Extraction and Purification of Flavonoids from <i>Radix Puerariae</i>

Abstract

Purpose: To develop an efficient method for the purification of flavonoids from Radix puerariae Methods: Optimal extraction technology was obtained using orthogonal test. Through adsorption and desorption tests, 8 resins with different polarity, diameter, and surface area were studied. Finally, a novel macroporous resin, HPD200A, was applied in the work. Desorption tests were performed in a glass column packed with HPD200A resin, and several parameters of purification were studied. The content of puerarin and flavonoids in the samples were tested by a HPLC and a UV-Vis Spectrophotometer, respectively. Results: Optimum extraction technology was confirmed as follows: extraction time is 1.5 h; ratio of solvent to material 12; and repetition of extraction 3 times. Optimum purification technology was confirmed as follows: decoction is concentrated into 1.05 ~ 1.10 g/ml; 95 % ethanol is added to remove the impurities and the volume ratio is 1.5 : 1; the concentration of loading sample is 0.25 g/ml (based on the weight of the crude drug), the volume of loading sample is 2 BV (bed volume). The mobile phases of desorption are water (2BV) and 30 % ethanol (4BV) in succession. The contents of puerarin and flavonoids in the extract were improved greatly after the purification procedure, by up to 32 and 75 %, respectively. Conclusion: This efficient method has potential for purification and preparation of flavonoids in the future.

Coexisting flavonoids and administration route effect on pharmacokinetics of Puerarin in MCAO rats

“…Radix Puerariae decoction was concentrated into 1.05–1.10 g/mL, and 95% ethanol was added to precipitate the impurities. After that, macroporous resin was used to purify the flavonoids [ 4 ]. The total flavonoids in the final product were determined by ultraviolet spectrophotometry to be about 72%.…”

“…The analysis was conducted with methanol–water by gradient elution at a flow rate of 1.0 mL/min and detected at the wavelength of 250 nm. The content of Puerarin in the Extract was about 35.06% [ 4 ]. There are five main ingredients in the extract (shown in the chromatograph at the wavelength of 250 nm), which were identified as 3′-hydroxypuerarin, puerarin, puerarin xyloside, 3′-methoxypuerarin and daidzin by ultra performance liquid chromatography (UPLC)-mass spectrometry (MS)/MS.…”