Anadenanthera peregrina

# Research Output: Anadenanthera peregrina

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## Botanical Identity

**Accepted name:** *Anadenanthera peregrina* (L.) Speg.
**Authority & publication:** First published by Carlos Luis Spegazzini in *Physis* (Buenos Aires) 6: 314 (1923) [Ref 15]. The Linnaean basionym was *Mimosa peregrina* L., subsequently transferred by Bentham to *Piptadenia peregrina* (L.) Benth. before Spegazzini erected the current genus.

**Family:** Fabaceae (Leguminosae), subfamily Mimosoideae [Ref 40]. Confirmed by POWO and multiple phylogenetic studies [Ref 15].

**Synonyms (selected from 13 total):**
- *Mimosa peregrina* L. (basionym)
- *Acacia peregrina* (L.) Willd.
- *Piptadenia peregrina* (L.) Benth.
- *Acacia niopo* (Humb. & Bonpl. ex Willd.) Kunth
- *Niopa peregrina* (L.) Britton & Rose
- *Acacia angustiloba* DC.; *Acacia microphylla* Willd.

The genus *Anadenanthera* has historically been treated as containing two species — *A. peregrina* and *A. colubrina* (Vell.) Brenan — with several varieties [Ref 40]. A 2024 molecular genetics study of the genus supports a four-species hypothesis (*A. colubrina*, *A. macrocarpa*, *A. peregrina*, and *A. falcata*), treating the cerrado taxon (*A. peregrina* var. *falcata*) as a distinct species; this reclassification is not yet universally adopted [web-retrieved, cited in search result from Botanical Journal of the Linnean Society 204(1):47, 2024].

**Varieties currently recognized under A. peregrina:**
- *A. peregrina* var. *peregrina* — Caribbean and northern South America; primary cohoba/yopo source
- *A. peregrina* var. *falcata* (Benth.) Altschul — Brazilian cerrado savanna; may be a distinct species per molecular data

**Native range:** Caribbean and South Tropical America: Bolivia, Brazil (North, Northeast, Southeast regions), Colombia, Dominican Republic, French Guiana, Guyana, Haiti, Leeward Islands, Puerto Rico, Suriname, Trinidad-Tobago, Venezuela, Windward Islands [Ref 15]. Introduced to St. Helena.

**Habitat:** Seasonally dry tropical biome; Brazilian cerrado savanna for var. *falcata* (Athayde & Morellato 2014 [Ref 39]). Grows in gallery forests and savanna edges across its range.

**Cultivation status:** Primarily wild-harvested for traditional and commercial use. No formal cultivar development documented. Seeds sold commercially in Europe and North America via online retailers without standardized alkaloid content or quality controls.

**Morphology:** Deciduous to semi-deciduous tree, typically 5–20 m tall; bipinnate leaves with numerous small leaflets; spherical white flower heads; flat, spirally twisted seed pods; seeds dark brown to black, lenticular. The bark and seeds contain high tannin content [Ref 3, 4].

**Misidentification risk:** *A. colubrina* (cebil/vilca) is morphologically similar; bark anatomy differences between the two species are too small to be used alone for taxonomic identification (Mota et al. 2017 [Ref 4]). The two species have similar alkaloid profiles but different geographic ranges: *A. colubrina* predominates in the Andes/southern South America, *A. peregrina* in the Orinoco basin, Amazon, and Caribbean.

**Discrepancies with brief seed data:** All botanical fields were absent from seed data. Family (Fabaceae), genus/species, native range, and cultivation status have been populated from primary sources above. The brief's "plant" type designation is correct.

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## Alkaloid / Cannabinoid Profile

### Primary Alkaloids

**Bufotenine (5-hydroxy-N,N-dimethyltryptamine; 5-OH-DMT)**
- PubChem CID: 10257; IUPAC: 3-[2-(dimethylamino)ethyl]-1H-indol-5-ol; Formula: C₁₂H₁₆N₂O; MW: 204.27 [database lookup]
- **Dominant alkaloid in mature seeds.** Schultes, Holmstedt, Lindgren & Rivier (1977) [Ref 42] reported:
  - Southern Venezuela seeds: **7.5% bufotenine** (as the primary alkaloid)
  - Rio Negro specimen (1854, Spruce collection): 0.6% bufotenine, no DMT or 5-MeO-DMT detected
  - Puerto Rico seeds (March 1975 collection, analyzed 1977): bufotenine = **80% of total alkaloid**; 3.5% by weight as sole alkaloid after 2-year storage
  - Brazilian seeds (Álvarez Pereira 1957, cited in [Ref 42]): 1.1% bufotenine
- Average per gram of seeds: approximately **74 mg bufotenine, 1.6 mg DMT, 0.4 mg 5-MeO-DMT** [Ref 16, web-retrieved from ICEERS]

