The Research On Extraction, Purification And Antioxidantion Of Bamboo-leaf Flavonoids

Bamboo leaves flavone is a natural ingredient and has many bioactivities such as antibiosis, antioxidant, anti-free radicals, anti-aging, antitumor activity and protect our cardiovascular. Bambusa textiles var. persistens. was the main research object in this dissertation. First of all, total flavonoids in six species of bamboo leaves was measured by Uv spectrophotometry and HPLC analysis of orientin and rutin’s were established as also, six bamboo species are Bambusa textiles var. persistens., Phyllostachys pubescens Mazelex H.deLehaie, Phyllostachys kwangsiensis W. Y. Hsiung et al, Phyllostachys bambusoides f. lacrima-deae, Phyllostachys heteroclada Oliver, Bambusa multiplex cv. Alphonse-Karr. And then, based on single-factor experiment, the extraction process was optimized by orthogonal design, than the bamboo leaf extract was purified by polyamide. At last, in vitro DPPH and ABTS free-radicals scavenging experiment is operated to measure the antioxidant ability of flavonoids from Bambusa textiles var. persistens. leaves, and flavonoids from Phyllostachys pubescens Mazelex H.deLehaie leaves and Vc were used as contrast.Main results are shown as follow:(1)Rutin as the standard sample, using Uv spectrophometry to measure total flavonoids in six species of bamboo leaves. The linear equation was A=0.018C-0.004, R2=0.9999, it is shown a good linear relationship at the range of0～34.56mg·L-1. Repetivity, stability and recovery rate experiment indicates this method is workable.(2)HPLC analysis of orientin and rutin in six species of bamboo leaves were established. The baseline separation of orientin and rutin was obtained under the chromatographic conditions. Linear equation of orientin was S=37762c+65734, R2=0.9997; Linear equation of rutin was S=30914c-4862, R2=0.9997. Precision, repetivity, stability and recovery rate experiment indicates this method is workable.(3)Based on single-factor experiment, extraction process was optimized by orthogonal design, and the optimum conditions were ethanol concentration of70%, ratio of solid-liquid to1:25(g:mL),3extraction times,1.5h for each time. The yield of flavonoids were up to1.85%under the optimum conditions.(4)Flavonoids were purified by polyamide column chromatography. Polyamide was more fittable to purify flavonoids by the contrast to AB-8macroporous resin. And the suitiable purification conditions were4BV crude extract contained1.08mg·mL-1flavonoids passed the polyamide column at the speed of2BV·h-1. After a while, the column washed by water till effluent colorless, then8BV of80%ethanol was used to desorption. At this condition, the product contained51.2%of flavonoids, nearly4times of the crude extract and the transfer rate were up to83%.(5)In vitro DPPH and ABTS free-radicals scavenging experiment was conducted, flavonoids from Phyllostachys pubescens Mazelex H.deLehaie leaves and Vc were used as contrast to flavonoids from Bambusa textiles var. persistens. leaves. DPPH free-radicals’half inhibitory concentration IC50of three material were respectively107.7mg·L-1,78.2mg·L-1and42.9mg-L-1; ABTS free-radicals’half inhibitory concentration IC50of three material were respectively72.0mg·L-1,37.1mg·L-1and75.0mg·L-1. the DPPH and ABTS free-radicals scavenging abilities goes to54.9%Vc and49.5%Vc respectively. It was showed that flavonoids from Bambusa textiles var. persistens. leaves owned a strong antioxidant ability.