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Rationale: Acute restraint stress (ARS) is an experimental paradigm used for the induction of rodent models of stress-produced neuropsychiatric disorders, such as depression and anxiety. β-carbolines and serotonin (5-HT) systems are involved in the modulation of depression and anxiety behaviors. Objective: This study was designed to examine the effects of intracerebroventricular (i.c.v.) injection of cinanserin (5-HT2 receptor antagonist) on harmaline-induced responses on depression- and anxiety-like behaviors in the ARS mice. Methods: For i.c.v. infusion, guide cannula was surgically implanted in the left lateral ventricle of mice. The ARS model was conducted via movement restraint at a period of 4 h. Depression- and anxiety-related behaviors were evaluated by forced swim test (FST) and elevated plus maze (EPM), respectively. Results: The results displayed that the ARS mice showed depressive- and anxiety-like responses. I.p. administration of different doses of harmaline (0.31, 0.625 and 1.25 mg/kg) or i.c.v. microinjection of cinanserin (1, 2.5, and 5 μg/mouse) blocked depression- and anxiogenic-like behaviors in the ARS mice. Furthermore, co-administration of harmaline (1.25 mg/kg; i.p.) and cinanserin (5 μg/mouse; i.c.v.) prevented the depression- and anxiogenic-like effects in the ARS mice. We found a synergistic antidepressant- and anxiolytic-like effects of harmaline and cinanserin in the ARS mice. Conclusions: These results propose an interaction between harmaline and cinanserin to prevent depressive- and anxiogenic-like behaviors in the ARS mice. [ABSTRACT FROM AUTHOR]

CYP2D6 metabolically inactivates several neurotoxins, including beta-carbolines, which are implicated in neurodegenerative diseases. Variation in CYP2D6 within the brain may alter local inactivation of neurotoxic beta-carbolines, thereby influencing neurotoxicity. The beta-carboline harmine, which induces hypothermia and tremor, is metabolized by CYP2D6 to the non-hypothermic/non-tremorgenic harmol. Transgenic mice (TG), expressing human CYP2D6 in addition to their endogenous mouse CYP2D, experience less harmine-induced hypothermia and tremor compared with wild-type mice (WT). We first sought to elucidate the role of CYP2D in general within the brain in harmine-induced hypothermia and tremor severity. A 4-h intracerebroventricular (ICV) pretreatment with the CYP2D inhibitor propranolol increased harmine-induced hypothermia and tremor in TG and increased harmine-induced hypothermia in WT. We next sought to specifically demonstrate that human CYP2D6 expressed in TG brain altered harmine response severity. A 24-h ICV propranolol pretreatment, which selectively and irreversibly inhibits human CYP2D6 in TG brain, increased harmine-induced hypothermia. This 24-h pretreatment had no impact on harmine response in WT, as propranolol is not an irreversible inhibitor of mouse CYP2D in the brain, thus confirming no off-target effects of ICV propranolol pretreatment. Human CYP2D6 activity in TG brain was sufficient in vivo to mitigate harmine-induced neurotoxicity. These findings suggest that human CYP2D6 in the brain is protective against beta-carboline-induced neurotoxicity and that the extensive interindividual variability in CYP2D6 expression in human brain may contribute to variation in susceptibility to certain neurotoxin-associated neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

1. Beta-carbolines are indole alkaloids with a wide range of pharmacological and toxicological activities. Beta-carbolines are structurally related to the neurotoxin 1-methyl-4-phenylpyridinium (MPP+), a known substrate of organic cation transporters (OCTs). The goal of this study is to determine the interaction of β-carbolines with human OCT1, 2, and 3 (SLC22A1-3). 2. Dose-dependent inhibition studies were performed for five commercially available β-carbolines using a fluorescent substrate assay in HEK293 cells stably expressing hOCT1-3. The substrate potential was evaluated by uptake assays and the impact of active transport on cellular toxicity examined. 3. All tested β-carbolines potently inhibited hOCT2 with IC50values in the sub- or low micromolar range. Harmaline is the most potent hOCT2 inhibitor (IC50 = 0.50 ± 0.08 μM). hOCT1 and hOCT3 are less sensitive to β-carboline inhibition. Harmaline, norharmanium, and 2,9-dimethyl-4,9-dihydro-3H-β-carbolinium accumulated 2- to 7-fold higher in cells expressing hOCT1-3. HEK293 cells expressing hOCT1-3 were 6.5- to 13-fold more sensitive to harmane and norharmanium toxicity. 4. Our data support a significant role of hOCT1-3 in tissue uptake and disposition of β-carbolines. Importantly, the potent inhibition of hOCT2 by β-carbolines also raises the concern of potential drug interactions between naturally occurring bioactive alkaloids and drugs eliminated by hOCT2. [ABSTRACT FROM PUBLISHER]