**N,N-Dimethyltryptamine (DMT)**
- PubChem CID: 6089; IUPAC: 2-(1H-indol-3-yl)-N,N-dimethylethanamine; Formula: C₁₂H₁₆N₂; MW: 188.27 [database lookup]
- First detected in *A. peregrina* seeds by Holmstedt & Lindgren (1967) [Ref 43]
- Schultes et al. (1977) [Ref 42]: immature Puerto Rico seeds (December 1972): **0.16% DMT (75% of total alkaloid)** + 0.04% 5-MeO-DMT + 0.01% bufotenine — demonstrating that immature seeds are DMT-dominant
- Puerto Rico seeds (March 1975, analyzed fresh): DMT = **19% of total alkaloid**
- Puerto Rico (1948): 0.009% DMT
- **DMT is less stable than bufotenine** and degrades during seed maturation and storage; in the 120-year-old Spruce collection specimen, DMT was entirely absent [Ref 42, 17]

**5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT)**
- PubChem CID: 1832; IUPAC: 2-(5-methoxy-1H-indol-3-yl)-N,N-dimethylethanamine; Formula: C₁₃H₁₈N₂O; MW: 218.29 [database lookup]
- First detected in A. peregrina seeds from Rio Branco region, Brazil (1953) by Holmstedt & Lindgren (1967) [Ref 43]
- Maximum reported: **0.04% in immature seeds** (1% of total alkaloid in 1975 fresh Puerto Rico material)
- Rapidly degrades in storage; not detected in seeds aged >2 years [Ref 42, 17]

### Minor Alkaloids
- **DMT-N-oxide** and **bufotenine-N-oxide**: detected in some snuff preparations [Ref 17]
- **2-Methyl-1,2,3,4-tetrahydro-β-carboline**: detected in trace amounts in Puerto Rico 1975 seeds [Ref 42]
- No β-carboline MAO inhibitors detected in the seeds themselves (in contrast to Banisteriopsis caapi)

### Alkaloid Variability
Concentration profiles vary substantially by: (1) geographic origin — Venezuelan seeds consistently show highest bufotenine; (2) seed maturity — immature seeds are DMT/5-MeO-DMT-rich, mature seeds are bufotenine-dominant; (3) storage duration — DMT and 5-MeO-DMT degrade rapidly; bufotenine is stable for decades [Ref 42, 17]. Commercial seeds sold without maturity/provenance information may vary widely in alkaloid composition.

### Bark Phytochemistry
Bark contains high condensed tannin content (587 mg CE/g extract), gallic acid, catechin, and epicatechin identified by HPLC; also flavonoids, saponins, phenols, coumarins [Ref 3, 4]. Bark extract shows antibacterial activity against *Staphylococcus aureus* [Ref 3]. These constituents are distinct from the seed alkaloid profile and not relevant to psychoactive effects.

### How Preparation Alters Constituent Ratios
- **Alkaline ash addition** (traditional preparation with lime or plant ash): raises pH, converting alkaloid salts to free-base form, which dramatically improves nasal absorption of all three alkaloids
- **Heat during roasting**: may cause partial degradation of DMT and 5-MeO-DMT relative to bufotenine; specific data absent
- **Admixture with B. caapi** (Piaroa practice, documented by Rodd 2002 [Ref 2]): introduces harmaline and harmine (MAO-A inhibitors), which inhibit enzymatic degradation of all three alkaloids, increasing systemic exposure dramatically; CYP2D6-mediated O-demethylation of 5-MeO-DMT to bufotenine is also modulated by harmaline at higher doses [Ref 12, 13]
- **Vaporization of free-base bufotenine**: active at 2–8 mg; much lower dose threshold than nasal snuff [web-retrieved]

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## History & Ethnobotany

### First Scientific Description
The species was originally described by Linnaeus as *Mimosa peregrina* in *Species Plantarum* (1753). It was subsequently transferred through several genera — to *Acacia* (Willd.), *Piptadenia* (Benth.) — before Spegazzini established the current binomial in 1923 [Ref 15]. Richard Evans Schultes played a central role in characterizing the alkaloid chemistry and consolidating the ethnobotany of *Anadenanthera* snuffs throughout the mid-20th century [Ref 42]; the 1977 monograph by Schultes, Holmstedt, Lindgren, and Rivier remains the foundational alkaloid quantification study.

