Mitraversine

Mitraversine at a Glance

Mitraversine is one of the oldest names in Mitragyna alkaloid chemistry — it appears in the title of the same 1921 paper that gave mitragynine its name ^{1Reference 1Field E · 1921XCVIII.—Mitragynine and mitraversine, two new alkaloids from species of mitragyneView study →}. It has survived for a century on kratom constituent lists, including this database’s own.

It has survived on very little else. There is no reported structure, no molecular formula from a primary source, no bioassay, no pharmacology, and no modern detection. The compound has no PubChem CID, no ChEBI entry, no KNApSAcK species–metabolite record and no Wikidata item, and a PubMed search for the name returns zero papers (checked July 2026). Where it does appear in the modern literature it appears in an inherited constituent list — a 2023 kratom review, for example, names it in passing as “an indole derivative” with no source data and no pharmacology attached ^{15Reference 15Hossain R et al. · 2023ReviewA critical review of the neuropharmacological effects of kratom: an insight from the functional array of identified natural compoundsView study →}.

The honest reading is that mitraversine is a historical name whose chemical identity was never settled, and whose attribution to kratom rests on a 1937 report that the leading twentieth-century Mitragyna chemist described as probably a mixture of alkaloids ^{2Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →}. This page exists to say that plainly, and to keep mitragynine’s evidence from leaking onto a molecule that has none of its own.

The name is real; the molecule is not established.Ellen Field coined it in 1921 in Journal of the Chemical Society, Transactions, in a paper titled for “two new alkaloids from species of Mitragyne” — plural, meaning the two alkaloids came from different plants ^{1Reference 1Field E · 1921XCVIII.—Mitragynine and mitraversine, two new alkaloids from species of mitragyneView study →}. Mitragynine’s source (M. speciosa) is undisputed; mitraversine’s is not.

Its kratom attribution was doubted by 1974.Shellard’s review for the UN Bulletin on Narcotics records that Denis named alkaloids from M. speciosa “mitraversine and mitraspecine” in 1937, “but these were probably mixtures of alkaloids” ^{2Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →}. Shellard’s own laboratory then isolated 22 alkaloids from 30 samples of M. speciosa leaf over a decade — mitraversine was not among them ^{2Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →}.

No modern analysis has found it.The two most thorough contemporary characterisations of kratom alkaloids report 19 and 10 compounds respectively, none of them mitraversine ^{3,4Reference 3Flores-Bocanegra L et al. · 2020The chemistry of kratom [Mitragyna speciosa]: updated characterization data and methods to elucidate indole and oxindole alkaloidsView study →Reference 4Chear NJ et al. · 2021Exploring the chemistry of alkaloids from Malaysian Mitragyna speciosa (kratom) and the role of oxindoles on human opioid receptorsView study →}, and neither of the recent untargeted foliar-metabolomics studies across four Mitragyna species detected it — both cite the name only as historical background ^{8,9Reference 8Andriyas T et al. · 2025Interspecific and environmental influence on the foliar metabolomes of Mitragyna species through recursive OPLSDA modelingView study →Reference 9Andriyas T et al. · 2026Environmental influence on the untargeted foliar metabolome of naturally growing Mitragyna species in ThailandView study →}.

The Identity Problem

The single most important fact about mitraversine is that nobody has published what it is.

For a compound to be usable, the literature needs a structure, a formula, and characterisation data — the kind of ¹H/¹³C NMR, HRMS and ECD dataset that modern natural-product chemistry treats as the minimum. Mitraversine has none of it in the accessible record. It is absent from PubChem, ChEBI, KNApSAcK and Wikidata, which means no formula, no CAS number, no InChIKey and no reference structure exists in any public chemical database. Molecular formulas circulating on consumer kratom websites are not traceable to a primary source and are not repeated here.

This matters because the era that named it was working before those standards existed. As the authors of the most recent full characterisation of kratom’s alkaloids put it, kratom has been studied for over a century, yet “the characterization data in the literature for many of the alkaloids are either incomplete or inconsistent with modern standards” ^{3Reference 3Flores-Bocanegra L et al. · 2020The chemistry of kratom [Mitragyna speciosa]: updated characterization data and methods to elucidate indole and oxindole alkaloidsView study →}. That paper existed precisely to re-derive clean reference data for 19 indole and oxindole alkaloids, four of which turned out to be new. Mitraversine was not one of the 19 — nor one of the 10 alkaloids independently isolated from Malaysian M. speciosa leaf a year later ^{4Reference 4Chear NJ et al. · 2021Exploring the chemistry of alkaloids from Malaysian Mitragyna speciosa (kratom) and the role of oxindoles on human opioid receptorsView study →}.

