Investigating the Impact of Caftaric Acid and Chicoric Acid From Echinacea Purpurea on NF‐κB p65 (pS529) Expression in THP‐1 Cells

ABSTRACT The therapeutic potential of natural compounds has gained significant attention in recent years due to their ability to offer safer alternatives to synthetic drugs. Echinacea purpurea , a plant traditionally used for its immune‐boosting properties, contains bioactive phenolic compounds, including caftaric acid and chicoric acid. These compounds are thought to modulate key signaling pathways, including the nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) pathway, which plays a crucial role in the regulation of immune responses and inflammation. In this research, potentials effect of the two compounds derived from Echinacea purpurea on NF‐κB p65 (pS529) transcription factor is analyzed. Cell viability assays were first performed to determine non‐cytotoxic working concentrations of caftaric acid and chicoric acid. THP‐1 cells were then treated with selected concentrations of each compound, with lipopolysaccharide (LPS) used as a positive control and untreated cells as a negative control. NF‐κB p65 (Ser529) phosphorylation was quantified by flow cytometry using a phospho‐specific antibody. All treatments and controls were processed in parallel under identical conditions. Both caftaric acid and chicoric acid induced a measurable increase in NF‐κB p65 (Ser529) phosphorylation compared with untreated cells, while LPS produced the expected robust activation of NF‐κB signaling. Caftaric acid showed a stronger effect on NF‐κB phosphorylation. These findings demonstrate that caftaric acid and chicoric acid can modulate NF‐κB signaling in immune cells. This study provides preliminary insight into the cellular responses associated with Echinacea‐derived phenolic compounds and supports further investigation into their immunomodulatory mechanisms.