Study On Flavonoids Content, Extraction And Purification Process In Pigeonpea Leaves

In the study, a method was established to detect the total flavonoids content of the pigeonpea leaves.131 kinds of pigeonpea were collected and the total flavonoids content were detected in leaves. The total flavonoids contents from different parts of the pigeonpea were also researched. In addition, the theme studied the ultrasonic extraction and purification processes from the pigeonpea leaves of total flavonids. The main studies were performed just as follows:1. A detection method of total flavonoids by UV spectrophotometer was established. The standard curve of the method had higher linearity (R2=0.9999) in the concentration of 0-100 ug/mL. The average recoveries of the detection method were 99.01-102.72%. The result indicated that the method had excellent stability and repeatability.2. The total flavonoids contents were detected in pigeonpea leaves from 131 different kinds. As a result, There were extremely significant difference in the total flavonoids contents of the pigeonpea leaves among different kinds. The highest content was 4.73%, while the lowest was 1.10%, the highest content was 3.3 times more than the lowest.3. Researches about the total flavonoids in the different parts of the pigeonpea have been done in this stage. The results showed that, the flavonoids were mainly distributed in pigeonpea flowers and leaves, there was little flavonoids content in the seeds. The flavonoids content from highest to lowest as follows:leaves> flowers> pod skins> petiole> pods. Then, the total flavonoids in the leaves of different growth period were analyzed, new leaves has higher total flavonoids content than that of the mature and old leaves. In the different growing period which is from 75 days after seeding to blossom time, the flavonoids content in the pigeonpea leaves showed significant accumulation phenomenon as time went on.4. Researches of ultrasonic extracting of total flavonoids in pigeonpea leaves were taken in this stage. Using single factor design and L9(34) orthogonal experiment, this stage discussed the effects of the following factors:ultrasonic extraction time, the concentration of ethanol and the solid-liquid ratio condition. And found the optimal extraction conditions which was:20 min ultrasonic extraction,70% ethanol,1:30 solid-liquid ratio. With above extraction condition, the yield of total flavonoids was 38.1%, the purity of total flavonoids was 9.32%.5. Purification of the extract solution of pigeonpea leaves was studied. The result indicated that the flavonoids content in the extract could be trapped 15.78% by the microfiltration membrane,62.52% by ultrafiltration membrane, and 97.92% by nanofiltration. After the separation of the microfiltration, ultrafiltration and nanofiltration, the total flavonoids in the extractions had the purity of 50.13%. In the ultrafitration concentrate, the content of vitexin was 0.069 mg/g (HPLC) and isovitexin was 4.31 mg/g(HPLC).