Harmaline and harmine occur naturally in plants and are distributed endogenously in human and animal tissues. The two β-carboline alkaloids possess potential for treating Alzheimer's disease, Parkinson's disease, depression and other central nervous system diseases. However, studies have showed that the two compounds have similar structures but with quite different bioavailability. The aim of this study was to elucidate the exposure difference and characterize the in vitro transport, metabolism, and pharmacokinetic properties of harmaline and harmine. The results showed that the harmaline and harmine transport across the Caco-2 and MDCK cell monolayers was varied as the time, concentration, pH and temperature changed. The absorption of harmaline and harmine was significantly decreased when ES (OATPs inhibitor), TEA (OCTs/OCTNs substrate), NaN3 (adenosine triphosphate inhibitor), or sodium vanadate (ATPase Na+/K+-dependent inhibitor) was added. However, when given MK571 and probenecid (the typical MRP2 inhibitor), the PappAB of harmine was increased (1.62- and 1.27-folds), and the efflux ratio was decreased from 1.59 to 0.98 and from 1.59 to 1.19, respectively. In addition, the uptake ratio of harmine at 1 μM was >2.65 in the membrane vesicles expressing human MRP2. Furthermore, harmine could slightly up-regulate the expression of MRP2, which implying harmine might be the substrate of MRP2. Particularly, the CLint-value for harmine was ~1.49-folds greater than that of harmaline in human liver microsomes. It was worth noting that the F-value of harmine was increased 1.96-folds after harmine co-administration with probenecid. To summarize, comprehensive analysis indicated that harmaline and harmine were absorbed by transcellular passive diffusion and a pH- and Na+-dependent mechanism might be mediated by OATPs and OCTs/OCTNs. MRP2 but MDR1 or BCRP might be involved in the transport of harmine. Furthermore, harmine was more unstable and easily metabolized than harmaline. All these findings suggested that harmine not only appears be an MRP2 substrate, but also possesses weak metabolic stability, and eventually leads to a low oral bioavailability. Taken together, the elucidated absorption, transport, metabolism as well as pharmacokinetic characteristics of harmaline and harmine provide useful information for designing delivery systems, pharmacological applications and avoiding drug-drug interactions. [ABSTRACT FROM AUTHOR]

The β-carboline alkaloids harmaline and harmine are widely present in hallucinogenic plants with great potential for treating depression, Parkinson's disease, and Alzheimer's disease. The present study was to elucidate metabolic difference of harmaline and harmine in 11 mammalian liver microsomes in order to quantitate species-specific metabolic profiles. Using the probe substrate reaction, the enzymatic activities for 8 CYP450 isozymes of 11 liver microsomes were characterized. Combining ultra performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q/TOF-MS) and ultra performance liquid chromatography combined with electrospray ionization quadrupole tandem mass spectrometry (UPLC-ESI-MS/MS) methods, 18 metabolites for harmaline and 11 for harmine were identified. The metabolism patterns differences of them presented discrepancy in the quality and quantity of metabolites. It was notable that O-sulfate conjugation was detected in all species except sheep. The intrinsic clearance CL int, LM values for the metabolites harmine and harmol in rabbits (37.5 and 42.4 μL/min/mg) were higher than those in other animals, while dogs (16.2 and 16.7 μL/min/mg) and humans (16.0 and 16.3 μL/min/mg) exhibited similar in vitro metabolic clearance. These observations suggested that harmaline and harmine were rapidly metabolized in liver microsomes of rat, mouse, and rabbit; moderately metabolized in human and dog; while weakly metabolized in sheep. Comprehensive analysis of the metabolism indicated that dogs and humans showed considerable similarity in the elimination of parent drugs, metabolic profiles, and catalytic processes. To summarize, these findings illustrated that in vitro studies of harmaline and harmine metabolic profiles in different species are helpful for the proper selection and interpretation of animal models for pharmacological and toxicological evaluation, and will ultimately provide useful guidance for the development of β-carboline alkaloids. Copyright © 2016 John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Background and Aim: Burn wound is a susceptible site for incidence of resistant infections. Therefore, research for finding effective drugs against Pseudomonas aeruginosa, the leading pathogen causing burn wound infection, is necessary. The current study aimed at investigating the antibacterial effect of herbs including: Daenensis thyme, Chavill (Frulago angulata), and Harmala on burn infection caused by Pseudomonas aeruginosa and then comparing the obtained results with the results of selected antibiotics on the infection. Methods and Materials: Anti-Pseudomonas activity of plants' extractions was evaluated by well diffusion method. The evaluation of burn wound recovery treated with Peganum harmala and daenensis thyme on burn wounds of albinos. Wound area and recovery percentage was measured. The number of neutrophils and lymphocytes, from all infected groups the sample of blood was obtained. Results: The measurement results of the zone of inhibition against Pseudomonas aeruginosa showed better consequences for Thymus daenensis. The number of colonies in the treated group with plants and ciprofloxacin showed significant differences as compared with the control group and the group treated with gentamicin. In counting the white blood cells of infected control group and gentamicin treated group, the number of white blood cells was below the normal level while the number of blood cells in groups treated with medicinal plants and ciprofloxacin were normal. Conclusion: Based on the obtained results of this study on these plant species and their positive activity on treatment of infected burn wounds, it was concluded that these plants can be considered and used as an anti-Pseudomonas. [ABSTRACT FROM AUTHOR]

