Optimization of supercritical extraction process, compositional analysis and anti-inflammatory and analgesic effects of Zanthoxylum schinifolium essential oil.

Zanthoxylum schinifolium is used traditionally as herbal medicine, spice and flavouring agent, with its 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 optimized using Response Surface Methodology. The composition of the ZEO was analyzed using gas chromatography-mass spectrometry (GC-MS), while the role of the ZEO in inhibiting the release of inflammatory factors from LPS-stimulated RAW264.7 cells. In addition, classical pharmacological experiments were conducted to examine its anti-inflammatory and analgesic effects. The study found that 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 hours, temperature of 55℃, and granularity of 40 mesh. The yield of ZEO under these conditions were 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.