Ibogaine: a review

Dimethyltryptamine (DMT) and ibogaine elicit membrane effects in HEK cells transiently transfected with the human 5-HT2A receptor

Psychedelics show promise in treating psychiatric disorders. Therapeutic effects appear to involve activation of the 5-Hydroxytryptamine 2A receptor (5-HT2AR), a G protein-coupled receptor (GPCR). Several SNPs of the 5-HT2AR naturally occur, which are associated with differences in receptor function and altered responsiveness to treatments. New compounds suspected to act at the 5-HT2AR are actively being generated. HEK cells are not commonly used to study membrane effects induced by agonists of GPCRs. In this study, for the first time, membrane actions of two psychedelics, dimethyltryptamine (DMT) and ibogaine on HEK cells transiently transfected with either the human wildtype (WT) or the human I197V mutated 5-HT2AR were investigated using whole-cell electrophysiology. Membrane effects were observed in both genotypes and with both drugs in most cells, while no responses were observed in non-transfected HEK cells suggesting that responses were due to 5-HT2AR activation. In HEK cells transfected with the I197V SNP, a significantly shorter duration of the DMT response was observed, however there were no differences in drug-elicited amplitudes between drug or receptor genotype. I-V curves showed a significant effect of drug exposure for both DMT and ibogaine at the highest concentration evaluated. Taken together, our data show transfection of the 5-HT2AR, a GPCR, in HEK cells is able to activate downstream ion channels following exposure to two different 5-HT2AR agonists. Accordingly, investigations of novel compounds suspected to act at 5-HT2ARs can include examination of elicitation of ionic currents in 5-HT2AR transfected HEK cells, and drug effects at SNPs can also be evaluated.

A case series of ibogaine toxicity reported to the United Kingdom National Poisons Information Service (NPIS) over a 10-year period

INTRODUCTION

Ibogaine is a psychoactive alkaloid derived from the root bark of the West African shrub Tabernanthe iboga. It is not licensed in the United Kingdom but is used by individuals to alleviate drug or alcohol use.

METHODS

A retrospective analysis of telephone enquiries involving ibogaine between 1 January 2012 and 31 December 2022 to the United Kingdom National Poisons Information Service was performed.

CASE SERIES

Eleven enquiries relating to seven patients were made to the United Kingdom National Poisons Information Service in this period. Five of these patients were male (71%) with the majority in the age category 31-40 years (57%). All patients presented symptomatically. The circumstances for all seven cases were recorded as "recreational abuse." The exact indication was not specified in three cases but in two cases it was being used to alleviate diacetylmorphine (heroin) use and in another two cases it was being used for relief from insomnia. Three sources of ibogaine were reported - in one case it was bought online, in one case by a dealer and in two cases it was bought from a shaman. When reported, the dose ingested ranged from 5g to 34g. Two patients took it in tablet form and four patients ingested the root bark. The time since exposure, when reported, ranged from 16 h to 1 month. Seven patients experienced neurological symptoms and six displayed features of cardiotoxicity. The most frequently reported features included cardiac arrest, hypoxia, torsade de pointes, QT interval prolongation, coma, convulsions, stupor, bradycardia, vomiting and anxiety.

DISCUSSION

Our cases are consistent with other case reports that demon-strate ibogaine can cause severe cardiotoxicity, including ventricular tachyarrhythmias, prolonged QT interval, and tor-sade de pointes; which can lead to loss of cardiac output and arrest.

CONCLUSIONS

Individuals using ibogaine in variable doses to self-treat for drug use are at risk of developing severe cardiotoxicity and neurological symptoms. Further studies to quantify dose-response relationship and to further improve knowledge of its pharmacokinetics are required.

Case report: Significant lesion reduction and neural structural changes following ibogaine treatments for multiple sclerosis

Multiple sclerosis (MS) is a debilitating neurodegenerative disease characterized by demyelination and neuronal loss. Traditional therapies often fail to halt disease progression or reverse neurological deficits. Ibogaine, a psychoactive alkaloid, has been proposed as a potential neuroregenerative agent due to its multifaceted pharmacological profile. We present two case studies of MS patients who underwent a novel ibogaine treatment, highlighting significant neuroimaging changes and clinical improvements. Patient A demonstrated substantial lesion shrinkage and decreased Apparent Diffusion Coefficient (ADC) values, suggesting remyelination and reduced inflammation. Both patients exhibited cortical and subcortical alterations, particularly in regions associated with pain and emotional processing. These findings suggest that ibogaine may promote neuroplasticity and modulate neurocircuitry involved in MS pathology.

Current Perspectives on the Clinical Research and Medicalization of Psychedelic Drugs for Addiction Treatments: Safety, Efficacy, Limitations and Challenges

Mental health disorders and substance use disorders (SUDs) in particular, contribute greatly to the global burden of disease. Psychedelics, including entactogens and dissociative substances, are currently being explored for the treatment of SUDs, yet with less empirical clinical evidence than for other mental health disorders, such as depression or post-traumatic stress disorder (PTSD). In this narrative review, we discuss the current clinical research evidence, therapeutic potential and safety of psilocybin, lysergic acid diethylamide (LSD), ketamine, 3,4-methylenedioxymethamphetamine (MDMA) and ibogaine, particularly in the context of the SUD treatment. Our aim was to provide a balanced overview of the current research and findings on potential benefits and harms of psychedelics in clinical settings for SUD treatment. We highlight the need for more clinical research in this particular treatment area and point out some limitations and challenges to be addressed in future research.

Ibogaine administration following repeated morphine administration upregulates myelination markers 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and myelin basic protein (MBP) mRNA and protein expression in the internal capsule of Sprague Dawley rats

Ibogaine is a psychedelic alkaloid being investigated as a possible treatment for opioid use disorder. Ibogaine has a multi-receptor profile with affinities for mu and kappa opioid as well as NMDA receptors amongst others. Due to the sparsity of research into ibogaine's effects on white matter integrity and given the growing evidence that opioid use disorder is characterized by white matter pathology, we set out to investigate ibogaine's effects on two markers of myelination, 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and myelin basic protein (MBP). Fifty Sprague Dawley rats were randomly assigned to five experimental groups of n = 10; (1) a saline control group received daily saline injections for 10 days, (2) a morphine control group received escalating morphine doses from 5 to 15 mg/kg over 10 days, (3) an ibogaine control group that received 10 days of saline followed by 50 mg/kg ibogaine hydrochloride, (4) a combination morphine and ibogaine group 1 that received the escalating morphine regime followed by 50 mg/kg ibogaine hydrochloride and (5) a second combination morphine and ibogaine group 2 which followed the same morphine and ibogaine regimen yet was terminated 72 h after administration compared to 24 h in the other groups. White matter from the internal capsule was dissected and qPCR and western blotting determined protein and gene expression of CNP and MBP. Morphine upregulated CNPase whereas ibogaine alone had no effect on CNP mRNA or protein expression. However, ibogaine administration following repeated morphine administration had an immediate effect by increasing CNP mRNA expression. This effect diminished after 72 h and resulted in a highly significant upregulation of CNPase protein at 72 h post administration. Ibogaine administration alone significantly upregulated protein expression yet downregulated MBP mRNA expression. Ibogaine administration following repeated morphine administration significantly upregulated MBP mRNA expression which increased at 72 h post administration resulting in a highly significant upregulation of MBP protein expression at 72 h post administration. These findings indicate that ibogaine is able to upregulate genes and proteins involved in the process of remyelination following opioid use and highlights an important mechanism of action of ibogaine's ability to treat substance use disorders.

