Study on the enhancement of volatile components extraction from Lysimachia foenum-graecum Hance essential oil by metal salts

To investigate the effects of various metal salt solutions on the extraction efficiency of Lysimachia foenum-graecum Hance essential oil (LHEO), steam distillation coupled with comprehensive two-dimensional gas chromatography mass spectrometry was applied for volatile characterization. Single-factor experiments and orthogonal experimental design were adopted to evaluate four metal salts (FeCl₃, MgCl₂, MnCl₂, ZnCl₂). All four metal salts significantly improved essential oil yield with a maximum increase of 106%, and the optimal intensification condition was determined as 1.2% ZnCl₂ with 24 h extraction. A total of 235 compounds were detected in five samples. Orthogonal partial least squares-discriminant analysis revealed obvious sample differences based on 72 common volatiles, and 17 differential compounds including furfural, neophytadiene, phytol, isophytol, α-terpineol, linalool and geraniol were identified according to VIP scores. The findings clarify the influences of different metal salt solutions on LHEO volatile profiles and provide theoretical basis and practical reference for extraction process optimization and quality control.