Metabolic profiling of icariin in rat feces, urine, bile and plasma after oral administration using ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry

Comprehensive characterization of Epimedium-Rhizoma drynariae herb pair in rat plasma, urine, and feces metabolic profiles by UHPLC-Q-Orbitrap HRMS combined with diagnostic extraction strategy and multicomponent pharmacokinetic study by UHPLC-MS/MS

Epimedium-Rhizoma drynariae (EP-RD) was a well-known herb commonly used to treat bone diseases in traditional Chinese medicine. Nevertheless, there was incomplete pharmacokinetic behavior, metabolic conversion and chemical characterization of EP-RD in vivo. Therefore, this study aimed to establish metabolic profiles combined with multicomponent pharmacokinetics to reveal the in vivo behavior of EP-RD. Firstly, the diagnostic product ions (DPIs) and neutral losses (NLs) filtering strategy combined with UHPLC-Q-Orbitrap HRMS for the in vitro chemical composition of EP-RD and metabolic profiles of plasma, urine, and feces after oral administration of EP-RD to rats were proposed to comprehensively characterize the 47 chemical compounds and the 97 exogenous in vivo (35 prototypes and 62 metabolites), and possible biotransformation pathways of EP-RD were proposed, which included phase I reactions such as hydrolysis, hydrogenation, dehydrogenation, hydroxylation, dehydroxylation, isomerization, and demethylation and phase II reactions such as glucuronidation, acetylation, methylation, and sulfation. Moreover, a UHPLC-MS/MS quantitative approach was established for the pharmacokinetic analysis of seven active components: magnoflorine, epimedin A, epimedin B, epimedin C, icariin, baohuoside II, and icariin II. Results indicated that the established method was reliably used for the quantitative study of plasma active ingredients after oral administration of EP-RD in rats. Compared to oral EP alone, the increase in area under curves and maximum plasma drug concentration (P < 0.05). This study increased the understanding of the material basis and biotransformation profiles of EP-RD in vivo, which was of great significance in exploring the pharmacological effects of EP-RD.

Liver protecting effects and molecular mechanisms of icariin and its metabolites

As a detoxification and metabolism organ, the liver plays a vital role in human health. However, an excessive consumption of drugs and toxins, exposure to pathogenic viruses, and unhealthy living habits can lead to liver damage, which may even develop into liver cirrhosis and liver cancer. Epimedium brevicornum Maxim. is a traditional Chinese medicine and dietary supplement in which the flavonoid icariin is a main functional component. Although the protective mechanisms of icariin and its metabolites against liver injury are not yet comprehensively understood, an increasing number of studies have confirmed their liver-protective and anticancer effects. Indeed, icaritin, one of the metabolites of icariin, is currently utilized as an active component of an anti-cancer drug. This paper presents a review of the molecular mechanisms through which icariin and its metabolites actively protect against the occurrence and development of liver injury, and, thus, provides a comprehensive reference for further research and their application in liver protection.

Network pharmacology analysis of Icariside II against bladder cancer

As a global health threat, bladder cancer (BC) is a common urological disease characterized by a high risk of progression and recurrence. Icariside II (ICA-II), a flavonol glycoside, exhibits antitumor ability in various tumors. However, there is no systematic study exploring the pharmacological mechanism of ICA-II in BC. We used public databases to obtain potential targets of ICA-II and related genes in BC. Bioinformatics analysis and molecular docking were used to identify potential targets and signaling pathways. Then, MTT, cell cycle assays and western blot (WB) were used to validate the predicted pathways in bladder cell lines, and in situ bladder cancer models were also established to verify the effect of ICA-II. Our research demonstrated that these ICA-II hub genes were related to the cell cycle. Then, our molecular docking analysis confirmed the interaction between ICA-II and CCNB1. In addition, our in vitro experiment demonstrated that ICA-II restrained the proliferation of BC cells mainly by blocking the cell cycle. WB also verified that ICA-II decreased the expression levels of CCNB1. In situ BC models showed that ICA-II had no hepatotoxicity or nephrotoxicity and could suppress the growth of in situ BC. In summary, during this study, we found that ICA-II had low toxicity in the kidney and liver. Network pharmacology was used, and both cell and animal experiments verified that ICA-II has a good therapeutic effect on bladder cancer, which may inhibit the proliferation and progression of bladder cancer by blocking the cell cycle of BC cells.

Characterization of metabolites of sagittatoside B in rats using UPLC-QTOF-MS spectrometry

Sagittatoside B is one of the principal diglucosides in Herba Epimedii. In this work, an ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was applied to the rapid analysis of sagittatoside B metabolites in rats after oral administration. A total number of 17 metabolites were detected or tentatively identified from rat plasma, bile, urine and feces. The major metabolic pathways of sagittatoside B in rats were hydrolysis, hydrogenation, hydroxylation, dehydrogenation, demethylation, decarbonylation and conjugation with glucuronic acid and different sugars. This work revealed the metabolism of sagittatoside B in vivo, and reported the characteristic metabolic reactions of sagittatoside B for the first time. This provided the basis for the further research and development of sagittatoside B, and also provided reference for the metabolism of active flavonoid compounds.