Ibogaine Induces Cardiotoxic Necrosis in Rats-The Role of Redox Processes

Ibogaine is an organic indole alkaloid that is used in alternative medicine to combat addiction. Numerous cases of life-threatening complications and sudden deaths associated with ibogaine use have been reported, and it has been hypothesized that the adverse effects are related to ibogaine's tendency to induce cardiac arrhythmias. Considering that the bioavailability of ibogaine and its primary metabolite noribogaine is two to three times higher in female rats than in male rats, we here investigated the effect of a single oral dose (1 or 20 mg/kg) of ibogaine on cardiac histopathology and oxidative/antioxidant balance. Our results show that ibogaine induced dose-dependent cardiotoxic necrosis 6 and 24 h after treatment and that this necrosis was not a consequence of inflammation. In addition, no consistent dose- and time-dependent changes in antioxidant defense or indicators of oxidative damage were observed. The results of this study may contribute to a better understanding of ibogaine-induced cardiotoxicity, which is one of the main side effects of ibogaine use in humans and is often fatal. Nevertheless, based on this experiment, it is not possible to draw a definitive conclusion regarding the role of redox processes or oxidative stress in the occurrence of cardiotoxic necrosis after ibogaine administration.

Natural L-type calcium channels antagonists from Chinese medicine

L-type calcium channels (LTCCs), the largest subfamily of voltage-gated calcium channels (VGCCs), are the main channels for Ca2+ influx during extracellular excitation. LTCCs are widely present in excitable cells, especially cardiac and cardiovascular smooth muscle cells, and participate in various Ca2+-dependent processes. LTCCs have been considered as worthy drug target for cardiovascular, neurological and psychological diseases for decades. Natural products from Traditional Chinese medicine (TCM) have shown the potential as new drugs for the treatment of LTCCs related diseases. In this review, the basic structure, function of LTCCs, and the related human diseases caused by structural or functional abnormalities of LTCCs, and the natural LTCCs antagonist and their potential usages were summarized.

Psychedelic Therapy: A Primer for Primary Care Clinicians-Ibogaine

BACKGROUND

Ibogaine is a plant-derived alkaloid that has been used for thousands of years in rites of passage and spiritual ceremonies in West-Central Africa. In the West, it has primarily been used and studied for its anti-addictive properties and more recently for other neuropsychiatric indications, including post-traumatic stress disorder, depression, anxiety, and traumatic brain injury.

AREAS OF UNCERTAINTY

Ibogaine requires careful patient screening and monitoring because of significant safety issues. There is potential for cardiotoxicity (prolonged QT interval); without rigorous screening, fatal arrhythmias may occur. However, preliminary research suggests that co-administration of ibogaine with magnesium may mitigate cardiotoxicity. Additionally, ibogaine may have dangerous interactions with opiates, so patients who receive ibogaine treatment for opioid use disorder must withdraw from long-acting opioids. Other potential concerning effects of ibogaine include rare incidences of mania or psychosis. Anticipated transient effects during ibogaine treatment can include ataxia, tremors, and gastrointestinal symptoms.

THERAPEUTIC ADVANCES

Robust effects after a single treatment with ibogaine have been reported. In open-label and randomized controlled trials (RCTs), ibogaine reduces heroin and opioid cravings by upwards of 50%, up to 24 weeks after the treatment. An observational study of 30 Special Operations Forces veterans with mild traumatic brain injury reported that 86% were in remission from post-traumatic stress disorder, 83% from depression, and 83% from anxiety, one month after a single-dose ibogaine treatment.

LIMITATIONS

Although there are several observational and open-label studies, there is only a single double-blind, placebo-controlled RCT on ibogaine. More RCTs with large sample sizes must be conducted to support ibogaine's safety and efficacy.

CONCLUSIONS

Given the promising preliminary findings, ibogaine could potentially fill a much-needed gap in treatments for challenging conditions, including opioid dependence. Ibogaine's remarkable effects in traditionally treatment-resistant, combat-exposed individuals hints at its potential in broader populations with physical and psychological trauma.

Magnesium-ibogaine therapy in veterans with traumatic brain injuries

Traumatic brain injury (TBI) is a leading cause of disability. Sequelae can include functional impairments and psychiatric syndromes such as post-traumatic stress disorder (PTSD), depression and anxiety. Special Operations Forces (SOF) veterans (SOVs) may be at an elevated risk for these complications, leading some to seek underexplored treatment alternatives such as the oneirogen ibogaine, a plant-derived compound known to interact with multiple neurotransmitter systems that has been studied primarily as a treatment for substance use disorders. Ibogaine has been associated with instances of fatal cardiac arrhythmia, but coadministration of magnesium may mitigate this concern. In the present study, we report a prospective observational study of the Magnesium-Ibogaine: the Stanford Traumatic Injury to the CNS protocol (MISTIC), provided together with complementary treatment modalities, in 30 male SOVs with predominantly mild TBI. We assessed changes in the World Health Organization Disability Assessment Schedule from baseline to immediately (primary outcome) and 1 month (secondary outcome) after treatment. Additional secondary outcomes included changes in PTSD (Clinician-Administered PTSD Scale for DSM-5), depression (Montgomery-Åsberg Depression Rating Scale) and anxiety (Hamilton Anxiety Rating Scale). MISTIC resulted in significant improvements in functioning both immediately (Pcorrected < 0.001, Cohen's d = 0.74) and 1 month (Pcorrected < 0.001, d = 2.20) after treatment and in PTSD (Pcorrected < 0.001, d = 2.54), depression (Pcorrected < 0.001, d = 2.80) and anxiety (Pcorrected < 0.001, d = 2.13) at 1 month after treatment. There were no unexpected or serious adverse events. Controlled clinical trials to assess safety and efficacy are needed to validate these initial open-label findings. ClinicalTrials.gov registration: NCT04313712 .

Reactivity of the Iboga Skeleton: Oxidation Study of Ibogaine and Voacangine

The iboga alkaloids scaffold shows great potential as a pharmacophore in drug candidates for the treatment of neuropsychiatric disorders. Thus, the study of the reactivity of this type of motif is particularly useful for the generation of new analogs suitable for medicinal chemistry goals. In this article, we analyzed the oxidation pattern of ibogaine and voacangine using dioxygen, peroxo compounds, and iodine as oxidizing agents. Special focus was placed on the study of the regio- and stereochemistry of the oxidation processes according to the oxidative agent and starting material. We found that the C16-carboxymethyl ester present in voacangine stabilizes the whole molecule toward oxidation in comparison to ibogaine, especially in the indole ring, where 7-hydroxy- or 7-peroxy-indolenines can be obtained as oxidation products. Nevertheless, the ester moiety enhances the reactivity of the isoquinuclidinic nitrogen to afford C3-oxidized products through a regioselective iminium formation. This differential reactivity between ibogaine and voacangine was rationalized using computational DFT calculations. In addition, using qualitative and quantitative NMR experiments combined with theoretical calculations, the absolute stereochemistry at C7 in the 7-hydroxyindolenine of voacangine was revised to be S, which corrects previous reports proposing an R configuration.

Underground ibogaine use for the treatment of substance use disorders: A qualitative analysis of subjective experiences

INTRODUCTION

Ibogaine is one of the alkaloids naturally found in plants such as Tabernanthe iboga, which has been traditionally used by members of the Bwiti culture. Since the discovery of its anti-addictive properties by Howard S. Lotsof in 1962, ibogaine has been used experimentally to treat substance use disorders (SUD), especially those involving opioids. We aim to provide a detailed understanding of the underlying psychological aspects of underground ibogaine use for the treatment of SUD.

METHODS

Semi-structured interviews were carried out with 13 participants with SUD, which motivated their self-treatment with ibogaine. The data were analysed using the grounded theory approach and considered the context of the treatment, and the nature of the occurring hallucinogenic and cognitive phenomena during the treatment experience.

RESULTS

We identified several psychological effects that the study respondents experienced, which seem to play a substantial role in the therapeutic process concerning SUD. The evoking of interpersonal and transpersonal experiences, autobiographical memories, and preparation, integration and motivation for a lifestyle change are important components that participants reported during and after ibogaine intake.

DISCUSSION AND CONCLUSION

Ibogaine is increasingly being used for the treatment of SUD, due in part to the limited treatment options currently available. Its beneficial effects seem to be related not only to its complex pharmacology but also to the subjective experience that ibogaine induces. The main aspects of this experience are related to autobiographical memories and valuable personal insights, which together appear to help individuals cope with their SUD.

