Induction of cytochrome P450-dependent monooxygenase in mouse liver and kidney by rutaecarpine, an alkaloid of the herbal drug Evodia rutaecarpa

Effects of xenobiotics on CYP1 enzyme-mediated biotransformation and bioactivation of estradiol

Endogenous estradiol (E2) exerts diverse physiological and pharmacological activities, commonly used for hormone replacement therapy. However, prolonged and excessive exposure to E2 potentially increases estrogenic cancer risk. Reportedly, CYP1 enzyme-mediated biotransformation of E2 is largely concerned with its balance between detoxification and carcinogenic pathways. Among the three key CYP1 enzymes (CYP1A1, CYP1A2, and CYP1B1), CYP1A1 and CYP1A2 mainly catalyze the formation of nontoxic 2-hydroxyestradiol (2-OH-E2), while CYP1B1 specifically catalyzes the formation of genotoxic 4-hydroxyestradiol (4-OH-E2). 4-OH-E2 can be further metabolized to electrophilic quinone intermediates accompanied by the generation of reactive oxygen species (ROS), triggering DNA damage. Since abnormal alterations in CYP1 activities can greatly affect the bioactivation process of E2, regulatory effects of xenobiotics on CYP1s are essential for E2-associated cancer development. To date, thousands of natural and synthetic compounds have been found to show potential inhibition and/or induction actions on the three CYP1 members. Generally, these chemicals share similar planar polycyclic skeletons, the structural motifs and substituent groups of which are important for their inhibitory/inductive efficiency and selectivity toward CYP1 enzymes. This review comprehensively summarizes these known inhibitors and/or inductors of E2-metabolizing CYP1s based on chemical categories and discusses their structure-activity relationships, which would contribute to better understanding of the correlation between xenobiotic-regulated CYP1 activities and estrogenic cancer susceptibility.

Pharmacological blockage of the AHR-CYP1A1 axis: a call for in vivo evidence

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that can be activated by structurally diverse compounds arising from the environment and the microbiota and host metabolism. Expanding evidence has been shown that the modulation of the canonical pathway of AHR occurs during several chronic diseases and that its abrogation might be of clinical interest for metabolic and inflammatory pathological processes. However, most of the evidence on the pharmacological abrogation of the AHR-CYP1A1 axis has been reported in vitro, and therefore, guidance for in vivo studies is needed. In this review, we cover the state-of-the-art of the pharmacodynamic and pharmacokinetic properties of AHR antagonists and CYP1A1 inhibitors in different in vivo rodent (mouse or rat) models of disease. This review will serve as a road map for those researchers embracing this emerging therapeutic area targeting the AHR. Moreover, it is a timely opportunity as the first AHR antagonists have recently entered the clinical stage of drug development.

Traditional uses, phytochemistry, pharmacology, pharmacokinetics and toxicology of the fruit of Tetradium ruticarpum: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The fruit of Tetradium ruticarpum (FTR) known as Tetradii fructus or Evodiae fructus (Wu-Zhu-Yu in Chinese) is a versatile herbal medicine which has been prescribed in Chinese herbal formulas and recognized in Japanese Kampo. FTR has been clinically used to treat various diseases such as headache, vomit, diarrhea, abdominal pain, dysmenorrhea and pelvic inflammation for thousands of years.

AIM OF THE REVIEW

The present paper aimed to provide comprehensive information on the ethnopharmacology, phytochemistry, pharmacology, pharmacokinetics, drug interaction and toxicology of FTR in order to build up a foundation on the mechanism of ethnopharmacological uses as well as to explore the trends and perspectives for further studies.

MATERIALS AND METHODS

This review collected the literatures published prior to July 2020 on the phytochemistry, pharmacology, pharmacokinetics and toxicity of FTR. All relevant information on FTR was gathered from worldwide accepted scientific search engines and databases, including Web of Science, PubMed, Elsevier, ACS, ResearchGate, Google Scholar, and Chinese National Knowledge Infrastructure (CNKI). Information was also obtained from local books, PhD. and MSc. Dissertations as well as from Pharmacopeias.

RESULTS

FTR has been used as an herbal medicine for centuries in East Asia. A total of 165 chemical compounds have been isolated so far and the main chemical compounds of FTR include alkaloids, terpenoids, flavonoids, phenolic acids, steroids, and phenylpropanoids. Crude extracts, processed products (medicinal slices) and pure components of FTR exhibit a wide range of pharmacological activities such as antitumor, anti-inflammatory, antibacterial, anti-obesity, antioxidant, insecticide, regulating central nervous system (CNS) homeostasis, cardiovascular protection. Furthermore, bioactive components isolated from FTR can induce drug interaction and hepatic injury.