### Traditional and Indigenous Use
The use of *A. peregrina* seeds as a psychoactive snuff (cohoba, yopo, jopo, paricá) represents one of the oldest documented ritual drug practices in the Americas.

**Caribbean (cohoba):** The first European account dates to **1496**, when Friar Ramon Pane, commissioned by Christopher Columbus, documented the Taino of Hispaniola inhaling cohoba snuff through Y-shaped tubes during shamanic rituals [Ref 21]. Archaeological residue analysis from Puerto Rico (dated ~1150–1250 CE) has identified starch grains consistent with *A. peregrina* seeds on ceremonial snuffing paraphernalia. The Taino used cohoba for diagnosis, healing, and communication with ancestral spirits (*zemis*) [web-retrieved]. Saladoid peoples migrating from the Orinoco basin to the Caribbean ~500 BCE likely brought the practice and seeds with them.

**South America (yopo/paricá):** Archaeological chemical evidence from a ritual bundle in the Lípez Altiplano, Bolivia (~1,000 CE) identified bufotenine and DMT — indicative of *Anadenanthera* seeds — alongside harmine (from *Banisteriopsis caapi*) and cocaine, in snuffing paraphernalia (Miller et al. 2019 [Ref 24]). This is the oldest biochemically confirmed evidence of a combined ayahuasca-like admixture and *Anadenanthera* snuff.

**Ethnographic diversity of use:**
- **Yanomami (Venezuela/Brazil):** Use *yakoana* (yopo) snuff; shamans inhale to call *xapiripë* spirits for healing and protection; sometimes combined with powdered *Virola elongata* bark (yielding an ebene mixture) [web-retrieved]
- **Piaroa/Hüottüja (Venezuela):** Shamans add *B. caapi* cuttings to yopo preparation and consume B. caapi doses prior to snuff inhalation to modulate vision intensity; yopo is central to cosmological narratives and shamanic identity (Rodd 2002 [Ref 2])
- **Cuiva (Colombia/Venezuela):** Yopo consumption linked to cultural resistance and assertion of indigenous identity; community-level ritual use (Rodd & Sumabila 2011 [Ref 1])
- **Piaroa and Cuiva comparative:** Missionary activity and social change have altered attitudes but not eliminated yopo use; shamanic ethics and cosmological function remain central (Rodd & Sumabila 2011 [Ref 1])

Traditional preparation involves: toasting seeds over low heat, grinding to fine powder, mixing with alkaline material (calcium carbonate from shells/snail shells, or plant ash), sometimes adding other plant materials; the resulting powder is blown by one person through a long tube into another's nostrils, or self-administered with a Y-shaped tube [Ref 2, 16].

**⚠ FLAG: Traditional-use accounts constitute the primary evidence base for effects, phenomenology, and dose-response data for this substance. No controlled human studies exist. This section should be flagged for editorial review.**

### Western Scientific History
- 1496: First European account (Pane)
- 1854: Richard Spruce collects seeds at Rio Negro; specimen analyzed ~120 years later [Ref 42]
- 1955: Identification of bufotenine as major constituent (Fischer Wasels and Gessner, cited in secondary sources)
- 1967: Holmstedt & Lindgren [Ref 43] first detect 5-MeO-DMT and DMT in seeds
- 1977: Schultes, Holmstedt, Lindgren & Rivier [Ref 42] publish definitive alkaloid quantification study
- 2006: Torres & Repke publish *Anadenanthera: Visionary Plant of Ancient South America* [Ref 26] — the definitive ethnobotanical monograph
- 2019: Miller et al. [Ref 24] provide first biochemical proof of combined *Anadenanthera* + ayahuasca-like snuff use in a pre-Columbian ritual context

### Regulatory Timeline
- **1971:** DMT scheduled as Schedule I under the UN Convention on Psychotropic Substances; bufotenine and 5-MeO-DMT not listed; plants not controlled [Ref 33]
- **US:** Bufotenine placed on Schedule I (DEA code 7433) under the Controlled Substances Act; DMT and 5-MeO-DMT also Schedule I
- **UK (1971):** Bufotenine and DMT classified as Class A drugs under the Misuse of Drugs Act 1971
- **Australia:** Bufotenine classified Schedule 9 (Prohibited substance) under the Poisons Standard

