Vincamajine

Vincamajine at a Glance

Vincamajine is a monoterpenoid indole alkaloid built on the ajmalan skeleton — chemically, a close relative of Rauvolfia’s ajmaline rather than of the vincamine that gives periwinkle its reputation ^{5,14Reference 5Jokela R · 1996A ¹H- and ¹³C-NMR study of seven ajmaline-type alkaloidsView study →Reference 14PubChem CID 292620 — Vincamajine (C₂₂H₂₆ et al. · 2026National Center for Biotechnology Information (accessed 31 July 2026)View study →}. It sits among the minor alkaloids of Vinca major, the species covered by this database’s periwinkle monograph, and turns up across the wider Apocynaceae in Rauvolfia and Alstonia ^{2,8,16Reference 2Patel MB et al. · 1965Vincamajine, the major alkaloid of leaves of Rauwolfia mannii StapfView study →Reference 8Frezza C et al. · 2026A new isolation of vincamajine from Vinca difformis subsp. sardoa StearnView study →Reference 16Namjoshi OA · 2016Sarpagine and related alkaloidsView study →}.

Its chemistry is well settled. Its structure was worked out in the late 1950s and 1960s by Janot and Le Men’s Paris group ^{1,3Reference 1Janot MM et al. · 1958Janot MM, Le Men J, Fan C (1958). [The alkaloids of the periwinkles (Vinca): relation between vincamedine and vincamajine]. Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences 247(25):2375–2377. https://pubmed.ncbi.nlm.nih.gov/13619121/View study →Reference 3Plat M et al. · 1965Plat M, Lemay R, Le Men J, Janot MM, Djerassi C, Budzikiewicz H (1965). [New alkaloids of Vinca major L. (Apocynaceae): alkaloids of the periwinkle. 32]. Bulletin de la Société Chimique de France 9:2497–2501. https://pubmed.ncbi.nlm.nih.gov/5848683/View study →}, its full NMR assignment was published and corrected in 1996 ^{5Reference 5Jokela R · 1996A ¹H- and ¹³C-NMR study of seven ajmaline-type alkaloidsView study →}, a family of synthetic routes to “vincamajine-related” alkaloids was developed by Cook’s group from 2004 ^{6Reference 6Yu J et al. · 2005A general strategy for the synthesis of vincamajine-related indole alkaloids: stereocontrolled total synthesis of (+)-dehydrovoachalotine, (−)-vincamajinine, and (−)-11-methoxy-17-epivincamajine as well as the related quebrachidine diol, vincamajine diol, and vincarinolView study →}, and the molecule itself was finally reached by total synthesis in 2022 ^{7Reference 7Chen W et al. · 2022Structure units oriented approach towards collective synthesis of sarpagine-ajmaline-koumine type alkaloidsView study →}.

Its pharmacology is close to a blank. A PubMed search for vincamajine returns seven records, and every one is chemistry: isolation, NMR, chemotaxonomy or synthesis. ClinicalTrials.gov returns zero (both checked 31 July 2026). Everything below comes from screening campaigns in which vincamajine was one library member among dozens — it is not named in a single abstract of its own. Nothing here should be read across from vincamine’s cerebral-circulation literature, from ajmaline’s antiarrhythmic drug record, or from the Catharanthus chemotherapy alkaloids.

Which Vinca Alkaloid Family It Belongs To

This is the single most useful thing the page can establish, because the name invites exactly the wrong inference. “Vincamajine” looks like a variant of “vincamine”. It is not one.

Vinca major’s alkaloids split into at least three unrelated structural series, and vincamajine and vincamine sit in different ones:

• The eburnamine–vincamine series — vincamine, apovincamine, eburnamenine, eburnamonine, vincaminoreine. This is the pentacyclic eburnane skeleton, the one behind the semi-synthetic nootropic vinpocetine and behind every cerebral-blood-flow claim ever attached to periwinkle. Vincamajine is not a member.
• The sarpagine–ajmaline series — vincamajine, plus akuammidine and 11-hydroxypolyneuridine. These are cage-like, bridged alkaloids sharing a common biosynthetic origin and, as expected, real structural similarity ^{16Reference 16Namjoshi OA · 2016Sarpagine and related alkaloidsView study →}.
• The oxindole / heteroyohimbine series — majdine, reserpinine.

