Isolation And Determination Of Procyanidins From Flos Rosae Rugosae And Study Of Their Antioxidant Activity

Flos Rosae Rugosae is a kind of chinese traditional medicine material.It is recorded in 'Compendium of Materia Medica' that it has great effectiveness on keeping young,and this is recepted extensively.Procyanidins are kinds of polyphenol with great antioxidant activity and then extensive pharmacological activity. Procyanidins are natural antioxidants which have prospects of development and hasve been marketed by a lot of countries as medicine,health food and cosmetics.This paper studied on the extraction and isolation of procyanidins from Flos Rosae Rugosae,developed a HPLC analysis method for determination of them and evaluated the antioxidant activity of procyanidins comparing with that of VC.Procyanidins were extracted from Flos Rosae Rugosae with microwave assisted. The effection of microwave reaction time,times and ratio of solid/solvent on the percentage of procyanidins extraction was investigated by the single-factor experiment.The best extracting conditions were as follows:60%ethanol as the extracting solvent,ratio of solid/solvent 1:20,microwave power 5.00V,microwave reaction time 20min,one times,percentage of procyanidins extraction can achieve to 1.59%.Compared with solvent extraction only,extraction with microwave assisted had better performance.The extracted crude procyanidins powder was purified by macroporous adsorbent resin.In the beginning,a suitable type of macroporous adsorbent resin had been selected from five types including D101,D1300,NKA,AB-8 and NKA-â…¡.Evaluated by static saturated adsorption ability and elution percentage,D101 was thought to be the most suitable type of macroporous adsorbent resin for the purification of procyanidins.Its static saturated adsorption ability was 9.3mg/g wet resin and elution percentage 7.2%.Evaluated by product purity and recovery,the influence of concentration of sample,pH of sample,concentration of eluant and flow rate of elution had been investigated by orthogonal experimental design.Analysis of range and analysis of variance were used to determine the optimal parameters of the purification process,the results were:1.25mg/ml as the concentration of sample,2 as the pH value of sample,70%ethanol aqueous solution as the eluant and 2ml/min as the flow rate of elution.Kinetics about process of purification had also been studied.The curves of dynamic adsorption-elution process had been plotted,and the kinetic equation was ⁽Y = 1.18(e^0.31x -e^-0.79x))A HPLC method was developed for analysing monomers and dimers of procyanidins from Flos Rosae Rugosae.The column was Eslipse XDB-C18, 4.6mm×150mm,5μm,and thermostated at 30℃.The elution conditions were as follows:flow rate,1 ml/min;solvent A,1.0%AcOH in H₂O;solvent B,CH₃CN; elution starting with 5%B and continuing with a linear gradient from 5 to 10%B in 10min,then 10%to 25%in 100min.The method was validated with respect to resolution,linearity,precision and recovery.Epicatechin,epicatechingallate and procyanidins B2 had been quantitatively analysised,and their contents respectivly were 0.612%,0.257%,2.54%.The antioxidant activity of procyanidins was evaluated by the amount of antioxidant necessary to decrease by 50%the initial DPPH concentration.The study showed that EC50 for procyanidins was 0.052mg/ml while for VC was 0.066 mg/ml, the conclusion can be drawn that the antioxidant activity of procyanidins is strong than that of VC.