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## Neuroscience & Mechanism

### Primary Receptor Targets

**Bufotenine (primary active compound):**
- **5-HT₂A agonist:** The 5-OH group at position 5 of the indole ring provides key binding interactions at 5-HT₂A. Zhang et al. (2025) [Ref 7] demonstrated that bufotenine forms a hydrogen bond with residue L229 (guiding entry to the orthosteric site) and a stable salt bridge and hydrogen bond with residue D155 in the 5-HT₂A binding site. Head twitch response (HTR) — a validated proxy for hallucinogenic activity in rodents — is elicited by bufotenine [Ref 7].
- **5-HT₂C:** Also active; less selective than at 5-HT₂A [Ref 31]
- **Antagonism of 5-HT excitation in brainstem neurons:** Bradley & Briggs (1974) [Ref 23] demonstrated via microiontophoresis in rats that bufotenine (5-HODMT), like LSD, specifically antagonizes 5-HT excitatory effects on brainstem neurons — a proposed mechanism of psychotomimetic action
- Sigma-1 receptor: proposed activity based on structural similarity to DMT [Ref 27]; not specifically confirmed for bufotenine

**5-MeO-DMT (secondary alkaloid):**
- Primary affinity for **5-HT₁A** > 5-HT₂A (Warren et al. 2024 [Ref 35])
- **CYP2D6 O-demethylation** converts 5-MeO-DMT → bufotenine in vivo; CYP2D6 genetic polymorphism modulates this conversion [Ref 13]
- MAO-A deaminates 5-MeO-DMT (primary inactivation); harmaline inhibits this, dramatically increasing exposure [Ref 9, 12]

**DMT (tertiary alkaloid):**
- 5-HT₁A/2A/2C agonist; sigma-1 receptor ligand; TAAR1 agonist; intracellular 5-HT₂A receptor activation (enabling CNS effects despite MAO-A metabolism); endogenous production documented in pineal gland and brain (Barker et al. 2013 [Ref 29])
- Nearly inactive orally without MAO inhibition; nasal route bypasses some first-pass but MAO-A still active in nasal mucosa

### CNS Mechanism
All three alkaloids are serotonin agonists/modulators acting primarily through 5-HT₂A (hallucinogenic effects) and 5-HT₁A (anxiolytic/dissociative component). The 5-HT₂A pathway drives the head-twitch response in rodents and is the primary substrate for psychedelic phenomenology [Ref 7, 23, 31]. The Gq/phosphoinositide hydrolysis cascade downstream of 5-HT₂A activation is the primary intracellular signal for psychedelic effects [Ref 27].

The combination with MAO inhibitors (B. caapi admixture) creates a fundamentally different pharmacological profile: inhibition of MAO-A dramatically increases exposure to all three alkaloids; CYP2D6-mediated conversion of 5-MeO-DMT to bufotenine is also modulated [Ref 12, 13, 9]. This synergistic effect is pharmacologically documented and explains traditional Piaroa practice of combining yopo with B. caapi for stronger experiences.

### Pharmacokinetics by Route
- **Intranasal (snuff) — primary traditional route:** Onset very rapid (1–5 minutes); duration 20–60 minutes for main effects. Alkaline ash free-basing essential for efficient mucosal absorption; without alkalinization, absorption is substantially reduced [Ref 16]. No published human PK studies with quantified Tmax, Cmax, or half-life for bufotenine via intranasal route.
- **Bufotenine biodistribution (mice, chronic IP):** Found in heart and kidney at all doses (0.63–2.1 mg/animal/day); brain and lung penetration confirmed at higher doses (Vigerelli et al. 2018 [Ref 11]). Challenges early assumptions that bufotenine does not cross the BBB.
- **5-MeO-DMT metabolism:** O-demethylated by CYP2D6 to bufotenine; inactivated by MAO-A deamination. CYP2D6 poor metabolizers produce less bufotenine from 5-MeO-DMT [Ref 13]. Harmaline co-administration: 3.6–4.4× increase in systemic 5-MeO-DMT exposure; 9.9× increase in bufotenine exposure in CYP2D6-humanized mice [Ref 13].
- **Vaporized free-base bufotenine:** Active at 2–8 mg (web-retrieved). No published human PK data.

