Study On The Enrichment And Separation Of Flavonoids In Propolis

Propolis is the natural bee product contains highest concentration and most kinds of flavonoids in world, with widely biological and pharmacological value. Nowadays, flavonoids concentration of propolis is low because the unsatisfied domestic technology which affects the export price of propolis. It's now of great need to solve this problem. And it will also be of great meaning to new medicine research and development related to flavonoids if the single flavonoid can be separated respectively. This paper dwell on the enrichment of total flavonoids in propolis and separation of its main single flavonoid.Study on determination of flavonoids: AlCl₃ colorimetric method for determination of total flavonoids in propolis was more reliable compared with NaNO₂-Al(NO₃)₃ colorimetric method. A simple and rapid method to detect total flavonoids in propolis was established. Flavonoids in propolis reacts with AlCl₃ to form a stable yellow complex, and its maximum absorption wavelength is 420nm. Regression equation is A=2.367ρ-0.0004, correlation coefficient r = 0. 9997. The absorbance (A) was linear with the concentration of rutin in the range of 0～0.040mg/mL, the detection limit is 0.002mg/mL. The average recovery and RSD(n=10) are 97.8% and 1.6 % respectively.Study on enrichment of total flavonoids by resins: 1)Propolis water solution was obtained by ethanol extraction and water precipitation.Orthogonal experiment was employed to investigate the effect of 4 different factors on solid yield and total flavonoids in water solution. Analytical results showed different importance of the factors: water amount>amount of propolis dissolved in ethanol>temperature>time. 2)Macroporous resins of different chemical and physical property was synthesized. It was found that addition of polar monomer(methyl methacrylate or acrylamide), large surface area and aperture is in favor of flavonoids. Synthesized proper resin to study the technics of flavonoids enrichment. The effect of time and temperature on adsorption and the effect of temperature, ethanol concentration and eluent volumn on desorption of flavonoids was studied. The results showed an optimal process to enrich flavonoids in propolis: adsorption at 35℃water bath for 5h, when using 7BV 75% ethanol as eluent, desorption rate will reach up to 90%. Flavonoid concentration is 36³8% in final products when untreated propolis is about 25%.Study on separation of single flavonoid in propolis: 1)The main flavonoids of propolis was separated through pH gradient extraction, 7,4'-dihydroxy and 7-hydroxy flavonoids are primarily separated. 3 products was gained: product 1(mainly rutin 11.8%, myricetin 12.7%, quercetin17.7%, apigenin3.9%), product 2 (chrysin16.1%, galangin12.4%), product 3 (pino- cembrin15.3%), Single flavonoid concentration is increased 2¹3 times in final products. 2)Dry column chromatography was used finally to separate single flavonoid and get final purity over 60%.