Chuanqi Xie¹, Shufen Wang¹, Xinying Lin^{1, 2}, Fan Yang^{1, 3}, Juwu Hu¹, Jing Wu¹, Wei Xiong^1,, Lei Wu^1,

Camellia oleifera fruit hull has a variety of biological activities such as anti-oxidation, lipid regulation, and anti-cancer etc, however the effect of C. oleifera fruit hull on inflammatory responses has not been clearly elucidated. This study aimed to explore the effect of n-hexane extract of C. oleifera fruit hull on lipopolysaccharide (LPS)-induced inflammatory responses in RAW264.7 cells using Griess assay, ELISA, western blotting analysis, PCR and immunofluorescence technology. The results demonstrated that n-hexane extract of C. oleifera fruit hull ameliorated the secretion of nitric oxide (NO), prostaglandin E2 (PGE2), tumour necrosis factor α (TNFα), interleukin (IL)-1β, and IL-6, inhibited the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2), downregulated the mRNA level of iNOS, COX2, TNFα, IL-1β, and IL-6, and improved the cell viability in LPS-induced RAW264.7 cells. Moreover, the phosphorylation of ERK, P38, and JNK and nuclear translocation of nuclear factor-kappa B (NF-κB) were restrained by the treatment of n-hexane extract of C. oleifera fruit hull in LPS-induced RAW264.7 cells. Taken together, these data imply that n-hexane extract of C. oleifera fruit hull alleviates the inflammatory response by regulating the activation of mitogen-activated protein kinases (MAPKs) and NF-κB signaling pathways in LPS-induced RAW264.7 cells.

C. oleifera fruit hull, n-hexane extract, inflammatory responses, MAPKs, NF-κB