CONCLUSIONS

Therapeutic potential of FTR has been demonstrated with the pharmacological effects on cancer, inflammation, cardiovascular diseases, CNS, bacterial infection and obesity. Pharmacological and pharmacokinetic studies of FTR mostly focus on its main active alkaloids. Further in-depth studies on combined medication and processing approaches mechanisms, pharmacological and toxic effects not limited to the alkaloids, and toxic components of FTR should be designed.

Rutaecarpine derivative Cpd-6c alleviates acute kidney injury by targeting PDE4B, a key enzyme mediating inflammation in cisplatin nephropathy

Acute kidney injury (AKI), characterized by a rapid decline in renal function, is triggered by an acute inflammatory response that leads to kidney damage. An effective treatment for AKI is lacking. Using in vitro and in vivo AKI models, our laboratory has identified a series of anti-inflammatory molecules and their derivatives. In the current study, we identified the protective role of rutaecarpine (Ru) on renal tubules. We obtained a series of 3-aromatic sulphonamide-substituted Ru derivatives exhibiting enhanced renoprotective and anti-inflammatory function. We identified Compound-6c(Cpd-6c) as having the best activity and examined its protective effect against cisplatin nephropathy both in vivo and in vitro in cisplatin-stimulated tubular epithelial cells (TECs). Our results showed that Cpd-6c restored renal function more effectively than Ru, as evidenced by reduced blood urea nitrogen and serum creatinine levels in mice. Cpd-6c alleviated tubular injury, as shown by PAS staining and molecular analysis of kidney injury molecule-1 (KIM-1), with both prevention and treatment protocols in cisplatin-treated mice. Moreover, Cpd-6c decreased kidney inflammation, oxidative stress and programmed cell death. These results have also been confirmed in cisplatin-treated TECs. Using web-prediction algorithms, molecular docking, and cellular thermal shift assay (CETSA), we identified phosphodiesterase 4B (PDE4B) as a Cpd-6c target. In addition, we firstly found that PDE4B was up-regulated significantly in the serum of AKI patients. After identifying the function of PDE4B in cisplatin-treated tubular epithelial cells by siRNA transfection or PDE4 inhibitor rolipram, we showed that Cpd-6c treatment did not protect against cisplatin-induced injury in PDE4B knockdown TECs, thus indicating that Cpd-6c exerts its renoprotective and anti-oxidative effects via the PDE4B-dependent pathway. Collectively, Cpd-6c might serve as a potential therapeutic agent for AKI and PDE4B may be highly involved in the initiation and progression of AKI.

Catalyst-controlled selective mono-/dialkylation of 2-aryl-4(3H)-quinazolinones

Catalyst-controlled selective mono-/dialkylation of 2-aryl-4(3H)-quinazolinones with α-diazotized Meldrum's acid has been achieved successfully via a metal carbene migratory insertion process.

Biologically active quinoline and quinazoline alkaloids part I

Quinoline and quinazoline alkaloids, two important classes of N-based heterocyclic compounds, have attracted tremendous attention from researchers worldwide since the 19th century. Over the past 200 years, many compounds from these two classes were isolated from natural sources, and most of them and their modified analogs possess significant bioactivities. Quinine and camptothecin are two of the most famous and important quinoline alkaloids, and their discoveries opened new areas in antimalarial and anticancer drug development, respectively. In this review, we survey the literature on bioactive alkaloids from these two classes and highlight research achievements prior to the year 2008 (Part I). Over 200 molecules with a broad range of bioactivities, including antitumor, antimalarial, antibacterial and antifungal, antiparasitic and insecticidal, antiviral, antiplatelet, anti-inflammatory, herbicidal, antioxidant and other activities, were reviewed. This survey should provide new clues or possibilities for the discovery of new and better drugs from the original naturally occurring quinoline and quinazoline alkaloids.

