The Research On Purification And Properties Of Curcuminoids

Turmeric(Curcuma longa L.),a kind of traditional perennial herb,used as medicine and food as well,is widely cultivated in Southeast and Southwest of China.It widely applied in the field of traditional Chinese medicine with the function on adjusting menstruation and analgesia,dispelling wind and activating blood and fending off the cold and anti-inflammatory.As major function compositions in turmeric,curcuminoids are used as a series of natural pigments widely used in the food industry for good dyeing effect and high security.Due to its excellent properties of anti-oxidation,anti-cancer and scavenging free radicals,curcuminoids have been broadly applied in clinic as anti-cancer drugs,and shows good anti-oxidation and whitening effect in the cosmetics industry.Recently,more and more studies of curcumin compounds are applied to health foods.This paper was mainly carried out to detect,extract and purify curcuminoid in the rhizome of turmeric,and the anti-oxidation of curcuminoid and the liquid of purification were studied.The main researched contents and results are as follows:Firstly,using the turmeric root as source of curcuminoids,a HPLC method was established for the determination on the contents of the three kinds of curcuminoids in rhizomes,and the method was verified by testing turmeric of different planting areas,years and curcumin beverage.The HPLC method adoped DIKMA Platisil ODS column(4.6 mm × 250 mm,5 ?m)and acetonitrile-water(pH=3.0 adjusted by phosphoric acid)with gradient elution at a flow rate of 1 mL/min.The column temperature was set at 30 °C,the UV detection wavelength was 415 nm and the injection volume was 20 ?L.Gradient elution program was: 0 ~ 10 min,acetonitrile concentration was 60%,10 ~ 15 min,acetonitrile concentration from 60% to 65%,15 ~ 20 min,acetonitrile concentration from65% to 60%.The result showed that the precision,stability and reproducibility of the method are good and reliable.Secondly,with the turmeric in Burma in 2015 as source of curcuminoids,the result of test showed ultrasonic-assisted extraction was suitable for the curcuminoids extraction from turmeric.Single factor method,Plaekett-Burman experimental design and the response surface analysis were used to optimize the extraction process which employed curcumins yield as the response and ethanol concentration,solid/liquid ratio,extraction temperature,extraction time and ultrasonic power as the independent variables.The optimal extraction conditions for curcumins were determined as follows: ethanolconcentration,80.4%;solid/liquid ratio,1:21.9 g/m L;ultrasonic temperature,41 °C;ultrasonic time,40 min;and ultrasonic power,200 W;Under these conditions,the yield of curcuminoids was 4.43% and the extraction yield was 92.87%.The optimized extraction method could greatly improve the extraction yield of curcuminoids.Thirdly,adopting the curcumin adsorption and desorption rate as index,the result of test showed macroporous resin was suitable to purify curcuminoids by comparing the effect of macroporous resin,anion exchange resin and cation exchange resin.By comparing the macroporous resin from AB-8?ADS-17?S-8?D101?DM130?DA201?HPD-100?HPD-400?HPD-600 and HPD-750,the screened appropriate macroporous resin was aforementioned macroporous resin DA201.On the basis of static research,the optimal condition for the purification of curcuminoids with the appropriate macroporous resin DA201 was obtained by the method of dynamic adsorption and desorption: the ratio of diameter to height was 1:10,the pH value of liquid sample was 6.0,the speed of the sample was 2 BV/h,the concentration of sample concentration of bisdemethoxycurcumin,demethoxycurcumin and curcumin were 286.39 mg/L,267.90 mg/L,324.23 mg/L,total curcuminoids concentration was 878.52 mg/L,the sample volume was 3.5~4 BV;the rate of elution was 2 BV/h,the concentration of eluent was 90%~100%,the desorption volume was 5.25 BV.Under this condition,the purification recovery of bisdemethoxycurcumin,demethoxy curcumin and curcumin were 95.78%,91.34%,79.92%,the purity of curcuminoids was 80.25%,which increased 42.23% by comparing with the content before and after purification.Finally,The antioxidant activity of curcuminoids was studied through the vitro antioxidant activity,including the ability of scavenging ABTS+·?DPPH·?OH·?O2-·and the ability of chelating ferrous ion and reducing iron.The results of the study showed:curcuminoids had abilities of scavenging ABTS+·?DPPH·?OH·?O2-·,chelating ferrous ion and reducing iron,and with the concentration increasing,oxidation resistance increased in a certain concentration range.Due to antioxidant ability of curcuminiods are related to its chemical structure,the antioxidant activity of curcumin,demethoxycurcumin and bisdemethoxycurcumin are difference.Hydroxyl hydrogen on the benzene ring,the methylene hydrogen in the middle of beta diketone and the number of phenolic hydroxyl and the chemical environment could influence its antioxidant activity.