Vincamajine’s PubChem systematic name states the point outright: it is the methyl ester of 19,20-didehydro-17-hydroxy-ajmalan-16-carboxylic acid ^{14Reference 14PubChem CID 292620 — Vincamajine (C₂₂H₂₆ et al. · 2026National Center for Biotechnology Information (accessed 31 July 2026)View study →} — an ajmalan, i.e. ajmaline’s own ring system. The 1996 NMR study that fixed its shifts did so in a paper titled, plainly, “A ¹H- and ¹³C-NMR study of seven ajmaline-type alkaloids”, where vincamajine sits alongside ajmaline, isoajmaline and vincamedine ^{5Reference 5Jokela R · 1996A ¹H- and ¹³C-NMR study of seven ajmaline-type alkaloidsView study →}.

Why it matters practically. Vinca major’s cognitive billing is borrowed from a molecule vincamajine is not related to, and its safety reputation should not be borrowed from ajmaline either. Ajmaline is a licensed class-Ia antiarrhythmic used to unmask Brugada syndrome; that pharmacology belongs to ajmaline, has never been shown for vincamajine, and vincamajine has never been tested on a cardiac sodium channel in any published screen. Relatedness in a biosynthetic family predicts a shared skeleton, not shared drug activity.

Identity & Skeleton

Vincamajine is C₂₂H₂₆N₂O₃, molecular weight 366.5, CAS 2506-26-5 ^{14Reference 14PubChem CID 292620 — Vincamajine (C₂₂H₂₆ et al. · 2026National Center for Biotechnology Information (accessed 31 July 2026)View study →}. Structurally it is a hexacyclic, cage-like ajmalan alkaloid carrying an N_a-methyl group on the indoline nitrogen, a C-17 hydroxyl, a C-16 methyl ester, and an E-ethylidene side chain ^{5,14Reference 5Jokela R · 1996A ¹H- and ¹³C-NMR study of seven ajmaline-type alkaloidsView study →Reference 14PubChem CID 292620 — Vincamajine (C₂₂H₂₆ et al. · 2026National Center for Biotechnology Information (accessed 31 July 2026)View study →}.

Two of its synonyms are the most economical description of where it sits in the family:

• O-Deacetylvincamedine — vincamedine is simply vincamajine’s 17-O-acetate. The relationship between the two was the subject of the 1958 paper that put vincamajine on the map ^{1Reference 1Janot MM et al. · 1958Janot MM, Le Men J, Fan C (1958). [The alkaloids of the periwinkles (Vinca): relation between vincamedine and vincamajine]. Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences 247(25):2375–2377. https://pubmed.ncbi.nlm.nih.gov/13619121/View study →}, and it turns out to be the load-bearing structural difference for the one activity anyone has measured (see below).
• N-Methylquebrachidine — quebrachidine is the N_a-desmethyl parent. Cook’s synthetic programme treats quebrachidine, vincamajine, vincamajinine and 11-methoxy-17-epi-vincamajine as one “vincamajine-related” cluster reachable by a single strategy ^{6Reference 6Yu J et al. · 2005A general strategy for the synthesis of vincamajine-related indole alkaloids: stereocontrolled total synthesis of (+)-dehydrovoachalotine, (−)-vincamajinine, and (−)-11-methoxy-17-epivincamajine as well as the related quebrachidine diol, vincamajine diol, and vincarinolView study →}.

Vincamajine also appears in the literature as a scaffold rather than an endpoint — its C-17 and N-1 positions are esterified in nature to give vincamedine, vincamajine 17-O-veratrate and related derivatives, several of which are more biologically interesting than the parent ^{16Reference 16Namjoshi OA · 2016Sarpagine and related alkaloidsView study →}.

What It's Used For

There is very little, and none of it was collected with vincamajine as the subject. Every data point below comes from a screen in which the molecule was one entry in a natural-product library — which is why a name search finds none of them.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. There is exactly one application with any positive signal, and the bar below is deliberately low: a single in-vitro data point, read from a curated database rather than from a result the paper discusses by name.

