| Cannabis sativa L.is an annual herb in the Cannabis family.The Cannabidiol(CBD)is the main component of Cannabis sativa L.functioning in anti-inflammatory and analgesic effects,as well as the treatment of epilepsy.However,the current extraction and purification methods of CBD in industrial cannabis are complicated and the extraction rate is low,which causes a waste of resources.Ionic liquid is an efficient and pollution-free green solvent.Using ionic liquid as an extractant can effectively solve many problems when traditional solvents used and further improve the yield of active substances.In this study,we used single-factor experimental design and response surface experimental analysis to optimize the extraction method of CBD in industrial cannabis leaves.After the extract of CBD,its purification study was carried out.The purified CBD was then embedded with β-cyclodextrin to obtain CBD lyophilized powder,and its physicochemical properties and antioxidant analysis were performed,aiming at providing a theoretical basis for the application of industrial cannabis leaves in the fields of medicine,food,and cosmetics..The main research contents and results are as follows:(1)Optimization of CBD extraction from the industrial cannabis leaves.The optimal ionic liquid[C8mim]NTF2 was identified from 16 kinds of ionic liquids.Using the single-factor experiments,the preliminary extraction process was confirmed:ultrasonic heating temperature 50℃,ultrasonic power 280 W,ultrasonic time 60 min,molar concentration of[C8mim]NTF20.25 mol/L(prepared with 65%ethanol),liquid-to-material ratio 25:1 mL/g.Next,the four main factors were further analyzed using response surface analysis,and the optimal process confirmed in this study was as follows:ultrasonic temperature 50℃,ultrasonic time 61 min,liquid-to-material ratio 23:1 mL/g,molar concentration of ionic liquid 0.28 mol/L.According to the optimal extraction process,the yield of CBD is 7.65 mL/g,higher than the yield when traditional solvents used.(2)Study on the purification of CBD.Compared with 5 types of macroporous resins as for the static adsorption and desorption capacity,the S-8 resin was finally adopted to purify CBD.The optimal purification parameters were as follows:sample loading temperature is 30℃;the sample concentration is 0.75 mg/mL;the sample solution pH is 4;the elution concentration is 80%;the sample flow rate is 1.5 mL/min;the elution volume is 100 mL;the washing flow rate is 1.5 mL/min.Based on the optimal purification method identified in this study,the purity of CBD was increased from 26.70%to 83.57%,showing the significant purification effect.(3)Embedding of purified CBD by β-cyclodextrin.After lyophilization,the CBD powder was successfully embeded by β-cyclodextrin.The encapsulation rate of the lyophilized CBD powder is 67.66%;the drug loading of CBD lyophilized powder was 3.82%;the average particle size was 241.7 nm.The physical and chemical properties of CBD powder and βcyclodextrin-embedded CBD lyophilized powder were compared and analyzed by infrared spectroscopy,X-ray diffraction,differential scanning thermogravimetry,thermogravimetric analysis and solubility analysis.The results indicated that the β-cyclodextrin-embedded CBD lyophilized powder has the small particle size,good water solubility,and easy storage.(4)The anti-oxidant ability of β-cyclodextrin-embedded CBD lyophilized powder and the suspension of CBD reference substance in vitro(including the ability to scavenge DPPH and ABTS+)were studied.Using Vc aqueous solution as a control,the IC50 values were calculated.The results were shown below:the IC50 value of the VC is 83.52 μg/mL;the IC50 value of theβ-lyophilized powder CBD is 4713.59 μg/mL;the IC50 value of the CBD suspension is 25280.26 μg/mL.According to these resulys,the strength of antioxidant capacity in vitro is:VC>β-cyclodextrin embedded CBD lyophilized powder>β-CBD suspension.In summary,using the extraction and purification methods confirmed in this study,the yield of industrial cannabis leaf CBD was obviously enhanced compared with traditional methods.In parallel,the water solubility and antioxidant capacity of the β-cyclodextrinembedded CBD lyophilized powder were also improved.The results of this study will provide a basis for the development of deep processing of industrial cannabis leaves and the development of CBD products in the future. |
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