Study on extraction of bamboo leaves flavonoids by homogenate extraction technique and its antioxidant activity
Based on the results of single-factor research,the optimum homogenate extraction conditions of total flavonoids from bamboo leaves were confirmed as follows:80%(v/v) ethanol aqueous solution,ratio of solid to liquid of 1:40 and homogenate time of 40 s.Total flavonoids were obtained by isolation of the crude extracts through AB-8 resin column chromatography.Compared with the ethanol reflux method,the homogenate extraction method resulted in the reduction of extraction time from 3 h to 40 s,an increase of 20.2% in the yield of total flavonoids and 63.3% in the yield of isoorientin.DPPH method was used to identify and compare antioxidant activity of total flavonoids obtained by those two methods,and the effect on the elimination of DPPH of total flavonoids obtained by the homogenate extraction method was better than those using ethanol reflux method.The composition analysis showed that total flavonoids in bamboo leaves of Phyllostachys nigra var.henonis mainly contained orientin,vitexin and isovitexin.The homogenate extraction was a simple and high efficient method for extracting bamboo leaves flavonoids.