Luteolin decreases the UVA-induced autophagy of human skin fibroblasts by scavenging ROS

Abstract

Luteolin (LUT) is a flavone, which is universally present as a constituent of traditional Chinese herbs, and certain vegetables and spices, and has been demonstrated to exhibit potent radical scavenging and cytoprotective properties. Although LUT has various beneficial effects on health, the effects of LUT on the protection of skin remain to be fully elucidated. The present study investigated whether LUT can protect human skin fibroblasts (HSFs) from ultraviolet (UV) A irradiation. It was found that, following exposure to different doses of UVA irradiation, the HSFs exhibited autophagy, as observed by fluorescence and transmission electron microscopy, and reactive oxygen species (ROS) bursts, analyzed by flow cytometry, to differing degrees. Following incubation with micromolar concentrations of LUT, ROS production decreased and autophagy gradually declined. In addition, the expression of hypoxia-inducible factor-1α and the classical autophagy-associated proteins, LC3 and Beclin 1 were observed by western blotting. Western blot analysis showed that the expression levels of HIF-1α, LC3-II and Beclin 1 gradually decreased in the UVA-irradiated HSFs following treatment with LUT. These data indicated that UVA-induced autophagy was mediated by ROS, suggesting the possibility of resistance against UV by certain natural antioxidants, including LUT.

The effect of Cyanidin-3-o-glucoside on UVA-induced damage in human dermal fibroblasts

“…However, 80 μmol/L C3G increased HDF survival rate (Figure D) and reduced oxidative damage (Figure A,B,D) and apoptosis (Figure. C,E) induced by UVA, consistent with the findings from luteolin . In addition, C3G clearly increased the ratio of the anti‐apoptotic protein Bcl‐2 to the pro‐apoptotic protein Bax and decreased the expression of cleaved caspase‐3 (Figure ).…”

“…3C,E) induced by UVA, consistent with the findings from luteolin. 24 In addition, C3G clearly increased the ratio of the anti-apoptotic protein Bcl-2 to the pro-apoptotic protein Bax and decreased the expression of cleaved caspase-3 (Figure 4). Thus, C3G protected HDFs against UVA-induced damage, as demonstrated by the antioxidative and antiapoptotic effects of C3G on primary HDFs.…”

Ultraviolet A protective potential of plant extracts and phytochemicals

“…In addition, the protein expression of hypoxia inducible factor-1α and the classical autophagy-associated proteins, microtubule-associated protein light chain 3 and beclin 1 were decreased in the UVA-irradiated NHDF (ref. 133 ).…”

A Review on the Antioxidative and Prooxidative Properties of Luteolin

“…It was found that mice treated with luteolin exhibited significantly lowered incidence of rectal crypt lesions and upregulated levels of catalase, SOD, glutathione reductase, and glutathione S-transferase during the azoxymethaneinduced colon carcinogenesis [33]. Moreover, luteolin may interfere with the oxidative production of some cellular components, probably through the inhibition of corresponding enzymes [34].…”

“…A number of studies have indicated that ultraviolet light induces generation of harmful ROS burst, contributing to the development of human skin carcinoma. Considering luteolin's capacity to penetrate into deep skin layers, it may be useful in counteracting the oxidative stress as well as affording antiinflammatory effects in skin carcinoma [34]. Another potential protective effect of luteolin was shown in children with autism, where a formulation containing luteolin significantly improved children's attention and behavior [79].…”