On-line incubation and real-time detection by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry for rapidly analyzing metabolites of anthraquinones in rat liver microsomes

Some evidence supporting the use of optically pure R-(-)-diniconazole: Toxicokinetics and configuration conversion on chiral diniconazole

Diniconazole is a chiral pesticide that exists in two enantiomers, R-(-)-diniconazole and S-(+)-diniconazole, with the R-enantiomer being much more active than the S-enantiomer. Previous enantioselective toxicology studies of diniconazole focused mostly on simple environmental model organisms. In this study, we evaluated the toxicokinetics of the two diniconazole enantiomers in rats and mice to provide a more comprehensive risk assessment. The two enantiomers displayed clear differences in their stereoselective contents in vivo. The t1/2 of R-(-)-diniconazole was 7.06 ± 3.35 h, whereas that of S-(+)-diniconazole was 9.14 ± 4.60 h, indicating that R-(-)-diniconazole was eliminated faster in vivo. The excretion rates of R-(-)-diniconazole and S-(+)-diniconazole were 4.08 ± 0.50 % and 2.68 ± 0.58 %, respectively, indicating more excretion of R-(-)-diniconazole. S-(+)-diniconazole had a higher bioavailability than R-(-)-diniconazole (52.19 % vs. 42.44 %). S-(+)-Diniconazole was also found in relatively high abundance in tissues such as the stomach, large intestine, small intestine, cecum, liver, kidney, brain, and testes, with the abundance being 1.71-2.48-fold that of R-(-)-diniconazole. The selective degradation of both enantiomers in the tissues and their mutual conversion in vivo were not observed, and this could indicate that configuration conversion did not contribute to the differences in the content of enantiomers in the tissues. Instead, such differences were mainly caused by the differences in affinity of each enantiomer for the tissues. Furthermore, investigation of the interconversion between optically pure R-(-)-diniconazole and S-(+)-diniconazole monomers in soil revealed no interconversion. All of the above results indicated no interconversion between R-(-)-diniconazole and S-(+)-diniconazole in vivo and in the soil, and that S-(+)-diniconazole tends to have a greater potential to accumulate in vivo. Thus, if only R-(-)-diniconazole is used as a pesticide, the negative impact on mammals and the environment will be reduced, suggesting that in agriculture, the application of optically pure R-(-)-diniconazole may be a better strategy.

A Review on Bioactive Anthraquinone and Derivatives as the Regulators for ROS

Anthraquinones are bioactive natural products, which are often found in medicinal herbs. These compounds exert antioxidant-related pharmacological actions including neuroprotective effects, anti-inflammation, anticancer, hepatoprotective effects and anti-aging, etc. Considering the benefits from their pharmacological use, recently, there was an upsurge in the development and utilization of anthraquinones as reactive oxygen species (ROS) regulators. In this review, a deep discussion was carried out on their antioxidant activities and the structure-activity relationships. The antioxidant mechanisms and the chemistry behind the antioxidant activities of both natural and synthesized compounds were furtherly explored and demonstrated. Due to the specific chemical activity of ROS, antioxidants are essential for human health. Therefore, the development of reagents that regulate the imbalance between ROS formation and elimination should be more extensive and rational, and the exploration of antioxidant mechanisms of anthraquinones may provide new therapeutic tools and ideas for various diseases mediated by ROS.

Comparative pharmacokinetics of six bioactive components of Shen-Wu-Yi-Shen tablets in normal and chronic renal failure rats based on UPLC-TSQ-MS/MS

ETHNOPHARMACOLOGICAL RELEVANCE

Shen-Wu-Yi-Shen tablets (SWYST), a Chinese patent medicine consisting of 12 herbal medicines, was formulated by a famous TCM nephrologist, Zou Yunxiang. It is clinically used to improve the symptoms of nausea, vomiting, poor appetite, dry mouth and throat, and dry stool in patients with chronic renal failure (CRF) accompanied by qi and yin deficiency, dampness, and turbidity. SWYST can reduce urea nitrogen, blood creatinine, and urinary protein loss, and increase the endogenous creatinine clearance rate. However, little is known about its pharmacokinetics.

