Ethnopharmacological investigation of Fallopia dumetorum: anti-inflammatory activity and molecular mechanisms in...

Fallopia dumetorum (L.) Holub has been traditionally used in folk medicine and has attracted interest for its potential pharmacological activities. However, its pharmacological effects and underlying molecular mechanisms associated with skin inflammation have not been scientifically elucidated.

This study aimed to evaluate the anti-inflammatory activity of F. dumetorum methanolic extract (FDME), a traditionally used medicinal plant, and to investigate its potential molecular mechanisms in LPS-stimulated HaCaT cells.

The anti-inflammatory effects of FDME were evaluated in LPS-stimulated HaCaT human keratinocytes by assessing the production of inflammatory mediators, nitric oxide (NO) and prostaglandin E₂ (PGE₂), as well as the expression of inflammatory cytokines. The involvement of mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), and activator protein-1 (AP-1) signaling pathways was examined using Western blot and transcriptional analyses. Phytochemical profiling of FDME was performed using LC-MS/MS and HPLC analyses, and the contribution of the major constituent was further validated.

FDME significantly suppressed LPS-induced production of NO and PGE₂ by downregulating inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. The extract also markedly reduced the expression and secretion of pro-inflammatory cytokines, including interleukin-6 and interleukin-1β. Mechanistically, FDME inhibited the phosphorylation of MAPK signaling components (ERK, JNK, and p38), leading to the suppression of NF-κB and AP-1 activation. LC-MS/MS analysis identified emodin as a phytochemical constituent of FDME, and additional experiments indicated that emodin may contribute to the observed anti-inflammatory effects.

These findings indicate that FDME attenuates inflammatory responses in LPS-stimulated human keratinocytes through modulation of MAPK/NF-κB/AP-1 signaling pathways. This study provides initial experimental evidence supporting the anti-inflammatory potential of F. dumetorum and contributes to the pharmacological understanding of this traditionally used plant.