Compounds derived from natural products are becoming promising alternative drugs/tools in Alzheimer's disease (AD) therapeutics. From an in-house natural products library, seventeen hits were selected for their inhibitory effect on the production of amyloid-β (Aβ) with IC50 lower than 10 μM without causing obvious toxicity. Among these compounds, camptothecin (CPT) and its analogs showed inhibitory effects on amyloid-β 1-42 (Aβ42) with the IC50 value in the nanomolar range in HEKsw cells and SHSY5Ysw cells. Further studies showed that CPT and its analogs inhibited Aβ42 via a p53 dependent pathway. Meanwhile, CPT and its analogs could also inhibit Aβ42 induced IL-1β production in the THP-1 cells. Taken together, our results indicate that CPT and its analogs would be a promising therapeutic candidates for AD. [ABSTRACT FROM AUTHOR]

1. Cytochrome P450 2D6 (CYP2D6) is a pivotal enzyme responsible for a major drug oxidation polymorphism in human populations. Distribution of CYP2D6 in brain and its role in serotonin metabolism suggest that CYP2D6 may have a function in the central nervous system. 2. To establish an efficient and accurate platform for the study of CYP2D6 in vivo, a human CYP2D6 (Tg-2D6) model was generated by transgenesis in wild-type (WT) C57BL/6 mice using a P1 phage artificial chromosome clone containing the complete human CYP2D locus, including the CYP2D6 gene and 5′- and 3′-flanking sequences. 3. Human CYP2D6 was expressed not only in the liver but also in the brain. The abundance of serotonin and 5-hydroxyindoleacetic acid in brain of Tg-2D6 is higher than in WT mice, either basal levels or after harmaline induction. Metabolomics of brain homogenate and cerebrospinal fluid revealed a significant up-regulation of L-carnitine, acetyl-L-carnitine, pantothenic acid, 2′-deoxycytidine diphosphate (dCDP), anandamide, N-acetylglucosaminylamine and a down-regulation of stearoyl-L-carnitine in Tg-2D6 mice compared with WT mice. Anxiety tests indicate Tg-2D6 mice have a higher capability to adapt to anxiety. 4. Overall, these findings indicate that the Tg-2D6 mouse model may serve as a valuable in vivo tool to determine CYP2D6-involved neurophysiological metabolism and function. [ABSTRACT FROM AUTHOR]

Ayahuasca is a botanical hallucinogenic preparation traditionally consumed by Northwestern Amazonian indigenous groups. Scientific evidence suggests good tolerability after acute administration of ayahuasca and also after years or even decades of its ritual consumption. Nevertheless, some scientific and media reports associate ayahuasca or some of its alkaloids with severe intoxications. The purpose of the present text is to do a critical evaluation of these reports. The evaluation of the cases highlights the fact that some lack accurate forensic/toxicological information, while others are not directly relevant to traditional ayahuasca preparations. These limitations reduce the possibility of an accurate risk assessment, which could indicate potential contraindications and sus- ceptibilities for ayahuasca consumption. Nevertheless, even with these limitations, the cases suggest that previous cardiac and hepatic pathologies and current use of serotonergic drugs/medications are contraindications to ayahuasca use, and that caution should be taken when using different botanical species and extracted/synthetic alkaloids to prepare ayahuasca analogues. [ABSTRACT FROM AUTHOR]

