Substances
Mesembrine — Compound Profile
Mesembrine 2D structure of Mesembrine (C17H23NO3) — source: PubChem CID 394162 Chemistry CID: 394162 · PubChem Formula: C17H23NO3 Molecular weight: 289.4 g/mol IUPAC: (3aS,7aS)-3a-(3,4-dimethoxyphenyl)-1-methyl-2,3,4,5,7,7a-hexahydroindol-6-one CAS: 24880-43-1 Family & pharmacology Family: Sceletium alkaloid (mesembrane-type tricyclic) Pharmacological class: Serotonin reuptake inhibitor (SRI) and phosphodiesterase type 4 (PDE4) inhibitor. Mesembrine inhibits the serotonin transporter (SERT) with potency comparable to SSRIs, increasing synaptic serotonin availability. The concurrent PDE4 inhibition — which raises intracellular cAMP — is a mechanistic feature not found in conventional SSRIs and may contribute to anxiolytic and cognitive effects observed in preclinical and clinical studies. Mesembrine does not exhibit monoamine oxidase inhibition at relevant concentrations. Natural source: Mesembrine is the primary alkaloid in Sceletium tortuosum (kanna), a small succulent plant native to the semi-arid regions of South Africa, particularly the Western Cape and Northern Cape provinces. The plant contains at least four major alkaloids (mesembrine, mesembrenone, mesembrenol, and mesembranol); mesembrine typically predominates in fermented preparations (called kougoed). Total alkaloid content varies significantly between chemotypes and growing conditions. Historical context Sceletium tortuosum has one of the longest documented histories of use of any psychoactive plant. The earliest written account was by Jan van Riebeeck, the Dutch VOC commander who established the Cape Colony, who recorded Khoisan use of kanna in his diary in 1662. Subsequent colonial-era accounts describe kanna as a valuable trade commodity between Khoisan groups, sometimes used in lieu of tobacco or exchanged for livestock. Mesembrine as an alkaloid was first isolated in 1898 by German pharmacologists Bodendorf and Krieger from dried Sceletium material. Its full chemical structure was elucidated over the following decades, with the mesembrane carbon skeleton fully described by the mid-20th century. Modern pharmacological characterisation of its serotonergic mechanism was established in the 1990s. Traditional use Khoisan and early Cape Coloured communities chewed, smoked, or used fermented kanna (kougoed) as snuff for mood elevation, sociality, and pain relief Hunters used kanna to suppress hunger and thirst on long treks; it was also used for toothache and intestinal complaints Kanna functioned as an important trade good between Khoisan groups across the Cape, sometimes commanding high barter value Fermentation (kougoed preparation) involved burying plant material and allowing it to ferment over days, which transforms alkaloid ratios — increasing mesembrenone relative to mesembrine and affecting potency Modern research context Scientific interest in mesembrine and Sceletium extracts accelerated from the 2000s. The commercial extract Zembrin® (a standardised 2:1 extract of Sceletium tortuosum) has been evaluated in multiple clinical studies. Harvey et al. published the first randomised controlled trial in humans in 2011 (J Ethnopharmacol 2011, PMID 22234675), demonstrating anxiolytic effects and improved cognitive flexibility in healthy volunteers. A subsequent randomised double-blind crossover trial (Nell et al. 2013) found that Zembrin attenuated threat-related amygdala reactivity in healthy subjects — a finding consistent with anxiolytic activity. The dual SRI+PDE4 mechanism distinguishes mesembrine from classic SSRIs, and its relatively rapid onset of effect (hours rather than weeks, as reported in qualitative user accounts) has been a subject of mechanistic interest. PDE4 inhibition alone (as seen in roflumilast) has antidepressant-like effects in animal models, potentially synergising with SERT blockade. Safety Mesembrine and Sceletium tortuosum preparations are generally considered to have a benign safety profile at low-to-moderate doses. Reported adverse effects include mild headache, nausea, and initial sedation. The most significant pharmacological interaction risk is with other serotonergic agents: co-administration of Sceletium preparations with SSRIs, SNRIs, or MAOIs raises the theoretical risk of serotonin syndrome and should be avoided. Case reports of serotonin syndrome with kanna have appeared in the literature. Sceletium has no meaningful cardiovascular or hepatotoxic risk profile at doses used traditionally or in clinical studies. It is not considered habit-forming in the classical sense, though tolerance and mild psychological dependence are plausible with regular high-dose use. It is not recommended during pregnancy or lactation in the absence of safety data. Legal status in Germany As of 2026, mesembrine and Sceletium tortuosum are not scheduled in the German Narcotics Act (BtMG, Anlagen I–III) or the New Psychoactive Substances Act (NpSG). The plant, its extracts, and mesembrine as an isolated alkaloid are legal to possess, sell, and purchase in Germany. Kanna and Sceletium extracts are openly available in health supplement and botanical retail channels in Germany and the EU. Related content Plant Extracts at amama Mitragynine — Compound Profile Muscimol — Compound Profile
