In this study, the quantitative analysis of saikosaponins from Radix Bupleuri in China was performed by high performance liquid chromatography. Saikosaponin-a and-d were converted completely into saikosaponin-b1 and -b2 by mild acid treatment. Distinctive measuring of these converted diene-saponins provided a rapid and selective method for the determination of saikosaponin-a and-d in commercial samples of Radix Bupleuri. The conditions of extraction and conversion of saikosaponins were optimized using orthogonal design L9 (34). The HPLC analysis was performed on ODS-C18 column with a flow rate of 1.0ml/min and detection wavelength of 250 nm. Well resolved chromatograms of saikosaponin-b1 and-b2 were obtained with an isocratic elution of ace-tonitrile:1%formic acid water (37.5:62.5). Calibration curves of saikosaponin-b1 and-b2 were linear in the range of 4.9-98.0

目的：测定不同产地川芎中川芎嗪的含量以控制其质量。方法：采用Xttera C18（4.6mm×250mm，5μm）色谱柱，以甲醇－10mmol．L-l醋酸铵（pH=9.05）－四氢呋喃（19:81:2）为流动相，流速为0.6·mLmin-1，柱温为室温，检测波长为281nm，以外标法测定了川芎药材中川芎嗪的含量。结果：川芎嗪在0.3－24μg．mL-l(r=0.9995)的浓度范围内呈线性关系。川芎嗪的平均回收率（n=6）为98.3%。结论：该方法准确、简便、易行，可用于质量控制。

Sambucus chinensis L. is a native perennial herb distributed throughout China. In traditional Chinese medicine (TCM), this herb is known as Lu-Ying. Ursolic acid is the major effective constituent of Lu-Ying. A rapid, sensitive, and accurate liquid chromatography-mass spectrometry (LC-MS) method for the determination of ursolic acid in rat plasma was developed and validated. Plasma samples taken from rats that had received Lu-Ying extract orally were acidified with acetic acid and then extracted with a mixture of hexane-dichloromethane-2-propanol (20:10:1,v/v/v). Separation of ursolic acid was accomplished on a C18 column interfaced with a single quadrupole mass spectrometer. The mobile phase consisting of methanol and water (95:5, v/v) was delivered at a flow rate of 1.0 ml/min. Atmospheric pressure chemical ionization was operated in negative-ion mode. Using selected ion-monitoring mode, the deprotonat-ed molecules [M-H] at m/z 455 and 469 were used to quantify ursolic acid and glycyrrhetic acid (internal standard), respectively. The assay was shown to be linear over the range of 10-1000 ng/ml (r> 0.9960) with a lower limit of quantification of 10 ng/ml. The method was shown to be reproducible and reliable with intraday precision below 7.8%, inter-day precision below 8.1%, accuracy within ±4.3%, and mean extraction recovery excess of 83.6%, which were all calculated from the blank plasma sample spiked with ursolic acid at three concentrations of 20, 200, and 800ng/ml. The LC-MS method has been successfully applied to pharmacokinetic studies of ursolic acid after oral administration of LuYing ethanolic extract (at a dose containing 80.32 mg/kg ursolic acid) to rats. The main pharmacokinetic parameters were: ℓ1/2, 4.3 h; Ke,0.16 1/h; ℓmax, 1.0 h; Cmax, 294.8 ng/ml; A UC0-t and A UC0- 1007.1 ng•h/ml and 1175.3 ng•h/ ml, respectively.

A sensitive, simple, and accurate method for the determination and pharmacokinetic study of vanillic acid in rat plasma was developed using reverse-phase HPLC with UV detection after oral administration of the traditional Chinese medicine preparation of the Di-Gu-Pi decoction. Plasma samples taken from rats were extracted with methanol. The constituent vanillin acid was separated on a C18 stationary phase and a mobile phase of acetonitrile-water (15:85, v/v) (adjusted to pH 3.0 using phosphoric acid), with a UV detector setting at 260 nm. The validated HPLC method developed was used to determine the pharmacokinetic profile of vanillin acid in rat plasma after administration of the Di-Gu-Pi decoction.