Natural Products for the Treatment of Drug Addiction: Narrative Review

Drug addiction is considered a chronic disorder affecting the individual's life, his/her family and society. Up till now the treatment of drug addiction is considered a problematic issue. Synthetic drugs available for the treatment of drug addiction are few, of limited efficacy and associated with serious side effects. Therefore, there is a continuous search for better therapeutic agents for drug addiction. Natural products represent a promising source for drug addiction treatment. This review summaries drug addiction definition, its mechanism of action, its types, its diagnosis, factors affecting its development and different available approaches for its treatment especially the use of natural products. Six plants were discussed thoroughly in this review, including, Tabernanthe iboga Baill., Mitragyna speciosa Korth., Pueraria montana var. lobata (Willd.) Sanjappa & Pradeep, Hypericum perforatum L., Panax ginseng C.A. Mey., and Withania somnifera (L.) Dunal.

Therapeutic (Sub)stance: Current practice and therapeutic conduct in preparatory sessions in substance-assisted psychotherapy-A systematized review

BACKGROUND

Clinical trials are currently investigating the potential of substance-assisted psychotherapy (SAPT) as treatment for several psychiatric conditions. The potential therapeutic effects of SAPT may be influenced by contextual factors including preparation prior to and integration after the substance-assisted therapy sessions.

AIMS

This systematized review outlines recommendations for current practice in preparatory sessions in SAPT including safety measures and screening procedures, preparation of set and setting, session contents, methods, and roles, prerequisites, and appropriate conduct of therapists.

METHODS

A systematized review of the literature was conducted based on PRISMA guidelines. MEDLINE (OVID), PsycINFO (OVID), and Cochrane Library were searched and clinical trials, treatment manuals, study protocols, case studies, qualitative studies, descriptive studies, theoretical papers, reviews, book chapters, and conference proceedings published until February 1, 2022 were retrieved.

RESULTS

The final synthesis included k = 83 sources. Information about safety measures including screening of participants, set and setting, contextual-, physiological-, and psychological preparation, roles, competencies, prerequisites, and characteristics of the therapists, and the establishment of a therapeutic relationship were summarized and discussed.

CONCLUSION

It is concluded that there is a consensus in the literature about the importance of adequate preparation before the administration of psychoactive substances in SAPT. However, the extent and approaches for these sessions vary across different models and there is a need for timelier and more rigorous qualitative and quantitative investigations assessing different approaches and techniques for the optimal preparation of clients in SAPT.

Three Naturally-Occurring Psychedelics and Their Significance in the Treatment of Mental Health Disorders

Classical psychedelics represent a family of psychoactive substances with structural similarities to serotonin and affinity for serotonin receptors. A growing number of studies have found that psychedelics can be effective in treating various psychiatric conditions, including post-traumatic stress disorder, major depressive disorder, anxiety, and substance use disorders. Mental health disorders are extremely prevalent in the general population constituting a major problem for the public health. There are a wide variety of interventions for mental health disorders, including pharmacological therapies and psychotherapies, however, treatment resistance still remains a particular challenge in this field, and relapse rates are also quite high. In recent years, psychedelics have become one of the promising new tools for the treatment of mental health disorders. In this review, we will discuss the three classic serotonergic naturally occurring psychedelics, psilocybin, ibogaine, and N, N-dimethyltryptamine, focusing on their pharmacological properties and clinical potential. The purpose of this article is to provide a focused review of the most relevant research into the therapeutic potential of these substances and their possible integration as alternative or adjuvant options to existing pharmacological and psychological therapies.

The adverse events of ibogaine in humans: an updated systematic review of the literature (2015-2020)

CONTEXT

Ibogaine is the main alkaloid of the African shrub Tabernanthe iboga. It produces hallucinogenic and psychostimulant effects, but it is currently known for the anti-addictive properties. Despite the potential therapeutic effects, several cases of fatalities and serious adverse events related to ibogaine/noribogaine use can be found in the literature. Most studies consist in case reports or were conducted under non-controlled settings, so causation cannot be clearly established.

OBJECTIVES

To update (2015-2020) the literature on the adverse events and fatalities associated with ibogaine/noribogaine administration.

METHODS

Systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Eighteen studies were included in the final selection. Highly heterogeneous results were found in terms of kind of product used or the known dosages. The adverse events were classified in acute effects (< 24 h), mainly cardiac (the most common was QTc prolongation), gastrointestinal, neurological, and clinical alterations, and long-lasting effects (> 24 h), mainly persistent cardiac alterations, psychiatric, and neurological signs.

CONCLUSIONS

There is a high need of phase I clinical trials that can describe the safety of different dosages of ibogaine with standardized products. Further research should perform clinical profiling of vulnerable populations, and design effective screening methods and clinical procedures.

The promises and perils of psychedelic pharmacology for psychiatry

Psychedelic drugs including psilocybin, N,N'-dimethyltryptamine (DMT) and lysergic acid diethylamide (LSD) are undergoing a renaissance as potentially useful drugs for various neuropsychiatric diseases, with a rapid onset of therapeutic activity. Notably, phase II trials have shown that psilocybin can produce statistically significant clinical effects following one or two administrations in depression and anxiety. These findings have inspired a 'gold rush' of commercial interest, with nearly 60 companies already formed to explore opportunities for psychedelics in treating diverse diseases. Additionally, these remarkable phenomenological and clinical observations are informing hypotheses about potential molecular mechanisms of action that need elucidation to realize the full potential of this investigative space. In particular, despite compelling evidence that the 5-HT_2A receptor is a critical mediator of the behavioural effects of psychedelic drugs, uncertainty remains about which aspects of 5-HT_2A receptor activity in the central nervous system are responsible for therapeutic effects and to what degree they can be isolated by developing novel chemical probes with differing specificity and selectivity profiles. Here, we discuss this emerging area of therapeutics, covering both controversies and areas of consensus related to the opportunities and perils of psychedelic and psychedelic-inspired therapeutics. We highlight how basic science breakthroughs can guide the discovery and development of psychedelic-inspired medications with the potential for improved efficacy without hallucinogenic or rewarding actions.

Drug Transporters ABCB1 (P-gp) and OATP, but not Drug-Metabolizing Enzyme CYP3A4, Affect the Pharmacokinetics of the Psychoactive Alkaloid Ibogaine and its Metabolites

The psychedelic alkaloid ibogaine is increasingly used as an oral treatment for substance use disorders, despite being unlicensed in most countries and having reported adverse events. Using wild-type and genetically modified mice, we investigated the impact of mouse (m)Abcb1a/1b and Abcg2 drug efflux transporters, human and mouse OATP drug uptake transporters, and the CYP3A drug-metabolizing complex on the pharmacokinetics of ibogaine and its main metabolites. Following oral ibogaine administration (10 mg/kg) to mice, we observed a rapid and extensive conversion of ibogaine to noribogaine (active metabolite) and noribogaine glucuronide. Mouse Abcb1a/1b, in combination with mAbcg2, modestly restricted the systemic exposure (plasma AUC) and peak plasma concentration (Cmax) of ibogaine. Accordingly, we found a ∼2-fold decrease in the relative recovery of ibogaine in the small intestine with fecal content in the absence of both transporters compared to the wild-type situation. Ibogaine presented good intrinsic brain penetration even in wild-type mice (brain-to-plasma ratio of 3.4). However, this was further increased by 1.5-fold in Abcb1a/1b;Abcg2−/− mice, but not in Abcg2−/− mice, revealing a stronger effect of mAbcb1a/1b in restricting ibogaine brain penetration. The studied human OATP transporters showed no major impact on ibogaine plasma and tissue disposition, but the mOatp1a/1b proteins modestly affected the plasma exposure of ibogaine metabolites and the tissue disposition of noribogaine glucuronide. No considerable role of mouse Cyp3a knockout or transgenic human CYP3A4 overexpression was observed in the pharmacokinetics of ibogaine and its metabolites. In summary, ABCB1, in combination with ABCG2, limits the oral availability of ibogaine, possibly by mediating its hepatobiliary and/or direct intestinal excretion. Moreover, ABCB1 restricts ibogaine brain penetration. Variation in ABCB1/ABCG2 activity due to genetic variation and/or pharmacologic inhibition might therefore affect ibogaine exposure in patients, but only to a limited extent. The insignificant impact of human CYP3A4 and OATP1B1/1B3 transporters may be clinically advantageous for ibogaine and noribogaine use, as it decreases the risks of undesirable drug interactions or interindividual variation related to CYP3A4 and/or OATP activity.