Structure-Activity Relationships of the Main Bioactive Constituents of Euodia rutaecarpa on Aryl Hydrocarbon Receptor Activation and Associated Bile Acid Homeostasis

Rutaecarpine (RUT), evodiamine (EOD), and dehydroevodiamine (DHED) are the three main bioactive indoloquinazoline alkaloids isolated from Euodia rutaecarpa, a widely prescribed traditional Chinese medicine. Here, the structure-activity relationships of these analogs for aryl hydrocarbon receptor (AHR) activation were explored by use of Ahr-deficient (Ahr^-/-) mice, primary hepatocyte cultures, luciferase reporter gene assays, in silico ligand-docking studies, and metabolomics. In vitro, both mRNA analysis of AHR target genes in mouse primary hepatocytes and luciferase reporter assays in hepatocarcinoma cell lines demonstrated that RUT, EOD, and DHED significantly activated AHR, with an efficacy order of RUT > DHED > EOD. Ligand-docking analysis predicted that the methyl substitute at the N-14 atom was a key factor affecting AHR activation. In vivo, EOD was poorly orally absorbed and failed to activate AHR, whereas RUT and DHED markedly upregulated expression of the hepatic AHR gene battery in wild-type mice, but not in Ahr^-/- mice. Furthermore, RUT, EOD, and DHED were not hepatotoxic at the doses used; however, RUT and DHED disrupted bile acid homeostasis in an AHR-dependent manner. These findings revealed that the methyl group at the N-14 atom of these analogs and their pharmacokinetic behaviors were the main determinants for AHR activation, and suggest that attention should be given to monitoring bile acid metabolism in the clinical use of E. rutaecarpa.

Features and outcomes of drugs for combination therapy as multi-targets strategy to combat Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD), a deleterious neurodegenerative disorder that impairs memory, cognitive functions and may lead to dementia in late stage of life. The pathogenic cause of AD remains incompletely understood and FDA approved drugs are partial inhibitors rather than curative. Most of drugs are synthetic or natural products as galanthamine is an alkaloid obtained from Galanthus spp. Huperzine A, an alkaloid found in Huperzia spp., gingkolides a diterpenoids from Gingko biloba and many ethnobotanicals like Withania somnifera (L.) Dunal., Physostigma venenosum Balf., Bacopa monnieri (L.) Wettst., Centella asiatica (L.) Urb. have been used by traditional Indian, Chinese, and European system of medicines in AD. Clinical significance opioid alkaloid in Papaver somniferum has shown another dimension to this study. Over exploitation of medicinal plants with limited bioactive principles has provided templates to design synthetic drugs in AD e.g. rivastigmine, phenserine, eptastigmine based on chemical structure of physostigmine of Physostigma venenosum Balf. Even ZT-1 a prodrug of Hup A and memogain a prodrug of galantamine has achieved new direction in drug development in AD. All these first-line cholinesterase-inhibitors are used as symptomatic treatments in AD. Single modality of "One-molecule-one-target" strategy for treating AD has failed and so future therapies on "Combination-drugs-multi-targets" strategy (CDMT) will need to address multiple aspects to block the progression of pathogenesis of AD. Besides, cholinergic and amyloid drugs, in this article we summarize proteinopathy-based drugs as AD therapeutics from a variety of biological sources. In this review, an attempt has been made to elucidate the molecular mode of action of various plant products, and synthetic drugs investigated in various preclinical and clinical tests in AD. It also discusses current attempts to formulate a comprehensive CDMT strategy to counter complex pathogenesis in AD.

MATERIALS AND METHODS

Information were collected from classical books on medicinal plants, pharmacopoeias and scientific databases like PubMed, Scopus, GoogleScholar, Web of Science and electronic searches were performed using Cochrane Library, Medline and EMBASE. Also published scientific literatures from Elsevier, Taylor and Francis, Springer, ACS, Wiley publishers and reports by government bodies and documentations were assessed.

RESULTS

60 no. of natural and synthetic drugs have been studied with their significant bioactivities. A decision matrix designed for evaluation of drugs for considering to the hypothetic "CDMT" strategy in AD. We have introduced the scoring pattern of individual drugs and based on scoring pattern, drugs that fall within the scoring range of 18-25 are considered in the proposed CDMT. It also highlights the importance of available natural products and in future those drugs may be considered in CDMT along with the qualified synthetic drugs.

CONCLUSION

A successful validation of the CDMT strategy may open up a debate on health care reform to explore other possibilities of combination therapy. In doing so, it should focus on clinical and molecular relationships between AD and CDMT. A better understanding of these relationships could inform and impact future development of AD-directed treatment strategies. This strategy also involves in reducing costs in treatment phases which will be affordable to a common man suffering from AD.