A name can outlive its evidence. In Mitragyna chemistry this has happened before: rotundifoline, named by Barger, Dyer and Sargent in 1939, took decades and the isolation of its isomer before a correct structure could be proposed ^{2,5Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →Reference 5Barger G et al. · 1939The alkaloids of Mitragyna rotundifoliaView study →}. The difference is that rotundifoline eventually got one. Mitraversine did not.

Which Mitragyna Species?

This database tags mitraversine as a kratom constituent. That tag deserves scrutiny, and it does not survive it intact.

What the 1921 paper says. Field’s title is “Mitragynine and mitraversine, two new alkaloids from species of mitragyne” — species, plural ^{1Reference 1Field E · 1921XCVIII.—Mitragynine and mitraversine, two new alkaloids from species of mitragyneView study →}. Mitragynine is universally credited to Mitragyna speciosa leaf. The plural therefore implies mitraversine came from a different Mitragyna species, which the title does not name. The paper itself is a closed-access 1921 item with no open version, so the second species could not be read directly.

What the kratom attribution rests on. Shellard’s 1974 review — the standard historical account of the genus, written by the chemist who spent two decades on it — credits Field with naming mitragynine only, and attributes the kratom claim to a later worker: “Denis named alkaloids he obtained from M. speciosa mitraversine and mitraspecine (1937) but these were probably mixtures of alkaloids” ^{2Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →}. That is the origin of mitraversine’s place on kratom constituent lists, and it was already being discounted fifty years ago.

What the M. parvifolia claim rests on. Secondary sources — encyclopaedias and commercial kratom pages — commonly say Field obtained mitraversine from the leaves of Mitragyna parvifolia. No primary report behind that claim could be located. Shellard and colleagues published a long series on M. parvifolia leaf and bark alkaloids through the 1960s and 70s ^{6,7Reference 6Shellard EJ et al. · 1968The Mitragyna species of AsiaView study →Reference 7Shellard EJ · 1971The Mitragyna species of AsiaView study →}, and mitraversine appears in none of their indexed titles; modern M. parvifolia work, including a chromosome-level genome that maps the species’ dominant spirooxindole chemistry, describes a mitraphylline-rich profile with no mention of it ^{10Reference 10Laforest LC et al. · 2025A chromosome-level Mitragyna parvifolia genome unveils spirooxindole alkaloid diversification and mitraphylline biosynthesisView study →}.

The verdict. Mitraversine cannot currently be assigned to any Mitragyna species with confidence. The defensible statement is genus-level: a name applied to alkaloid material from the genus Mitragyna in the 1920s–30s, whose specific plant source was never pinned down and whose kratom attribution traces to a 1937 report of probable mixtures. The kratom tag should be read as historical, not analytical.

Its Place Among the Mitragyna Alkaloids

The genus Mitragyna is a well-mapped chemical system, which makes the gap where mitraversine should sit conspicuous.

Mitragyna alkaloids are monoterpene indole alkaloids of the Corynanthe type, and Shellard’s classification sorts essentially all of them along two axes: whether the E ring is open (seco) or closed, and whether the molecule is an indole or a spiro-fused oxindole, with substitution at C(9) as the third variable ^{2Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →}. Mitragynine is the open-E-ring, C(9)-methoxy indole; speciogynine, speciociliatine and paynantheine are its stereo- and vinyl variants; mitraphylline and rhynchophylline are the closed- and open-E-ring oxindoles.

Every alkaloid with a settled identity in this genus can be placed on that grid. Mitraversine cannot, because there is no structure to place. A recent review covering nine Mitragyna species and their phytochemistry does not list it among the genus’s characterised alkaloids ^{11Reference 11Wangmo KS et al. · 2026ReviewA review on Mitragyna alkaloids pharmacology, biosynthesis and biotechnological insightsView study →}, and the standard mid-century review of Mitragyna and Ourouparia alkaloids belongs to an era whose analytical toolkit could not have settled the question either way ^{12Reference 12Saxton JE · 1965Alkaloids of Mitragyna and Ourouparia speciesView study →}.

