Screening Of Phenolic Acids And Glucuronides In Plants By Chemical Derivatization

Organic acids are referred to a class of compounds containing carboxyl groups in the molecular structure.They are widely distributed in roots,stems,leaves,fruits and other structures of plants.Phenolic acid and glucuronide are two important types of organic acids.Because phenolic acid and glucuronide have anti-oxidation,antibacterial and other pharmacological activities,they are widely used in foods,medicines and many other fields.In this work,phenolic acid and glucuronide are the research objects,and a simple chemical derivatization-high performance liquid chromatographydiode array detector(HPLC-DAD)method was established.Direct injectionmass spectrometry(DI-MS)was used to analyze the two types of organic acids before and after derivatization.Afterwards,the established method was successfully applied to the screening of organic acids such as phenolic acids and glucuronides in three plants Scutellaria baicalensis,Dandelion and Ginkgo biloba.The main contents are as follows:1.A simple chemical derivatization-HPLC-DAD method to screen phenolic acids was established.The effects of derivatization solvent,temperature,time and catalyst amount on the derivatization of benzoic acid and cinnamic acid were investigated.The best derivatization conditions of benzoic acid and cinnamic acid were obtained,and they were used to derive benzoic acid type phenolic acid(p-hydroxybenzoic acid and gallic acid)and cinnamic acid type phenolic acid(ferulic acid,2-hydroxycinnamic acid and Caffeic acid).Combined with HPLC-DAD,which provides a reference for screening phenolic acids.The mass spectrometric fragmentation pathway of phenolic acids before and after the derivatization were investigated by DI-MS.The results showed that phenolic acids would directly remove a carboxyl group before derivatization,and after derivatization,the methoxy group would be removed first.The exploration of the fragmentation pathway of phenolic acids can provide certain theoretical guidance for the follow-up study of phenolic acids.2.A simple chemical derivatization-HPLC-DAD method to screen glucuronides was established.The effects of derivatization solvent,temperature,time and catalyst amount on the derivatization of baicalin were investigated.The best derivatization conditions for baicalin were used to derive wogonoside,luteolin-7-O-?-D-glucuronide and apigenin-7-O-?-Dglucuronide.Combined with HPLC-DAD,which provides a reference for screening glucuronides.Through DI-MS,the mass spectrometric fragmentation pathway of glucuronides before and after derivatization was investigated.The results showed that the glucuronides directly broke the connected glycosidic bonds before and after derivatization.The exploration of the fragmentation pathway of glucuronides can provide certain theoretical guidance for its follow-up research.3.The established simple chemical derivatization-HPLC-DAD method for screening phenolic acids and glucuronides was successfully applied to the screening of organic acids in Scutellaria baicalensis,Dandelion and Ginkgo biloba.9 glucuronides in the Scutellaria baicalensis extract were successfully screened and identified by HPLC-MS/MS.10 substances with changed retention time were screened in the Dandelion extract,and caffeic acid and ferulic acid were confirmed.The Ginkgo biloba extract was derivatized under different conditions.A total of 9 substances with changed retention time were screened out.According to different derivatization conditions,it is speculated that 3 of them may be glucuronides.This method is simple and has wide applicability,which opens up a new way for the screening of plants containing a specific functional group of carboxylic acid.