Rutaecarpine effects on expression of hepatic phase-1, phase-2 metabolism and transporter genes as a basis of herb-drug interactions

ETHNOPHARMACOLOGICAL RELEVANCE

Rutaecarpine is an alkaloid of Evodia rutaecarpa which is traditionally used to treat human diseases. Rutaecarpine has been used in combination with other drugs in the treatment of disorders and found to produce herb-drug interactions. The basis of these herb-drug interactions is not completely understood.

AIM OF STUDY

To examine the effects of rutaecarpine on the expression of drug processing genes, including Phase-1 (P450 enzyme genes), Phase-2 (glucuronidation and sulfation genes) and Phase-3 (drug transporters) in liver of mice.

MATERIALS AND METHODS

Mice were orally administered rutaecarpine at the doses of 10, 20, and 30 mg/kg for consecutive 7 days. Twenty-four hours after the last dose, blood and liver were collected. Total RNA was isolated, purified, and subjected to real-time RT-PCR analysis of genes of interest.

RESULTS

Rutaecarpine administration induced Cyp1a2, 2b10 and 2e1 as previously reported. Cyp3a11 and Cyp4a10 were also induced. For phase-2 enzyme genes, rutaecarpine increased glucuronyltransferases (Ugt1a1 and Ugt1a6), but had no effects on sulfotransferase (Sult1a1 and Sult1b1). Most interestingly, rutaecarpine increased hepatic uptake of organic anion transporting peptides (Oatp1a1, Oayp1a4, Oatp1b2, and Oatp2b1) and induced efflux transporter such as multidrug resistance-associated proteins (Mrp1, Mrp2, Mrp3, and Mrp4), especially at the doses of 20mg/kg and above.

CONCLUSION

The interactions of rutaecarpine with drugs involve not only the induction of cytochrome P450 enzyme genes, but also the induction of hepatic transporters and phase-2 enzyme genes. The effects of rutaecarpine on these drug processing genes could play integrated roles in producing herb-drug interactions.

Influences of Fructus evodiae pretreatment on the pharmacokinetics of Rhizoma coptidis alkaloids

ETHNOPHARMACOLOGICAL RELEVANCE

Rhizoma coptidis is a traditional Chinese medicine with pharmacological properties. It is usually prescribed with Fructus evodiae as traditional Chinese medicine (TCM) formulas. Here we report the influences of Fructus evodiae on the pharmacokinetics of the Rhizoma coptidis alkaloids and propose possible mechanisms.

MATERIALS AND METHODS

Pharmacokinetic experiments were performed in rats. In vitro absorption experiments were performed in everted rat gut sacs, while in vitro metabolism experiments and determination of hepatic UDP-glucuronosyltransferase (UGT) 1A1 mRNA expression were performed in rat liver microsomes.

RESULTS

Pretreatment with Fructus evodiae extract for two weeks decreased the systemic exposure of the Rhizoma coptidis alkaloids. This effect was not due to inhibition of absorption or enhanced hepatic phase I metabolism of the Rhizoma coptidis alkaloids. However, Fructus evodiae pretreatment enhanced both the activity and expression of hepatic UGT1A1.

CONCLUSIONS

The results showed that Fructus evodiae pretreatment decreased the systemic exposure of the Rhizoma coptidis alkaloids by inducing hepatic UGT1A1.

Up-regulation of CYP1A1 by rutaecarpine is dependent on aryl hydrocarbon receptor and calcium

Rutaecarpine is a quinazolinocarboline alkaloid isolated from a traditional Chinese medicinal fruit, Evodia rutaecarpa. In the present study, we investigated the effect of rutaecarpine on CYP1A1 expression mediated by [Ca(2+)] and the AhR pathway in mouse hepatoma Hepa-1c1c7 cells. Rutaecarpine also significantly increased CYP1A1 enzyme activity and mRNA and protein levels. Rutaecarpine markedly induced XRE and AhR binding activity. CH-223191, an AhR antagonist, blocked the rutaecarpine-induced CYP1A1 enzyme activity and mRNA and protein expression. In addition, rutaecarpine remarkably induced the phosphorylation of Ca(2+)/calmodulin (CaM)-dependent protein kinase (CaMK). W7 and BAPTA/AM, a CaM antagonist and an intracellular Ca(2+) chelator, respectively, blocked the rutaecarpine-induced CYP1A1 enzyme activity and mRNA and protein expression. These results indicate that rutaecarpine induces CYP1A1 expression through AhR- and calcium-dependent mechanisms.

