Optimisation of extraction conditions for terpenoids in Schizandra chinensis Baillon using the response surface method

Terpenoids, which are the major volatile compounds of Schizandra chinensis Baillon (Omija), are the main component of phytoncide. The purpose of the present study was to provide more ways to utilise Omija by optimising terpenoid extraction. The response surface method (RSM) was used to maximise the levels of monoterpene, which has substantial physiological activity and sesquiterpene, which has strong impacts on flavour. Central composite design was used to optimise the extraction pressure (X₁: 0.01-0.1 Mpa), ethanol concentration (X₂: 0%-50%), and sample concentration (X₃: 0.01-0.2 g/mL). Analysis of variance showed that X₁, X₂ and X₃ affected total terpenoid levels (Y₁) and monoterpene levels (Y₂), whereas only X₁ and X₃ significantly affected sesquiterpene content (Y₃) (P <.05). The optimal conditions based on the individual responses were as follows: Y₁ and Y₂, X₁ = 0.07 Mpa, X₂ = 36% and X₃ = 0.17 g/mL; Y₃, X₁ = 0.10 Mpa, X₂ = 50% and X₃ = 0.20 g/mL.