Extensive metabolism of flavonoids relevant to their potential efficacy on Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disorder, the incidence of which is climbing with ever-growing aged population, but no cure is hitherto available. The epidemiological studies unveiled that chronic intake of flavonoids was negatively associated with AD risk. Flavonoids, a family of natural polyphenols widely distributed in human daily diets, were readily conjugated by phase II drug metabolizing enzymes after absorption in vivo, and glucuronidation could occur in 1 min following intravenous administration. Recently, as many as 191 metabolites were obtained after intragastric administration of a single flavonoid, indicating that other bioactive metabolites, besides conjugates, might be formed and account for the contradiction between efficacy of flavonoids in human or animal models and low systematic exposure of flavonoid glycosides or aglycones. In this review, metabolism of complete 68 flavonoid monomers potential for AD treatment, grouped in flavonoid O-glycosides, flavonoid aglycones, flavonoid C-glycosides, flavonoid dimers, flavonolignans and prenylated flavonoids according to their common structural elements, respectively, has been systematically retrospected, summarized and discussed, including their unequivocally identified metabolites, metabolic interconversions, metabolic locations, metabolic sites (regio- or stereo-selectivity), primarily involved metabolic enzymes or intestinal bacteria, and interspecies correlations or differences in metabolism, and their bioactive metabolites and the underlying mechanism to reverse AD pathology were also reviewed, providing whole perspective about advances on extensive metabolism of diverse potent flavonoids in vivo and in vitro up to date and aiming at elucidation of mechanism of actions of flavonoids on AD or other central nervous system (CNS) disorders.

Classification-based strategies to simplify complex traditional Chinese medicine (TCM) researches through liquid chromatography-mass spectrometry in the last decade (2011-2020): Theory, technical route and difficulty

The difficulty of traditional Chinese medicine (TCM) researches lies in the complexity of components, metabolites, and bioactivities. For a long time, there has been a lack of connections among the three parts, which is not conducive to the systematic elucidation of TCM effectiveness. To overcome this problem, a classification-based methodology for simplifying TCM researches was refined from literature in the past 10 years (2011-2020). The theoretical basis of this methodology is set theory, and its core concept is classification. Its starting point is that "although TCM may contain hundreds of compounds, the vast majority of these compounds are structurally similar". The methodology is composed by research strategies for components, metabolites and bioactivities of TCM, which are the three main parts of the review. Technical route, key steps and difficulty are introduced in each part. Two perspectives are highlighted in this review: set theory is a theoretical basis for all strategies from a conceptual perspective, and liquid chromatography-mass spectrometry (LC-MS) is a common tool for all strategies from a technical perspective. The significance of these strategies is to simplify complex TCM researches, integrate isolated TCM researches, and build a bridge between traditional medicines and modern medicines. Potential research hotspots in the future, such as discovery of bioactive ingredients from TCM metabolites, are also discussed. The classification-based methodology is a summary of research experience in the past 10 years. We believe it will definitely provide support and reference for the following TCM researches.

Tailor-made deep eutectic solvents extraction combined with UPLC-MS/MS determination of icarrin and icarisid II in rat plasma and its comparative pharmacokinetic application

Using green and high efficient solvents to extract and trace active ingredients of traditional Chinese medicine (TCM) in the complex biological samples was still challenging. In this paper, a co-friendly, fast pretreatment method with high extraction efficiency, based on the tailor-made deep eutectic solvent (DES) system, combined with ultra performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination of icarrin and icarisid II in rat plasma samples, which can be further applied to comparative pharmacokinetic studies after oral administration of Herba Epimedii and icarrin monomer in rats, respectively. PrE (l-proline: ethylene glycol = 1:4 mol/mol) and acetonitrile were optimized and combined as the tailor-made DES at the volumetric ratio of 3:7 to extract icarrin and icarisid II, and to precipitate the protein in rat plasma in one step simultaneously. The extraction efficiency of the tailor-made DES was about 1.7 times of DES (PrE). The extraction recovery of icarrin and icarisid II in rat plasma samples by this method were within the range of 90-110 %, and the lower limits of quantification (LLOQ) were 0.32 ng mL^-1 (icarrin) and 0.43 ng mL^-1 (icarisid II). There was a linear relationship between 0.32-80.16 ng mL^-1 (icarrin) and 0.43-107.4 ng mL^-1 (icarisid II), which effectively reduced the detection limit. In this comparative pharmacokinetic study, the maximum plasma concentration (C_max) and the area under plasma concentration-time curve (AUC_0-∞) of two analytes in rat plasma of Herba Epimedii group were both much higher than those in the icarrin monomer group, which suggested that other ingredients in Herba Epimedii may contribute to the in vivo absorption of icarrin and icarisid II. This simple, rapid, relatively green and high effeicient method would provide a new approach for the extraction of active ingredients from complex biological samples.

Metabolic profile of alkaloids in Rhizoma Coptidis in rat plasma, urine and feces after oral administration using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

RATIONALE

Rhizoma Coptidis (RC) has been used to treat diabetes, pertussis, bacillary dysentery, sore throat, eczema, and aphtha for thousands of years. Alkaloids are the major components in RC, and its curative effect is achieved by oral administration. However, information on its composition in vivo is weak.

METHODS

In this study, ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/QTOF-MS) was used to analyze the major active components and their metabolites in rat plasma, urine and feces after oral administration of RC extract.

RESULTS

A total of 96 compounds including 8 prototype compounds and 88 metabolites were identified, and hydroxylation, reduction, demethylenation, demethylation, dehydrogenation, sulfation, glucuronidation and methylation were the major metabolic pathways.

CONCLUSIONS

This study analyzed metabolic processes of the major active components in RC in vivo, which provided important information for its active composition and in vivo mechanism research. Meanwhile, metabolic profile studies on representative compounds provided valuable reference materials to elucidate the full-scale metabolites of RC.