The effects of rutaecarpine on the pharmacokinetics of acetaminophen in rats

Rutaecarpine, an alkaloid originally isolated from the unripe fruit of Evodia rutaecarpa, has been shown to be anti-inflammatory as it inhibits cyclooxygenase-2. It induces the activities of hepatic CYP 1A2, 2B, and 2E1 in rats. A possible interaction between rutaecarpine and acetaminophen (APAP) was investigated in male Sprague Dawley rats in the present study. When 25 mg/kg APAP was intravenously administered concurrently with 80 mg/kg rutaecarpine, the area under the curve of APAP in plasma was significantly decreased when compared to that of APAP alone. When the rats were pre-treated orally with 40 and 80 mg/kg rutaecarpine for 3 days, the % value of C(max) and area under the curve of acetaminophen-sulfate conjugate were significantly decreased to 56.4% and 61.7% of the vehicle control group, respectively. These results suggest that rutaecarpine might cause changes in the pharmacokinetic parameters of APAP in rats.

Herbal product-drug interactions mediated by induction

Despite their common use, it is not widely recognized that herbal medicines can alter the efficacy of coadministered prescription drugs. Constituents in herbs interact with nuclear receptors to enhance metabolizing enzyme and/or transporter activity leading to reduced drug concentrations. Although St John's wort was the first and most frequently reported source of induction-style herb-drug interactions, this knowledge has not yet changed its current availability. This type of interaction is likely to be relevant to other herbal products. Caregivers need to be aware of the issues and options for therapeutic management.

Characterization of the Phase II metabolites of rutaecarpine in rat by liquid chromatography-electrospray ionization-tandem mass spectrometry

From the authors' previous studies on the Phase I metabolism of rutaecarpine, nine metabolites formed were identified as products of hydroxylation on the aromatic rings in rat liver microsomes. In order to determine the possible metabolic fate of rutaecarpine, the Phase II metabolites of rutaecarpine were characterized in the present study by using liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS). When male Sprague-Dawley rats were treated intravenously with 4 mg kg(-1) rutaecarpine, 16 different Phase I and II metabolites were identified in urine including four sulfate and four glucuronide conjugates. Phase I metabolites of rutaecarpine were identified as four mono-hydroxylated metabolites (M2-5) and four isobaric di-hydroxylated metabolites (M6-9). These metabolites were identical to the in vitro metabolites except one, which was hydroxylated in the aliphatic moiety. In addition, Phase II metabolites were identified as conjugated with sulfate (S1-4) and glucuronide (G1-4). In faeces, 11 different metabolites were identified. The metabolites M8 and glucuronide conjugated (G1-4) were not detected. Structures of all metabolites were confirmed with CID fragmentation spectra of MS(2), MS(3) and retention times by LC/ESI-MS.

Characterization of human liver cytochrome P450 enzymes involved in the metabolism of rutaecarpine

Rutaecarpine has recently been characterized to have an anti-inflammatory activity through cyclooxygenase-2 inhibition. The incubation of rutaecarpine with human liver microsomes in the presence of NADPH generated six isobaric mono-hydroxylated metabolites. The specific cytochrome P450 (CYP) isozymes responsible for rutaecarpine metabolites were identified using the combination of chemical inhibition, immuno-inhibition and metabolism by cDNA expressed CYP enzymes. The results suggested that CYP3A4 might play major roles in the metabolism of rutaecarpine in human liver microsomes. The production of M1, M2, M3, M4 and M6 formed in human liver microsomes was inhibited by ketoconazole, a selective CYP3A4 inhibitor, and anti-CYP3A4 antibody. CYP1A2 and CYP2C9 played minor roles in the metabolism of rutaecarpine. These results were confirmed in microsomes derived from cDNA expressed lymphoblastoid cells. CYP3A4 microsome clearly formed M1, M2, M3 and M6. CYP1A2 and CYP2C9 microsomes comparably formed M5.