### CYP Enzyme Involvement
- CYP2D6: catalyzes 5-MeO-DMT O-demethylation → bufotenine; also involved in harmaline metabolism [Ref 9, 13]
- MAO-A: primary deamination route for all three alkaloids [Ref 9]
- CYP2D6 polymorphism: clinically significant variation in bufotenine formation from 5-MeO-DMT; poor metabolizers (CYP2D6*2, *10 alleles: 2.6–40× lower catalytic efficiency) [Ref 13]

**⚠ FLAG: No published human pharmacokinetic studies exist for bufotenine or yopo snuff. PK data above is from animal studies and extrapolation from 5-MeO-DMT studies.**

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## Effects & Dose by Preparation

### Yopo Snuff (Nasal Insufflation) — Primary Preparation

**Dose data (ICEERS, non-peer-reviewed [Ref 16]; FLAG for editorial review):**
| Tier | Dose (mg of prepared snuff powder) |
|---|---|
| Threshold | 30 mg |
| Light | 65–300 mg |
| Medium | 300–540 mg |
| High | 540–800 mg |
| Very high | >800 mg |

These doses apply to traditionally prepared snuff (seeds + alkaline ash). Doses of raw seeds or standardized alkaloid content are not published.

**Onset:** 1–5 minutes following nasal insufflation
**Peak:** 5–20 minutes
**Duration:** 20–60 minutes for primary effects; 60–120 minutes total including residual effects (ICEERS [Ref 16]; traditional accounts; no peer-reviewed source)

**Subjective effects (from traditional accounts and ethnographic documentation; primary evidence basis):**
- **Physical:** Intense nausea and vomiting (nearly universal at psychoactive doses; prominent peripheral 5-HT effect); cardiovascular stimulation (tachycardia, increased blood pressure); intense skin flushing/purpling of face and neck; increased respiratory rate; muscle tension; dizziness; watery eyes
- **Perceptual:** Intense colored geometric patterns (closed-eye and open-eye); visual hallucinations; altered time perception; synesthesia reported in traditional contexts
- **Cognitive/affective:** Cognitive impairment and confusion at onset; states of mental silence and inner clarity (traditional accounts); emotional amplification; ego dissolution at high doses (reported)
- **Transpersonal/shamanic:** Entity contact; communication with spirits (*hekura*, *xapiripë*); access to shamanic knowledge; healing diagnosis (entirely from traditional accounts — no controlled study evidence)

**B. caapi admixture (Piaroa practice):**
Piaroa shamans add B. caapi (harmaline/harmine source) to yopo preparation and/or drink B. caapi before snuffing; this prolongs and intensifies effects via MAO-A inhibition, increasing all alkaloid exposures (Rodd 2002 [Ref 2]). The dose of B. caapi cuttings is not standardized.

**Vaporized free-base bufotenine:**
Active dose 2–8 mg; produces "ring-like, swirling, colored patterns with eyes closed" (web-retrieved; not peer-reviewed). Much lower dose than snuff preparation.

**Effect modifiers:**
- B. caapi co-administration: dramatic intensification via pharmacokinetic mechanism
- Seed maturity/provenance: immature seeds have higher DMT and 5-MeO-DMT content; mature seeds are predominantly bufotenine
- Alkaline ash quality: affects absorption efficiency
- User tolerance: rapid tolerance likely via 5-HT₂A downregulation (see Safety section)
- Set and setting: traditional ritual context with experienced guide strongly modulates experience; acute adverse reactions markedly higher outside traditional framework (reported, not published)

**⚠ FLAG: All dose values are from the ICEERS harm reduction resource (non-peer-reviewed) or traditional accounts. No dose-response data from controlled human studies exists. These values have not been verified against a published primary source or Curiosity v1 DB record.**

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## Safety & Toxicity

### Toxicity Data
- **LD50 for bufotenine in humans:** Not published. No human fatality attributed specifically to yopo or bufotenine identified in peer-reviewed literature.
- **Bufotenine in mice (Vigerelli et al. 2018 [Ref 11]):** Chronic IP dosing at 0.63, 1.05, and 2.1 mg/animal/day for 21 days produced dose-dependent mild behavioral alterations; no histological organ damage; no significant physiological dysfunction at effective dose (0.63 mg/day). Alkaloid found in heart and kidney at all doses; brain and lung at higher doses.
- **Cardiovascular effects:** Prominent and clinically significant at psychoactive doses; include tachycardia, hypertension, intense peripheral vasoconstriction/flushing from peripheral 5-HT receptor stimulation. These effects were documented in early human administration studies of bufotenine (Fabing and Hawkins 1956; Turner and Merlis 1959 — unverified via API, cited in secondary sources including [Ref 10, 17]). Historical subjects showed purpling/cyanosis of face and neck, chest heaviness, and increased respiratory rate.
- **Nausea and vomiting:** Nearly universal at psychoactive doses; caused by peripheral 5-HT3 and 5-HT4 receptor activation in the GI tract.