The Triprenylated Anthranoid Ferruginin A, a Promising Scaffold for the Development of Novel Antibiotics against Gram-Positive Bacteria

In today's post-antibiotic era, the search for new antimicrobial compounds is of major importance and nature represents one of the primary sources of bioactive molecules. In this work, through a cheminformatics approach, we clustered an in-house library of natural products and their derivatives based on a combination of fingerprints and substructure search. We identified the prenylated emodine-type anthranoid ferruginin A as a novel antimicrobial compound. We tested its ability to inhibit and kill a panel of Gram-positive and Gram-negative bacteria, and compared its activity with that of two analogues, vismione B and ferruanthrone. Furthermore, the capability of these three anthranoids to disrupt staphylococcal biofilm was investigated, as well as their effect on the viability of human keratinocytes. Ferruginin A showed a potent activity against both the planktonic and biofilm forms of Gram-positive bacteria (i.e., Staphylococcus aureus and S. epidermidis) and had the best therapeutic index compared to vismione B and ferruanthrone. In conclusion, ferruginin A represents a promising scaffold for the further development of valuable antimicrobial agents.

Tabernaemontana arborea and ibogaine induce paroxysmal EEG activity in freely moving mice: involvement of serotonin 5-HT1A receptors

Several Apocynaceae species, most notably Tabernanthe iboga, Voacanga africana and many Tabernaemontana species, produce ibogan-type alkaloids. Although a large amount of information exists about the Tabernaemontana genus, knowledge concerning chemistry and biological activity remains lacking for several species, especially related to their effects on the central nervous system (CNS). The aim of this study was to evaluate the effect of Tabernaemontana arborea Rose ex J.D.Sm. (T. arborea) hydroalcoholic extract (30, 56.2 and 100 mg/kg, i.p.) and two of its main alkaloids (ibogaine and voacangine, 30 mg/kg, i.p.) on electroencephalographic (EEG) activity alone and in the presence of the chemical convulsant agent pentylenetetrazole (PTZ, 85 mg/kg, i.p.) in mice. EEG spectral power analysis showed that T. arborea extract (56.2 and 100 mg/kg) and ibogaine (30 mg/kg, i.p.) promoted a significant increase in the relative power of the delta band and a significant reduction in alpha band values, denoting a CNS depressant effect. Voacangine (30 mg/kg, i.p.) provoked an EEG flattening pattern. The PTZ-induced seizures were not modified in the presence of T. arborea, ibogaine, or voacangine. However, sudden death was observed in mice treated with T. arborea extract at 100 mg/kg, i.p., combined with PTZ. Because T. arborea extract (100 mg/kg, i.p.) and ibogaine (30 mg/kg, i.p.), but not voacangine (30 mg/kg, i.p.), induced paroxysmal activity in the EEG, both were explored in the presence of a serotonin 5-HT_1A receptor antagonist (WAY100635, 1 mg/kg, i.p.). The antagonist abolished the paroxysmal activity provoked by T. arborea (100 mg/kg, i.p.) but not that observed with ibogaine, corroborating the participation of serotonin neurotransmission in the T. arborea effects. In conclusion, high doses of the T. arborea extract induced abnormal EEG activity due in part to the presence of ibogaine and involving serotonin 5-HT_1A receptor participation. Nevertheless, other possible constituents and mechanisms might participate in this complex excitatory activity that would be interesting to explore in future studies.

Ibogaine Has Sex-Specific Plasma Bioavailability, Histopathological and Redox/Antioxidant Effects in Rat Liver and Kidneys: A Study on Females

Ibogaine induces rapid changes in cellular energetics followed by the elevation of antioxidant activities. As shown earlier in male rats, ibogaine treatment with both 1 and 20 mg/kg b.w. per os led to significant glycogenolytic activity in the liver. In this work, female rats treated with the same doses of ibogaine per os displayed lower liver glycogenolytic activity relative to males, dilatation of the central vein and branches of the portal vein, and increased concentration of thiols 6 h after treatment. These changes were followed by increased catalase activity and lipid peroxidation, and decreased xanthine oxidase activity after 24 h. In kidneys, mild histopathological changes were found in all treated animals, accompanied by a decrease of glutathione reductase (after 6 and 24 h at both doses) and an increase of catalase (6 h) and xanthine oxidase activity (6 and 24 h). Ibogaine did not affect antioxidant enzymes activity in erythrocytes. Bioavailability of ibogaine was two to three times higher in females than males, with similar kinetic profiles. Compared to previous results in males, ibogaine showed sex specific effect at the level of antioxidant cellular system. Effects of ibogaine in rats are sex- and tissue-specific, and also dose- and time-dependent.

Ibogaine-Mediated ROS/Antioxidant Elevation in Isolated Rat Uterus Is β-Adrenergic Receptors and KATP Channels Mediated

Ibogaine effects are mediated by cellular receptors, ATP depletion followed by ROS production and antioxidant enzyme activity elevation in a dose and time dependent manner. Since the role of K_ATP channels and β-adrenoceptors in ROS cellular circuit was established here we explored their role in ibogaine pro-antioxidant effectiveness. Single dose of ibogaine (10 mg/L i.e., 28.8 μmol/L) was applied to isolated rat uterus (spontaneous and Ca²⁺-stimulated) and contractility and antioxidant enzymes activity were monitored during 4 h. Ibogaine increased amplitude and frequency of spontaneous active uteri immediately after addition that was prevented by propranolol (β₁ and β₂ adrenoceptors selective antagonists) and glibenclamide (K_ATP sensitive channels inhibitor; only frequency) pre-treatment. In Ca²⁺-stimulated uteri, ibogaine decreased both amplitude and frequency after 4 h. Pre-treatment with propranolol abolished ibogaine induced amplitude lowering, while glibenclamide had no effect. In both types of active uterus, ibogaine induced a decrease in SOD1 and an increase in CAT activity after 2 h. In Ca²⁺-stimulated uterus, there was also a decrease of SOD2 activity after 2 h. After 4 h, SOD1 activity returned to the baseline level, but GSH-Px activity increased. Pre-treatment with both propranolol and glibenclamide abolished observed changes of antioxidant enzymes activity suggesting that ibogaine pro-antioxidative effectiveness is β-adrenergic receptors and K_ATP channels mediated.

Identification of Effective Anticancer G-Quadruplex-Targeting Chemotypes through the Exploration of a High Diversity Library of Natural Compounds

In the quest for selective G-quadruplex (G4)-targeting chemotypes, natural compounds have been thus far poorly explored, though representing appealing candidates due to the high structural diversity of their scaffolds. In this regard, a unique high diversity in-house library composed of ca. one thousand individual natural products was investigated. The combination of molecular docking-based virtual screening and the G4-CPG experimental screening assay proved to be useful to quickly and effectively identify-out of many natural compounds-five hit binders of telomeric and oncogenic G4s, i.e., Bulbocapnine, Chelidonine, Ibogaine, Rotenone and Vomicine. Biophysical studies unambiguously demonstrated the selective interaction of these compounds with G4s compared to duplex DNA. The rationale behind the G4 selective recognition was suggested by molecular dynamics simulations. Indeed, the selected ligands proved to specifically interact with G4 structures due to peculiar interaction patterns, while they were unable to firmly bind to a DNA duplex. From biological assays, Chelidonine and Rotenone emerged as the most active compounds of the series against cancer cells, also showing good selectivity over normal cells. Notably, the anticancer activity correlated well with the ability of the two compounds to target telomeric G4s.

