Abstract: To study the effects of compound enzyme pretreatment on the extraction rate of total terpene lactones in Ginkgo biloba leaves.Five key factors of enzyme type,enzyme dosage,enzymolysis time,enzymolysis temperature and pH value during the pretreatment of G.biloba were studied by single factor experiment.After enzymolysis,G.biloba extract was extracted with 20% ethanol solution,purified by LX-5 macroporous adsorption resin,concentrated and dried.Then,G.biloba extract product was obtained.High performance liquid chromatography was used to detect the contents of total terpene lactones.The results showed that the enzymolysis effect was the best when the ratio of cellulose to pectinase was 1∶1,the ratio of enzyme to G.biloba was 1∶300,the enzymolysis time was 4.0 h,the enzymolysis temperature was 50  ℃ and the initial pH was 4.0.The extraction rate of total terpene lactone was 0.55% and the total terpene lactone content in G.biloba extract was 8.96% which was higher than G.biloba extract international business standards (total lactone content≥6%).The results showed that the extraction rate of total terpene lactones in G.biloba leaves was high under the condition of compound enzyme pretreatment.This study provided a theoretical basis for the industrial production of high quality G.biloba extract.

Key words: Ginkgo biloba, cellulase, pectinase, total terpene lactones, extraction rate