Application Of Micellar Electrokinetic Capillary Chromatography In The Study Of Active Components In Tripterygium Wilfordii

Objective:The purpose of this paper is to study triptolide(TPL),triptophenolide(TPNL),triptonide(TPN),wilfortrine(WTR),wilforgine(WG),wilfordine(WD),wilforine(WR)in Tripterygium wilfordii Hook.F.(TWHF)and Tripterygium preparations by micellar electrokinetic capillary chromatography(MEKC)and establish a simple,comprehensive and high-efficiency method to determine the content of seven active components in TWHF and Tripterygium preparations.Additionally,the proposed method provides scientific evidences for quality control of TWHF.Method:(1)The optimal extraction scheme of terpenoids and alkaloids in Tripterygium wilfordii Hook.F.(TWHF)and Tripterygium preparations was obtained by investigating the different extraction solvent and combining with sample pretreatment method.(2)A micellar electrokinetic capillary chromatography method was established for the determination of three terpenoids(triptolide,triptophenolide,triptonide)and four alkaloids(wilfortrine,wilforgine,wilfordine,wilforine)in TWHF and Tripterygium preparations.The buffer solution was borax,with sodium dodecyl sulfate(SDS)as surfactant and methanol as organic modifier.The best separation condition of seven target analytes was obtained by investigating the influence of the concentration of SDS,the concentration and pH value of the buffer solution,the content of methanol,operatingvoltage,and temperature on the separation.The total length of uncoated fused capillary column was 40.2 cm(effective length 30.0 cm,75 ?m inner diameter);The buffer solution was 10 mM borax solution,30 mM SDS,and 30%(v/v)methanol.The operating voltage was of 20 kV;The temperature of the system was set at 25°C;The detection wavelength was fixed at 218 nm;The injection pressure was 0.5 psi,and the injection time was 5 s.Results:(1)The experimental results showed that the target analytes could be obtained by ultrasonic extraction of Tripterygium wilfordii Hook.F.(TWHF)using chloroform-ethyl acetate(1:1,v/v);The Tripterygium preparations was firstly extracted in an ultrasonic bath with methanol,followed by neutral alumina column,and then eluted by chloroform-ethyl acetate(1:1,v/v).Under this condition,seven target analytes can be obtained to the maximum extent.Meanwhile,the target analytes could be well separated from other substances in samples.(2)Under the optimal separation condition,baseline separation of seven effective components of Tripterygium wilfordii can be achieved within 26 min.After method validation,the seven target analytes had a good linear relationship in the range of 10-100 ?g/mL,and the correlation coefficient was from0.9991 to 0.9995.The limits of detection was within 1.2-4.2 ?g/mL and the limits of quantitation was within 4.0-14 ?g/mL.The RSD values of intraday precision was0.2-1.9%,and the RSD values of interday precision was 0.2-1.7%.The recovery rate of seven target analytes in TWHF and Tripterygium preparations was 98.4%-102.5%.Conclusion:In this paper,a simple and efficient micellar electrokinetic capillary chromatography(MEKC)method was developed for the simultaneous separation of three terpenoids and four alkaloids in Tripterygium wilfordii,and the proposed method was successfully applied to the determination of seven effective components in Tripterygium wilfordiiHook.F.(TWHF)and three different preparations.This method provides the scientific reference for quality control of TWHF and its preparations,and contributes to the efficacy and safety of its clinical application.