Elimination of rutaecarpine and its metabolites in rat feces and urine measured by liquid chromatography

Major Indole Alkaloids in Evodia Rutaecarpa: The Latest Insights and Review of Their Impact on Gastrointestinal Diseases

Evodia rutaecarpa, the near-ripe fruit of Euodia rutaecarpa (Juss.) Benth, Euodia rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang, or Euodia rutaecarpa (Juss.) Benth. var. bodinieri (Dode) Huang, is a famous herbal medicine with several biological activities and therapeutic values, which has been applied for abdominalgia, abdominal distension, vomiting, and diarrhea as a complementary and alternative therapy in clinic. Indole alkaloids, particularly evodiamine (EVO), rutaecarpine (RUT), and dedhydroevodiamine (DHE), are received rising attention as the major bioactivity compounds in Evodia rutaecarpa. Therefore, this review summarizes the physicochemical properties, pharmacological activities, pharmacokinetics, and therapeutic effects on gastrointestinal diseases of these three indole alkaloids with original literature collected by PubMed, Web of Science Core Collection, and CNKI up to June 2023. Despite sharing the same parent nucleus, EVO, RUT, and DHE have different structural and chemical properties, which result in different advantages of biological effects. In their wide range of pharmacological activities, the anti-migratory activity of RUT is less effective than that of EVO, and the neuroprotection of DHE is significant. Additionally, although DHE has a higher bioavailability, EVO and RUT display better permeabilities within blood-brain barrier. These three indole alkaloids can alleviate gastrointestinal inflammatory in particular, and EVO also has outstanding anti-cancer effect, although clinical trials are still required to further support their therapeutic potential.

Chromatographic and mass spectrometric technologies for chemical analysis of Euodiae fructus: A review

INTRODUCTION

Euodiae fructus, also known as Evodiae fructus, is a popular Chinese herbal medicine derived from the dried, nearly ripe fruits of Tetradium ruticarpum (A. Juss.) T. G. Hartley. The main bioactive constituents of Euodiae fructus are alkaloids, limonoids, flavonoids, and anthraquinones. The contents of these compounds vary greatly between different plant species, geographic locations, and harvest times, which thus affect the therapeutic effects.

OBJECTIVES

We aimed to summarize the chromatographic and mass spectrometric technologies applied for chemical analysis and quality evaluation of Euodiae fructus. Moreover, we aimed to emphasize the diverse soft ionization techniques and mass analyzers of LC-MS methods for assessment of Euodiae fructus.

METHODOLOGY

A literature study was carried out by retrieving articles published between January 1988 and December 2021 from well-known databases, including PubMed, ASC, Elsevier, ScienceDirect, J·STAGE, Thieme, Taylor & Francis, Springer Link, Wiley Online Library, and CNKI. The chemical analysis methods were described in several categories in accordance with the used analytical techniques, including thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), high-performance liquid chromatography-mass spectrometry (HPLC-MS), gas chromatography-mass spectrometry (GC-MS), capillary electrophoresis (CE), and counter-current chromatography (CCC).

RESULTS

This review systematically summarizes the achievements in chemical analysis and quality evaluation of Euodiae fructus published in over three decades, covering the various chromatographic and mass spectrometric technologies applied for identification and quantification of phytochemical constituents.

CONCLUSION

The summary serves as an important basis for future phytochemical research and implementation of quality control methods in order to ensure the efficacy and safety of Euodiae fructus.

Detection and characterization of the metabolites of rutaecarpine in rats based on ultra-high-performance liquid chromatography with linear ion trap-Orbitrap mass spectrometer

CONTEXT

Rutaecarpine is an active indoloquinazoline alkaloid ingredient originating from Evodia rutaecarpa (Wu-zhu-yu in Chinese), which possesses a variety of effects. However, its metabolism has not been investigated thoroughly yet.

OBJECTIVE

This study develops a highly sensitive and effective method for detection and characterization of the metabolites of rutaecarpine in Sprague-Dawley (SD) rats.

MATERIALS AND METHODS

In this study, an efficient method was developed using ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometer (UHPLC-LTQ-Orbitrap MS) to detect the metabolism profile of rutaecarpine in rat plasma. First, a blood sample (1 mL) was withdrawn 2 h after oral administration of rutaecarpine in SD rats (50 mg/kg). Second, the blood was centrifuged at 4000 rpm for 10 min and pretreated by solid-phase extraction method. Third, 2 μL of the plasma was injected into UHPLC-LTQ-Orbitrap MS for analysis. Finally, the metabolites of rutaecarpine were tentatively identified based on accurate mass measurements, fragmentation patterns and chromatographic retention times.