AIM OF STUDY

To compare the pharmacokinetics of six bioactive components after oral administration of SWYST in normal and adenine-induced CRF rats.

MATERIALS AND METHODS

A method based on ultra-performance liquid chromatography coupled with a triple-stage quadrupole mass spectrometer (UPLC-TSQ-MS/MS) was developed and validated to determine the six bioactive compounds (albiflorin, paeoniflorin, plantagoguanidinic acid, rhein, aloe-emodin, and emodin) in rat plasma. Rat plasma samples were prepared using protein precipitation. Chromatography was performed on an Agilent Eclipse Plus C18 column (3.0 × 50 mm, 1.8 μm) using gradient elution with a mobile phase composed of acetonitrile and water containing 0.1% (v/v) formic acid, while detection was achieved by electrospray ionization MS under the multiple selective reaction monitoring modes. After SWYST administration, rat plasma was collected at different time points, and the pharmacokinetic parameters of six analytes were calculated and analyzed based on the measured plasma concentrations.

RESULTS

The UPLC-TSQ-MS/MS method was fully validated for its satisfactory linearity (r ≥ 0.9913), good precisions (RSD <11.5%), and accuracy (RE: -13.4∼13.1%), as well as acceptable limits in the extraction recoveries, matrix effects, and stability (RSD <15%). In normal rats, the six analytes were rapidly absorbed (Tmax ≤ 2 h), and approximately 80% of their total exposure was eliminated within 10 h. Moreover, in normal rats, the AUC0-t and Cmax of albiflorin, plantagoguanidinic acid, and rhein exhibited linear pharmacokinetics within the dose ranges, while that of paeoniflorin is non-linear. However, in CRF rats, the six analytes exhibited reduced elimination and significantly different AUC or Cmax values. These changes may reflect a decreased renal clearance rate or inhibition of drug-metabolizing enzymes and transporters in the liver and gastrointestinal tract caused by CRF.

CONCLUSIONS

A sensitive UPLC-TSQ-MS/MS method was validated and used to investigate the pharmacokinetics of SWYST in normal and CRF rats. This is the first study to investigate the pharmacokinetics of SWYST, and our findings elucidate the causes of their different pharmacokinetic behaviors in CRF rats. Furthermore, the results provide useful information to guide further research on the pharmacokinetic-pharmacodynamic correlation and clinical application of SWYST.

Development and Validation of a SPE-HPLC Method for Quantification of Rhein, Emodin, Chrysophanol and Physcion in Rhamnus petiolaris Boiss. & Balansa

Anthraquinones exhibit a significant group of natural and synthetic quinone derivatives because of their biological activities and industrial applications. Rhamnaceae is one of the families known to contain different kinds of anthraquinones. In this study, it was aimed to quantify rhein, emodin, chrysophanol and physcion in fruits of Rhamnus petiolaris Boiss. & Balansa belonging to Rhamnaceae by solid phase extraction and high performance liquid chromatography with ultraviolet detection. The anthraquinones were separated using a C18 analytical column. Gradient elution was performed using a mobile phase consisted of 0.1% o-phosphoric acid solution and methanol. Analytes were detected at 254 nm. Calibration curves were prepared in the range of 0.25-5.00 μg/mL for rhein, chrysophanol, physcion, 1.00-50.00 μg/mL for emodin. Limits of detection and quantification were between 0.07-0.11 and 0.20-0.34 μg/mL, respectively. Relative standard deviations were ≤ 5.78% in repeatability and intermediate precision studies. Accuracy was determined as relative mean error (8.17-12.06%). Extraction was achieved by maceration with acetone and ethanol, followed by hydrophilic-lipophilic balance solid phase extraction. Recoveries were between 96.2 and 109.6%. The developed and validated method was successfully performed to quantify rhein, emodin, chrysophanol and physcion in R. petiolaris fruit extracts. Only physcion was not detected above limit of detection.