### Adverse Events by Preparation Type
- No published peer-reviewed case reports of yopo snuff-specific adverse events found in literature search.
- Historical accounts describe intense acute distress during ceremonial use, managed within traditional ritual container (traditional accounts [Ref 1, 2]).
- Recreational/non-traditional use: anxiety, panic, and psychotic episodes reported anecdotally; no published case series.

**⚠ FLAG: No peer-reviewed case reports of adverse events from yopo snuff identified. Cardiovascular toxicity data derives from historical bufotenine administration studies (1950s–60s) not retrieved via API. The generation agent should note this gap explicitly.**

### Psychological Risks
- **Acute anxiety/panic:** High risk outside ritual container; intense rapid onset can produce acute anxiety, especially for unprepared users
- **Psychotomimetic effects:** Bufotenine is psychotomimetic at psychoactive doses; risk of acute psychotic episodes, particularly in individuals with personal or family history of psychotic disorders
- **Delirium:** At very high doses, consistent with classical psychedelic toxidrome
- **HPPD:** Hallucinogen-persisting perception disorder is a known adverse outcome of serotonergic psychedelic use; risk following yopo not specifically published; extrapolated from LSD/psilocybin literature [Ref 38]

### Herb-Drug Interactions

| Interactant | Mechanism | Severity | Evidence Basis |
|---|---|---|---|
| MAO-A inhibitors (harmaline, B. caapi, Syrian rue) | Inhibit MAO-A deamination of all three alkaloids; 3.6–9.9× increase in systemic exposure to 5-MeO-DMT and bufotenine | **Severe** | Pharmacokinetic mechanism (animal studies) [Ref 12, 13] |
| Pharmaceutical MAOIs (phenelzine, tranylcypromine, moclobemide) | Same as above; serotonin toxicity risk | **Severe** | Pharmacokinetic mechanism; class effect [Ref 9, 14] |
| SSRIs / SNRIs | Pharmacodynamic: additive serotonergic load; 5-HT₂A downregulation from chronic SSRI may blunt hallucinogenic effects; acute combination raises serotonin syndrome risk | **Moderate-Severe** | Pharmacokinetic/pharmacodynamic mechanism; no clinical case report specific to yopo [Ref 14] |
| CYP2D6 inhibitors (fluoxetine, paroxetine, bupropion) | Reduce 5-MeO-DMT O-demethylation to bufotenine; alter exposure unpredictably | **Moderate** | Pharmacokinetic mechanism [Ref 13, 14] |
| Serotonergic agents generally (triptans, tramadol, fentanyl, linezolid) | Additive serotonergic load; serotonin syndrome risk | **Moderate** | Class effect; pharmacodynamic mechanism [Ref 14] |

**⚠ FLAG: Herb-drug interaction severities are based on pharmacokinetic mechanism (animal data) and pharmacodynamic class effects, NOT clinical case reports specific to yopo. No clinical case report of serotonin syndrome from yopo + pharmaceutical interaction has been identified in the literature.**

### Tolerance, Dependence & Withdrawal
- **Tolerance:** Classical psychedelics including serotonergic tryptamines produce rapid tolerance via 5-HT₂A receptor downregulation in frontal cortex (de la Fuente Revenga et al. 2022 [Ref 32]). Tolerance to head twitch response induced after repeated 4-day dosing; single-dose tolerance observed at 24h. **Cross-tolerance** between serotonergic psychedelics (LSD and DOI cross-tolerant) documented [Ref 32]. No bufotenine-specific tolerance studies published.
- **Dependence liability:** Classical psychedelics are widely characterized as having very low physical dependence potential; no compulsive use syndrome equivalent to stimulant or opioid use disorders is documented. The 5-HT₂A downregulation mechanism makes self-escalating use pharmacologically self-limiting [Ref 27, 32].
- **Withdrawal:** No documented withdrawal syndrome. No physical dependence evidence for any classical psychedelic including bufotenine.
- **Abuse potential:** Traditional cultural framework structures and limits use among indigenous communities (Rodd & Sumabila 2011 [Ref 1]). Compulsive use has not been documented in the clinical or ethnographic literature.

