Mechanism-Based Pharmacokinetic Model for the Deglycosylation Kinetics of 20(S)-Ginsenosides Rh2.

Aim: The 20(S)-ginsenoside Rh2 (Rh2) is being developed as a new antitumor drug. However, to date, little is known about the kinetics of its deglycosylation metabolite (protopanoxadiol) (PPD) following Rh2 administration. The aim of this work was to 1) simultaneously characterise the pharmacokinetics of Rh2 and PPD following intravenous and oral Rh2 administration, 2) develop and validate a mechanism-based pharmacokinetic model to describe the deglycosylation kinetics and 3) predict the percentage of Rh2 entering the systemic circulation in PPD form. Methods: Plasma samples were collected from rats after the I.V. or P.O. administration of Rh2. The plasma Rh2 and PPD concentrations were determined using HPLC-MS. The transformation from Rh2 to PPD, its absorption, and elimination were integrated into the mechanism based pharmacokinetic model to describe the pharmacokinetics of Rh2 and PPD simultaneously at 10 mg/kg. The concentration data collected following a 20 mg/kg dose of Rh2 was used for model validation. Results: Following Rh2 administration, PPD exhibited high exposure and atypical double peaks. The model described the abnormal kinetics well and was further validated using external data. A total of 11% of the administered Rh2 was predicted to be transformed into PPD and enter the systemic circulation after I.V. administration, and a total of 20% of Rh2 was predicted to be absorbed into the systemic circulation in PPD form after P.O. administration of Rh2. Conclusion: The developed model provides a useful tool to quantitatively study the deglycosylation kinetics of Rh2 and thus, provides a valuable resource for future pharmacokinetic studies of glycosides with similar deglycosylation metabolism.

Pharmacokinetics of the prototype and hydrolyzed carboxylic forms of ginkgolides A, B, and K administered as a ginkgo diterpene lactones meglumine injection in beagle dogs.

Ginkgo diterpene lactones meglumine injection (GDLI) is a commercially available product used for neuroprotection. However, the pharmacokinetic properties of the prototypes and hydrolyzed carboxylic forms of the primary components in GDLI, i.e., ginkgolide A (GA), ginkgolide B (GB), and ginkgolide K (GK), have never been fully evaluated in beagle dogs. In this work, a simple, sensitive, and reliable method based on ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was developed, and the prototypes and total amounts of GA, GB, and GK were determined in beagle dog plasma. The plasma concentrations of the hydrolyzed carboxylic forms were calculated by subtracting the prototype concentrations from the total lactone concentrations. For the first time, the pharmacokinetics of GA, GB, and GK were fully assessed in three forms, i.e., the prototypes, the hydrolyzed carboxylic forms, and the total amounts, after intravenous administration of GDLI in beagle dogs. It was shown that ginkgolides primarily existed in the hydrolyzed form in plasma, and the ratio of hydrolysates to prototype forms of GA and GB decreased gradually to a homeostatic ratio. All of the three forms of the three ginkgolides showed linear exposure of AUC to the dosages. GA, GB, and GK showed a constant half-life approximately 2.7, 3.4, and 1.2 h, respectively, which were consistent for the forms at three dose levels (0.3, 1.0, and 3.0 mg·kg-1) and after a consecutive injection of GDLI for 7 days (1.0 mg·kg-1).

[Metabolomic approach to evaluating the effect of the mixed decoction of kelp and licorice on system metabolism of SD rats].

The aim of the study is to evaluate the effects of the single and mixed decoction of Thallus laminariae (kelp) and Glycyrrhiza glabra (licorice) on the metabolism and their difference. The mixed decoction of kelp and licorice and the single decoction were made and intragastrically administered to the SD rats. The effect on system metabolism, the toxicity of liver and kidney were assessed by GC-MS profiling of the endogenous molecules in serum, routine biochemical assays and histographic inspection of tissues from SD rats, separately. The mixed decoction of kelp and licorice induced more obvious pathological abnormalities in SD rats than a single decoction of kelp, while the extracts of licorice did not show any pathological change. Neither the mixed, nor the single decoction showed abnormal histopathology. After intragastric administration of extracts for 5 days, the mixed decoction induced a decrease of ALT (no significant change in the groups of single decoction) and an increase of BUN (so did the single decoction of kelp). Metabolomic profile of the molecules in serum revealed that the metabolic patterns were all obviously affected for the three groups, i.e., the mixed and single decoction of kelp and licorice. The rats given with the single decoction of kelp showed a similar pattern to that of the mixed decoction, indicating that the kelp primarily contributed the perturbation of metabolism for the mixed decoction. All three groups induced a decrease of branched chain amino acids, TCA cycle intermediates and glycolysis intermediates (e.g., pyruvic acid and lactic acid) and an increase of 3-hydroxybutyric acid. Kelp decoction showed stronger potential in reducing TCA cycle intermediates and glycolysis intermediates than the other two groups, while the levels of branched chain amino acids were the lowest after licorice extracts were given. These results suggested that the effect of the mixed decoction on metabolism was closely associated with both kelp and licorice. The continuous administration of single decoction of kelp and the mixed decoction of licorice and kelp resulted in pathological abnormalities in kidney of SD rats. The mixed decoction of kelp and licorice distinctly perturbed sera molecules and hence system metabolism, which showed associated with those of kelp and licorice. Although the metabolic effect was associated with both kelp and licorice, the results suggested kelp contributed to it primarily.

