Anti-inflammatory effects of Elsholtzia ciliata extract on Poly I:C-treated RAW264.7 cells

Inflammation is a vital biological response to noxious stimuli, including physical injury and pathogenic infection, and involves immune cells and various inflammatory mediators, limiting cell damage and eliminating pathogens. Although essential for healing, inflammation can cause symptoms, such as fever, swelling, pain, and itching, potentially reducing quality of life. Elsholtzia ciliata used in traditional medicine has numerous medicinal characteristics such as antiviral, antibacterial, antipyretic, diaphoretic, carminative, astringent, and diuretic effects.

This study aimed to evaluate the anti-inflammatory properties of E. ciliata extract (ECE) in RAW264.7 cells treated with polyinosinic polycytidylic acid (Poly I:C).

PGE₂, IL-1β, TNF-α, IFN-β, and IL-6 levels were quantified by ELISA and/or real-time PCR. COX-2 and iNOS expression was analyzed using western blotting and real-time PCR. Phosphorylation and expression levels of signaling proteins, including AKT, IRF3, TBK1, STAT1, MAPKs, IκB, and IκK were analyzed using western blotting. The active substance of ECE was determined using high-performance liquid chromatography-mass spectrometry (HPLC-MS).

Our detections revealed that ECE inhibited the levels of nitric oxide and central inflammatory mediators, such as iNOS and COX-2. Furthermore, ECE downregulated the expression of pro-inflammatory cytokines, including PGE₂, IL-1β, TNF-α, IFN-β, and IL-6. Additionally, ECE inhibited the phosphorylation of several cell signaling pathways, including AKT, TBK1/IRF3, MAPK, and NF-κB, in Poly I:C-treated RAW264.7 cells.

These results highlight E. ciliata as a candidate for mitigating virus-induced inflammation, providing valuable insights into its use in the development of new anti-inflammatory therapeutics.