Study on mechanism of transdermal administration of eugenol for pain treatment by network pharmacology and molecular docking technology

Abstract

The objective of this study was to explore the pharmacological mechanism of transdermal administration of eugenol (EUG) for pain treatment. Firstly, network pharmacology techniques were employed to identify the potential targets responsible for the analgesic effect of EUG. Subsequently, molecular docking technology was used to validate interactions between EUG and the crystal structure of the core target protein. Finally, the impact of EUG on the expression and activation of TRPV1 receptors in HaCaT cells was evaluated through in vitro experiments, thus confirming the analysis of network pharmacology. The study suggested that the transdermal administration of EUG for pain treatment might target the TRPV1 receptor. Molecular docking revealed that EUG could spontaneously bind to the TRPV1 receptor with a high binding ability. The analysis of Western blot (WB) and intracellular Ca²⁺ levels demonstrated that EUG could increase the expression of TRPV1 in HaCaT cells, activating TRPV1 to induce intracellular Ca²⁺ influx (P < 0.05). These findings suggested that the initial application of EUG would cause a brief stimulation of TRPV1 receptors and upregulation of TRPV1 expression. Upon continued exposure, EUG would act as a TRPV1 agonist, increasing intracellular Ca²⁺ levels that might be associated with desensitization of pain sensations.

Keywords: Eugenol; Molecular docking technology; Network pharmacology; Pain treatment; Transdermal administration.

Fig. 1

Flowchart of investigating transdermal administration of EUG for pain treatment.

Fig. 2

EUG chemical structure.

Fig. 3

EUG targets and EUG-pain targets. (A)EUG target PPI network. (B) EUG target PPI subnetwork was clustered using the k-means clustering method. All nodes in network and subnetwork were organized by node degree. （C）Target genes matching of pain and EUG.

Fig. 4

EUG-pain target PPI network. All nodes were organized by node degree, where larger nodes indicated greater degree. The strength of the interactions between nodes was represented by the thickness of the edges, with thicker edges indicating higher combine score.

Fig. 5

GO enrichment analysis of potential targets of EUG related to pain treatment: (A)Biological Process (BP), (B)Cellular Component (CC), and (C)Molecular Function (MF).

Fig. 6

KEGG pathway enrichment analysis of potential targets of EUG related to pain treatment.

Fig. 7

Docking results for ligands and receptor: (A) Molecular docking model of EUG and TRPV1 receptor. (B) Molecular docking model of CAP and TRPV1 receptor.

Fig. 8

Effects of EUG on TRPV1 receptors in HaCaT cells. (A & B) Effects of EUG on the expression of TRPV1 receptors in HaCaT cells. (C) Effects of EUG on Ca²⁺ influx in HaCaT cells. (D) Cell viability. *P < 0.05 vs. control, **P < 0.01 vs. control. All experiments are repeated three times.

figs1