[Metabonomic phenotype of "formula corresponding to pattern types" based on "qi and yin deficiency pattern" of myocardial ischemia rat model].

In order to explore the scientific connotation of "Fangzhengduiying (formula corresponding to pattern types)", "Qiyinliangxuzheng (Qi and Yin deficiency pattern)" of myocardial ischemia rat model and GC-TOF/MS based metabonomic method were used for comparing the effects of Sheng-mai injection, Salvia injection and propranolol in the present study. After data processing and pattern recognition, Sheng-mai injection showed better efficacy than the other two drugs in accordance with not only visual observation from PLS-DA scores plots but also the number of abnormal endogenous compounds restored to the normal level. Further studies showed that Sheng-mai injection could normalize the level of plasma endothelin-1, the index related to cardiovascular diseases and sleep disorders, which verified the results of metabonomics. Finally, the regulated metabolites and related metabolic pathways were analyzed, and it was supposed that the effects of Sheng-mai injection involved in the alternation of energy metabolism, lipid metabolism, amino acids metabolism, and so on. These findings provided scientific evidence to Shengmai "Fang" used for "Qi and Yin deficiency pattern" correspondingly, indicating that metabonomics has great potential in traditional Chinese medical research, which provides a novel approach and way to modernization of traditional Chinese medicine.

Application of GC/MS-based metabonomic profiling in studying the lipid-regulating effects of Ginkgo biloba extract on diet-induced hyperlipidemia in rats.

AIM: To evaluate the lipid-regulating effects of extract from Ginkgo biloba leaves (EGB) using pharmacological methods and metabonomic profiling in a rat model of diet-induced hyperlipidemia. METHODS: EGB was orally administered at a dose level of 40 mg/kg in both the EGB-prevention and -treatment groups. All rat samples obtained were examined for known and potential biomarkers and enzyme activity using commercial assay kits and GC/MS-based metabonomic profiling coupled with principal component analysis (PCA). RESULTS: The data obtained from the assay kits indicated that EGB reduced total cholesterol and low density lipoprotein cholesterol levels and increased high density lipoprotein cholesterol levels in rat plasma obtained from both the EGB-prevention and -treatment groups compared with those of the diet-induced hyperlipidemia group. EGB also increased the activities of lipoprotein lipase and hepatic lipase and excretion of fecal bile acid in rats from the EGB-prevention and-treatment groups. Using GC/MS-based metabonomic analysis, more than 40 endogenous metabolites were identified in rat plasma. PCA of rat plasma samples obtained using GC/MS produced a distinctive separation of the four treatment groups and sampling points within each group. Metabolic changes during hyperlipidemia formation and improvement resulting from EGB treatment were definitively monitored with PCA score plots. Furthermore, elevated levels of sorbitol, tyrosine, glutamine and glucose, and decreased levels of citric acid, galactose, palmitic acid, arachidonic acid, acetic acid, cholesterol, butyrate, creatinine, linoleate, ornithine and proline, were observed in the plasma of rats treated with EGB. CONCLUSION: EGB exerts multi-directional lipid-lowering effects on the rat metabonome, including limitation of the absorption of cholesterol, inactivation of HMGCoA and favorable regulation of profiles of essential polyunsaturated fatty acid (EFA). Further experiments are warranted to explore the mechanisms of action underlying the lipid-regulating effects of EGB against hyperlipidemia.

Study on LC-MS fingerprint for quality assessment of Aristolochia manshuriensis with chemical pattern recognition / 中国中药杂志

<p><b>OBJECTIVE</b>To analyze LC-MS fingerprints of Aristolochia manshuriensis for quality assessment with two different chemical pattern recognition models.</p><p><b>METHOD</b>LC-MS fingerprints of A. manshuriensis were established from 24 batches of samples from different habitats. SIMCA and Clustering analysis were used to compare the parameters of the 29 common peaks.</p><p><b>RESULT</b>Two methods had good consistency, while they reflected the inherent sample information from different perspectives, respectively.</p><p><b>CONCLUSION</b>Modern equipment analysis technology and multivariable chemical pattern recognition would be an efficient way for quality control and variety identification of A. manshuriensis.</p>

[Study on the metabolites of guanfu base A hydrochloride in rat urine by high performance liquid chromatograph-mass spectrum].

AIM: To study the metabolites of guanfu base A hydrochloride (GFA) in rat urine. METHODS: Rat urine was collected after i.v. injection of GFA. Phase I metabolites were identified by HPLC/MS and by comparison with authentic standards. Phase II conjugates were treated with either glucuronidase or sulfatase in presence or absence of glucuronidase specific inhibitor D-saccharic acid beta-1,4-lactone. The aglycones were identified by HPLC/MS. RESULTS: Phase I metabolites guanfu base I (GFI) and guanfu alcohol-amine (AA) were separated and identified in rat urine by comparison with authentic standards. Phase II conjugates, for which no authentic standards were available, GFA glucuronide and sulfate conjugates, GFI glucuronide and sulfate were separated and tentatively identified by hydrolysis with glucuronidase or sulfatase, the aglycones, GFA and GFI, were identified in rat urine. CONCLUSION: After i.v. injection of GFA, GFA is metabolized into GFI, AA, GFA glucuronide and sulfate conjugates, GFI glucuronide and sulfate conjugates in rat urine. The polarity of the metabolites is increased, and the effectiveness of them is lower than the parent drug.