Screening and characterization of xenobiotics in rat bio-samples after oral administration of Shen-Wu-Yi-Shen tablet using UPLC-Q-TOF-MS/MS combined with a targeted and non-targeted strategy

Shen-Wu-Yi-Shen tablet (SWYST), a well-known traditional Chinese medicine prescription (TCMP), has been effectively used for treating chronic kidney disease (CKD) in clinically. However, an in-depth study of in vivo metabolism of SWYST is lacking. In this study, a targeted and non-targeted strategy based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) was developed to screen and characterize SWYST-related xenobiotics in rats. Based on the in-house library, a chemical database of SWYST including 215 constituents was constructed through "find by formula" and further verified by characteristic fragmentations or the literatures. Then the constructed chemical database was applied for the targeted screening of prototypes. As for metabolites, the non-targeted screening was achieved combined the peak picking using the function "find by auto-MS/MS" and peak filtration of the prototypes and endogenous components, while the targeted screening was performed using Metabolite ID according to the possible metabolic reactions. Furthermore, the potential metabolites were preliminarily identified by comparison of the parent compounds or references to the literatures. As a result, 201 exogenous components (87 prototypes and 121 metabolites) were characterized in rats after administration of SWYST, including 55 (17 prototypes and 38 metabolites) in plasma, 151 (52 prototypes and 99 metabolites) in urine, and 121 (74 prototypes and 47 metabolites) in feces. Finally, their possible metabolic pathways were summarized, and the metabolic reactions mainly involved phase I reactions (hydroxylation, deoxygenation, hydrogenation, methylation, oxidation, hydrolysis and esterification) and phase II reactions (glucuronidation and sulfation). The findings of this research reveal the potential active ingredients of SWYST, providing an important material basis for the pharmacokinetics and pharmacodynamics of SWYST.

Metabolic profile and dynamic characteristic of rhubarb during the vitro biotransformation by human gut microbiota

Rhubarb is a popular food in the world with laxative effects and steamed pieces of rhubarb (SP) have been widely applied to treatment of constipation in China due to its safety and effectiveness. In the study, metabolism in vitro was conducted to study influence of gut microbiota between raw pieces of rhubarb (RP) and SP. The results showed obvious classifications in metabolic profile between RP and SP were revealed by chemometric analysis, and prompted gut microbiota affected metabolism of rhubarb. Furthermore, 16 characteristic components were identified to distinguish the differences in metabolism. Finally, quantitative analysis of 14 components were verified the regulation of gut microbiota on rhubarb and discovered concentration of components affected the rate of metabolism. The study indicated regulation by gut microbiota could be probably responsible for differences of laxative effects between RP and SP, providing new perspective for exploring mechanisms of effectiveness in clinical application for SP.

HRPIF data mining based on data-dependent/independent acquisition for Rhei Radix et Rhizoma metabolite screening in rats

In traditional Chinese medicine (TCM), components with identical nuclei often share structural similarity, indicating the possibility of similar second-level mass spectrometry (MS/MS) fragments. High-resolution product-ion filter (HRPIF) technique can be utilized to identify metabolites, with similar fragments, in vivo. In principle, this technique applies to TCM; however, its application has been restricted due to the limitations of traditional MS/MS data acquisition. Therefore, a novel analysis strategy, based on data-dependent acquisition (DDA) and data-independent acquisition (DIA) datasets, has been developed for the determination of template product ions and efficient non-targeted identification of TCM-related components in vivo by HRPIF and background subtraction (BS). This DDA-DIA combination strategy, taking Rhei Radix et Rhizoma as a test case, identified 71 anthraquinone prototype components in vitro (36 of which were discovered for the first time), and 45 related components in vivo, confirming glucuronidation and sulfation as the main reactions. The developed strategy could rapidly identify TCM-related components in vivo with high sensitivity, indicating the immense importance of this novel HRPIF data mining technology in TCM analysis.