01VasorelaxationShaky15%One in-vitro isolate screen on rat aortic rings; the potency in that series belonged to a different alkaloid ^{9,13Reference 9Arai H et al. · 2012Alstiphyllanines I–O, ajmaline type alkaloids from Alstonia macrophylla showing vasorelaxant activityView study →Reference 13ChEMBL compound record CHEMBL607365 — vi et al. · 2026EMBL-EBIView study →}

Screened & Found Inactive

The negative record is worth stating explicitly, because it is more substantial than the positive one:

• HIV-1 reverse transcriptase — vincamajine was one of 156 pure natural products run through an HIV-1 RT inhibition assay by Tan and colleagues in 1991; its result is a non-inhibition, IC₅₀ >200 µg/mL ^{12,13Reference 12Tan GT et al. · 1991Evaluation of natural products as inhibitors of human immunodeficiency virus type 1 (HIV-1) reverse transcriptaseView study →Reference 13ChEMBL compound record CHEMBL607365 — vi et al. · 2026EMBL-EBIView study →}.
• Sodium–glucose cotransporters — in the SGLT arm of the same Alstonia macrophylla programme, vincamajine inhibited glucose uptake by only 11.5% at SGLT1 and 30.6% at SGLT2 at 50 µM, well below the compounds the paper highlights (the active ones carried an ester side chain at C-17 — the same structural theme as the vasorelaxant series) ^{10,13Reference 10Arai H et al. · 2010Alstiphyllanines E–H, picraline and ajmaline-type alkaloids from Alstonia macrophylla inhibiting sodium glucose cotransporterView study →Reference 13ChEMBL compound record CHEMBL607365 — vi et al. · 2026EMBL-EBIView study →}.
• High-throughput screening — the PubChem BioAssay record for vincamajine lists 18 assays, all with an “inactive” outcome, spanning MITF, Sonic-hedgehog, STK33, NF-κB, STAT3, c-Myc, mutant p53, IDH1/2, NSD2 and EZH2/PRC2 endpoints ^{14Reference 14PubChem CID 292620 — Vincamajine (C₂₂H₂₆ et al. · 2026National Center for Biotechnology Information (accessed 31 July 2026)View study →}.

None of this rules out activity that nobody has looked for. It does mean vincamajine has been put in front of a reasonable spread of targets and has not lit up.

Mechanisms

None characterised. No molecular target, receptor, enzyme or signalling pathway has been established for vincamajine, so there is no mechanism table here.

Reasoning from the skeleton is not available either. Ajmaline-type alkaloids as a class cover cardiac sodium-channel blockade (ajmaline), calcium-channel-mediated vasorelaxation (vincamedine) and transporter inhibition (the C-17-esterified picraline/ajmaline series) — with the activity in every case tracking the substituents, not the shared core ^{9,10Reference 9Arai H et al. · 2012Alstiphyllanines I–O, ajmaline type alkaloids from Alstonia macrophylla showing vasorelaxant activityView study →Reference 10Arai H et al. · 2010Alstiphyllanines E–H, picraline and ajmaline-type alkaloids from Alstonia macrophylla inhibiting sodium glucose cotransporterView study →}. Vincamajine is the least substituted member of those series and the one that consistently comes out weakest.

Pharmacokinetics

No pharmacokinetic study exists. There is no absorption, oral bioavailability, distribution, metabolism, half-life or excretion data for vincamajine in any species.

The one relevant measurement is an in vitro surrogate, and it is a good one. Könczöl and colleagues validated a blood–brain-barrier-specific parallel artificial membrane permeability assay (PAMPA-BBB) for use on plant extracts, demonstrating it on extracts of Tanacetum parthenium, Vinca major, Salvia officinalis and Corydalis cava, with NMR/LC-MS dereplication of whatever reached the acceptor plate ^{11Reference 11Könczöl A et al. · 2013Applicability of a blood-brain barrier specific artificial membrane permeability assay at the early stage of natural product-based CNS drug discoveryView study →}. Vincamajine was one of the compounds recovered, with log P_e −4.99 — alongside majdine at −5.05 from the same extract ^{13Reference 13ChEMBL compound record CHEMBL607365 — vi et al. · 2026EMBL-EBIView study →}. In the banding convention derived from that assay, log P_e above −4.5 is the highest permeability tier and above −5.5 the next, so −4.99 sits comfortably in the permeable range ^{17Reference 17Sánchez-Martínez JD et al. · 2022Blood-brain barrier permeability study of potential neuroprotective compounds recovered from plants and agri-food by-productsView study →}.

Two caveats, both load-bearing. A PAMPA membrane is passive diffusion only — no efflux transporters, no metabolism, no plasma protein binding — so it predicts that a molecule can cross a lipid barrier, not that it reaches the brain in a living animal. And a molecule getting into the brain is not a molecule doing anything there: vincamajine has no CNS target, no behavioural study and no neuropharmacology of any kind.

