Optimization of Supercritical Extraction Process, Compositional Analysis and Anti-Inflammatory and Analgesic Effects of Zanthoxylum schinifolium Essential Oil

Abstract

Zanthoxylum schinifolium is used traditionally as a herbal medicine and spice and flavouring agent, with its essential oil (Z. schinifolium essential oil [ZEO]) having potential anti-inflammatory and analgesic activity. In this study, the ZEO was extracted using supercritical CO₂ (Sup-CO₂), and the extraction process was optimized using response surface methodology (RSM). The composition of the ZEO was analysed using gas chromatography–mass spectrometry (GC–MS), whereas the role of the ZEO in inhibiting the release of inflammatory factors from lipopolysaccharide (LPS)-stimulated RAW264.7 cells was investigated. In addition, classical pharmacological experiments were conducted to examine its anti-inflammatory and analgesic effects. The study found that the best conditions for Sup-CO₂ extraction of EO from Z. schinifolium were a pressure of 14 MPa, CO₂ flow rate of 18 L/h, extraction time of 1.5 h, temperature of 55°C and granularity of 40 mesh. The yield of ZEO under these conditions was 9.40%. Analysis of the ZEO revealed 18 components, with linalool (72.44%), d-limonene (4.94%) and 4,6-dimethyldodecane (3.74%) being the most abundant. The ZEO showed significant inhibitory effects on mouse ear swelling, foot swelling, hot plate analgesia and writhing response. In addition, the ZEO reduced the production of inflammatory markers in macrophages. These findings suggested that the ZEO extracted by Sup-CO₂ has potential pharmaceutical applications due to its anti-inflammatory and analgesic effects.