Learn moreIbogaine — Compound Profile
Ibogaine 2D structure of Ibogaine (C20H26N2O) — source: PubChem CID 197060 Chemistry CID: 197060 · PubChem Formula: C20H26N2O Molecular weight: 310.4 g/mol IUPAC: (1R,15R,17S,18S)-17-ethyl-7-methoxy-3,13-diazapentacyclo[13.3.1.02,10.04,9.013,18]nonadeca-2(10),4(9),5,7-tetraene CAS: 83-74-9 Family & pharmacology Family: Indole alkaloid (ibogamine-type) Pharmacological class: NMDA receptor antagonist; kappa-opioid receptor agonist; sigma-2 receptor agonist; serotonin transporter inhibitor (SERT); nicotinic acetylcholine receptor antagonist. Preclinical data also indicate upregulation of BDNF (brain-derived neurotrophic factor), which may underlie reported neuroplastic effects in animal models. Natural source: Ibogaine is the principal psychoactive alkaloid in the root bark of Tabernanthe iboga, a perennial understory shrub native to the rainforests of Gabon, Cameroon, and the Republic of Congo. The root bark contains a complex of 12 or more iboga alkaloids; ibogaine typically constitutes 10–20 % of total alkaloid content. Historical context Ibogaine was first isolated in 1901 by French pharmacologists Dybowski and Landrin from Tabernanthe iboga, two years after iboga root bark was exhibited at the Paris Exposition. Its full chemical structure was determined in 1958, followed by the first total synthesis by Büchi et al. (J. Am. Chem. Soc. 1958). Western pharmaceutical interest peaked in the 1960s when it was briefly marketed in France as Lambarène — a stimulant tonic — before being withdrawn from the market. Modern addiction-interruption research traces to self-experimenter Howard Lotsof, who in 1962 observed that a single session appeared to interrupt his heroin use and filed the first treatment patents in the 1980s. Alper et al. (Alkaloids 1999, PMID 10332749) published a systematic review of 33 cases, establishing ibogaine's profile in the clinical literature. Traditional use — Bwiti ceremony Central to the Bwiti initiation rite of the Mitsogo and Fang peoples of Gabon and Cameroon, where large doses of root bark are consumed over multi-day initiation ceremonies Considered a sacrament that enables contact with ancestral spirits; the full initiatory dose is taken once in a lifetime in traditional contexts Smaller doses are used in ongoing Bwiti ritual practice, notably as a collective stimulant during all-night ceremonies (ngoze) Listed as part of the UNESCO-recognized Bwiti intangible cultural heritage of Gabon (2008) Modern research context Contemporary clinical interest centres on ibogaine's reported ability to reduce opioid withdrawal symptoms and craving in a single session. Noller et al. (Subst Abuse 2018, PMID 29869598) found significant reductions in opioid use scores 12 months after treatment in a New Zealand open-label study (n=14). A Stanford retrospective (Nat Med 2023, PMID 36905680) of military veterans reported substantial reductions in PTSD, depression, and anxiety scales. Mechanistically, the multi-receptor profile — including BDNF upregulation, NMDA antagonism, and kappa-opioid activity — distinguishes ibogaine from single-target pharmacotherapies. It is actively investigated at MAPS, NYU, and the Universidade Federal Fluminense. Safety Ibogaine carries a well-documented cardiac risk: QT interval prolongation that can trigger fatal ventricular arrhythmia (Torsades de Pointes). Litjens & Brunt (Regul Toxicol Pharmacol 2016, PMID 26284997) reviewed 19 ibogaine-related fatalities; most involved pre-existing cardiac conditions or concomitant substances. Medical screening (ECG, electrolytes) and cardiac monitoring during administration are considered standard of care in clinical research settings. Ibogaine is not suitable for self-administration. Legal status in Germany Ibogaine is not listed in the Narcotics Act (BtMG, Anlagen I–III) or the New Psychoactive Substances Act (NpSG) as of 2026. Possession and purchase of the compound are not prohibited under substance law. However, ibogaine has no medicinal approval (Arzneimittelgesetz / AMG), meaning it cannot be prescribed or administered therapeutically by healthcare providers in Germany. The distinction between legal possession and unlicensed medical use is critical. See the full analysis in Iboga Legal Status in Germany & Europe 2026. Related content Iboga Guide: The Complete Plant Profile Iboga Effects: Pharmacology & Mechanism of Action Ibogaine Therapy in Europe: Clinics & Research Iboga Legal Status in Germany & Europe 2026
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