Current Perspective on the Therapeutic Preset for Substance-Assisted Psychotherapy

The present narrative review is the first in a series of reviews about the appropriate conduct in substance-assisted psychotherapy (SAPT). It outlines a current perspective onpreconditions and theoretical knowledge that have been identified as valuable in the literaturefor appropriate therapeutic conduct in SAPT. In this context, considerations regarding ethics and the spiritual emphasis of the therapeutic approaches are discussed. Further, current methods, models, and concepts of psychological mechanism of action and therapeutic effects of SAPT are summarized, and similarities between models, approaches, and potential mediators for therapeutic effects are outlined. It is argued that a critical assessment of the literature might indicate that the therapeutic effect of SAPT may be mediated by intra- and interpersonal variables within the therapeutic context rather than specific therapeutic models per se. The review provides a basis for the development and adaptation of future investigations, therapeutic models, training programs for therapists, and those interested in the therapeutic potential of SAPT. Limitations and future directions for research are discussed.

Efficient Access to the Iboga Skeleton: Optimized Procedure to Obtain Voacangine from Voacanga africana Root Bark

Iboga alkaloids are a group of monoterpenoid indole alkaloids with promising and intriguing biological activities. Ibogaine is the representative member of the series and has become widely known as a potent atypical psychedelic with promising effects to treat substance use disorder. Nowadays, an efficient and scalable enantioselective total synthesis of ibogaine and related iboga alkaloids is still lacking, so direct extraction from natural sources or semi-synthetic schemes are the methods of choice to obtain them in a preparative scale. In particular, ibogaine can be obtained either by a low yielding direct isolation from Tabernanthe iboga or using a semi-synthetic procedure from voacangine, an iboga alkaloid occurring in a higher yield in the root bark of Voacanga africana. In this work, we describe an optimized process to obtain voacangine from V. africana root bark as a precursor of the iboga scaffold. Using a direct acetone-based extraction procedure (0.5 kg of root bark), voacangine was isolated in ∼0.8% of root bark dried weight, while the major alkaloids isolated from the bark were identified as iboga-vobasinyl dimers (∼3.7%) such as voacamine and voacamidine. Since these alkaloids contain the voacangine moiety in their structure, the cleavage of the dimers was further optimized, affording an extra amount of voacangine in ∼50% isolated molar yield. In this manner, the total amount of voacangine obtained by application of the whole procedure to the plant material (extraction and dimer cleavage) could almost duplicate the content originally found in the root bark.

Registered clinical studies investigating psychedelic drugs for psychiatric disorders

Psychedelics are a hallucinogenic class of psychoactive drugs with the primary effect of activating non-ordinary states of consciousness. Due to the positive preliminary findings of these drugs in the treatment of psychiatric disorders, the number of registered clinical studies has risen significantly. In this paper, clinical studies registered on clinicaltrials.gov that evaluate the treatment of any psychiatric disorder with psychedelics (excluding ketamine) are summarized and analyzed. 70 registered studies were identified from a clinicaltrials.gov search on December 3, 2020. The majority of studies aim to investigate methylenedioxymethamphetamine (MDMA) (45.7%) and psilocybin (41.4%). Studies evaluating ayahuasca, lysergic acid diethylamide (LSD), ibogaine hydrochloride, salvia divinorum, 5-MeO-DMT and DMT fumarate were less common at 1.4%, 4.2%, 2.8%, 1.4%, 1.4% and 1.4% of total registered studies, respectively. Most of the studies on MDMA, psilocybin, ayahuasca and salvia divinorum investigated their therapeutic effect on post-traumatic stress disorder (PTSD) and major depressive disorder (MDD). LSD was investigated for MDD, anxiety, and severe somatic disorders and ibogaine hydrochloride was investigated for substance and alcohol use disorders. 5-MeO-DMT and DMT fumarate were both investigated for MDD. Only 21/70 registered studies had published results with the majority not yet completed. In view of the large number of ongoing studies investigating psychedelics, it is imperative that these studies are considered by researchers and stakeholders in deciding the most relevant research priorities for future proposed studies.

Biosynthesis and synthetic biology of psychoactive natural products

Psychoactive natural products play an integral role in the modern world. The tremendous structural complexity displayed by such molecules confers diverse biological activities of significant medicinal value and sociocultural impact. Accordingly, in the last two centuries, immense effort has been devoted towards establishing how plants, animals, and fungi synthesize complex natural products from simple metabolic precursors. The recent explosion of genomics data and molecular biology tools has enabled the identification of genes encoding proteins that catalyze individual biosynthetic steps. Once fully elucidated, the "biosynthetic pathways" are often comparable to organic syntheses in elegance and yield. Additionally, the discovery of biosynthetic enzymes provides powerful catalysts which may be repurposed for synthetic biology applications, or implemented with chemoenzymatic synthetic approaches. In this review, we discuss the progress that has been made toward biosynthetic pathway elucidation amongst four classes of psychoactive natural products: hallucinogens, stimulants, cannabinoids, and opioids. Compounds of diverse biosynthetic origin - terpene, amino acid, polyketide - are identified, and notable mechanisms of key scaffold transforming steps are highlighted. We also provide a description of subsequent applications of the biosynthetic machinery, with an emphasis placed on the synthetic biology and metabolic engineering strategies enabling heterologous production.

EEG Gamma Band Alterations and REM-like Traits Underpin the Acute Effect of the Atypical Psychedelic Ibogaine in the Rat

Ibogaine is a psychedelic alkaloid that has attracted large scientific interest because of its antiaddictive properties in observational studies in humans as well as in animal models. Its subjective effect has been described as intense, vivid dream-like experiences occurring while awake; hence, ibogaine is often referred to as an oneirogenic psychedelic. While this unique dream-like profile has been hypothesized to aid the antiaddictive effects, the electrophysiological signatures of this psychedelic state remain unknown. We previously showed in rats that ibogaine promotes a waking state with abnormal motor behavior along with a decrease in NREM and REM sleep. Here, we performed an in-depth analysis of the intracranial electroencephalogram during "ibogaine wakefulness". We found that ibogaine induces gamma oscillations that, despite having larger power than control levels, are less coherent and less complex. Further analysis revealed that this profile of gamma activity compares to that of natural REM sleep. Thus, our results provide novel biological evidence for the association between the psychedelic state and REM sleep, contributing to the understanding of the brain mechanisms associated with the oneirogenic psychedelic effect of ibogaine.

Psychoactive Substances of Natural Origin: Toxicological Aspects, Therapeutic Properties and Analysis in Biological Samples

The consumption of new psychoactive substances (NPSs) has been increasing, and this problem affects several countries worldwide. There is a class of NPSs of natural origin, consisting of plants and fungi, which have a wide range of alkaloids, responsible for causing relaxing, stimulating or hallucinogenic effects. The consumption of some of these substances is prompted by religious beliefs and cultural reasons, making the legislation very variable or even ambiguous. However, the abusive consumption of these substances can present an enormous risk to the health of the individuals, since their metabolism and effects are not yet fully known. Additionally, NPSs are widely spread over the internet, and their appearance is very fast, which requires the development of sophisticated analytical methodologies, capable of detecting these compounds. Thus, the objective of this work is to review the toxicological aspects, traditional use/therapeutic potential and the analytical methods developed in biological matrices in twelve plant specimens (Areca catechu, Argyreia nervosa, Ayahuasca, Catha edulis, Datura stramonium, Lophophora williamsii, Mandragora officinarum, Mitragyna speciosa, Piper methysticum Forst, Psilocybe, Salvia divinorum and Tabernanthe iboga).

The iboga enigma: the chemistry and neuropharmacology of iboga alkaloids and related analogs

Covering: 2000 up to 2020 Few classes of natural products have inspired as many chemists and biologists as have the iboga alkaloids. This family of monoterpenoid indole alkaloids includes the anti-addictive compound ibogaine as well as catharanthine, a precursor to the chemotherapeutic vinblastine. Despite being known for over 120 years, these small molecules continue to challenge our assumptions about biosynthetic pathways, catalyze our creativity for constructing complex architectures, and embolden new approaches for treating mental illness. This review will cover recent advances in both the biosynthesis and chemical synthesis of iboga alkaloids as well as their use as next-generation neurotherapeutics. Whenever appropriate, we provide historical context for the discoveries of the past decade and indicate areas that have yet to be resolved. While significant progress regarding their chemistry and pharmacology has been made since the 1960s, it is clear that the iboga alkaloids will continue to stoke scientific innovation for years to come.