Nor does it feature in the genus’s chemotaxonomy. Distinguishing M. speciosa from its congeners is a real analytical problem — the two most recent untargeted foliar-metabolomics studies exist to do exactly that across M. diversifolia, M. hirsuta, M. rotundifolia and M. speciosa ^{8,9Reference 8Andriyas T et al. · 2025Interspecific and environmental influence on the foliar metabolomes of Mitragyna species through recursive OPLSDA modelingView study →Reference 9Andriyas T et al. · 2026Environmental influence on the untargeted foliar metabolome of naturally growing Mitragyna species in ThailandView study →} — and the markers that do the work are mitragynine, paynantheine, speciogynine, mitraphylline and rhynchophylline. Mitraversine plays no part in it. Whatever chemotaxonomic role its name once implied, contemporary practice does not use it.

What It's Used For

There is no pharmacology to report. Mitraversine has never been tested for opioid-receptor binding, analgesia, sedation, stimulation, toxicity, antimicrobial activity, or anything else. It has no isolate data and no whole-plant data attributable to it specifically. That is the finding, not a gap in the search.

The temptation with a molecule like this is to reason from its neighbours: it is a Mitragyna indole alkaloid, mitragynine is a Mitragyna indole alkaloid, therefore it probably does something similar. That inference is not available here, for two reasons. First, there is no structure, so there is nothing to reason from — “indole alkaloid” is a class covering molecules with wildly different targets. Second, even within this genus the structure–activity relationships are steep and unforgiving: mitragynine’s diastereomers speciogynine and speciociliatine differ from it only in stereochemistry and behave very differently at opioid receptors, and the oxindoles are a separate pharmacological story again — corynoxine, for instance, binds µ-opioid receptors at K_i 16.4 nM while most of its relatives do not ^{4Reference 4Chear NJ et al. · 2021Exploring the chemistry of alkaloids from Malaysian Mitragyna speciosa (kratom) and the role of oxindoles on human opioid receptorsView study →}.

Kratom’s evidence base belongs to mitragynine, 7-hydroxymitragynine and a handful of characterised minor alkaloids. None of it transfers here.

Mechanisms

None characterised. No target, pathway, receptor affinity or mode of action has been reported for mitraversine.

Pharmacokinetics

No data. Absorption, metabolism, bioavailability, half-life and metabolites are all unstudied — as they must be for a compound with no reference standard.

Clinical Trials

None, and none preclinical. Mitraversine has never entered a trial of any kind and has no preclinical programme behind it.

Completed	Planned	Terminated	Preclinical
—	—	—	—

Last checked: July 2026.

Prevalence in Nature

Mitraversine’s occurrence is unquantified everywhere, and unconfirmed almost everywhere.

In kratom. The only source that places it in kratom (Mitragyna speciosa) is Denis’s 1937 report, discounted as probable mixtures ^{2Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →}. Against that: Shellard’s laboratory examined 30 leaf samples of M. speciosa from Malaya, Thailand and New Guinea between 1961 and 1970 and isolated 22 alkaloids, listing mitragynine, speciogynine, paynantheine and speciociliatine as present in all leaves, with a variable oxindole fraction — and no mitraversine anywhere in that account ^{2Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →}. Later phytochemical characterisations of M. speciosa leaf, including a US-grown sample analysed alongside a commercial Thai one, likewise report the familiar indole and oxindole set plus flavonoids, saponins and glycosides, and not this compound ^{13Reference 13León F et al. · 2009Phytochemical characterization of the leaves of Mitragyna speciosa grown in U.S.AView study →}. Two modern natural-products studies re-derived reference data for 19 and 10 kratom alkaloids respectively without encountering it ^{3,4Reference 3Flores-Bocanegra L et al. · 2020The chemistry of kratom [Mitragyna speciosa]: updated characterization data and methods to elucidate indole and oxindole alkaloidsView study →Reference 4Chear NJ et al. · 2021Exploring the chemistry of alkaloids from Malaysian Mitragyna speciosa (kratom) and the role of oxindoles on human opioid receptorsView study →}.

