Application LPME In Medicine Oleanolic Acid And Ursolic Acid Analysis And Protein Binding In

Isomeric triterpenic acids of oleanolic acid (OA) and ursolic acid (UA) bothhave very low UV absorption and always exist in the same plant, so the separationand simultaneous determination of them have been a difficult task. Objective In thisstudy, a sensitive method combining dispersive liquid-liquid microextraction(DLLME) with HPLC-UV detection was developed for the extraction anddetermination of OA and UA in traditional Chinese medicinal herbs (CMHs). Whichis an effective, convenient and encironment-friendly pre-processing method forCMHs. Methods Variables influencing DLLME such as type and volume ofextraction solvent, volume of dispersive solvent, ionic strength, aqueous phase pH,extraction time, centrifugation speed and time, and sample volume were investigatedand optimized. The analytes were extracted by DLLME system and analyzed byHPLC. Results Under the optimum conditions, both OA and UA attained favorableextraction efficiencies with enrichment factors1378and933, respectively. The lineardynamic ranges of0.07-30.4μg/mL for OA and0.08-33.6μg/mL for UA wereobtained with square correlation coefficients of0.9963. The detection limits of OAand UA were both0.02μg/mL. The method recoveries ranged between88.2%-116.2%for OA and85.7%-108.2%for UA with the relative standarddeviations (n=5) lower than8.6%. Conclusion The proposed method was applied toconcentrate and simultaneously determine these two triterpenic acids in Hedyotisdiffusa and Eriobotrya japonica samples. Being friendly to environment, it is a quickand effective technique for CMHs pre-processing. In this work, hollow fiber solvent bar microextraction coupled with HPLCand used in concentration and determination of oleanolic acid (OA) and ursolic acid(UA) in Chinese medicinal herbs. Objective Analyzed and discussed the extractionmechanism of HFSBME; applied to the real samples for enrichment anddetermination of OA and UA. Methods On some factors influencing HFSBME wereoptimizated, compared the extraction results with several other extraction modes andrevealed extraction mechanism; the extraction recovery (ER) and enrichment factor(EF) of analytes after HFSBME and their relationship were defined and derived.Results Under the optimum conditions, the EFs of OA and UA were141.8and47.3;the linear range were3.6-1820.0ng/mL and4.2-2080.0ng/mL; the detection limitwere1.3and1.5ng/mL; the average recovery ranges were between93.2%-116.7%for OA and83.3%-114.2%for UA, respectively. Conclusion HFSBME combinedwith HPLC was used in simultaneous extraction, enrichment and determination ofOA and UA, it was turned out that HFSBME coupled with HPLC is a mode withsimple operation and high sensitivity, low detection limit. In the present work, hollow fiber solvent bar microextraction (HFSBME)combined with HPLC was applied to research interaction between drug and protein.Objective and Methods HFSBME combined HPLC determined simultaneously andrapidly the protein-binding rates between drugs and bovine serum albumin (BSA) orhuman serum albumin (HSA), calculate and obtained the numbers of binding sitesand binding constants of two triterpenic acids compounds; Ttried to investigateinteractions between drugs and colon cancer cell line HCT116, implemented positivecontrol experiment of indomethacin and HCT116cells, got some preliminaryconclusions. Results The protein binding rates of OA and UA were73.5%and90.9%，the binding constants were53500and90900, the number of binding sites bothwere0.2with BSA, respectively; the protein binding rates of OA and UA were81.1%and91.0%，the binding constants were87400and121300, the number of bindingsites were0.2and0.1with HSA, respectively. Conclusion The results demonstratedthe utility of HFSBME method for measuring drug-protein binding is simple andreliable. It provides a potential tool for screening the active ingredients of TCMs andclarifying the material basis for pharmacodynamics.