Advances in the study of emodin: an update on pharmacological properties and mechanistic basis

Rhei Radix et Rhizoma, also known as rhubarb or Da Huang, has been widely used as a spice and as traditional herbal medicine for centuries, and is currently marketed in China as the principal herbs in various prescriptions, such as Da-Huang-Zhe-Chong pills and Da-Huang-Qing-Wei pills. Emodin, a major bioactive anthraquinone derivative extracted from rhubarb, represents multiple health benefits in the treatment of a host of diseases, such as immune-inflammatory abnormality, tumor progression, bacterial or viral infections, and metabolic syndrome. Emerging evidence has made great strides in clarifying the multi-targeting therapeutic mechanisms underlying the efficacious therapeutic potential of emodin, including anti-inflammatory, immunomodulatory, anti-fibrosis, anti-tumor, anti-viral, anti-bacterial, and anti-diabetic properties. This comprehensive review aims to provide an updated summary of recent developments on these pharmacological efficacies and molecular mechanisms of emodin, with a focus on the underlying molecular targets and signaling networks. We also reviewed recent attempts to improve the pharmacokinetic properties and biological activities of emodin by structural modification and novel material-based targeted delivery. In conclusion, emodin still has great potential to become promising therapeutic options to immune and inflammation abnormality, organ fibrosis, common malignancy, pathogenic bacteria or virus infections, and endocrine disease or disorder. Scientifically addressing concerns regarding the poor bioavailability and vague molecular targets would significantly contribute to the widespread acceptance of rhubarb not only as a dietary supplement in food flavorings and colorings but also as a health-promoting TCM in the coming years.

Color-reflected chemical regulations of the scorched rhubarb (Rhei Radix et Rhizoma) revealed by the integration analysis of visible spectrophotometry, Fourier transform infrared spectroscopy and high performance liquid chromatography

Rhubarb has been used as herbal purgative with a worldwide long history. In traditional Chinese medicine, rhubarb can be stir-baked to scorch to eliminate the purgative function when it is a side effect. Under-scorched rhubarb still has the side effect of purgative, while over-scorched rhubarb can lose all bioactivities. Empirically, the degree of scorching is determined by manual observation of the rhubarb color. In order to find the reasonable and objective scorching endpoint criteria, visible spectrophotometry, FTIR spectroscopy and HPLC were used to reveal the color-reflected chemical changes. It was found that the blackening of rhubarb corresponded to the elimination of combined anthraquinones and the rise-fall inflection of free anthraquinones. The scorching endpoint criteria should include the upper limit for combined anthraquinones to avoid under-scorch and the lower limit for free anthraquinones to avoid over-scorch. Visible and FTIR spectroscopy can be process analytical techniques for the rhubarb scorching.

Pharmacokinetics, tissue distribution and excretion of five rhubarb anthraquinones in rats after oral administration of effective fraction of anthraquinones from rheum officinale

Rhubarb, a famous traditional Chinese medicine, shows a wide range of physiological activities and pharmacological benefits. Rhubarb anthraquinones are perceived as the pharmacologically active compounds of Rhubarb, and understanding metabolism of them is crucial to assure safety and effectiveness of clinical application. In this study, the pharmacokinetics, tissue distribution and excretion of five rhubarb anthraquinones (aloe-emodin, rhein, emodin, chrysophanol, physcion) were systematically investigated after oral administration of rhubarb extract to rats.An HPLC method was developed and validated for quantitation of five rhubarb anthraquinones in rat plasma, tissues, urine and faeces to investigate the Pharmacokinetic characteristics. The results showed that the proposed method was suitable for the quantification of five anthraquinones in plasma, tissue and excreta samples with satisfactory linear (r > 0.99), precision (<10%) and recovery (85.12-104.20%). The plasma concentration profiles showed a quick absorption with the mean T_max of 0.42-0.75 h and t_1/2 of 6.60-15.11 h for five anthraquinones. The analytes were widely distributed in most of the tissues. Approximately 0.13-10.59% and 28.47-81.14% of five anthraquinones were recovered in urine and faeces within 132 h post-dosing, which indicated the major elimination route was faeces excretion.In summary, this study lays a foundation for elucidating the pharmacokinetic rule of rhubarb anthraquinone and the important data can provide reliable scientific resource for further research.

