Camellia cake extracts reduce burn injury through suppressing inflammatory responses and enhancing collagen synthesis

Abstract

Background: Burn injury accidents happen in our daily life, and the burn mortality is especially high in the low-to-middle-income countries. Camellia cake extracts (CCEs) are compound extracts from Camellia cake, and the major ingredients in CCEs may have antimicrobial, anti-oxidative, and anti-inflammatory effects. However, the effects of CCEs on burn inflammation and injury remain unknown. Objective: This study is to investigate the effects of CCEs in burn injury and explore its mechanism. Design: First, CCEs were identified to mainly contain camelliaside A and B using Ultra High Performance Liquid Chromatography-Time of Flight Mass Spectrometer (UHPLC-TOF-MS) method. Second, the CCEs’ effect on burn was tested. Burn was induced by boiling water in mice, and then CCEs (30, 50, and 100 mg/mL) were applied on the damaged skin at 3, 7, and 14 days after burn induction. Results: The results showed that CCEs protected the skin from burn-induced inflammation and enhanced the wound healing in a dose-dependent manner. CCEs decreased the expression levels of various cytokines including IL-6, TNF-α, IL-1β, MCP-1, TGF-β, and IL-10, as well as inflammatory related factors iNOS. Moreover, CCEs increased the levels of collagens, including the mRNA of COLα-1 and COL-3, and inhib-ited the mRNA of MMP-1 and TIMP-1, and increased the collagen staining. CCEs also reversed the im-pairment of activity levels of anti-oxidative enzymes. Furthermore, CCEs suppressed the gene expression of pro-inflammatory cytokines in LPS-stimulated human skin keratinocyte, possibly through inhibiting NF-κB signaling pathway. In addition, toxicological safety experiments on CCEs showed that the oral median lethal dose (LD50) was 2,000 mg/kg, the percutaneous LD50 was greater than 2,000 mg/kg, and CCEs did not cause gene mutation. Conclusion: CCEs exert a potent anti-inflammatory effect against burn damage in mice. And toxicological safety experiments suggest that CCEs are safe for usage.