Anti-inflammatory effects and mechanism of triterpene alcohols from camellia oil

Camellia oil, which contains a high content of triterpene alcohol, is known for a series of bioactivities including anti-inflammation. Amyrins are recognized as high bioactivity of anti-inflammation. However, no comparative study on triterpene alcohols from camellia oil. In this study, four high content triterpene alcohols from camellia oil, namely <i>β</i>-amyrin, <i>ψ</i>-taraxasterol, parkeol, and butyrospermol were evaluated through lipopolysaccharide induced RAW264.7 cell inflammation. The results showed that butyrospermol exhibited the highest anti-inflammatory activity, surpassing that of <i>β</i>-amyrin. Characterization of signaling pathways showed that butyrospermol inhibited Toll-like receptor 4 (TLR4), nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways, suppressing the transcription of <i>Tlr4</i>, expression of p65, NF-κB inhibitor α (IκBα), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, and the phosphorylation of p65, IκBα, ERK, and p38. The anti-inflammatory effect of butyrospermol was further validated by phorbol 12-myristate 13-acetate induced mouse ear edema. The results in mouse showed that butyrospermol could inhibit the increase of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), p-JNK, p-p38, p-IκBα, and their corresponding mRNA levels. Our study provides new perspective on the anti-inflammatory role of different triterpene alcohols and explaining the bioactivity of camellia oil.