Study On The Preparation Of Myricetin And Myricetin-zn(?)and Its Antioxidant Activity

The myricetin monomer is prepared from the blod matter of bayberry leaves by crystallization mainly at this paper,and the zinc ion complexes of myricetin-myricetin-Zn(?)is prepared too.By comparing them with Vc,four antioxidant activities(DPPH radical scavenging rate,hydroxyl radical scavenging rate,superoxide radical scavenging rate and total reducing power)were studied.This study reached the following results.(1)Through the study about the effect of different concentrations of ethanol on crystalline effect,we can derived that applying 60%ethanol concentrations at myricetin recrystallization can achieve good crystallization effect.Under this condition,the purity of myricetin crystallization can be up to 98.5%after 5 times repetition crystallization,and the yield was 46.7%,in addition,the preparative myricetin and its purity were identified by HPLC and ultraviolet spectrum.(2)Within the range of pH7?8,the complex reaction of myricetin with zinc ions was taken,and the chemical structures of myricetin and its complexe were analyzed by UV absorption spectroscopy and Fourier infrared spectra.Taking the composite analysis on Fourier infrared spectroscopy,ultraviolet spectra,the result of elemental analysis and thermal gravimetric analysis,it can be inferred synergism occurred between myricetin and zinc ions,and the substances which produced by reaction composed to[C15H8O8Zn]·2H2O.There also taking preliminary exploration and analysis on reaction mechanism between myricetin and zinc ion.(3)By comparing the research experiments of myricetin,myricetin-Zn(?)and Vc,we can find that myricetin and myricetin-Zn(?)with DPPH radical scavenging rate,hydroxyl radical scavenging rate,superoxide radical scavenging rate,and total reducing power showed a good positive correlation.Meanwhile,all indexes of myricetin-Zn(?)about DPPH radical scavenging rate,hydroxyl radicals scavenging rate and superoxide radicals scavenging rate were higher than myricetin monomer,and it also showed good results in total anti-oxidation ability test,indicating that the antioxidant capacity of myricetin has improved greatly after composing with zinc ion.