Helianthus annuus L. flower prevents UVB-induced photodamage in human dermal fibroblasts by regulating the MAPK/AP-1, NFAT, and Nrf2 signaling pathways

Abstract

Background: Excessive ultraviolet radiation usually causes skin photoaging, inflammation, and even photocarcinogenesis. UV radiation-generated reactive oxygen species (ROS) are a major contributing factor to photodamage. The flowers of Helianthus annuus L. have been reported to possess strong anti-inflammatory and antioxidant activity. However, there are few reports on the use of H. annuus L. to relieve UVB-induced photoaging.

Purpose: In this study, we evaluated the protective effect of a 50% ethanol extract of H. annuus L. flower (HAF) against UVB-induced photodamage using normal human dermal fibroblasts.

Methods: The secretion of ROS, interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMPs), procollagen type I, and transforming growth factor-β1 (TGF-β1) was measured with kits. The messenger RNA levels of COX-2, iNOS, and TGF-α were measured by RT-PCR. The AP-1, MAPK, NFAT, and Nrf2 pathways were investigated by Western blot analysis.

Results: HAF extract significantly blocked UVB-induced ROS and MMP (MMP-1 and MMP-3) production and procollagen type I reduction. Further study demonstrated that the photoaging inhibitory actions were related to promotion of Nrf2 nuclear translocation, upregulation of TGF-β1 level, and downregulation of AP-1 and MAPK phosphorylation. Importantly, HAF effectively inhibited UVB-induced VEGF and inflammatory cytokines such as IL-6, COX-2, iNOS, and TNF-α secretion, which might be involved in the regulation of the NFAT signaling pathway.

Conclusion: Our results indicate that HAF is a useful botanical source protecting against UVB-mediated skin photodamage.

Keywords: Helianthus annuus L; MAPK/AP-1; NFATc1; Nrf2; photodamage; ultraviolet radiation B.