Optimization of Ultrasound-Assisted Extraction of Monoterpene Glycoside from Oil Peony Seed Cake.

Ultrasound-assisted extraction (UAE) of total monoterpene glycosides extract (TMGE) from oil peony seed cakes was investigated. The extraction yield was optimized using response surface methodology (RSM). The chemical constituents of the monoterpene glycosides extract were isolated by repeated column chromatography, and the contents of the main isolated monoterpene glycosides in the oil peony seed cakes were determined by HPLC. The optimum conditions were as follows: a liquid-to-solid ratio of 27 mL/g, ultrasonic extraction time of 16 min, ultrasonic extraction temperature of 26 °C, and ethanol concentration of 67%. Under these conditions, the extraction yield of TMGE was 10.24%. Twenty monoterpene glycosides were isolated from the oil peony seed cakes, and compounds 11-12, 16 and 20 showed strong inhibitory activities on NO production. TMGE from oil peony seed cakes can also to be used as promising immunosuppressive drug due to its high content of monoterpene glycosides and immune-inhibitory activity. PRACTICAL AAPPLICATION: The peony seed oil was authorized as a new food by the Ministry of Health of the People's Republic of China. Peony seed cake is one of the most important by-products in the preparation of peony seed oil, and accounts for approximately 40% of the total mass of the peony seed. Total monoterpene glycosides are the main active ingredient of oil peony seed cake. This research has optimized the extraction conditions of total monoterpene glycoside from seeds cake of Paeonia ostii, which will provide useful reference information for further studies, and offer related industries with helpful guidance in practice.