Preparation Of Alkaloids Deep Eutectic Solvent And Its Application In Extracting Artemisinin And Flavone Substance In Bamboo Leaves

Traditional Chinese medicine(TCM)is an important part of Chinese medicine and health field.It has distinct national characteristics,unique diagnosis and treatment methods and remarkable clinical efficacy.From 2011 to 2019,the TCM industry developed rapidly,which indicates that the development of Chinese herbal medicine will become an important development direction of Chinese medicine and health in the future.The active substances in Chinese herbs are the key to their effectiveness.But at present,Chinese herbal medicine active substances extraction methods such as traditional impregnation method,reflux method,column chromatography,supercritical fluid extraction,etc.,the commonly used solvent extraction are mainly include ethanol,methanol,diethyl ether,cyclohexane and so on.They have the disadvantages of long cycle,many processes,low efficiency,solvent destruction of active components,greater toxicity,difficult separation,complex follow-up treatment and so on.Therefore,it is very necessary to use efficient,feasible,green and economical extraction method and new extraction solvent to extract the activity of Chinese herbal medicine.A series of NADES were synthesized by ultrasonic and magneton stirring,and their structure and physical and chemical properties were tested.MTT assay was used to test the biocompatibility of mouse breast cancer cells,and the results showed that the synthesized NADES had good biocompatibility,which could realize the process of non-separation of the subsequent active substances and extracts and reduce the production cost.Artemisinin in artemisia annua was extracted by ultrasonic assisted DES.Response surface optimization(RSM)combined with central composite design(CCD)was used to optimize the extraction conditions.The results showed that the extraction efficiency of Ca Is DES was the best when the solid-liquid ratio was 1:20,the extraction temperature was 48℃,the extraction time was 32.62 min,and the concentration of DES aqueous solution was 62.81%w/v.The formation mechanism of DES and the action mechanism of DES extraction of artemisinin were studied by DFT quantum chemical calculation.Combined with FT-IR,1H NMR and quantum computation,the results show that hydrogen bond is the main driving force of DES formation.For the mechanism of ultrasonic assisted DES to extract artemisinin,in addition to hydrogen bond forces,there were van der Waals forces between DES and artemisinin to affect the extraction rate.Aiming at the problem that hydrophilic DES in water is easy to be affected by hydrogen bond and reduce the extraction efficiency,four oleic hydrophobic DES were prepared and synthesized,and their physicochemical properties and structures were also characterized.The biocompatibility was tested by mouse breast cancer cells and MTT assay,and the results showed that the synthesized DES had good biocompatibility within a certain concentration range,but some concentrations with higher cytotoxicity should be avoided.Ultrasonic assisted extraction of bamboo leaves flavonoids,combined with high performance liquid chromatography determination of the total amount of flavonoids in bamboo leaves,the results showed that the hydrophobic DES extraction of bamboo leaves flavonoids extraction efficiency reached the traditional solvent effect.Through ABTS free radical scavenging experiments and DPPH free radical scavenging experiments,the excellent antioxidant properties of oleic acid based DES flavone extract were verified.DFT quantum chemical calculation was used to study the formation mechanism of oleic acid based DES and the action mechanism of DES extraction of bamboo flavone.Combined with FT-IR,~1H NMR and quantum calculation,the results show that hydrogen bond is the main driving force of DES formation,and the van der Waals weak interaction force plays a certain role.As for the mechanism of the extraction of bamboo flavone by ultrasonic assisted oleic acid group DES,hydrogen bond and van der Waals force play a role simultaneously.Through experiments and theories,we can get that the deep eutectic solvent prepared in this paper can be used as a natural DES and as a green non-toxic solvent,which can overcome the shortcomings of traditional extraction methods and extract artemisinin and bamboo flavone in a green and efficient way.Besides,due to its good biocompatibility,the subsequent treatment process is saved and the production cost is reduced.The results of this study can further expand the application scope of NADES in extracting bioactive substances from various plants and provide a new idea for the development of environmental protection extraction technology in the future.