Study on extracting technology of flavonoids from Pueraria Lobata Ohwi and determination of flavonoids by three-wavelength spectrophotometry

To optimize the ethanol reflux extraction of flavonoids from Pueraria lobata Ohwi,ethanol concentration,extraction time,material-solvent ratio and extraction times were used as the criteria in the progressive single factor experiment,and an orthogonal test of L9(34) was designed.Taking rutin as the standard,determination of Pueraria lobata Ohwi flavonoids measured by adopting three-wavelength spectrophotometry can eliminate the absorbance error.The regression equation of concentration ΔA was obtained and listed as follows: ΔA=0.011 7+0.012 6c with a relation coefficient r=0.999 6.The experimental results demonstrating the rutin concentrations in 0-30 μg·mL-1 was measured at wavelength λ1=495 nm,λ2=412 nm,λ3=368 nm.The influence factors' priority was: the ethanol concentrationextraction timematerial-solvent ratioextraction times.For the primise condition of puerarin material for a 80 mesh pharmacopoeia sieve and temperature of 70 ℃,the optimum ethanol extraction process was as follows: ethanol concentration of 70%,material-solvent ratio of 1∶ 20,extraction times of 2 and each time of 2.5 hours.In this condition,the Pueraria lobata Ohwi flavonoids extraction rate was 0.145 2 mg/g.