A Single Administration of the Atypical Psychedelic Ibogaine or Its Metabolite Noribogaine Induces an Antidepressant-Like Effect in Rats

Anecdotal reports and open-label case studies in humans indicated that the psychedelic alkaloid ibogaine exerts profound antiaddictive effects. Ample preclinical evidence demonstrated the efficacy of ibogaine, and its main metabolite, noribogaine, in substance-use-disorder rodent models. In contrast to addiction research, depression-relevant effects of ibogaine or noribogaine in rodents have not been previously examined. We have recently reported that the acute ibogaine administration induced a long-term increase of brain-derived neurotrophic factor mRNA levels in the rat prefrontal cortex, which led us to hypothesize that ibogaine may elicit antidepressant-like effects in rats. Accordingly, we characterized behavioral effects (dose- and time-dependence) induced by the acute ibogaine and noribogaine administration in rats using the forced swim test (FST, 20 and 40 mg/kg i.p., single injection for each dose). We also examined the correlation between plasma and brain concentrations of ibogaine and noribogaine and the elicited behavioral response. We found that ibogaine and noribogaine induced a dose- and time-dependent antidepressant-like effect without significant changes of animal locomotor activity. Noribogaine's FST effect was short-lived (30 min) and correlated with high brain concentrations (estimated >8 μM of free drug), while the ibogaine's antidepressant-like effect was significant at 3 h. At this time point, both ibogaine and noribogaine were present in rat brain at concentrations that cannot produce the same behavioral outcome on their own (ibogaine ∼0.5 μM, noribogaine ∼2.5 μM). Our data suggests a polypharmacological mechanism underpinning the antidepressant-like effects of ibogaine and noribogaine.

Quantitative Evaluation of a Mexican and a Ghanaian Tabernaemontana Species as Alternatives to Voacanga africana for the Production of Antiaddictive Ibogan Type Alkaloids

In continuation of our efforts to provide quantitative information on antiaddictive ibogan type alkaloid-producing Tabernaemontana species, we used gas chromatography-mass spectrometry (GC/MS) to compare the alkaloid profiles of the barks and/or leaves of one Mexican and one African species - T. arborea and T. crassa, respectively, with the primary sources of commercially available semisynthetic ibogaine, Voacanga africana root and stem bark. The qualitative and quantitative similarities between T. arborea and V. africana barks consolidate previous reports regarding the potential of the former as a promising alternative source of voacangine and ibogaine. The results also suggest that T. crassa could be used to produce conopharyngine and ibogaline, two compounds with the same basic skeletal structure and possibly similar antiaddictive properties as ibogaine.

Recent applications of the Wittig reaction in alkaloid synthesis

The Wittig reaction is the chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide (the Wittig reagent) to afford an alkene and triphenylphosphine oxide. Noteworthy, this reaction results in the synthesis of alkenes in a selective and predictable fashion. Thus, it became as one of the keystone of synthetic organic chemistry, especially in the total synthesis of natural products, where the selectivity of a reaction is paramount of importance. A literature survey disclosed the existence of vast numbers of related reports and comprehensive reviews on the applications of this important name reaction in the total synthesis of natural products. However, the aim of this chapter is to underscore, the applications of the Wittig reaction in the total synthesis of one the most important and prevalent classes of natural products, the alkaloids, especially those showing important and diverse biological activities.

Non-Opioid Neurotransmitter Systems that Contribute to the Opioid Withdrawal Syndrome: A Review of Preclinical and Human Evidence

Opioid misuse and abuse is a major international public health issue. Opioid use disorder (OUD) is largely maintained by a desire to suppress aversive opioid withdrawal symptoms. Opioid withdrawal in patients seeking abstinence from illicit or prescribed opioids is often managed by provision of a μ-opioid agonist/partial agonist in combination with concomitant medications. Concomitant medications are administered based on their ability to treat specific symptoms rather than a mechanistic understanding of the opioid withdrawal syndrome; however, their use has not been statistically associated with improved treatment outcomes. Understanding the central and/or peripheral mechanisms that underlie individual withdrawal symptom expression in humans will help promote medication development for opioid withdrawal management. To support focused examination of mechanistically supported concomitant medications, this review summarizes evidence from preclinical (N = 68) and human (N = 30) studies that administered drugs acting on the dopamine, serotonin, cannabinoid, orexin/hypocretin, and glutamate systems and reported outcomes related to opioid withdrawal. These studies provide evidence that each of these systems contribute to opioid withdrawal severity. The Food and Drug Administration has approved medications acting on these respective systems for other indications and research in this area could support the repurposing of these medications to enhance opioid withdrawal treatment. These data support a focused examination of mechanistically informed concomitant medications to help reduce opioid withdrawal severity and enhance the continuum of care available for persons with OUD.

Nigritanine as a New Potential Antimicrobial Alkaloid for the Treatment of Staphylococcus aureus-Induced Infections

Staphylococcus aureus is a major human pathogen causing a wide range of nosocomial infections including pulmonary, urinary, and skin infections. Notably, the emergence of bacterial strains resistant to conventional antibiotics has prompted researchers to find new compounds capable of killing these pathogens. Nature is undoubtedly an invaluable source of bioactive molecules characterized by an ample chemical diversity. They can act as unique platform providing new scaffolds for further chemical modifications in order to obtain compounds with optimized biological activity. A class of natural compounds with a variety of biological activities is represented by alkaloids, important secondary metabolites produced by a large number of organisms including bacteria, fungi, plants, and animals. In this work, starting from the screening of 39 alkaloids retrieved from a unique in-house library, we identified a heterodimer -carboline alkaloid, nigritanine, with a potent anti-Staphylococcus action. Nigritanine, isolated from Strychnos nigritana, was characterized for its antimicrobial activity against a reference and three clinical isolates of S. aureus. Its potential cytotoxicity was also evaluated at short and long term against mammalian red blood cells and human keratinocytes, respectively. Nigritanine showed a remarkable antimicrobial activity (minimum inhibitory concentration of 128 µM) without being toxic in vitro to both tested cells. The analysis of the antibacterial activity related to the nigritanine scaffold furnished new insights in the structure-activity relationships (SARs) of -carboline, confirming that dimerization improves its antibacterial activity. Taking into account these interesting results, nigritanine can be considered as a promising candidate for the development of new antimicrobial molecules for the treatment of S. aureus-induced infections.

Biosynthesis of an Anti-Addiction Agent from the Iboga Plant

(−)-Ibogaine and (−)-voacangine are plant derived psychoactives that show promise as treatments for opioid addiction. However, these compounds are produced by hard to source plants, making these chemicals difficult for broad-scale use. Here we report the complete biosynthesis of (−)-voacangine, and de-esterified voacangine, which is converted to (−)-ibogaine by heating, enabling biocatalytic production of these compounds. Notably, (−)-ibogaine and (−)-voacangine are of the opposite enantiomeric configuration compared to the other major alkaloids found in this natural product class. Therefore, this discovery provides insight into enantioselective enzymatic formal Diels–Alder reactions.

Extraction and Conversion Studies of the Antiaddictive Alkaloids Coronaridine, Ibogamine, Voacangine, and Ibogaine from Two Mexican Tabernaemontana Species (Apocynaceae)

Several species from the Apocynaceae family, such as Tabernanthe iboga, Voacanga africana, and many Tabernaemontana species, produce ibogan type alkaloids, some of which present antiaddictive properties. In this study, we used gas chromatography/mass spectrometry (GC/MS) to examine the efficiency of methanol, acetone, ethyl acetate, dichloromethane, chloroform, and hydrochloric acid in extracting the antiaddictive compounds coronaridine, ibogamine, voacangine, and ibogaine (altogether the CIVI-complex) from the root barks of Tabernaemontana alba and Tabernaemontana arborea. These Mexican species have recently shown great potential as alternative natural sources of the aforementioned substances. Methanol proved to be the most suitable solvent. Furthermore, the crude methanolic extracts could be engaged in a one-step demethoxycarbonylation process that converted coronaridine and voacangine directly into its non-carboxylic counterparts ibogamine and ibogaine, respectively, without the intermediacy of their carboxylic acids. The established protocol straightforwardly simplifies the alkaloid mixture from four to two majority compounds. In summary, our findings facilitate and improve both the qualitative and quantitative analysis of CIVI-complex-containing plant material, as well as outlining a viable method for the bulk production of these scientifically and pharmaceutically important substances from Mexican Tabernaemontana species.