Pharmacokinetics of Anthraquinones from Medicinal Plants

Anthraquinones are bioactive natural products, some of which are active components in medicinal medicines, especially Chinese medicines. These compounds exert actions including purgation, anti-inflammation, immunoregulation, antihyperlipidemia, and anticancer effects. This study aimed to review the pharmacokinetics (PKs) of anthraquinones, which are importantly associated with their pharmacological and toxicological effects. Anthraquinones are absorbed mainly in intestines. The absorption rates of free anthraquinones are faster than those of their conjugated glycosides because of the higher liposolubility. A fluctuation in blood concentration and two absorption peaks of anthraquinones may result from the hepato-intestinal circulation, reabsorption, and transformation. Anthraquinones are widely distributed throughout the body, mainly in blood-flow rich organs and tissues, such as blood, intestines, stomach, liver, lung, kidney, and fat. The metabolic pathways of anthraquinones are hydrolysis, glycuronidation, sulfation, methylation/demethylation, hydroxylation/dehydroxylation, oxidation/reduction (hydrogenation), acetylation and esterification by intestinal flora and liver metabolic enzymes, among which hydrolysis, glycuronidation and sulfation are dominant. Of note, anthraquinones can be transformed into each other. The main excretion routes for anthraquinones are the kidney, recta, and gallbladder. Conclusion: Some anthraquinones and their glycosides, such as aloe-emodin, chrysophanol, emodin, physcion, rhein and sennosides, have attracted the most PK research interest due to their more biological activities and/or detectability. Anthraquinones are mainly absorbed in the intestines and are mostly distributed in blood flow-rich tissues and organs. Transformation into another anthraquinone may increase the blood concentration of the latter, leading to an increased pharmacological and/or toxicological effect. Drug-drug interactions influencing PK may provide insights into drug compatibility theory to enhance or reduce pharmacological/toxicological effects in Chinese medicine formulae and deserve deep investigation.

A comparative study of aurantio-obtusin metabolism in normal and liver-injured rats by ultra performance liquid chromatography quadrupole time-of-flight mass spectrometry

Aurantio-obtusin, an anthraquinone isolated from cassiae semen, possesses diverse pharmacological activities, including hypotensive, hypolipidemic and anti-inflammatory effects. However, our previous studies demonstrated that exposure to aurantio-obtusin induced hepatotoxicity, but the mechanisms of the toxic effects remain unknown. The purpose of the present study is to establish a strategy for the metabolite profiling of aurantio-obtusin in normal and liver-injured rats. This study aimed at identifying the in vivo metabolites and the metabolic profiling in rats after oral administration at a dose of aurantio-obtusin (4 and 200 mg/kg) by using an ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and metabolynx™ software. A total of 39 metabolites were detected and 3 of them were compared with standard substances. The results indicated that the principal metabolism pathways of aurantio-obtusin in normal rats were glucuronidation and sulfation, while in rats with liver injury, demethylation, dehydroxylation and reduction were also observed and regarded as new metabolic patterns of aurantio-obtusin. These findings helped us to understand the pharmacological and toxicological mechanisms of aurantio-obtusin. Moreover, this study could help to elucidate the metabolic profiling of other anthraquinones.

Corydalis Rhizoma as a model for herb-derived trace metabolites exploration: A cross-mapping strategy involving multiple doses and samples

Deciphering the metabolites of multiple components in herbal medicine has far-reaching significance for revealing pharmacodynamic ingredients. However, most chemical components of herbal medicine are secondary metabolites with low content whose in vivo metabolites are close to trace amounts, making it difficult to achieve comprehensive detection and identification. In this paper, an efficient strategy was proposed: herb-derived metabolites were predicted according to the structural characteristics and metabolic reactions of chemical constituents in Corydalis Rhizoma and chemical structure screening tables for metabolites were conducted. The fragmentation patterns were summarized from representative standards combining with specific cleavage behaviors to deduce structures of metabolites. Ion abundance plays an important role in compound identification, and high ion abundance can improve identification accuracy. The types of metabolites in different biological samples were very similar, but their ion abundance might be different. Therefore, for trace metabolites in biological samples, we used the following two methods to process: metabolites of high dose herbal extract were analyzed to characterize those of clinical dose herbal extracts in the same biological samples; cross-mapping of different biological samples was applied to identify trace metabolites based on the fact that a metabolite has different ion abundance in different biological samples. Compared with not using this strategy, 44 more metabolites of clinical dose herbal extract were detected. This study improved the depth, breadth, and accuracy of current methods for herb-derived metabolites characterization.