Clinical Trials

None, in any indication, at any phase. ClinicalTrials.gov returns zero records for vincamajine (checked 31 July 2026), and there is no animal efficacy study to precede one.

Last checked: July 2026.

Isolate vs. Plant Studies

The split here is unusual: every result here is an isolate result, and none of them came from the plant it is filed under.

• The vasorelaxant and SGLT screens used vincamajine isolated from — or profiled alongside alkaloids of — Alstonia macrophylla, a Southeast Asian tree, not a periwinkle ^{9,10Reference 9Arai H et al. · 2012Alstiphyllanines I–O, ajmaline type alkaloids from Alstonia macrophylla showing vasorelaxant activityView study →Reference 10Arai H et al. · 2010Alstiphyllanines E–H, picraline and ajmaline-type alkaloids from Alstonia macrophylla inhibiting sodium glucose cotransporterView study →}.
• The HIV-1 RT screen used a purified reference compound in a 156-product library ^{12Reference 12Tan GT et al. · 1991Evaluation of natural products as inhibitors of human immunodeficiency virus type 1 (HIV-1) reverse transcriptaseView study →}.
• The one study that touched Vinca major at all used a whole extract, and its endpoint was membrane permeability rather than any pharmacological effect ^{11Reference 11Könczöl A et al. · 2013Applicability of a blood-brain barrier specific artificial membrane permeability assay at the early stage of natural product-based CNS drug discoveryView study →}.

Running the other way, the pharmacological results published for Vinca extracts have never been attributed to vincamajine. Alkaloid-enriched extracts of Vinca sardoa reduced proliferation of a B-lymphoblast leukaemia line by up to 50% at 1–15 µg/mL without harming normal cells ^{19Reference 19De Vita D et al. · 2023In vitroPhytochemical analysis and in vitro antileukemic activity of alkaloid-enriched extracts from Vinca sardoa (Stearn) PignattiView study →} — and vincamajine was subsequently isolated from that same species ^{8Reference 8Frezza C et al. · 2026A new isolation of vincamajine from Vinca difformis subsp. sardoa StearnView study →} — but no one has tested the isolate against those cells, and the extract contains many alkaloids. That is a hypothesis, not a finding.

No effect of any kind has been demonstrated for vincamajine in a Vinca plant, extract, animal or person.

Prevalence in Nature

Vincamajine’s occurrence is confirmed across several Apocynaceae genera and quantified in none of them.

Where the numbers are. The only abundance statement anywhere in the record belongs to a plant outside the periwinkles: Patel and colleagues reported vincamajine as the major alkaloid of the leaves of Rauwolfia mannii Stapf in 1965 ^{2Reference 2Patel MB et al. · 1965Vincamajine, the major alkaloid of leaves of Rauwolfia mannii StapfView study →}. No percentage accompanies the claim, and no comparable statement exists for any Vinca.

In the periwinkles. Vincamajine came out of Janot and Le Men’s Vinca programme — the same Paris series whose part 32 was devoted to new alkaloids of Vinca major ^{1,3Reference 1Janot MM et al. · 1958Janot MM, Le Men J, Fan C (1958). [The alkaloids of the periwinkles (Vinca): relation between vincamedine and vincamajine]. Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences 247(25):2375–2377. https://pubmed.ncbi.nlm.nih.gov/13619121/View study →Reference 3Plat M et al. · 1965Plat M, Lemay R, Le Men J, Janot MM, Djerassi C, Budzikiewicz H (1965). [New alkaloids of Vinca major L. (Apocynaceae): alkaloids of the periwinkle. 32]. Bulletin de la Société Chimique de France 9:2497–2501. https://pubmed.ncbi.nlm.nih.gov/5848683/View study →} — and the major in its name tracks that species. It is worth being precise about the strength of that link: a PubMed search pairing “vincamajine” with “Vinca major” returns zero records (checked 31 July 2026), because the mid-century French chemistry that established it is not indexed at the abstract level. The modern confirmation is indirect but solid: the 2013 PAMPA-BBB study dereplicated vincamajine out of a Vinca major extract, next to majdine ^{11,13Reference 11Könczöl A et al. · 2013Applicability of a blood-brain barrier specific artificial membrane permeability assay at the early stage of natural product-based CNS drug discoveryView study →Reference 13ChEMBL compound record CHEMBL607365 — vi et al. · 2026EMBL-EBIView study →}. Occurrence in Vinca is also not uniform — a 1982 analysis of Vinca major cv. Variegata leaves isolated seven alkaloids (reserpinine, majdine, akuammicine, strictosidine lactam, pseudoakuammigine, akuammine and a tentative 10-hydroxycathofoline) and vincamajine was not among them ^{18Reference 18Balsevich J et al. · 1982Alkaloids of Vinca major cvView study →}, a reminder that these profiles shift with cultivar, plant part and growing conditions.

