Aqueous enzymatic pretreatment ionic liquid–lithium salt based microwave–assisted extraction of essential oil and procyanidins from pinecones of Pinus koraiensis

In this study, in order to simultaneously extract procyanidins and essential oil from pinecones of Pinus koraiensis , aqueous enzymatic pretreatment ionic liquid–lithium salt based microwave–assisted extraction (AEILLME) with a modified hydrodistillation concatenated Soxhlet extraction apparatus was proposed. 1-Butyl-3-methylimidazolium bromide solution was selected as extraction solvent , while LiCl and mixture of cellulase and pectinase (1:1, w/w) as additives by single factor experiment. Other parameters that affect the yield of target components were investigated and optimized by Plackett–Burman design and Box–Behnken design. The obtained optimal conditions were: microwave irradiation power 581.49 W, microwave irradiation time 15.95 min and liquid–solid ratio 11.91 mL/g. Under the optimized conditions, the predicted yields of oligomeric procyanidins, polymeric procyanidins and essential oil were 13.02, 32.19 and 7.76 mg/g, respectively. Analysis of chemical constituents in the essential oil was performed on gas chromatography–mass spectrometry and there was no significant difference on the components of essential oil obtained by proposed method and traditional methods. Ionic liquids were successfully recycled and reused, which could lower the process cost and being beneficial to industrial production. This study provides an approach with good prospects for the application in extracting active components from natural plant material.