In the genus. Two recent untargeted metabolomics studies of naturally growing Mitragyna species in Thailand cite mitraversine, alongside mitragynine, as a genus-level metabolite of ethnomedicinal interest — but only in their introductions, referencing the 1939 Barger literature; neither reports detecting it ^{8,9Reference 8Andriyas T et al. · 2025Interspecific and environmental influence on the foliar metabolomes of Mitragyna species through recursive OPLSDA modelingView study →Reference 9Andriyas T et al. · 2026Environmental influence on the untargeted foliar metabolome of naturally growing Mitragyna species in ThailandView study →}. A comprehensive review of the genus written to clarify what is actually in products sold as kratom likewise treats it as inherited nomenclature rather than a measured constituent ^{14Reference 14Brown PN et al. · 2017ReviewA botanical, phytochemical and ethnomedicinal review of the genus Mitragyna korth: implications for products sold as kratomView study →}.

The conclusion. There is no plant part, no species, and no concentration range that can honestly be attached to this molecule, so no “Content by Source” figures are given. If mitraversine corresponds to a real, discrete compound, the modern analytical record has not yet found it; if it does not, the record explains why.

Discovery & Synthesis

The naming (1921). Ellen Field, working in Britain, published “XCVIII.—Mitragynine and mitraversine, two new alkaloids from species of mitragyne” in Journal of the Chemical Society, Transactions, volume 119, pages 887–891 ^{1Reference 1Field E · 1921XCVIII.—Mitragynine and mitraversine, two new alkaloids from species of mitragyneView study →}. Field’s mitragynine — obtained from M. speciosa leaf, following Hooper’s earlier isolation of an alkaloid from the same plant — went on to become one of the most-studied natural products of the twenty-first century. Her mitraversine went nowhere. The etymology is transparent for the first name (Mitragyna → mitragyn-ine) and opaque for the second, and no source consulted explains what the “-vers-” refers to.

The kratom claim (1937). Denis, publishing in the Bulletin de l’Académie Royale de Belgique, applied the names mitraversine and mitraspecine to material from M. speciosa; Shellard’s later assessment was that both were probably mixtures ^{2Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →}.

The structure. Never determined. There is no report of a structure elucidation, no X-ray, no NMR dataset, and no revision — the molecule simply dropped out of the primary literature. Compare mitraphylline, whose structure was settled in 1958, or mitragynine, settled by X-ray crystallography in 1964 ^{2Reference 2Shellard EJ · 1974The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, KorthView study →}.

Total synthesis. None reported, and none possible in any meaningful sense: you cannot synthesise a target that has never been defined.

Manufacture today. None. Mitraversine is not produced, not sold, and not available as an analytical reference standard, which is one practical reason it never appears in a modern quantitative method.

Patents: not yet researched.

Toxicity & Safety

Toxicity is not established, and cannot be. There is no toxicology, no genotoxicity assay, no repeat-dose study and no human exposure data for mitraversine, because there is no characterised isolate to study. The unknown grading here reflects a total absence of data, not a judgement of safety.

Two cautions follow from that, and they run in opposite directions.

Do not read safety from silence. Nothing here says mitraversine is harmless. A compound with no reported hazard and no reported testing is simply unassessed.

Do not read kratom’s risks onto it either. Kratom carries a real safety profile — tolerance, dependence, a withdrawal syndrome, rare cholestatic liver injury, and a clinically confirmed CYP3A interaction — and that profile belongs to the leaf and to its characterised alkaloids, chiefly mitragynine and 7-hydroxymitragynine. Those cautions are set out on the kratom herb page, where intake is actually decided. Attributing any of them to a trace, uncharacterised name would be as unfounded as attributing benefits to it.

Safety at a Glance

Toxicity unknown

Toxicity genuinely unknown. No toxicology, genotoxicity, reproductive or human-exposure data exist for mitraversine. Absence of reported harm is not evidence of safety.
No characterised isolate. Without a structure, formula or reference standard, there is nothing to test and nothing to standardise — any product claim naming this compound is unverifiable.
Kratom’s own risks are real and belong elsewhere. Dependence, withdrawal, rare liver injury and a CYP3A interaction are documented for kratom leaf and its major alkaloids; see the herb page. Do not transfer them to — or excuse them by — this molecule.

Dosage

There is no dose, and no basis for one. Mitraversine has never been isolated to a modern standard, never assayed, never administered to an animal or a person, and is not sold in any form. No study anywhere reports a quantity of it.

Kratom’s own dose-response literature — the low-dose stimulant / higher-dose sedative pattern, and every figure attached to it — belongs to the leaf and to mitragynine, not to this compound, and is not reproduced here. Nothing here is dosing guidance.