Elsewhere in the genus. In 2026 Frezza and colleagues reported vincamajine from Vinca difformis subsp. sardoa for the first time, publishing its full NMR, IR and MS characterisation and the first chemophenetic evaluation of the compound ^{8Reference 8Frezza C et al. · 2026A new isolation of vincamajine from Vinca difformis subsp. sardoa StearnView study →}. The alkaloids of the genus as a whole are compiled in a 2025 structural and biological review ^{15Reference 15Vrabec R et al. · 2025ReviewAlkaloids from the genus Vinca L. (Apocynaceae): a comprehensive biological and structural reviewView study →}.

Beyond Vinca. Vincamajine and its N-1 and C-17 esters are recurring constituents of Alstonia macrophylla leaves, where they appear in surveys of the sarpagine–macroline–ajmaline alkaloid pool ^{9,16Reference 9Arai H et al. · 2012Alstiphyllanines I–O, ajmaline type alkaloids from Alstonia macrophylla showing vasorelaxant activityView study →Reference 16Namjoshi OA · 2016Sarpagine and related alkaloidsView study →}. Sarpagine-related alkaloids as a family are dispersed across roughly 25 plant genera, principally in the Apocynaceae ^{16Reference 16Namjoshi OA · 2016Sarpagine and related alkaloidsView study →}.

No concentration figure of any kind is published for vincamajine in any species. That is the highest-value gap on the compound.

Its Place in Sarpagan Biosynthesis

Vincamajine’s own biosynthesis has never been traced — no enzyme, gene or labelling study names it. What is established is the pathway that produces its structural family, and it explains why the ajmaline-type alkaloids keep company with the sarpagine ones in the same plants.

All monoterpenoid indole alkaloids begin from strictosidine, the condensation product of tryptamine and secologanin. Downstream of that, geissoschizine is oxidatively cyclised by cytochrome-P450 enzymes known as sarpagan bridge enzymes, which build the bridged sarpagan core and yield polyneuridine aldehyde and its C-16 epimer akuammidine aldehyde; a cascade of aldehyde reductases, deformylases and decarbomethoxylases then epimerises C-16 and diversifies the pool into species-specific products ^{20Reference 20Mann SGA et al. · 2025Stereochemical insights into sarpagan and akuammiline alkaloid biosynthesisView study →}. The ajmaline branch runs off this same sarpagan intermediate — which is precisely why a “collective synthesis” of sarpagine-, ajmaline- and koumine-type alkaloids through a single common intermediate is chemically natural, and why that synthesis delivered akuammidine, quebrachidine, vincamedine and vincamajine in one campaign ^{7Reference 7Chen W et al. · 2022Structure units oriented approach towards collective synthesis of sarpagine-ajmaline-koumine type alkaloidsView study →}.

The practical reading: vincamajine’s relatives here — akuammidine and 11-hydroxypolyneuridine — are biosynthetic neighbours, while vincamine and the eburnane alkaloids branch off much earlier and elsewhere.