Metabolic profile of rosmarinic acid from Java tea (Orthosiphon stamineus) by ultra-high-performance liquid chromatography coupled to quadrupole-time-of-flight tandem mass spectrometry with a three-step data mining strategy

Rosmarinic acid (RA) is a caffeic acid derivative and one of the most abundant and bioactive constituents in Java tea (Orthosiphon stamineus), which has significant biological activities. However, relatively few studies have been conducted to describe this compound's metabolites in vivo. Therefore, an ultra-high-performance liquid chromatography coupled to quadrupole-time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) analysis with a three-step data mining strategy was established for the metabolic profile of RA. Firstly, the exogenously sourced ions were filtered out by the MarkerView software and incorporated with Microsoft Office Excel software. Secondly, a novel modified mass detects filter strategy based on the predicted metabolites was developed for screening the target ions with narrow, well-defined mass detection ranges. Thirdly, the diagnostic product ions and neutral loss filtering strategy were applied for the rapid identification of the metabolites. Finally, a total of 16 metabolites were reasonably identified in urine, bile and feces, while metabolites were barely found in plasma. The metabolites of RA could also be distributed rapidly in liver and kidney. Glucuronidation, methylation and sulfation were the primary metabolic pathways of RA. The present findings might provide the theoretical basis for evaluating the biological activities of RA and its future application.

Chrysophanol: a review of its pharmacology, toxicity and pharmacokinetics

OBJECTIVE

Chrysophanol is a natural anthraquinone, also known as chrysophanic acid and 1,8-dihydroxy-3-methyl-anthraquinone. It has been widely used in the food and pharmaceutical fields. This review is intended to provide a comprehensive overview of the pharmacology, toxicity and pharmacokinetic researches of chrysophanol.

KEY FINDING

Information on chrysophanol was collected from the Internet database PubMed, Elsevier, ResearchGate, Web of Science, Wiley Online Library and Europe PM using a combination of keywords including 'pharmacology', 'toxicology' and 'pharmacokinetics'. The literature we collected included from January 2010 to June 2019. Chrysophanol has a wide spectrum of pharmacological effects, including anticancer, antioxidation, neuroprotection, antibacterial and antiviral, and regulating blood lipids. However, chrysophanol has obvious hepatotoxicity and nephrotoxicity, and pharmacokinetics indicate that the use of chrysophanol in combination with other drugs can reduce toxicity and enhance efficacy.

SUMMARY

Chrysophanol can be used in many diseases. Future research directions include how the concentration of chrysophanol affects pharmacological effects and toxicity; the mechanism of synergy between chrysophanol and other drugs.

Exploration of the hepatoprotective chemical base of an orally administered herbal formulation (YCHT) in normal and CCl4-intoxicated liver injury rats. Part 1: Metabolic profiles from the liver-centric perspective

ETHNOPHARMACOLOGICAL RELEVANCE

Yin-Chen-Hao Tang (YCHT), derived from "Treatise on Febrile Diseases" in ancient China, has been a very popular hepatoprotective three-herb formula in China and Japan, although its chemical base remains unclear.

AIM OF THIS STUDY

As the first step in revealing the hepatoprotective chemical base of YCHT, we aimed to clarify the absorbed ingredients and associated metabolic pathways for orally dosed YCHT in both normal and liver injury rats from a liver-centric perspective.

MATERIALS AND METHODS

With the aid of 10 reference compounds, the absorbed ingredients and generated metabolites were systematically characterized by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF) in the portal vein plasma (the plasma before hepatic disposition) - liver - systemic plasma (the plasma after hepatic disposition), following oral administration of YCHT in normal and CCl₄-induced liver injury rats.

