MOA of Total phenolics in Echinacea extract
1.Instruments and Solvents
Instruments: Ultraviolet spectrophotometer
F-C Solvents: Measure 350ml water to 1000 ml round bottom flask.then add 50 gram Na2WO4.H2O, 12.5gram Na2MO4, 25mL85%H3PO4 , 50mLconcentrated hydrochloric acid and a few zeolum, heating reflux for 10 hours ,then flush the condenser pipe with 50ml water ,add 75gLi2SO4.H2O，several drops of Br2, Boiling for 15mins,the solvent turn to yellow finally, cool to room temperature, dilute to volume with water. filter to amber bottle .
20% Na2CO3 solvent: Dissolving 40gram anhydrous sodium carbonate to 150ml water and still standing it for a whole night, then filter it .
Preparation of reference solution: Accurately measure 500mg dry gallic acid to 100ml volumetric flask. dilute to volume with water.
Preparation sample solution :Accurately measure 30mg Echinacea extract powder to 25ml volumetric flask, ultrasonic oscillating 20 mins in 20ml water ,cool to room temperature , dilute to volume with water.
3.Determination of the sample
Standard curve drawing: Accurately pipet the above reference solution 0,1,2,3,5,10 mL to different 100ml volumetric flask, dilute to volume with water; and then pipet 1ml above solvent to 100ml volumetric flask respectively, add 60ml water and shake well. then add 5ml F-C solvent ,30 seconds later, add 15ml 20% Na2CO3 solvent, shake well , dilute to volume with water. still standing for 2hours,and then measure absorption value at 760nm With the reagent blank as reference, Drawing A – C standard curve。
Assaying: take sample solvent 1ml in 100ml volumetric flask, test absorbance same as the standard curve(from the step add 60 ml water on).
4.Calculate: read and calculate the content according to the standard curve.