Study On Extraction And Purification Technology And Biological Activity Of Red Pigment From Flowers Of Cercis Chinensis Bge

Cercis chinensis Bge. belongs to Cercis of Leguminosae, is widely cultivated all parts of our country, having a long flower season, blooming in bright color and giving a high -yield output of pigment. Hence it is a comparatively ideal natural source of red pigment.However,so far there has been no systemic report on the development of this natural source. This thesis is composed of six parts:an introduction to the study on natural plant pigments, the study on ultrasonic extraction of the red pigment from Cercis chinensis Bge., the study on purification by macroporous adsorptive resin, the study on stability and physic-chemical characteristics, the study on antioxidant activity of this red pigment and a conclusion. The purpose of this thesis is that providing some experimental date for further development and utilization , providing some theoretical basis for increasing the value of this pigment.Introductory chapter provides an introduction to the study on the development of some plant pigments both at home and abroad,bringing up the topic of this thesis.As a new method of extraction,ultrasonic was used to extract red pigment from flowers of Cercis chinensis Bge.Orthogonal test and mono-factor test explores the ultrasonic extraction conditions, the factors that affecting ultrasonic extraction: ratio of raw material to solvent >ultrasonic power≈alcohol concentration>extraction time; specifically as follows: dry flower 2.000 g and twice of extraction, 25～35℃, solid : liquid l:20(g:ml), 15min, 70 W, 85% alcohol. Through the optimum conditions , the products were special purple flower paste objects,theλmax was 526 nm, color value E (1%, 526 nm) was 25.6.The conditions were studied to refine red pigments from flowers of Cercis chinensis Bge.using the macroporous adsorptive resin. And the performance of adsorption and desorption for red pigment with five macroporous resins X-5,AB-8,S-8,D4020 and NKA-9 was compared.By AB-8 static and dynamatic experiments, the results showed that: the AB-8 was better than the others,and the 100% acetone was good eluant. As the following conditions: concentration of flower original solution(to represent with absorbance) was 0.7 more or less,20～40℃, pH=1～2, acetone desorption, adsorption velocities of flow 2.0 ml/min, desorption velocities of flowl.5 ml/min,the product yield of the pigment was 4.31 %,and the color scale E(l%, 526 nm) of purificatory pigment was 271.The stability and physic-chemical characteristics of red pigment have obviously enhanced after purification. It melts in water, alcohol,acetone and other polar solvents freely, not dissoluble in petroleum ether and other non-polar solvents. It was red in acidic solutions,and more brighter in pH=1～2. It was sensitive to H₂O₂, Na₂SO₃, and was stable to light,heat, sodium benzoie acid ,malic acid,citic acid,sucrose, VC ,Na⁺,Mg²⁺,Zn²⁺,Al³⁺.Fe²⁺and Cu²⁺ can protect the extracted colorant, Fe³⁺ make it brown. Chemistry color reaction showed that: phenomena of colour reaction of red pigment is the same with color characteristics of anthocyanin. To sum up that it is a kind of anthocyanin pigment of flavonoid class.Antioxidant activity of the purificatory pigment was studied by established model systems in vitro. Its reducing power was mensurated,and its performance of scavenging Superoxide anion radical(O₂^-·)by oxidation of pyrogallal method and scavenging hydroxyl radical(·OH )by fenton method was mensurated too.The result shows that: the antioxidant activity has to do with its concentration,and its reducing power higher than VC, its inhibiting effects O₂^-·more than·OH. When the concentration of pigment solution is 0.100 g/L, the ratio of scavenging·OH is 80.69%, scavengingO₂^-·44.87%, and they both more than VC.