Optimized Extraction, Comprehensive Chemical Profiling, and Antioxidant Evaluation of Volatile Oils from Wurfbainia villosa (Lour.) Škorničk. & A.D.Poulsen Leaves

This study employed cellulase-assisted hydrodistillation (cellulase-HD) to extract volatile oils from Wurfbainia villosa (Lour.) Škorničk. & A.D.Poulsen (W. villosa) leaves, with process optimization conducted via the response surface methodology (RSM). The optimized extraction parameters were as follows: enzyme dosage 2.2%, enzymatic hydrolysis temperature 49 °C, hydrolysis duration 73 min, and material/liquid ratio (1:10.7 mg/mL). Under these optimal conditions, the volatile oil yield reached 0.772%, representing a 31.29% increase compared to conventional hydrodistillation (HD). GC-MS analysis identified 54 and 49 volatile compounds in cellulase-HD and HD extracts, respectively, with 39 shared components. The cellulase-HD extract was predominantly composed of γ-terpinene (14.981%), limonene (13.352%), β-phellandrene (10.634%), 4-terpineol (10.145%), and α-terpineol (8.085%). In contrast, the HD extract showed higher contents of β-phellandrene (41.881%), followed by β-myrcene (8.656%) and limonene (8.444%). Notably, cellulase pretreatment significantly increased the yield of oxygenated compounds. Orthogonal partial least squares discriminant analysis (OPLS-DA) revealed substantial compositional differences between the two extraction methods, with key differential components including fenchol, borneol, and γ-elemene. Antioxidant activity assessment demonstrated superior free radical scavenging capacity in cellulase-HD extracts. Structure–activity relationship analysis identified seven compounds with DPPH radical scavenging rates >50%, particularly, epi-bicyclosesquiphellandrene (71.51%) and γ-elemene (78.91%). Furthermore, thirteen components, including isopinocamphone (66.58%) and α-terpineol (66.95%), exhibited ABTS radical scavenging rates above 50%. This study provides theoretical and technical foundations for the extraction and functional development of volatile oils from W. villosa leaves.