Anti-inflammatory activity of Akebia quinata D. extracts by inhibiting MAPK and NF-κB signaling pathways in LPS-induced RAW 264.7 cells according to extraction solvents

Background

Akebia quinata D., a plant from the Lardizabalaceae family, has been traditionally used in East Asia for its medicinal properties. Its dried stem serves as a diuretic agent for treating edema and rheumatic pain.

Objective

This study aimed to explore the anti-inflammatory activity of A. quinata D. stem extracts in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. We also investigated potential mechanisms involving the mitogen-activated protein kinases (MAPK) and NF-kB signaling pathways.

Results

Extracts were obtained from dried A. quinata D. stems using ethanol (AQDE) and water (AQDW) extraction methods. The effects of A. quinata D. extracts on cytotoxicity, anti-inflammatory activity in RAW 264.7 macrophages were analyzed. A. quinata D. extracts were non-toxic in various concentrations (25–800 μg/mL) in RAW 264.7 cells. Treatment with extracts significantly reduced nitric oxide production, PGE2, proinflammatory cytokines (TNF-α, IL-1β, and IL-6), and PTGES2 in LPS-induced RAW 264.7 cells. Downregulation of the MAPK signaling pathway led to reduced phosphorylation of NF-κB, a transcription factor modulating inflammatory proteins, including JNK, ERK1/2, and p38. Based on the experimental results, it was confirmed that AQDE exhibits superior anti-inflammatory effects than AQDW.

Conclusion

These results indicate that A. quinata D. extracts exhibit anti-inflammatory effects without toxicity. Therefore, this suggests that they hold promise as a therapeutic candidate for inflammatory diseases, as well as potential a functional material for cosmeceuticals, food and medicine industries.