RESULTS

A total of 38 compounds with six chemical structures, consisting of 10 prototypes and 28 metabolites generated through 9 biotransformations, were absolutely or tentatively identified, and 25 compounds were first reported on YCHT treatments. Among them, 8 compounds were absolutely confirmed by comparing with standard substances, and some had published hepatoprotective activities. Compared with the 35, 15, and 29 compounds identified in the portal vein plasma, liver, and systemic plasma of normal rats, respectively, the corresponding numbers of characterized compounds were 37, 13 and 29 in the liver injury rats.

CONCLUSIONS

Sulfation and glucuronidation were the predominant biotransformations, and intestinal metabolism, prior to hepatic metabolism, occurred for most compounds. CCl₄-induced liver injury caused only slight changes in the metabolic profiles of rats orally administered YCHT. These results provided the precondition for further quantitative analysis and pharmacodynamic screening of compounds in YCHT.

Exploration of the hepatoprotective chemical base of an orally administered herbal formulation (YCHT) in normal and CCl4-intoxicated liver injury rats. Part 2: Hepatic disposition in vivo and hepatoprotective activity in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Yin-Chen-Hao Tang (YCHT) has been a very popular, hepatoprotective three-herb formula with an unclear chemical base.

AIM OF THIS STUDY

To reveal the hepatoprotective chemical base of oral-dosed YCHT, we bridged the hepatic disposition of six compounds in vivo and their hepatoprotection in vitro.

MATERIALS AND METHODS

In vivo, following the oral administration of YCHT in normal and CCl₄-induced liver injury rats, the determinations of chlorogenic acid, 4-hydroxyacetophenone, geniposide, genipin, rhein and emodin were conducted in the portal vein plasma, the liver, and the systemic plasma. In vitro, the hepatoprotective activities of these compounds were determined in the CCl₄-induced HepG2 cells.

RESULTS

Consistent with the highest content in YCHT, geniposide had the highest exposure in vivo. Inconsistent with the negligible content, rhein, 4-hydroxyacetophenone, emodin and genipin showed substantial hepatic accumulations. In contrast, chlorogenic acid, an ingredient that has a high content in YCHT, elicited no hepatic exposure. In normal rats, the hepatic disposition prevented the compounds entering into the systemic plasma from the portal vein plasma by 44.9-100%, except for rhein. CCl₄-induced liver injury caused a decreased hepatic exposure of 4-hydroxyacetophenone, rhein and emodin by 50%. In vitro, all six compounds exerted the hepatoprotection by increasing cell viability, decreasing hepatic marker enzymes and inhibiting lipid peroxidation at varying levels.

CONCLUSION

Geniposide, rhein, emodin, 4-hydroxyacetophenone and genipin directly resisted liver injury in oral-dosed YCHT, while chlorogenic acid likely played an indirect role. This study proved that YCHT exerted hepatoprotection through multiple components and multiple actions. However, close attention should be paid to the possible side effects and oral dosage of YCHT in clinics.

Characterization of in vitro metabolism of focal adhesion kinase inhibitors by LC/MS/MS

Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, is critically involved in cell migration, spreading and proliferation at the early step of various cancers. Small molecule inhibitors of FAK are effective to inhibit its activation in the process of tumor formation in cell. To better understand biotransformation of FAK inhibitors, this work has investigated in vitro phase I metabolism of inhibitors (namely PF-573228, PF-562271 and PF-03814735) by rat liver microsomes model. Using liquid chromatography - quadrupole time of flight mass spectrometry and tandem mass spectrometry (LC/Q-TOF/MS and MS/MS), three metabolites of PF-573228 and PF-562271 were observed and characterized, respectively. These in vitro metabolites were reported for the first time. The structures and fragmentation patterns of these metabolites were elucidated, and phase I metabolic pathways for FAK inhibitors were proposed. The main metabolic pathways of PF-573228 were hydroxylation, dehydrogenation and N-dealkylation. For PF-562271, they were hydroxylation and dehydrogenation. Hydroxylation was observed as the primary metabolism for PF-0381473.