Isolation, Purification, Identification And Antioxidant Activity Of Celery Leaf Phenolics

Celery is a perennial umbelliferae herbaceous plant,with antioxidant,anti-cancer,anti-inflammatory,blood pressure,blood lipid,analgesia and other functions.Among them,antioxidant activity is the basis of many biological activities.The phenolic compounds in celery are an important component of the above-mentioned effects,While the highest content of phenolic compounds in celery is celery leaves.However,the report about separation and purification of main phenolic compounds from celery was few,and the relationship between the structure and the biological activity of the phenolic compounds from celery could not be fully described.So,column chromatography and preparative liquid chromatography were used to enrich,separate and purify the phenolic compounds in celery leaves.Then,the monomers were identified by means of various instrumental analysis methods.Finally,the antioxidant activity of celery phenolic monomer was studied by cell model and chemical methods,in order to screen out components with high antioxidant activity and investigate the relationship between phenolic compounds structure and antioxidant activity.The results were as follows:(1)The extraction of phenolic from celery leaves was determined by HPLC,and there were 17 kinds of phenolic compounds in celery leaves.Then,D101 macroporous resin,preparative high performance liquid phase,and Sephadex LH-20 dextran gel column were used to separate and prepare the crude extract of celery leaves.A total of 14 compounds were obtained and the purity of HPLC was more than 96%.(2)The extraction of phenolic and the prepared fractions from celery leaves were determined by High performance liquid chromatography with electrospray ionization mass(HPLC-ESI-MS/MS),ultraviolet spectroscopy(UV),infrared spectroscopy(IR)and nuclear magnetic resonance(NMR).A total of 17 compounds were identified,which were chlorogenic acid,Pcoumaroylquinic acid,luteolin 7-O-?-D-apiofuranosyl(1?)-?-D-glucopyranoside,luteolin 7-O-?-D-glucopyranoside,apiin,chrysoeriol 7-O-?-D-apiofuranosyl(1?2)-?-D-glucopyranoside,apigenin 7-O-?-D-glucopyranoside,luteolin 7-O-[?-D-apiofuranosyl(1?2)-(6"-O-malonyl)]-?-D-glucopyranoside,chrysoeriol 7-O-?-D-glucopyranoside,luteolin 7-0-(6"-O-malonyl)-?-D-glucopyranoside,chrysoeriol 7-O-?-D-apiofuranosyl(1?2)-(6"-O-malonyl)]-?-D-glucopyranoside,apigenin 7-0-(6"-O-malonyl)-?-D-glucopyranoside,chrysoeriol 7-0-(6"-O-malonyl)-?-D-glucopyranoside,luteolin,apigenin,and chrysoeriol.It can be seen,celery phenolic compounds are mainly apigenin,luteolin,chrysoeriol and their derivatives and some phenolic acids.(3)The antioxidant activities of phenolic compounds in celery were studied by chemical assays(DPPH,ABTS,ORAC assays)and cellular antioxidant activity(CAA)method.The results of the four methods showed that luteolin,luteolin 7-O-?-D-glucopyranoside,luteolin 7-O-?-D-apiofuranosyl(1 ?2)-?-D-glucopyranoside,luteolin 7-0-(6"-O-malonyl)-?-D-glucopyranoside had high antioxidant activity and had a certain dose-effect relationship.Chlorogenic acid,apigenin,chrysoeriol and their derivatives showed good antioxidant activity in vitro antioxidant experiments,but showed very low cell antioxidant activity.Both DPPH and ABTS assays showed that the antioxidant activity of luteolin with 3',4'-OH on B-ring was significantly higher than that of apigenin with 4'-OH(P<0.05),and O-glycosides on A-ring had lower antioxidant activity than that of aglycones,while ORAC assay showed that apigenin had higher activity than luteolin(P<0.05).CAA results showed that apigenin and its glycosides with only one OH on B-ring but no C-OH had no cellular antioxidant activity,but luteolin and its glycosides with 3',4'-OH on B-ring had higher cellular antioxidant activity.It can be seen that celery phenolic monomer had good antioxidant activity and was closely related to the structure of the compound.Among them,luteolin and its derivatives played an important role in antioxidation of phenolic compounds of celery leaves.