mice. High-performance liquid chromatography/electrospray ionization tandem mass spectrometry was used to analyze the phenolic composition of HPE. The protective effects of HPE and its main components were compared in HaCaT cells. An enzyme-linked immunosorbent assay was used to detect DNA damage (8-hydroxydeoxyguanosine levels). Flow cytometry and western blotting were used to measure the extent of apoptosis and the levels of apoptosis-related proteins, respectively. Treatment with HPE or its polyphenol components inhibited the UVB-induced damage by removing an excess of reactive oxygen species (ROS), reducing DNA damage and p53 activation, regulating the protein expression of B-cell lymphoma 2 family members toward antiapoptotic ratios, and reducing caspase activation. Similar effects were observed in a UVB-irradiated mouse skin, as detected using terminal deoxynucleotidyl transferase dUTP nick-end labeling, immunohistochemistry, and western blotting assays. These results suggest that HPE can be used as a natural dietary supplement for the prevention and treatment of UVB radiation-induced skin damage. PRACTICAL APPLICATIONS: Hawthorn (Crataegus pinnatifida) shows antioxidant, anti-inflammatory, and lipid-lowering effects. As natural, healthy, and effective additives, HPEs have been widely used in food and health products. The results of this study reveal the molecular mechanisms underlying HPE effects, showing that HPE reverses the effects of UVB irradiation via removal of an excess of ROS and reduction of DNA damage and p53 expression in vitro and in vivo. Consequently, HPE upregulates the expression of antiapoptotic BCL-2 and downregulates that of proapoptotic BAX, thereby reducing the activation of caspase-3/9 and inhibiting apoptosis. These findings suggest that HPE can be used as the base ingredient for antiphotoaging food products. This study provides both theoretical and experimental background for hawthorn deep processing and utilization.
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