Metabolite Profiling of Anti-Addictive Alkaloids from Four Mexican Tabernaemontana Species and the Entheogenic African Shrub Tabernanthe iboga (Apocynaceae)

Ibogaine and other ibogan type alkaloids present anti-addictive effects against several drugs of abuse and occur in different species of the Apocynaceae family. In this work, we used gas chromatography-mass spectrometry (GC/MS) and principal component analysis (PCA) in order to compare the alkaloid profiles of the root and stem barks of four Mexican Tabernaemontana species with the root bark of the entheogenic African shrub Tabernanthe iboga. PCA demonstrated that separation between species could be attributed to quantitative differences of the major alkaloids, coronaridine, ibogamine, voacangine, and ibogaine. While T. iboga mainly presented high concentrations of ibogaine, Tabernaemontana samples either showed a predominance of voacangine and ibogaine, or coronaridine and ibogamine, respectively. The results illustrate the phytochemical proximity between both genera and confirm previous suggestions that Mexican Tabernaemontana species are viable sources of anti-addictive compounds.

Ibogaine Administration Modifies GDNF and BDNF Expression in Brain Regions Involved in Mesocorticolimbic and Nigral Dopaminergic Circuits

Ibogaine is an atypical psychedelic alkaloid, which has been subject of research due to its reported ability to attenuate drug-seeking behavior. Recent work has suggested that ibogaine effects on alcohol self-administration in rats are related to the release of Glial cell Derived Neurotrophic Factor (GDNF) in the Ventral Tegmental Area (VTA), a mesencephalic region which hosts the soma of dopaminergic neurons. Although previous reports have shown ibogaine’s ability to induce GDNF expression in rat midbrain, there are no studies addressing its effect on the expression of GDNF and other neurotrophic factors (NFs) such as Brain Derived Neurotrophic Factor (BDNF) or Nerve Growth Factor (NGF) in distinct brain regions containing dopaminergic neurons. In this work, we examined the effect of ibogaine acute administration on the expression of these NFs in the VTA, Prefrontal Cortex (PFC), Nucleus Accumbens (NAcc) and the Substantia Nigra (SN). Rats were i.p. treated with ibogaine 20 mg/kg (I₂₀), 40 mg/kg (I₄₀) or vehicle, and NFs expression was analyzed after 3 and 24 h. At 24 h an increase of the expression of the NFs transcripts was observed in a site and dose dependent manner. Only for I₄₀, GDNF was selectively upregulated in the VTA and SN. Both doses elicited a large increase in the expression of BDNF transcripts in the NAcc, SN and PFC, while in the VTA a significant effect was found only for I₄₀. Finally, NGF mRNA was upregulated in all regions after I₄₀, while I₂₀ showed a selective upregulation in PFC and VTA. Regarding protein levels, an increase of GDNF was observed in the VTA only for I₄₀ but no significant increase for BDNF was found in all the studied areas. Interestingly, an increase of proBDNF was detected in the NAcc for both doses. These results show for the first time a selective increase of GDNF specifically in the VTA for I₄₀ but not for I₂₀ after 24 h of administration, which agrees with the effective dose found in previous self-administration studies in rodents. Further research is needed to understand the contribution of these changes to ibogaine’s ability to attenuate drug-seeking behavior.

A case report SPECT study and theoretical rationale for the sequential administration of ibogaine and 5-MeO-DMT in the treatment of alcohol use disorder

Ibogaine is a plant-derived alkaloid and dissociative psychedelic that demonstrates anti-addictive properties with several substances of abuse, including alcohol. 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a naturally occurring psychedelic known to occasion potent mystical-type experiences and also demonstrates anti-addictive properties. The potential therapeutic effects of both compounds in treating alcohol use disorder require further investigation and there are no published human neuroimaging findings of either treatment to date. We present the case of a 31-year-old male military veteran with moderate alcohol use disorder who sought treatment at an inpatient clinic in Mexico that utilized a sequential protocol with ibogaine hydrochloride (1550mg, 17.9mg/kg) on day 1, followed by vaporized 5-MeO-DMT (bufotoxin source 50mg, estimated 5-MeO-DMT content, 5-7mg) on day 3. The patient received SPECT neuroimaging that included a resting-state protocol before, and 3 days after completion of the program. During the patient's ibogaine treatment, he experienced dream-like visions that included content pertaining to his alcohol use and resolution of past developmental traumas. He described his treatment with 5-MeO-DMT as a peak transformational and spiritual breakthrough. On post-treatment SPECT neuroimaging, increases in brain perfusion were noted in bilateral caudate nuclei, left putamen, right insula, as well as temporal, occipital, and cerebellar regions compared to the patient's baseline scan. The patient reported improvement in mood, cessation of alcohol use, and reduced cravings at 5 days post-treatment, effects which were sustained at 1 month, with a partial return to mild alcohol use at 2 months. In this case, serial administration of ibogaine and 5-MeO-DMT resulted in increased perfusion in multiple brain regions broadly associated with alcohol use disorders and known pharmacology of both compounds, which coincided with a short-term therapeutic outcome. We present theoretical considerations regarding the potential of both psychedelic medicines in treating alcohol use disorders in the context of these isolated findings, and areas for future investigation.

DARK Classics in Chemical Neuroscience: Ibogaine

The West African iboga plant has been used for centuries by the Bwiti and Mbiri tribes to induce hallucinations during religious ceremonies. Ibogaine, the principal alkaloid responsible for iboga's psychedelic properties, was isolated and sold as an antidepressant in France for decades before its adverse effects precipitated its removal from the market. An ibogaine resurgence in the 1960s was driven by U.S. heroin addicts who claimed that ibogaine cured their opiate addictions. Behavioral pharmacologic studies in animal models provided evidence that ibogaine could blunt self-administration of not only opiates but cocaine, amphetamines, and nicotine. Ibogaine displays moderate-to-weak affinities for a wide spectrum of receptor and transporter proteins; recent work suggests that its actions at nicotinic acetylcholine receptor subtypes may underlie its reputed antiopiate effects. At micromolar levels, ibogaine is neurotoxic and cardiotoxic and has been linked to several deaths by cardiac arrest. Structure-activity studies led to the isolation of the ibogaine analog 18-methoxycoronaridine (18-MC), an α3β4 nicotinic receptor modulator that retains ibogaine's anticraving properties with few or no adverse effects. Clinical trials of 18-MC treatment of nicotine addiction are pending. Ibogaine analogs may also hold promise for treating anxiety and depression via the "psychedelic-assisted therapy" approach that employs hallucinogens including psilocybin and methylenedioxymethamphetamine ("ecstasy").

Ibogaine as a treatment for substance misuse: Potential benefits and practical dangers

Ibogaine is an indole alkaloid found in the root bark of the Iboga shrub native to west Africa possessing hallucinogenic properties. For centuries it has been used in religious ceremonies and to gain spiritual enlightenment. However, since the early 1960s, its apparent ability to reduce craving for psychoactive substances including alcohol, cocaine, methamphetamine, opiates, and nicotine has led to its use in detoxification treatments. In many instances, clients receive treatment in non-medical settings, with little by way of robust scientific clinical trials. This chapter provides an overview of the potential benefits that could arise from such research. This is balanced against the serious adverse effects that can occur due to undiagnosed health conditions and/or concomitant use of other drugs. A detailed update is provided of the 33 deaths known to have occurred, including 5 in the UK. Looking forward, there is a need to develop better opiate detoxification treatment against a background of increasing opioid-related fatalities. A congener of ibogaine, 18-MC, appears to be safer and is to undergo clinical trials. In the meantime, would-be consumers and treatment providers must make more careful, detailed risk-assessments before using ibogaine. Treatment outcomes, including deaths, need to be accurately recorded and published.