Discovery & Synthesis

First characterised (1950s–60s). Vincamajine emerged from Janot and Le Men’s Paris programme on the alkaloids of the periwinkles, a long-running series in which the 1958 Comptes Rendus note establishing the relationship between vincamedine and vincamajine is the key entry ^{1Reference 1Janot MM et al. · 1958Janot MM, Le Men J, Fan C (1958). [The alkaloids of the periwinkles (Vinca): relation between vincamedine and vincamajine]. Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences 247(25):2375–2377. https://pubmed.ncbi.nlm.nih.gov/13619121/View study →}; the group’s part 32, on new alkaloids of Vinca major, followed in 1965 with Djerassi and Budzikiewicz supplying mass spectrometry ^{3Reference 3Plat M et al. · 1965Plat M, Lemay R, Le Men J, Janot MM, Djerassi C, Budzikiewicz H (1965). [New alkaloids of Vinca major L. (Apocynaceae): alkaloids of the periwinkle. 32]. Bulletin de la Société Chimique de France 9:2497–2501. https://pubmed.ncbi.nlm.nih.gov/5848683/View study →}. The name transparently tracks the source genus and species. Structural work continued through Farnsworth’s Vinca series, whose 1974 instalment used NMR of vincamajine to correct the structure of the related alkaloid herbamine ^{4Reference 4Aynillian GH et al. · 1974Alkaloids of Vinca speciesView study →}, and culminated in the full ¹H/¹³C assignment — with corrections to earlier ¹H data — published by Jokela and Lounasmaa in 1996 ^{5Reference 5Jokela R · 1996A ¹H- and ¹³C-NMR study of seven ajmaline-type alkaloidsView study →}.

Total synthesis. Vincamajine sat in the “related alkaloids” category for two decades before being made. Cook’s group at Wisconsin-Milwaukee built the general strategy: a stereocontrolled route to vincamajine-related indole alkaloids delivering (−)-vincamajinine, (−)-11-methoxy-17-epi-vincamajine and (+)-dehydrovoachalotine, plus quebrachidine diol, vincamajine diol and vincarinol, built on an asymmetric Pictet–Spengler reaction, an enolate-driven palladium cross-coupling and an acid-assisted cyclisation to form the C(7)–C(17) quaternary centre ^{6Reference 6Yu J et al. · 2005A general strategy for the synthesis of vincamajine-related indole alkaloids: stereocontrolled total synthesis of (+)-dehydrovoachalotine, (−)-vincamajinine, and (−)-11-methoxy-17-epivincamajine as well as the related quebrachidine diol, vincamajine diol, and vincarinolView study →}. The first total synthesis of vincamajine itself came in 2022, when Chen and colleagues reported a unified asymmetric route to sarpagine-, ajmaline- and koumine-type alkaloids that reached 14 natural products, eight of them for the first time — akuammidine, 19-Z-akuammidine, vincamedine, vincarine, quebrachidine, vincamajine, alstiphyllianine J and dihydrokoumine ^{7Reference 7Chen W et al. · 2022Structure units oriented approach towards collective synthesis of sarpagine-ajmaline-koumine type alkaloidsView study →}.

Manufacture today. None. Vincamajine is not produced commercially and is not sold in any form; it is obtained only by extraction from plant material, or by synthesis, in a research setting.

Patents: not yet researched.

Toxicity & Safety

Vincamajine’s toxicity is not established, and the unknown grading means exactly that — no acute or repeat-dose study, no LD₅₀, no genotoxicity assay, no reproductive or developmental data, no interaction work and no human exposure data of any kind. A PubMed search pairing the compound with toxicity returns nothing (checked 31 July 2026). There is nothing to grade.

Do not read safety from silence. A molecule that has never been tested is unassessed, not benign — and this one comes from a plant the periwinkle monograph flags as moderately toxic, with a whole-herb caution about nerve, kidney and liver damage on long-term use.

Do not import ajmaline’s pharmacology or its risks. Ajmaline is a real drug with real cardiac liabilities, and vincamajine shares its ring system. It does not share its clinical record: vincamajine has never been tested on a cardiac ion channel, in an arrhythmia model, or in a person. The shared skeleton is a reason to say “unknown”, not a reason to assume either an effect or a hazard.

Do not import the chemotherapy alkaloids either. The neurotoxicity, myelosuppression and vesicant injury of vincristine and vinblastine belong to bisindole cytotoxics from Catharanthus roseus, a different genus and a completely different chemical class.

The single suggestive datum is the permeability result: vincamajine crosses an artificial blood–brain barrier readily in vitro ^{11,13Reference 11Könczöl A et al. · 2013Applicability of a blood-brain barrier specific artificial membrane permeability assay at the early stage of natural product-based CNS drug discoveryView study →Reference 13ChEMBL compound record CHEMBL607365 — vi et al. · 2026EMBL-EBIView study →}. That is a reason for more caution about an unstudied alkaloid, not less — a compound that can reach the CNS and has never been profiled there is exactly the shape of an open question.

