Study On Composite Extraction Of Rosmarinic Acid From Rosemary Leaves With Ultrasound And Enzymolysis

Rosmarinic acid(RA)as a very strong antroxidant,which has various biological activities on anti-biotic,anti-inflammatory,anti-virus and anti-cancer.Now,it has been widely used in medicine,food and commodity.Rosemary(Rosmarinus offinalis L.)represents a popularly accepted source of RA due to its high content and widely grown.Many new methods have been used for RA extraction,such as ultrasound-assisted extraction,microwave-assisted extraction and supercritical CO2-assisted extraction.Enzyme-assisted extraction was attached much attention due to many advantages.In this paper,composite extraction methods with enzyme and ultrasound were compared,and simultaneous treatment with ultrasound and enzyme(SUE)was employed in the extraction of RA from rosemary leaves.Several experimental conditions were optimized.The macroporous resins were used for enriching RA.The process of static adsorption was analyzed through kinetics and thermodynamics.Several extraction methods through enzyme and ultrasound had been compared to extract RA from rosemary leaves.The microstructural changes of rosemary leaves after extraction and the activity of cellulase under ultrasound were investigated.The cellulase activity was improved obviously,after the ultrasound(ultrasonic power less then 140W)was employed.Glandular trichomes were collapsed most obvious after SUE,and many ruptures took place on the surface of cells.The developed SUE method provided an effective extraction for RA from rosemary leaves,when it was compared with traditional method and ultrasound-assisted extraction.Experimental parameters(pH,ultrasonic power,extraction temperature and extraction time)controlling the performance of SUE,were optimized using response surface methodology(RSM)based on Box-Behnken design(BBD).The analysis of variance shown the high quality of the polynomial model.It could be used to predict the results of extraction in some conditions.The optimal extraction conditions were: pH 5.0,sonicated at 44 ? for 40 min,140 W.The proposed method(SUE)was validated by stability of RA,repeatability,recovery experiments.The yield of rosmarinic acid based on dry mass of raw materials was 8.399 mg/g(RSD=1.35%)at the optimal conditions.The static adsorption and desorption behaviors of four macroporous resins(AB-8,D101,X-5,NKA-II)for enriching RA were investigated.The results showed that AB-8 was selected as the favorable resin,according to adsorption capacity,desorption capacity,adsorption rate and desorption rate.1)The effect of temperature and time on the static adsorption of AB-8,as well as,the process of static adsorption was analyzed through kinetics and thermodynamics.i)The pseudo-second-order kinetics model can be applied in representing the adsorption process.Intraparticle diffusion is not the only rat–controlled step and the chemical interaction controls the adsorption to some degree.ii)Langmuir equation and Freundlich equation can be applied in representing the adsorption process.The adsorption behaviors were of monomolecule layer adsorption.AB-8 were then investigated.H was-13.449 8 kJ/mol.2)The effect of temperature and ethanol concentration on the static desorption of Both ethanol concentration and temperature affect the process of desorption.Ethanol concentration was the key factor on desorption rate of RA on AB-8 resin,and 60% ethanol(V/V)was appropriate.Finally,macroporous resin was used to enhance RA through dynamic adsorption and desorption,and the purity of RA could reach 98.6%.Structure identification results showed that,the target product was obtained;Bacteriostatic research shows that: RA has bacteriostatic activity against a broad of bacteria,as well as,Staphyloccocus aureu and Escherichia coli are more sensitive to RA.