Cytochrome P450 and O-methyltransferase catalyze the final steps in the biosynthesis of the anti-addictive alkaloid ibogaine from Tabernanthe iboga

Monoterpenoid indole alkaloids are a large (∼3000 members) and structurally diverse class of metabolites restricted to a limited number of plant families in the order Gentianales. Tabernanthe iboga or iboga (Apocynaceae) is native to western equatorial Africa and has been used in traditional medicine for centuries. Howard Lotsof is credited with bringing iboga to the attention of Western medicine through his accidental discovery that iboga can alleviate opioid withdrawal symptoms. Since this observation, iboga has been investigated for its use in the general management of addiction. We were interested in elucidating ibogaine biosynthesis to understand the unique reaction steps en route to ibogaine. Furthermore, because ibogaine is currently sourced from plant material, these studies may help improve the ibogaine supply chain through synthetic biology approaches. Here, we used next-generation sequencing to generate the first iboga transcriptome and leveraged homology-guided gene discovery to identify the penultimate hydroxylase and final O-methyltransferase steps in ibogaine biosynthesis, herein named ibogamine 10-hydroxylase (I10H) and noribogaine-10-O-methyltransferase (N10OMT). Heterologous expression in Saccharomyces cerevisiae (I10H) or Escherichia coli (N10OMT) and incubation with putative precursors, along with HPLC-MS analysis, confirmed the predicted activities of both enzymes. Moreover, high expression levels of their transcripts were detected in ibogaine-accumulating plant tissues. These discoveries coupled with our publicly available iboga transcriptome will contribute to additional gene discovery efforts and could lead to the stabilization of the global ibogaine supply chain and to the development of ibogaine as a treatment for addiction.

Psychedelic-Assisted Psychotherapy: A Paradigm Shift in Psychiatric Research and Development

Mental disorders are rising while development of novel psychiatric medications is declining. This stall in innovation has also been linked with intense debates on the current diagnostics and explanations for mental disorders, together constituting a paradigmatic crisis. A radical innovation is psychedelic-assisted psychotherapy (PAP): professionally supervised use of ketamine, MDMA, psilocybin, LSD and ibogaine as part of elaborated psychotherapy programs. Clinical results so far have shown safety and efficacy, even for “treatment resistant” conditions, and thus deserve increasing attention from medical, psychological and psychiatric professionals. But more than novel treatments, the PAP model also has important consequences for the diagnostics and explanation axis of the psychiatric crisis, challenging the discrete nosological entities and advancing novel explanations for mental disorders and their treatment, in a model considerate of social and cultural factors, including adversities, trauma, and the therapeutic potential of some non-ordinary states of consciousness.

Psychedelics Promote Structural and Functional Neural Plasticity

Atrophy of neurons in the prefrontal cortex (PFC) plays a key role in the pathophysiology of depression and related disorders. The ability to promote both structural and functional plasticity in the PFC has been hypothesized to underlie the fast-acting antidepressant properties of the dissociative anesthetic ketamine. Here, we report that, like ketamine, serotonergic psychedelics are capable of robustly increasing neuritogenesis and/or spinogenesis both in vitro and in vivo. These changes in neuronal structure are accompanied by increased synapse number and function, as measured by fluorescence microscopy and electrophysiology. The structural changes induced by psychedelics appear to result from stimulation of the TrkB, mTOR, and 5-HT2A signaling pathways and could possibly explain the clinical effectiveness of these compounds. Our results underscore the therapeutic potential of psychedelics and, importantly, identify several lead scaffolds for medicinal chemistry efforts focused on developing plasticity-promoting compounds as safe, effective, and fast-acting treatments for depression and related disorders.

Changes in Withdrawal and Craving Scores in Participants Undergoing Opioid Detoxification Utilizing Ibogaine

Opioid use disorder (OUD) is currently an epidemic in the United States (US) and ibogaine is reported to have the ability to interrupt opioid addiction by simultaneously mitigating withdrawal and craving symptoms. This study examined opioid withdrawal and drug craving scores in 50 participants with OUD undergoing a week-long detoxification treatment protocol with ibogaine. The Addiction Severity Index (ASI) was used for baseline characterization of participants' OUD. Clinical Opioid Withdrawal Scale (COWS), Subjective Opioid Withdrawal Scale (SOWS), and Brief Substance Craving Scale (BSCS) scores were collected at 48 and 24 hours prior to ibogaine administration, as well as 24 and 48 hours after ibogaine administration. At 48 hours following ibogaine administration, withdrawal and craving scores were significantly lowered in comparison to baseline: 78% of patients did not exhibit objective clinical signs of opioid withdrawal, 79% reported minimal cravings for opioids, and 68% reported subjective withdrawal symptoms in the mild range. Ibogaine appears to facilitate opioid detoxification by reducing opioid withdrawal and craving in participants with OUD. These results warrant further research using rigorous controlled trials.

The Effects of Ibogaine on Uterine Smooth Muscle Contractions: Relation to the Activity of Antioxidant Enzymes

Ibogaine is an indole alkaloid originally extracted from the root bark of the African rainforest shrub Tabernanthe iboga. It has been explored as a treatment for substance abuse because it interrupts drug addiction and relieves withdrawal symptoms. However, it has been shown that ibogaine treatment leads to a sharp and transient fall in cellular ATP level followed by an increase of cellular respiration and ROS production. Since contractile tissues are sensitive to changes in the levels of ATP and ROS, here we investigated an ibogaine-mediated link between altered redox homeostasis and uterine contractile activity. We found that low concentrations of ibogaine stimulated contractile activity in spontaneously active uteri, but incremental increase of doses inhibited it. Inhibitory concentrations of ibogaine led to decreased SOD1 and elevated GSH-Px activity, but doses that completely inhibited contractions increased CAT activity. Western blot analyses showed that changes in enzyme activities were not due to elevated enzyme protein concentrations but posttranslational modifications. Changes in antioxidant enzyme activities point to a vast concentration-dependent increase in H₂O₂ level. Knowing that extracellular ATP stimulates isolated uterus contractility, while H₂O₂ has an inhibitory effect, this concentration-dependent stimulation/inhibition could be linked to ibogaine-related alterations in ATP level and redox homeostasis.

Subjective effectiveness of ibogaine treatment for problematic opioid consumption: Short- and long-term outcomes and current psychological functioning

Background and aims

Very few studies have reported the effectiveness of ibogaine as a treatment for chronic opioid use. Therefore, this study evaluated the acute subjective effects of ibogaine, outcomes on problematic opioid consumption, and the long-term associations with psychological functioning.

Methods

Using online data collection, 88 patients who received ibogaine treatment in Mexico between 2012 and 2015 completed our survey.

Results

Most participants (72%) had used opioids for at least 4 years and 69% reported daily use. Most (80%) indicated that ibogaine eliminated or drastically reduced withdrawal symptoms. Fifty percent reported that ibogaine reduced opioid craving, some (25%) reporting a reduction in craving lasting at least 3 months. Thirty percent of participants reported never using opioids again following ibogaine treatment. And over one half (54%) of these abstainers had been abstinent for at least 1 year, with 31% abstinent for at least 2 years. At the time of survey, 41% of all participants reported sustained abstinence (>6 months). Although 70% of the total sample reported a relapse following treatment, 48% reported decreased use from pretreatment levels and an additional 11% eventually achieved abstinence. Treatment responders had the lowest rates of depressive and anxious symptoms, the highest levels of subjective well-being and rated their ibogaine treatment as more spiritually meaningful compared with treatment non-responders.

Conclusion

The results suggest that ibogaine is associated with reductions in opioid use, including complete abstinence, and has long-term positive psychological outcomes. Future research should investigate the efficacy of ibogaine treatment using rigorous longitudinal and controlled designs.