Safety at a Glance

❔ Toxicity unknown

• Toxicity genuinely unknown. No toxicology, genotoxicity, reproductive or human-exposure data exist for isolated vincamajine.
• No interaction data. No CYP, P-glycoprotein or transporter work has been done, so drug-interaction potential is entirely uncharacterised.
• Crosses an artificial BBB in vitro. A permeable, unprofiled CNS-reaching alkaloid is an open question, not a reassurance.
• Do not transfer ajmaline’s antiarrhythmic pharmacology — or its cardiac risks — to this molecule. Shared skeleton, unshared evidence.
• Do not transfer vincristine/vinblastine risks either. Those are bisindole cytotoxics from a different genus.
• Structurally well characterised. Settled structure, full NMR assignment, CAS number and a completed total synthesis — if it is ever studied properly, there is a defined molecule to study.

Dosage

There is no dose, and no basis for one. Vincamajine has never been administered to an animal or a person in any published study. It has no bioavailability, half-life or exposure data, no established route, and is not sold as a supplement, a drug or a research standard for human use.

No figure exists to repurpose either — the concentrations that appear in the literature are assay concentrations (30 µM in the aortic-ring screen, 50 µM in the SGLT screen, 100 µM in the permeability assay), which describe what was put in a dish, not what anyone has taken ^{9,10,11,13Reference 9Arai H et al. · 2012Alstiphyllanines I–O, ajmaline type alkaloids from Alstonia macrophylla showing vasorelaxant activityView study →Reference 10Arai H et al. · 2010Alstiphyllanines E–H, picraline and ajmaline-type alkaloids from Alstonia macrophylla inhibiting sodium glucose cotransporterView study →Reference 11Könczöl A et al. · 2013Applicability of a blood-brain barrier specific artificial membrane permeability assay at the early stage of natural product-based CNS drug discoveryView study →Reference 13ChEMBL compound record CHEMBL607365 — vi et al. · 2026EMBL-EBIView study →}. Nothing here is dosing guidance.

Dose decisions for the plant itself belong on the periwinkle monograph, where intake is actually decided — and that page’s position is that the crude herb is not a self-administered simple.