### Contaminant / Adulterant Risk
- No published contamination studies for commercially sold *A. peregrina* seeds or yopo preparations
- Seeds sold online without standardized alkaloid content testing; alkaloid concentrations vary substantially by provenance and maturity (see Alkaloid Profile section)
- Preparation with unverified "alkaline ash" substitutes may introduce variable contaminants
- **⚠ FLAG: No published contamination/adulterant data for commercial yopo preparations. This gap should be noted explicitly in the article.**

### Contraindications & Vulnerable Populations
- **MAO inhibitors:** Absolute contraindication; severe pharmacokinetic interaction
- **Cardiovascular disease:** Significant cardiovascular stimulation at psychoactive doses; hypertension, arrhythmia risk; contraindicated in ischemic heart disease, arrhythmias, uncontrolled hypertension
- **Psychotic disorders or strong family history:** Contraindicated; serotonergic psychedelics can precipitate or worsen psychosis [Ref 27]
- **Pregnancy:** No published safety data; alkaloids cross placenta based on structural properties; contraindicated
- **Pediatric use:** No published data; contraindicated outside traditional supervised contexts
- **Hepatic impairment:** May reduce MAO-A clearance, increasing alkaloid exposure; no specific data

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## Harm Reduction

- Traditional use within a supervised ritual context with an experienced guide appears to meaningfully reduce adverse outcomes; the cultural and interpersonal container is pharmacologically significant given rapid onset and intense physical effects (Rodd & Sumabila 2011 [Ref 1]; Rodd 2002 [Ref 2])
- **Avoid all MAO inhibitors:** Including pharmaceutical MAOIs, B. caapi / Syrian rue combinations, and some herbal preparations (passionflower, etc.) — interaction is pharmacokinetically severe
- **Avoid with SSRIs/SNRIs:** Taper/washout required; consult physician before use
- **Cardiovascular screening:** Given prominent cardiovascular stimulation, use is inadvisable for those with cardiovascular disease
- **Set and setting:** Calm, familiar environment; trusted guide; ability to lie down; bucket or container for expected vomiting
- **Avoid re-dosing:** Rapid onset and short duration may create pressure to redose; the rapid tolerance mechanism and unpredictable dose-response make this dangerous
- **Reagent testing:** Mecke reagent (green/blue with bufotenine), Ehrlich reagent (purple with tryptamine indole ring) can confirm presence of tryptamine alkaloids but cannot quantify. No standardized testing kit specifically validated for yopo seeds.
- No published cessation or recovery resources specific to yopo (low dependence potential makes formal treatment rarely required)
- Emergency response: serotonin syndrome management if severe toxicity occurs; cyproheptadine (5-HT antagonist) as adjunct; cardiovascular support; benzodiazepines for agitation

---

## Legal Status

### International
- **UN 1971 Convention on Psychotropic Substances [Ref 33]:** DMT listed as Schedule I; bufotenine not listed; 5-MeO-DMT not listed. **Plants containing scheduled substances are explicitly not subject to international control** under this treaty; *A. peregrina* as a plant is therefore not internationally controlled.
- The 1961 Single Convention (narcotics) and 1988 Convention (trafficking) do not apply to *Anadenanthera peregrina*.

### United States
- **Bufotenine:** Schedule I controlled substance, DEA Controlled Substance Code **7433**, under 21 U.S.C. § 812. Possession, distribution, and manufacture are federal crimes.
- **DMT:** Schedule I. **5-MeO-DMT:** Schedule I.
- ***A. peregrina* seeds/plant:** Not federally scheduled. However, possession with intent to extract scheduled alkaloids would likely trigger federal analog act provisions.
- No state-level analog schedules specifically targeting yopo have been identified.

### United Kingdom
- **Bufotenine:** Class A drug under the Misuse of Drugs Act 1971 (schedule from 1971 enactment). Maximum penalties: 7 years possession, life supply.
- **DMT:** Class A.
- The plant and seeds are not specifically listed; possession of seeds could be prosecuted if intent to produce a Class A drug is established.

### Australia
- **Bufotenine:** Schedule 9 (Prohibited Substance) under the Poisons Standard. Also listed under Criminal Code Regulations as a controlled substance.
- **DMT and 5-MeO-DMT:** Schedule 9.

### South America (Countries of Origin)
- **Venezuela:** Indigenous ceremonial use protected by the Constitution and Organic Law on Indigenous Peoples and Communities (LOPCI) [web-retrieved]. *A. peregrina* tree and seeds are not controlled for traditional use.
- **Brazil:** Seeds not federally controlled; isolated alkaloids (DMT) are listed by ANVISA as prohibited; extracted bufotenine is not on Brazil's scheduled substances list as of last review [web-retrieved, low confidence — FLAG for legal review].
- **Colombia:** Seeds not specifically controlled; traditional indigenous use tolerated; alkaloid status requires jurisdiction-specific legal review [web-retrieved, low confidence — FLAG for legal review].

