A New Continuous-flow Ultrasound-assisted Extraction Technique For The Extraction Of Curcumin

Objective:A new extraction technique,continuous-flow ultrasound-assisted extraction technique(CF-UAE),was established to extract curcumin from Curcuma longa L.,Curcuma zedoaria(Berg.)Rosc and Curcuma aromatica Salisb.The extraction condition and process were optimized,so as to establish an efficient,environmental and energy-saving extraction technology for the effective components of traditional Chinese medicine.Methods:(1)Optimization of ultrasonic extraction solvent and extraction process.Curcumin was used as detect indicators and was extracted from Curcuma longa L.by normal ultrasonic extraction.And the content was determined by high performance liquid chromatography.The extraction performance of 7 organic solvents(methanol,ethanol,chloroform,dichloromethane,ethyl ether,ethyl acetate and acetone)and 4surfactants(tween-80,span-80,Triton X-100 and SHS)were investigated,and the optimum extraction solvent of curcumin was optimized by taking into account the extraction rate and reagent toxicity.Some parameters including sample-solvent ratio,extraction time,extraction times and particle size were all investigated by the orthogonal test and the optimum extraction conditions of low toxicity,low pollution and high extraction rate were selected.(2)The extraction of curcumin by continuous-flow ultrasound-assisted extraction.Curcumin was extracted from Curcuma longa L,Curcuma aromatica Salisb and Curcuma zedoaria(Berg.)Rosc by continuous-flow ultrasound-assisted extraction made in our laboratory coupled with non-ionic surfactant containing extraction solvent system.Some parameters including extraction time and flow-rate of selected solvent were all investigated.Finally,the extraction rate by CF-UAE was compared with the normal ultrasound-assisted extraction(UAE),reflux extraction(RE)and Soxhlet extraction(SE)in order to investigate the difference between the method and the traditional extraction technology.Results:(1)Optimization of ultrasonic extraction solvent and extraction process.Among the 7 organic solvents,ethanol showed higher extraction performance(1.09±0.03%)and less toxicity.Among the four surfactants,tween-80 was preferred(extraction rate was 1.10±0.03%),and the optimum extraction solvent after optimizing was composed of tween-80-ethanol-water(2.5:67.5:30,v/v/v).The optimized conditions were:particle size 40-60 mesh,sample-solvent ratio 1:20,extraction time 20min for 2 times.Under the optimized conditions,the extraction rates of curcumin reached to 1.22±0.02%.(2)The extraction of curcumin by continuous-flow ultrasound-assisted extraction.The results indicated that highest extraction rate of curcumin was obtained using the extraction solvent system composed of tween-80-ethanol-water(2.5:67.5:30,v/v/v)with the flow rate of 0.4 mL·min~-11 in 30min.Under this condition,the extraction rates of curcumin from Curcuma longa L.,Curcuma zedoaria(Berg.)Rosc and Curcuma aromatica Salisb.reached to1.232±0.031%,0.033±0.001%and 0.012±0.000%,which were all higher than several traditional extraction technologies.Furthermore,the established method also has the advantages of low solvent toxicity,small environmental pollution and short extraction time.Conclusion:This research established a continuous-flow ultrasound-assisted extraction technique combined with surfactant which can be used in the extraction of curcumin from Curcuma longa L.,Curcuma zedoaria(Berg.)Rosc and Curcuma aromatica Salisb..Compared with the traditional extraction methods,it has the advantages of high efficiency,time saving,energy saving and environmental protection.The application of it in the preparation and production of curcumin will have wide application prospect.