ABSTRACT
To study the binding capacity of active ingredients of Daidai lipid-lowering flavonoid extract and plasma protein,investigate the ways to improve the traditional formula for calculating protein binding rates based on ultrafiltration,and increase the stability and reliability of the experimental results. UPLC-MS/MS was used to establish a quantitative analysis method for simultaneous determination of active ingredients( neohesperidin and narngin) in ultrafiltrate. The protein binding rates were calculated by the traditional ultrafiltration formula. The correction factors( F) were introduced later,and the binding rates calculated with the correction factors were compared with those without the correction factors. The binding capacity of the extract and plasma protein was evaluated. The quantitative analysis method established by UPLC-MS/MS had a good specificity. The standard curve and linear range,method accuracy,precision and lower limit of quantitation all met the requirements. The method met the requirement for quantitative detection of the active ingredients in ultrafiltrate after the rat plasma was filtrated in the ultrafiltration tube. Under the experimental conditions,the binding rates of both active ingredients( neohesperidin and narngin) were higher than 90%. The active ingredients and rat plasma protein were bound in a concentration-dependent manner,with statistically significant differences( P<0. 01). There was no statistically significant difference between the protein binding abilities of the two active ingredients with rat plasma protein. Therefore,the active ingredients of Daidai lipid-lowering flavonoid extract had a relatively strong binding strength with rat plasma protein,and they were bound in a concentration-dependent manner. Additionally,when calculating protein binding rates by the traditional ultrafiltration formula,the correction factors could be introduced to effectively reflect the errors of multiple ingredient groups in traditional Chinese medicine extracts.This correction method could provide a reference thinking and practical reference for the improvement of the determination method of the traditional Chinese medicine plasma protein binding ability based on ultrafiltration.