**⚠ FLAG: Legal status claims for Brazil and Colombia are based on web-retrieved information with low confidence. Legal review is strongly recommended before finalizing these sections.**

### European Union
- Individual member state laws vary; generally bufotenine and DMT are controlled under national psychotropic substance laws implementing the 1971 Convention. Specific national schedules require case-by-case verification. Not reviewed at individual EU member state level in this research pass.

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## Clinical Trials

No registered clinical trials for *Anadenanthera peregrina*, yopo, or bufotenine were identified in a search of ClinicalTrials.gov. This substance has not entered formal clinical development.

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## Community Feedback Analysis

No community feedback was submitted in Part A2 of the brief. No community feedback analysis is required.

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## Gaps & Flags

### Critical Safety Gaps
1. **No published human pharmacokinetic studies** for bufotenine or yopo snuff (Tmax, Cmax, half-life, bioavailability). All PK data is from animal studies or extrapolation from 5-MeO-DMT studies. **FLAG: All PK claims require explicit source attribution and uncertainty framing.**

2. **No published LD50 for bufotenine in humans.** Mouse chronic toxicity data exists (Vigerelli et al. 2018 [Ref 11]) but no human acute lethal dose data. Article must not present any human LD50 value.

3. **No peer-reviewed adverse event case reports** specific to yopo snuff found in literature. Cardiovascular toxicity documented in historical bufotenine injection studies (Fabing & Hawkins 1956; Turner & Merlis 1959) which were not retrieved via API and require unverifiable citation.

4. **Herb-drug interaction severities** (particularly SSRI + yopo and MAOI + yopo) are based on pharmacokinetic mechanism from animal studies, NOT clinical case reports. Severity ratings must be framed accordingly.

### Dose-Related Flags
5. **All dose values** (threshold 30 mg through very high >800 mg) derive from the ICEERS resource [Ref 16], which is an informational harm reduction service, not a peer-reviewed publication. These values have NOT been verified against a published source or Curiosity v1 DB record. **Generation agent must flag these as unverified in the article.**

6. **Duration estimates** (20–60 min main effects; 60–120 min total) are from ICEERS [Ref 16] and traditional accounts — no published dose-ranging study.

### Botanical/Taxonomic Flags
7. **Four-species hypothesis** (2024 Botanical Journal of the Linnean Society): if A. falcata becomes the accepted name for the cerrado variety, substantial taxonomic revision may follow. Article should note current uncertainty.

### Legal Flags
8. **Brazil and Colombia legal status** claims are web-retrieved with low confidence. Human legal review required before publication.

9. **European Union** member state schedules not individually verified. Low confidence for individual EU country claims.

### Evidential Gaps
10. **Traditional-use accounts are the primary evidence** for phenomenology, effects profile, and dose-response characterization. No controlled human study has been conducted. Every claim about subjective effects requires framing as traditional-use evidence. **FLAG: Effects section is based entirely on traditional accounts and ethnographic documentation.**

11. **Drug test detectability** of bufotenine on standard immunoassay panels: no published cross-reactivity data found. Standard urine drug screens do not target tryptamines; no published false-positive cases involving bufotenine.

12. **Contaminant risk** for commercial yopo seeds: no published analytical studies. Alkaloid concentration variability is documented but contaminant (pesticide, heavy metal, mycotoxin) risk is entirely unstudied.

13. **Tolerance data** for bufotenine specifically is absent; tolerance profile extrapolated from other classical psychedelics (5-HT₂A downregulation mechanism, cross-tolerance with DOI/LSD [Ref 32]).

14. **Bufotenine CNS penetration controversy:** Early 1950s–60s studies (Fabing & Hawkins; Turner & Merlis, not API-verified) suggested bufotenine was not psychedelic at tested doses, attributing effects to peripheral cardiovascular actions. More recent evidence (Vigerelli et al. 2018 [Ref 11]) confirms brain penetration at higher doses; Zhang et al. 2025 [Ref 7] confirms 5-HT₂A agonist activity. This historical controversy should be acknowledged in the pharmacology section.

15. **Schultes et al. 1977 [Ref 42] and Holmstedt & Lindgren 1967 [Ref 43]** — foundational alkaloid quantification sources — are listed as unverifiable (pre-digital publications); metadata confirmed through secondary references but DOIs unavailable.