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

Rutaecarpine is an alkaloid isolated from the medicinal herb Evodia rutaecarpa. This study was to evaluate the elimination pathway of rutaecarpine in rat feces and urine. Rutaecarpine and its metabolites (3-, 10-, 11- and 12-hydroxyrutaecarpine) in urine were measured after incubation with beta-glucuronidase. After the rutaecarpine was administered (25 and 100 mg/kg) orally to rats, the urine and fecal samples were collected using a metabolic cage for five consecutive days. For determining rutaecarpine, the mobile phase consisted of acetontrile-10 mM NaH(2)PO(4) (60:40, v/v, pH 4.2 adjusted with orthophosphoric acid) with a flow rate of 1 mL/min. The calibration curve was linear in concentrations of 0.05-50 microg/mL in fecal and urine sample. The results indicated that more than 42% of the rutaecarpine was excreted by feces after oral administration (25 and 100 mg/kg), but only a small amount of rutaecarpine was detected in urine at a higher dose of rutaecarpine (100 mg/kg). After incubation with beta-glucuronidase, the hydroxyrutaecarpine in urine was eluted using methanol-acetonitrile-0.04% formic acid (6:30:64, v/v) with a flow rate of 1.2 mL/min. We conclude that the metabolic pathway of rutaecarpine went through phase I hydroxylation and phase II conjugation, and the major metabolite is 10-hydroxyrutaecarpine eliminated from urine of the rat.

Herb-drug interaction of Evodia rutaecarpa extract on the pharmacokinetics of theophylline in rats

The extract of Evodia rutaecarpa fruit and its preparation were used for the treatment of gastrointestinal disorders and headache. To assess the possible herb-drug interaction, the ethanol extract of Evodia rutaecarpa fruit (1 and 2 g/kg/day, p.o.) and the herbal preparation Wu-Chu-Yu-Tang (1 and 5 g/kg/day) were given to rats daily for three consecutive days and on the fourth day theophylline was administered (2 mg/kg, i.v.). Theophylline concentration in blood was measured by a microdialysis coupled to a liquid chromatographic system. Pharmacokinetic data were calculated by noncompartmental model. The results indicate that the theophylline level was significantly decreased by the pretreatment with the extract of Evodia rutaecarpa and herbal preparation Wu-Chu-Yu-Tang with dose-related manner. It is suggested that the herb-drug interaction may occur through the induction of the metabolism of theophylline.

Alteration of the pharmacokinetics of theophylline by rutaecarpine, an alkaloid of the medicinal herb Evodia rutaecarpa, in rats

Rutaecarpine is a main active alkaloid present in the medicinal herb, Evodia rutaecarpa. The cytochrome P450 (CYP) 1A2 substrate, theophylline, is an important therapeutic agent for the treatment of asthma, but has a narrow therapeutic index. To evaluate the pharmacokinetic interaction of theophylline with rutaecarpine, the effects of rutaecarpine on CYP1A2 activity and theophylline pharmacokinetics were investigated. Oral treatment of Sprague-Dawley rats with 50 mg kg(-1) rutaecarpine for three days through a gastrogavage caused a 4- and 3-fold increase in liver microsomal 7-ethoxyresorufin O-deethylation (EROD) and 7-methoxyresorufin O-demethylation activity, respectively. In the kidney, rutaecarpine treatment caused a 3-fold increase in EROD activity. In the lungs, EROD activity was elevated from an undetectable to a detectable level by rutaecarpine. Pharmacokinetic parameters of theophylline were determined using a microdialysis sampling method. Rutaecarpine pre-treatment increased the clearance of theophylline in a dose-dependent manner. Pre-treatment of rats with 50 mg kg(-1) rutaecarpine caused a 3-fold increase in theophylline clearance and a 70%, 68% and 68% decrease in the area under the concentration-time curve (AUC), mean residence time (MRT) and half-life, respectively. These results demonstrated that rutaecarpine treatment elevated CYP1A2 catalytic activity and theophylline excretion in rats. In patients taking theophylline, adverse effects might be noticed when a rutaecarpine-containing herbal preparation is used concomitantly.

Identification of the microsomal oxidation metabolites of rutaecarpine, a main active alkaloid of the medicinal herb Evodia rutaecarpa

Rutaecarpine is a quinazolinocarboline alkaloid of the medicinal herb Evodia rutaecarpa and shows a variety of pharmacological effects. Four oxidation metabolites of rutaecarpine were prepared from 3-methylcholanthrene-treated rat liver microsomes. These metabolites had an [M + H]+ ion at m/z 304. The structures of metabolites were identified by comparison of their liquid chromatograms and mass, absorbance, and 1H NMR spectra with those of synthetic standards. Rutaecarpine was metabolized by microsomal enzymes to form 3-, 10-, 11-, and 12-hydroxyrutaecarpine. The formation of 10-hydroxyrutaecarpine was highly induced by a cytochrome P450 1A inducer, 3-methylcholanthrene.

