ABSTRACT
Astragali radix(AR,the dried root of Astragalus)is a popular herbal remedy in both China and the United States.The commercially available AR is commonly classified into premium graded(PG)and ungraded(UG)ones only according to the appearance.To uncover novel sensitive and specific markers for AR grading,we took the integrated mass spectrometry-based untargeted and targeted metabolomics ap-proaches to characterize chemical features of PG and UG samples in a discovery set(n=16 batches).A series of five differential compounds were screened out by univariate statistical analysis,including arginine,calycosin,ononin,formononetin,and astragaloside Ⅳ,most of which were observed to be accumulated in PG samples except for astragaloside Ⅳ.Then,we performed machine learning on the quantification data of five compounds and constructed a logistic regression prediction model.Finally,the external validation in an independent validation set of AR(n=20 batches)verified that the five com-pounds,as well as the model,had strong capability to distinguish the two grades of AR,with the pre-diction accuracy＞90％.Our findings present a panel of meaningful candidate markers that would significantly catalyze the innovation in AR grading.
ABSTRACT
Saikosaponins (SSs) are the main active components extracted from Bupleuri Radix (BR) which has been used as an important herbal drug in Asian countries for thousands of years.It has been reported that the intestinal bacteria plays an important role in the in vivo disposal of oral SSs.Although the deglycosylated derivatives (saikogenins,SGs) of SSs metabolized by the intestinal bacteria are speculated to be the main components absorbed into the blood after oral administration of SSs,no studies have been reported on the characteristics of SGs for their intestinal absorption,and those for SSs are also limited.Therefore,a rapid UHPLC-MS/MS method was developed to investigate and compare the apparent permeability of three common SSs (SSa,SSd,SSb2) and their corresponding SGs (SGF,SGG,SGD) through a bidirectional transport experiment on Caco-2 cell monolayer model.The method was validated according to the latest FDA guidelines and applied to quantify the six analytes in transport medium samples extracted via liquid-liquid extraction (LLE).The apparent permeability coefficient (Papp) determined in this study indicated that the permeability of SGs improved to the moderate class compared to the corresponding parent compounds,predicting a higher in vivo absorption.Moreover,the efflux ratio (ER) value demonstrated an active uptake of SSd and the three SGs,while a passive diffusion of SSa and SSb2.
ABSTRACT
A high-performance liquid chromatography coupled with mass spectrometry (HPLC–MS) method was established for the separation and determination of acetyl-glutamine enantiomers (acetyl-L-glutamine and acetyl-D-glutamine) simultaneously. Baseline separation was achieved on Chiralpak AD-H column (250 mm × 4.6 mm, 5 μm). n-Hexane (containing 0.1% acetic acid) and ethanol (75:25, v/v) were used as mobile phase at a flow rate of 0.6 mL/min. The detection was operated in the negative ion mode with an ESI source. [M-H]? m/z 187.0540 for enantiomers and [M-H]? m/z 179.0240 for aspirin (IS) were selected as detecting ions. The linear range of the calibration curve for each enantiomer was 0.05–40 μg/mL. The precision of this method at concentrations of 0.5–20 μg/mL was within 7.23%, and the accuracy was 99.81%–107.81%. The precision at LOQ (0.05 μg/mL) was between 16.28% and 17.56%, which was poor than that at QC levels. The average extraction recovery was higher than 85% for both enantiomers at QC levels. The pharmacokinetics of enantiomers was found to be stereoselective. There was not chiral inversion in vivo or in vitro between enantiomers.
ABSTRACT
A high-performance liquid chromatography coupled with mass spectrometry (HPLC–MS) method was established for the separation and determination of acetyl-glutamine enantiomers (acetyl-L-glutamine and acetyl-D-glutamine) simultaneously. Baseline separation was achieved on Chiralpak AD-H column (250 mm × 4.6 mm, 5 μm). n-Hexane (containing 0.1% acetic acid) and ethanol (75:25, v/v) were used as mobile phase at a flow rate of 0.6 mL/min. The detection was operated in the negative ion mode with an ESI source. [M-H]? m/z 187.0540 for enantiomers and [M-H]? m/z 179.0240 for aspirin (IS) were selected as detecting ions. The linear range of the calibration curve for each enantiomer was 0.05–40 μg/mL. The precision of this method at concentrations of 0.5–20 μg/mL was within 7.23%, and the accuracy was 99.81%–107.81%. The precision at LOQ (0.05 μg/mL) was between 16.28% and 17.56%, which was poor than that at QC levels. The average extraction recovery was higher than 85% for both enantiomers at QC levels. The pharmacokinetics of enantiomers was found to be stereoselective. There was not chiral inversion in vivo or in vitro between enantiomers.