Research On The Removal Of Ginkgoic Acid From Ginkgo Tea

Ginkgo tea is a kind of health tea,which is made of ginkgo bilobaleaf.In recent years, ginkgo tea is caused widely attention by its activeingredients ginkgo flavonoids and ginkgo terpene lactones in a significanteffect on the prevention and treatment of cardial-cerebrovascular disease.However,ginkgo tea also contains ginkgolic acids(Ginkgolic Acids,GAs),which are allergenic and induced cytotoxic, the National QualitySupervision Bureau had identified the ginkgo tea as health food formallyin2010.How to remove ginkgolic acid in ginkgo tea processing to ensuredrinking safety was less studied.In this study, using response surface analysis method to optimizethe ultrasonic assisted extraction processing of ginkgolic acid;Studyingon the method of detection of ginkgolic acid by using ultravioletspectrophotometer(UV) and high performance liquid chromatography(HPLC);Using response surface analysis method to optimize theultrasonic assisted extraction processing of ginkgo flavonoid;Studyingon the detection of ginkgo flavonoid by using ultravioletspectrophotometer. The results of this study were as follows:The optimum extraction conditions of ginkgolic acids in ginkgo teawere as follows: ultrasonic power was250W, ultrasonic time was44min,liquid-solid ratio was43:1, ultrasonic frequency was45KHz andextraction one time. Under these conditions, the ginkgolic acids was1.44%. The optimum extraction conditions of ginkgo flavonoid inginkgo tea were as follows: volume fraction of ethanol was80%，ultrasonic time was44min, liquid-solid ratio was43:1,ultrasonic powerwas259W,ultrasonic frequency was45KHz and extraction one time.Under these conditions, the ginkgo flavonoid was1.976%.The chromatographic conditions for HPLC detection of ginkgolicacids were as follows: the flow rate was1.0mL/min, the columntemperature was40℃,the mobile phase was methanol:1%aqueousacetic acid(88:12,V/V) and the detection wavelength was at310nm. This method is reproducible,chromatographic peak area was linearlycorrelated with GA concentration, the RSD is better, the recovery ofhigh accuracy. The method is simple, quick and accurate,and is thereforesuitable for the GAs analysis in ginkgo tea;The results on UV detectionof ginkgolic acids showed that there was a linear relationship within therange of0.009～0.093mg/mL（R~2=0.9997）, the RSD was2.15%,theaverage recovery was100.90%,the results being detected by UV wereclose to those by HPLC,absolute deviation <5%,which detectionequipment cheaper, more suitable for the laboratory.Study on method ofginkgo flavonoid quantitative analysis: using rutin as standard ofcomplex spectrophotometric,colored15min,then detecting at510nm.The extraction method is simple and easy to do. Detection method havegood stability and repeatability.Through the study of ginkgolic acids and ginkgo flavonoidscontents change with season and time of day rule, The results showedthe picking seasons selected8-10,at the same time the picking timesselected10:00-16:00. In these times,ginkgolic acids contents werelower, and ginkgo flavonoids contents were higher,The study of four different preprocessing methods (acid, alkali, lowtemperature) to remove GA showed that the best methods were choosingfrozen2h in-18℃, pH was8alkali solution soaking ginkgo biloba leaf.In these condition,ginkgolic acids contents were lower, and ginkgoflavonoids contents were higher.Four kinds of tea processing (green tea, oolong tea, black tea andblack tea) to remove GA showed that the black tea processed can getginkgolic acids contents down to0.57%, ginkgolic acids removal ratewas52.10%, and ginkgo flavonoids content was higher to1.87%. Theresult showed that ginkgo biloba after tea processing to some degree ofremoving ginkgolic acid, suitable for used in the manufacturing of thesmall side effects and health care component content high health caregingko tea.Through the removal of ginkgo acid production process from theself-made virus-free ginkgo tea, ginkgo tea compared with domesticmarket, which the low content of ginkgo acid, ginkgo flavonoids content were little difference.Ginkgolic acids and ginkgo flavonoids dissolution results showedthat each immersion ginkgolic acids and flavonoids were stripping, thetotal dissolution rate of ginkgolic acids was11.23%, the total dissolutionrate of ginkgo flavonoids was90.29%. As a result of ginkgolic acidsshowed weak polarity, difficult to dissolve in water, only part ofginkgolic acids dissolution, and ginkgo flavonoids contains morehydroxyl groups, showing a hydrophilic, at the same time thetemperature increase of ginkgo flavones water soluble, so that a largenumber of dissolution of ginkgo flavones.