Extraction And Separation Salidroside And Flavonoids From Rhodiola

Rhodiola as a medical plant has a long application history in China,the main active componets of Rhodiola are salidroside and flavonoids which can be used for antifatigue,anticancer,antioxidant,anti-inflammatory,antidepression,antialtitude sickness,protection of the heart and liver and improvement of the mental and physical disease.The traditional extraction method of the active componets has some disadvantages,such as low yield,poor quality,complicated operation and large energe consumption.In this paper,the extraction system coupled with adsorption column has been used for the extraction and separation of active components of Rhodiola.This method not only can enhance mass transfer during the extraction process,but also can separate and enrich the target componets.Based on this idea,the works of this paper as follow:(1)A microwave assisted ethanol and ionic liquid solution extraction technique was used to extract salidroside and tyrosol.The optimal conditions were optimized by single factor experiments and response surface methods.The results of microwave assisted ethanol extraction were: extraction temperature 60?,microwave power 600 W,extraction time 35 min,ethanol concentration 20%,liquid-solid ratio 10:1;the optimal conditions of microwave assisted ionic liquid solution were: extraction temperature 58?,extraction time 16 min,ionic liquid solution concentration 0.65mol/L,microwave power 600 W,liquid-solid ratio 30:1.In the optimum conditions,the extraction rate of salidroside and tyrosol were 0.5972%,0.1580% and 0.8762%,0.1674%,respectively.Compared with these two kinds of extraction solvents,the extraction of ionic liquid requires less time and has higher yield of salidroside and tyrosol.Detecting with scanning electron microscope(SEM),many tiny hole have been found on the cell wall of Rhodiola after treated by ionic liquid,while there is no hole on the cell wall aferr treated by ethanol.That is to say,ionic liquid could dissolve cellulose and destroy the cell wall,which made the target componets within the cell could effectively dissolve.(2)A static microwave and dynamic microwave assisted ionic liquids extraction method was used to extraction quercetin and kaempferol.The extraction conditionswere optimized by single factor experiments.The conditions of static microwave assisted extraction were: extraction time 80?,extraction time 15 min,liquid-solid ratio 20:1 mL/g,ionic liquid concentration 0.8 mol/L.The conditions of dynamic microwave assisted extraction were: exraction temperature 70?,extraction time 20 min,liquid-solid ratio 150:1 mL/g,ionic liquid concentration 0.8 mol/L,the pump flow 1.0 mL/min.In the optimum conditions,the extraction yields of quercetin and kaempferol were 6.94%,6.34% and 8.93%,8.03%,respectively.The dynamic microwave assisted extraction could keep the higher differential concentration between the extraction solution and raw material,and increase the mass transfer,which made the extraction efficiency higher than static microwave assisted extraction.(3)The adsorption behavior of salidroside,tyrosol,quercetin and kaempferol on resin were investigated,the adsorption rate and desorption rate of target componets on HPD-100 resin was better than other resins.The adsorption isotherm processes were fitted with Langmuir isotherm adsorption equation better than Freundlich,and the low temperature was favorable to adsorption,the adsorption processes were fitted with second order kinetics model.(4)Extraction coupled with separation method of salidroside and total flaconiods from Rhodiola were proposed according to the early study.the target componets were extracted by ionic liquid solution in dynamic extraction process,at the same time the solution flowed into adsorption column through the pump;after adsorbed by resins,the solution backed into the extraction system;finally,the adsorption column eluted by different concentration ethanol solution.the ionic liquid solution can be recycled in extraction system.Because the target componets could be taken away from extraction system by the pump in time,the destruction of target componets by microwave radition could be avoided.The effect of mass of resin,extraction temperature,extraction time,ionic liquid concentration and the extraction solution flow were investigated by single factor.The optimal extraction conditions were: extraction temperature 70?,mass of HPD-100 resin 1.5 g,extraction time 30 min,ionic liquid concentration 0.5 mol/L,ionic liquid solution 20 mL,extraction solution flow 1.0 mL/min.In optimal conditions,0.1 g Rhodiola powder was extracted,then the adsorption column eluted by 30% and 80%ethonal solution respectively.The 30% ethanol elution mainly contain salidroside and tyrosol,yields of salidroside and tyrosol were 0.5473% and 0.0437% respectively,the contents of flavonoids were very low.The 80% ethanol elution mainly contain flavonoids,yields of quercetin and kaempferol were 7.834% and 6.529% respectively without salidroside and tyrosol.