RESULTS

A total of 16 metabolites (four new metabolites, viz., dihydroxylation and sulphate conjugation products of rutaecarpine (M8-M11)) as well as parent drug itself, including three phase I and 12 phase II metabolites were detected and identified in rat plasma. Hydroxylation, sulphate conjugation and glucuronidation were confirmed as the primary metabolic pathways for rutaecarpine in rat plasma.

DISCUSSION AND CONCLUSION

These results provide an insight into the metabolism of rutaecarpine and also can give strong indications on the effective forms of rutaecarpine in vivo.

Metabolic activation of the indoloquinazoline alkaloids evodiamine and rutaecarpine by human liver microsomes: dehydrogenation and inactivation of cytochrome P450 3A4

Evodiamine and rutaecarpine are the main active indoloquinazoline alkaloids of the herbal medicine Evodia rutaecarpa, which is widely used for the treatment of hypertension, abdominal pain, angina pectoris, gastrointestinal disorder, and headache. Immunosuppressive effects and acute toxicity were reported in mice treated with evodiamine and rutaecarpine. Although the mechanism remains unknown, it is proposed that metabolic activation of the indoloquinazoline alkaloids and subsequent covalent binding of reactive metabolites to cellular proteins play a causative role. Liquid chromatography-tandem mass spectrometry analysis of incubations containing evodiamine and NADPH-supplemented microsomes in the presence of glutathione (GSH) revealed formation of a major GSH conjugate which was subsequently indentified as a benzylic thioether adduct on the C-8 position of evodiamine by NMR analysis. Several other GSH conjugates were also detected, including conjugates of oxidized and demethylated metabolites of evodiamine. Similar GSH conjugates were formed in incubations with rutaecarpine. These findings are consistent with a bioactivation sequence involving initial cytochrome P450-catalyzed dehydrogenation of the 3-alkylindole moiety in evodiamine and rutaecarpine to an electrophile 3-methyleneindolenine. Formation of the evodiamine and rutaecarpine GSH conjugates was primarily catalyzed by heterologously expressed recombinant CYP3A4 and, to a lesser extent, CYP1A2 and CYP2D6, respectively. It was found that the 3-methyleneindolenine or another reactive intermediate was a mechanism-based inactivator of CYP3A4, with inactivation parameters KI = 29 µM and kinact = 0.029 minute(-1), respectively. In summary, these findings are of significance in understanding the bioactivation mechanisms of indoloquinazoline alkaloids, and dehydrogenation of evodiamine and rutaecarpine may cause toxicities through formation of electrophilic intermediates and lead to drug-drug interactions mainly via CYP3A4 inactivation.

Pharmacokinetics and urine metabolite identification of dehydroevodiamine in the rat

This study investigates the oral bioavailability and characterizes urine metabolites of dehydroevodiamine (DeHE), one of the bioactive alkaloids isolated from the fruit of Evodia rutaecarpa . A freely moving rat model coupled with an automated blood sample system was used to evaluate the pharmacokinetics of DeHE. High-performance liquid chromatography (HPLC), mass spectrometry (MS), and nuclear magnetic resonance (NMR) spectrometry were applied to determine DeHE and its metabolites. The averaged oral bioavailability of DeHE (100 and 500 mg/kg) in the freely moving rats was approximately 15.35%. Cumulative fecal and urinary excretions of unchanged DeHE were 6 and 0.5%, respectively, after a single oral dose (500 mg/kg) of DeHE. The protein binding of DeHE in rat plasma was 65.6 ± 6.5%. Six metabolites, including five DeHE-O-glucuronides and one DeHE-sulfate, were identified after oral administration. The structures of two glucuronide conjugates, DeHE-10-O-glucuronide (M3) and DeHE-11-O-glucuronide (M4), and one sulfate conjugate, DeHE-12-sulfate (M6), were assigned. The findings indicate that the oral bioavailability of DeHE was much higher than that of evodiamine, and hydroxylation and conjugative metabolism were essential for the urinary elimination of DeHE.