Despite being relatively well studied from a botanical, chemical, and (acute) pharmacological perspective, little is known about the possible toxic effects of ayahuasca (an hallucinogenic brew used for magico-ritual purposes) in pregnant women and in their children, and the potential toxicity of long-term ayahuasca consumption. It is the main objective of the present text to do an overview of the risks and possible toxic effects of ayahuasca in humans, reviewing studies on the acute ayahuasca administration to humans, on the possible risks associated with long-term consumption by adults and adolescents, and on the possible toxic effects on pregnant animals and in their offspring. Acute ayahuasca administration, as well as long-term consumption of this beverage, does not seem to be seriously toxic to humans. Although some nonhuman developmental studies suggested possible toxic effects of ayahuasca or of some of its alkaloids, the limited human literature on adolescents exposed to ayahuasca as early as in the uterus reports no serious toxic effects of the ritual consumption of the brew. Researchers must take caution when extrapolating nonhuman data to humans and more data are needed in basic and human research before a definite opinion can be made regarding the possible toxic effects of ayahuasca in pregnant women and in their children. [ABSTRACT FROM AUTHOR]

The article presents a series of abstracts for articles on the subject of drug metabolism, including "A method for monitoring drug exposure in hematopoietic stem cell transplant recipients," "Absolute UGT protein quantification by LC-MS3," and "Application of the narrow window mass extraction technique for in vitro adme screening in drug discovery."

β-Carboline alkaloids are the main chemical constituents of the plant Peganum harmala, while they also could be formed endogenously and found in coffee, alcoholic beverages and tobacco. Considering the fact that the possibility of herb-drug interactions has recently received great attention worldwide, the aim of the current study was to assess the potential for the metabolism-based drug-drug interactions arising from five β-carboline alkaloids (harmine, harmaline, harmalol, harmol and harmane) from P. harmala in vitro. With microsome incubation assays and UPLC/HPLC methods, the inhibitions on human liver CYP3A4 and CYP2D6 enzymes by those β-carboline alkaloids were studied kinetically. Harmine, harmol and harmane exhibited noncompetitive inhibition on the activity of CYP3A4 with K(i) values of 16.76, 5.13 and 1.66 μM, respectively. These β-carboline alkaloids were also found to be both substrates and inhibitors for CYP2D6. Harmaline, harmine and harmol showed typical competitive inhibition on the activity of CYP2D6 with K(i) values of 20.69, 36.48 and 47.11 μM, respectively. The inhibition of the two major CYP enzymes by those β-carboline alkaloids suggested that changes in the pharmacokinetics of co-administered drugs were likely to have occurred. Therefore, caution should be exercised for possible drug interactions of medicinal plants containing those β-carboline alkaloids and CYP substrates. [ABSTRACT FROM AUTHOR]

Determining the in vivo significance of a specific enzyme, transporter, or xenobiotic receptor in drug metabolism and pharmacokinetics may be hampered by gene multiplicity and complexity, levels of expression, and interaction between various components involved. The development of knockout (loss-of-function) and transgenic (gain-of-function) mouse models opens the door to the improved understanding of gene function in a whole-body system. There is also growing interest in the development of humanized mice to overcome species differences in drug metabolism and disposition. This review, therefore, aims to summarize and discuss some successful examples of drug-metabolizing enzyme, transporter, and nuclear-receptor genetically modified mouse models. These genetically modified mouse models have been proven as invaluable models for understanding in vivo function of drug-metabolizing enzymes, transporters, and xenobiotic receptors in drug metabolism and transport, as well as predicting potential drug-drug interaction and toxicity in humans. Nevertheless, concerns remain about interpretation of data obtained from such genetically modified mouse models, in which the expression of related genes is altered significantly. [ABSTRACT FROM AUTHOR]

Although cyclic imines are present in various bioactive secondary metabolites, their degradative metabolism remains unknown. Here, we report that copper amine oxidases, which are important in metabolism of primary amines, catalyze a cyclic imine cleavage reaction. We isolate a microorganism (Arthrobacter sp. C-4A) which metabolizes a β-carboline alkaloid, harmaline. The harmaline-metabolizing enzyme (HarA) purified from strain C-4A is found to be copper amine oxidase and catalyze a ring-opening reaction of cyclic imine within harmaline, besides oxidative deamination of amines. Growth experiments on strain C-4A and Western blot analysis indicate that the HarA expression is induced by harmaline. We propose a reaction mechanism of the cyclic imine cleavage by HarA containing a post-translationally-synthesized cofactor, topaquinone. Together with the above results, the finding of the same activity of copper amine oxidase from E. coli suggests that, in many living organisms, these enzymes may play crucial roles in metabolism of ubiquitous cyclic imines. Little is known about the degradation pathway of cyclic imines that are frequently found in bioactive secondary metabolites. Here, the authors found and characterised a copper amine oxidase, HarA that catalyses a ring-opening reaction of cyclic imine in harmaline and oxidative deamination of amines. [ABSTRACT FROM AUTHOR]