References

Field E (1921). XCVIII.—Mitragynine and mitraversine, two new alkaloids from species of mitragyne. Journal of the Chemical Society, Transactions 119:887–891. https://doi.org/10.1039/CT9211900887
Shellard EJ (1974). The alkaloids of Mitragyna with special reference to those of Mitragyna speciosa, Korth. Bulletin on Narcotics 26(2):41–55. https://www.unodc.org/unodc/en/data-and-analysis/bulletin/bulletin_1974-01-01_2_page005.html
Flores-Bocanegra L, Raja HA, Graf TN, Augustinović M, Wallace ED, Hematian S, Kellogg JJ, Todd DA, Cech NB, Oberlies NH (2020). The chemistry of kratom [Mitragyna speciosa]: updated characterization data and methods to elucidate indole and oxindole alkaloids. Journal of Natural Products. https://pubmed.ncbi.nlm.nih.gov/32597657/
Chear NJ, León F, Sharma A, Kanumuri SRR, Zwolinski G, Abboud KA, Singh D, Restrepo LF, Patel A, Hiranita T, Ramanathan S, Hampson AJ, McMahon LR, McCurdy CR (2021). Exploring the chemistry of alkaloids from Malaysian Mitragyna speciosa (kratom) and the role of oxindoles on human opioid receptors. Journal of Natural Products. https://pubmed.ncbi.nlm.nih.gov/33635670/
Barger G, Dyer E, Sargent LJ (1939). The alkaloids of Mitragyna rotundifolia. I. The Journal of Organic Chemistry 4:418–427. https://doi.org/10.1021/jo01216a008
Shellard EJ, Phillipson JD, Gupta D (1968). The Mitragyna species of Asia. XI. The alkaloids of the leaves of Mitragyna parvifolia (Roxb.) Korth. obtained from the Maharashtra State of India. Planta Medica. https://pubmed.ncbi.nlm.nih.gov/5686769/
Shellard EJ, Houghton PJ (1971). The Mitragyna species of Asia. XIX. The alkaloid pattern in Mitragyna parvifolia (Roxb.) Korth. Planta Medica. https://pubmed.ncbi.nlm.nih.gov/5154608/
Andriyas T, Leksungnoen N, Uthairatsamee S, Ngernsaengsaruay C, Andriyas S (2025). Interspecific and environmental influence on the foliar metabolomes of Mitragyna species through recursive OPLSDA modeling. Plants. https://pubmed.ncbi.nlm.nih.gov/40941886/
Andriyas T, Leksungnoen N, Ngernsaengsaruay C, Uthairatsamee S, Andriyas S (2026). Environmental influence on the untargeted foliar metabolome of naturally growing Mitragyna species in Thailand. Plant-Environment Interactions. https://pubmed.ncbi.nlm.nih.gov/41613007/
Laforest LC, Nguyen TM, Matsumoto GO, Ramachandria P, Chanderbali A, Kanumuri SRR, Sharma A, McCurdy CR, Dang TT, Nadakuduti SS (2025). A chromosome-level Mitragyna parvifolia genome unveils spirooxindole alkaloid diversification and mitraphylline biosynthesis. The Plant Cell. https://pubmed.ncbi.nlm.nih.gov/40825067/
Wangmo KS, Wungsintaweekul J, Zhu Z, Yang M, Jaisi A (2026). A review on Mitragyna alkaloids pharmacology, biosynthesis and biotechnological insights. Journal of Genetic Engineering and Biotechnology. https://pubmed.ncbi.nlm.nih.gov/42309612/
Saxton JE (1965). Alkaloids of Mitragyna and Ourouparia species. The Alkaloids: Chemistry and Physiology 8:59–91. https://doi.org/10.1016/S1876-0813(08)60044-5
León F, Habib E, Adkins JE, Furr EB, McCurdy CR, Cutler SJ (2009). Phytochemical characterization of the leaves of Mitragyna speciosa grown in U.S.A. Natural Product Communications. https://pubmed.ncbi.nlm.nih.gov/19731590/
Brown PN, Lund JA, Murch SJ (2017). A botanical, phytochemical and ethnomedicinal review of the genus Mitragyna korth: implications for products sold as kratom. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/28330725/
Hossain R, Sultana A, Nuinoon M, Noonong K, Tangpong J, Hossain KH, Rahman MA (2023). A critical review of the neuropharmacological effects of kratom: an insight from the functional array of identified natural compounds. Molecules. https://pubmed.ncbi.nlm.nih.gov/37959790/