Effects of polysaccharide ginsan fromPanax ginseng on liver function

Ginsan, a polysaccharide isolated from Panax ginseng, has been shown to be a potent immunomodulator, producing a variety of cytokines such as TNF-alpha, IL-1, IL-2, IL-6, IL-12, IFN-gamma and GM-CSF, and stimulating lymphoid cells to proliferate. In the present study, we analyzed some immune functions 1st-5th days after ginsan i.p. injection, including the level of non-protein thiols (NPSH) as antioxidants, heme oxygenase (HO) activity as a marker of oxidative stress, zoxazolamine-induced paralysis time and level of hepatic cytochrome P-450 (CYP450) as indices of drug metabolism system, and activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin, and albumin level as indicators of hepatotoxicity. Ginsan in the dose of 100 mg/kg caused marked elevation (1.7 to approximately 2 fold) of HO activity, decrease of total CYP450 level (by 20-34%), and prolongation of zoxazolamine-induced paralysis time (by 65-70%), and showed some differences between male and female mice. Ginsan treatment did not seem to cause hepatic injury, since serum AST, ALT, and ALP activities and levels of total bilirubin and albumin were not changed.

Selective suppression of cytochrome P450 gene expression by the medicinal herb, Thonningia sanguinea in rat liver

The effect of the administration of Thonningia sanguinea (T. S.) on the abundance of individual components of the cytochrome P450 monooxygenase enzyme was examined using Western blotting and competitive reverse-transcriptase-polymerase chain reaction (RT-PCR). We also investigated the time-course of inhibition of T. S. on drug metabolizing enzymes. A single intraperitoneal dose of T. S. extract (5 ml/kg) suppressed CYP, cytochrome b5 and NADPH-CYP reductase activity by 45%, 34% and 22% respectively 24 h after T. S. administration. While T. S. did not have any significant effect on microsomal glutathione S-transferase activity, it inhibited p-nitrophenol hydroxylase (PNPH, CYP2E1) and 7-methoxyresorufin O-demethylase (MROD, CYP 1A2) activities by 37% and 32% respectively at 12 h post-T. S. administration. PNPH, erythromycin N-demethylase (ERDM, CYP 3A1/2) and MROD activities were inhibited by 28-36% 24 h after T. S. injection. Consistent with these observations, the levels of CYP2E1, CYP1A2 and CYP3A2 proteins were also suppressed 24 h post-T. S. administration. While CYP2E1 mRNA was unaffected by T. S. administration, CYP1A2 and CYP3A2 mRNAs were decreased by T. S. Cytosolic glutathione S-transferase activity was increased by 30%, 6 h after T. S injection. These data demonstrate that administration of T. S. differentially affect CYP isoforms in the liver of rats and that T. S. selectively suppresses CYP3A2 and CYP1A2 gene expression.

Interactions of herbs with cytochrome P450

A resurgence in the use of medical herbs in the Western world, and the co-use of modern and traditional therapies is becoming more common. Thus there is the potential for both pharmacokinetic and pharmacodynamic herb-drug interactions. For example, systems such as the cytochrome P450 (CYP) may be particularly vulnerable to modulation by the multiple active constituents of herbs, as it is well known that the CYPs are subject to induction and inhibition by exposure to a wide variety of xenobiotics. Using in vitro, in silico, and in vivo approaches, many herbs and natural compounds isolated from herbs have been identified as substrates, inhibitors, and/or inducers of various CYP enzymes. For example, St. John's wort is a potent inducer of CYP3A4, which is mediated by activating the orphan pregnane X receptor. It also contains ingredients that inhibit CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. Many other common medicinal herbs also exhibited inducing or inhibiting effects on the CYP system, with the latter being competitive, noncompetitive, or mechanism-based. It appears that the regulation of CYPs by herbal products complex, depending on the herb type, their administration dose and route, the target organ and species. Due to the difficulties in identifying the active constituents responsible for the modulation of CYP enzymes, prediction of herb-drug metabolic interactions is difficult. However, herb-CYP interactions may have important clinical and toxicological consequences. For example, induction of CYP3A4 by St. John's wort may partly provide an explanation for the enhanced plasma clearance of a number of drugs, such as cyclosporine and innadivir, which are known substrates of CYP3A4, although other mechanisms including modulation of gastric absorption and drug transporters cannot be ruled out. In contrast, many organosulfur compounds, such as diallyl sulfide from garlic, are potent inhibitors of CYP2E1; this may provide an explanation for garlic's chemoproventive effects, as many mutagens require activation by CYP2E1. Therefore, known or potential herb-CYP interactions exist, and further studies on their clinical and toxicological roles are warranted. Given that increasing numbers of people are exposed to a number of herbal preparations that contain many constituents with potential of CYP modulation, high-throughput screening assays should be developed to explore herb-CYP interactions.

