Studies On The Extraction, Separation, Purification Of Guava Leaf Flavonoids And Their Vitro Bioactivities

This paper introduces the research and application progress of guava both at home andabroad and makes the detailed narration about flavonoids.Due to the different guava varietiesand growth year,the type and content of flavonoids in guava leaves are different.We shouldstudy the type and content of flavonoids before we applicate them,therefore,it is necessary todo the research about different guavas.This research used guava leaves which is provide byjiangmen city jianghai district south guangdong gold pomegranate tea factory to study theextraction,separation-purification,and their vitro bioactivities of guava leaves.In general,the determination method of flavonoids is NaNO₂-Al（NO₃）₃colorimetricmethod,differential spectrophotometry, AlCl₃colorimetric method and HPLC method. On thebasis of high performance liquid chromatography（HPLC） method compared with orther threemethods,we choose the differential spectrophotometry,which is simpe,stable and accurate,as amethod for determination of the experiment.On the basis of single factor experiment,effects of ethanol concentration,solid-liquidratio,extraction period, extraction times were studied by taking the content of total flavonoidsas the main index and the dry paste yield as the secondary indicator.The proper condition wasdetermined by orthogonal experiment.The orthogonal test showed that the ethanolconcentraction,the solid-liquid,the extraction period,the extraction times were40%,1:20,1h,3times.Under this condition,the extraction rate of total flavonoids reached3.3%,the dry pasteyield reached27.8%.Used AB-8macroporous resin to purify guava leaf crude drug,the results showed that:the purify of the flavonoids in crude extracting from guava is7.8%,the flavonoids is13.28%after puritation.It is increased70.26%.Chosed DPPH free radical method,ferrous sulfate-salicylic acid-hydrogen peroxidemethod,and the determination of reducing power experiments,α-glucosidase inhibitoryexperiments, study the DPPH radical scavenging,hydroxyl radical scavenging,reducing powerand α-glucosidase inhibitory of sample A,sample B.The study found that the order of thestrength of radical scavenging and reducing power is:sample B>sample A.The inhibitoty ofsample B is stronger than sample A.