References

1. Janot MM, Le Men J, Fan C (1958). [The alkaloids of the periwinkles (Vinca): relation between vincamedine and vincamajine]. Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences 247(25):2375–2377. https://pubmed.ncbi.nlm.nih.gov/13619121/
2. Patel MB, Poisson J, Pousset JL, Rowson JM (1965). Vincamajine, the major alkaloid of leaves of Rauwolfia mannii Stapf. Journal of Pharmacy and Pharmacology 17(5):323–324. https://doi.org/10.1111/j.2042-7158.1965.tb07675.x
3. Plat M, Lemay R, Le Men J, Janot MM, Djerassi C, Budzikiewicz H (1965). [New alkaloids of Vinca major L. (Apocynaceae): alkaloids of the periwinkle. 32]. Bulletin de la Société Chimique de France 9:2497–2501. https://pubmed.ncbi.nlm.nih.gov/5848683/
4. Aynillian GH, Bell CL, Farnsworth NR (1974). Alkaloids of Vinca species. IV. NMR studies of herbamine and vincamajine. Corrected structure of herbamine, an alkaloid isolated from Vinca libanotica. Lloydia 37(4):589–592. https://pubmed.ncbi.nlm.nih.gov/4449406/
5. Jokela R, Lounasmaa M (1996). A ¹H- and ¹³C-NMR study of seven ajmaline-type alkaloids. Planta Medica 62(6):577–579. https://doi.org/10.1055/s-2006-957980
6. Yu J, Wearing XZ, Cook JM (2005). A general strategy for the synthesis of vincamajine-related indole alkaloids: stereocontrolled total synthesis of (+)-dehydrovoachalotine, (−)-vincamajinine, and (−)-11-methoxy-17-epivincamajine as well as the related quebrachidine diol, vincamajine diol, and vincarinol. The Journal of Organic Chemistry 70(10):3963–3979. https://pubmed.ncbi.nlm.nih.gov/15876085/
7. Chen W, Ma Y, He W, Wu Y, Huang Y, Zhang Y, Tian H, Wei K, Yang X, Zhang H (2022). Structure units oriented approach towards collective synthesis of sarpagine-ajmaline-koumine type alkaloids. Nature Communications 13(1):908. https://pubmed.ncbi.nlm.nih.gov/35177620/
8. Frezza C, Sciubba F, Serafini I, Mastellone E, Scipione L, Di Matteo P, Petrucci R, De Vita D (2026). A new isolation of vincamajine from Vinca difformis subsp. sardoa Stearn. Natural Product Research 40(3):896–900. https://pubmed.ncbi.nlm.nih.gov/40112011/
9. Arai H, Zaima K, Mitsuta E, Tamamoto H, Saito A, Hirasawa Y, Rahman A, Kusumawati I, Zaini NC, Morita H (2012). Alstiphyllanines I–O, ajmaline type alkaloids from Alstonia macrophylla showing vasorelaxant activity. Bioorganic & Medicinal Chemistry 20(11):3454–3459. https://pubmed.ncbi.nlm.nih.gov/22560833/
10. Arai H, Hirasawa Y, Rahman A, Kusumawati I, Zaini NC, Sato S, Aoyama C, Takeo J, Morita H (2010). Alstiphyllanines E–H, picraline and ajmaline-type alkaloids from Alstonia macrophylla inhibiting sodium glucose cotransporter. Bioorganic & Medicinal Chemistry 18(6):2152–2158. https://pubmed.ncbi.nlm.nih.gov/20189404/
11. Könczöl A, Müller J, Földes E, Béni Z, Végh K, Kéry A, Balogh GT (2013). Applicability of a blood-brain barrier specific artificial membrane permeability assay at the early stage of natural product-based CNS drug discovery. Journal of Natural Products 76(4):655–663. https://pubmed.ncbi.nlm.nih.gov/23565574/
12. Tan GT, Pezzuto JM, Kinghorn AD, Hughes SH (1991). Evaluation of natural products as inhibitors of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. Journal of Natural Products 54(1):143–154. https://pubmed.ncbi.nlm.nih.gov/1710653/
13. ChEMBL compound record CHEMBL607365 — vincamajine; curated bioactivity data drawn from refs 9, 10, 11 and 12 (accessed 31 July 2026). EMBL-EBI. https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL607365
14. PubChem CID 292620 — Vincamajine (C₂₂H₂₆N₂O₃, MW 366.5, CAS 2506-26-5), including the BioAssay results summary. National Center for Biotechnology Information (accessed 31 July 2026). https://pubchem.ncbi.nlm.nih.gov/compound/292620
15. Vrabec R, Drašar P, Opletal L, Kosturko Š, Blunden G, Cahlíková L (2025). Alkaloids from the genus Vinca L. (Apocynaceae): a comprehensive biological and structural review. Phytochemistry Reviews 24:3665–3735. https://doi.org/10.1007/s11101-025-10102-z
16. Namjoshi OA, Cook JM (2016). Sarpagine and related alkaloids. The Alkaloids: Chemistry and Biology 76:63–169. https://pubmed.ncbi.nlm.nih.gov/26827883/
17. Sánchez-Martínez JD, Valdés A, Gallego R, Suárez-Montenegro ZJ, Alarcón M, Ibañez E, Alvarez-Rivera G, Cifuentes A (2022). Blood-brain barrier permeability study of potential neuroprotective compounds recovered from plants and agri-food by-products. Frontiers in Nutrition 9:924596. https://pubmed.ncbi.nlm.nih.gov/35782945/
18. Balsevich J, Constabel F, Kurz WGW (1982). Alkaloids of Vinca major cv. Variegata. Planta Medica 44(2):91–93. https://pubmed.ncbi.nlm.nih.gov/17402086/
19. De Vita D, Frezza C, Sciubba F, Toniolo C, Badiali C, Petrucci R, Bortolami M, Di Matteo P, Rocco D, Stringaro A, Colone M, Maxia A, Petrucci MT, Serafini M, Foddai S (2023). Phytochemical analysis and in vitro antileukemic activity of alkaloid-enriched extracts from Vinca sardoa (Stearn) Pignatti. Molecules 28(15):5639. https://pubmed.ncbi.nlm.nih.gov/37570609/
20. Mann SGA, Paz-Galeano M, Shahsavarani M, Perley JO, Guo J, Garza-Garcia JJO, Qu Y (2025). Stereochemical insights into sarpagan and akuammiline alkaloid biosynthesis. New Phytologist 247(3):1335–1351. https://pubmed.ncbi.nlm.nih.gov/40458973/

View all 20 references▾