Modulation of drug-metabolizing enzymes by extracts of a herbal medicine Evodia rutaecarpa in C57BL/6J mice

Evodia rutaecarpa is a traditional Chinese medicine used for the treatment of gastrointestinal disorders and headache. To assess the possible drug interactions, effects of methanol and aqueous extracts of E. rutaecarpa on drug-metabolizing enzymes, cytochrome P450 (CYP), UDP-glucuronosyl transferase (UGT), and glutathione S-transferase (GST) were studied in C57BL/6J mice. Treatment of mice with methanol extract by gastrogavage caused a dose-dependent increase of liver microsomal 7-ethoxyresorufin O-deethylation (EROD) activity. In liver, methanol extract at 2 g/kg caused 47%, 7-, 8-, 4-fold, 81% and 26% increases of benzo(a)pyrene hydroxylation (AHH), EROD, 7-methoxyresorufin O-demethylation (MROD), 7-ethoxycoumarin O-deethylation (ECOD), benzphetamine N-demethylation, and N-nitrosodimethylamine N-demethylation activities, respectively. Aqueous extract at 2 g/kg caused 68%, 2-fold, and 83% increases of EROD, MROD, and ECOD activities, respectively. For conjugation activities, methanol extract elevated UGT and GST activities. Aqueous extract elevated UGT activity without affecting GST activity. Immunoblot analyses showed that methanol extract increased the levels of CYP1A1, CYP1A2, CYP2B-, and GSTYb-immunoreactive proteins. Aqueous extract increased CYP1A2 protein level. In kidney, both extracts had no effects on AHH, ECOD, UGT, and GST activities. Three major bioactive alkaloids rutaecarpine, evodiamine, and dehydroevodiamine were present in both extracts. These alkaloids at 25 mg/kg increased hepatic EROD activity. These results demonstrated that E. rutaecarpa methanol and aqueous extracts could affect drug-metabolizing enzyme activities. Rutaecarpine, evodiamine, and dehydroevodiamine contributed at least in part to the increase of hepatic EROD activity by extracts of E. rutaecarpa. Thus, caution should be paid to the possible drug interactions of E. rutaecarpa and CYP substrates.

Effects of Wu-chu-yu-tang and its component herbs on drug-metabolizing enzymes

The compound herbal medicine Wu-chu-yu-tang is used for the treatment of migraine and vomiting accompanying a cold. To assess the interactions of herb and drug metabolism, effects of Wu-chu-yu-tang on hepatic and renal cytochrome P450 (CYP), UDP-glucuronosyl transferase (UGT) and glutathione S-transferase (GST) were studied in C57BL/6J mice. Treatment of mice with 5 g/kg per day Wu-chu-yu-tang for 3 days caused 2.5-fold and 2.9-fold increases of liver microsomal 7-ethoxyresorufin O-deethylation (EROD) and 7-methoxyresorufin O-demethylation activities, respectively. However, CYP activities toward 7-ethoxycoumarin, benzphetamine, N-nitrosodimethylamine, erythromycin and nifedipine, and conjugation activities of UGT and GST were not affected. In kidney, Wu-chu-yu-tang-treatment had no effects on Cyp, UGT and GST activities. Among the four component herbs of Wu-chu-yu-tang, only Evodiae Fructus (Wu-chu-yu) extract increased EROD activity and CYP1a2 protein level. In E. Fructus, rutaecarpine, evodiamine and dehydroevodiamine are the main active alkaloids. At the doses corresponding to their contents in Wu-chu-yu-tang, rutaecarpine-treatment increased hepatic EROD activity, whereas evodiamine and dehydroevodiamine had no effects. These results demonstrated that ingestion of Wu-chu-yu-tang elevated mouse hepatic Cyp1a2 activity and protein level. E. Fructus and rutaecarpine contributed at least in part to the CYP1a2 induction by Wu-chu-yu-tang. Patients should be cautioned about the drug interaction of Wu-chu-yu-tang and CYP1A2 substrates.