Catharanthus roseus · PhytoNexus

01 Identity and provenance

Accepted binomial: Catharanthus roseus
Common names: Periwinkle
Family (APG IV): Apocynaceae
Part used: Leaf
Verification tier: Tier 2 · Verified Clinical columns reviewed and a source is on record.
Reviewer note (2026 audit): NOMENCLATURE WARNING: do NOT confuse with Vinca minor (VERIFIED batch 5), which yields vincamine, a vasodilator - not a cytotoxic. The obsolete synonym "Vinca rosea" for THIS species appears throughout older literature and will cross-contaminate any search keyed on "Vinca".
Reference not supplied - claim unverified against primary literature. | IDENTITY

02 Constituent chemistry

Chemical class	Marker compound	Synthetic analogue in use
Indole alkaloids	Vincristine Leaf	Vinorelbine

The analogue column is what makes the interaction reasoning tractable: where a constituent has a marketed structural counterpart, the counterpart's interaction profile is the starting hypothesis for the plant.

Looking up structures and physicochemical properties from PubChem…

03 Stated application

Reported activity: Hodgkin lymphoma
Marketed in: Vincristine injection
Reported adverse effects: Peripheral neuropathy

04 Interaction matrix

Source column, verbatim: CYP3A4 inhibitors
Normalised onto 1 canonical drug class below.

Curated from the reviewed source

Drug class	Severity	Mechanism type	Provenance	Expected effect
Narrow-therapeutic-index CYP3A4 substrates Pharmacokinetic	4Contraindicated	PK-CYP3A4	curated B	Toxic accumulation or subtherapeutic failure of the co-prescribed drug, s…	why ▾
Chemistry of this pair. Alkaloidal bases have pH-dependent absorption and commonly interact with hepatic CYP isoenzymes and efflux transporters. Class mechanism. Furanocoumarins, bergamottin, piperine, glabridin and berberine inhibit CYP3A4; hyperforin, andrographolide and several diterpenes induce it through PXR. Because CYP3A4 handles roughly half of marketed drugs, the affected list is broad and the direction is product-specific. Expected Toxic accumulation or subtherapeutic failure of the co-prescribed drug, sometimes fatal for antiarrhythmics, immunosuppressants and oncology agents. Management Screen the full regimen for 3A4 substrates. Where the substrate has a narrow index, avoid rather than monitor. Onset unspecified Evidence B - reviewed clinical column, source pending Matched on “cyp3a4 inhibitors” Find evidence for this pair Map this mechanism

Predicted from constituent chemistry

These edges are not clinical findings. Each one is a rule inference: a constituent class in this plant is known to act on a target that the drug class also acts on. They are shown because a blank cell reads as “safe”, and for a Tier 1 entry a blank cell only means “not yet looked at”. Treat them as a literature-search agenda, not as a warning.

Drug class	Severity	Mechanism type	Provenance	Expected effect
Antidepressants (SSRI, SNRI, TCA) CNS	4Contraindicated	PD-additive serotonergic + PK-CYP2D6	predicted D	Serotonin syndrome (agitation, clonus, hyperthermia, autonomic instabilit…	why ▾
Chemistry of this pair. Indole and beta-carboline alkaloids act on monoamine storage, reuptake and oxidation, and several are tubulin poisons. Class mechanism. Hypericin- and hyperforin-type constituents inhibit monoamine reuptake and induce CYP3A4/2C19 and P-glycoprotein; others inhibit CYP2D6, raising tricyclic and SSRI concentrations. Expected Serotonin syndrome (agitation, clonus, hyperthermia, autonomic instability) or loss of antidepressant effect on withdrawal of an inducer. Management Screen for serotonergic burden before adding. Taper rather than stop abruptly. Consider therapeutic drug monitoring for tricyclics. Onset rapid Evidence D - in silico rule prediction only Find evidence for this pair Map this mechanism
Antihypertensives Cardiovascular	4Contraindicated	PD-additive	predicted D	Orthostatic hypotension, dizziness, syncope and falls; or loss of blood-p…	why ▾
Chemistry of this pair. Indole and beta-carboline alkaloids act on monoamine storage, reuptake and oxidation, and several are tubulin poisons. Class mechanism. Vasodilator, diuretic, ACE-inhibitory and calcium-antagonist activity in botanical extracts adds to prescribed blood-pressure lowering. A minority (ephedrine-, glycyrrhizin- and caffeine-bearing) act in the opposite direction and antagonise control. Expected Orthostatic hypotension, dizziness, syncope and falls; or loss of blood-pressure control with pressor botanicals. Management Home BP log for 2 weeks after any change. Warn about postural symptoms; review in the elderly and in those on multiple agents. Onset rapid Evidence D - in silico rule prediction only Find evidence for this pair Map this mechanism
Cytotoxic and targeted anticancer drugs Oncology	4Contraindicated	PK-CYP3A4/UGT + PD-antagonistic	predicted D	Neutropenic sepsis and severe diarrhoea from over-exposure, or reduced an…	why ▾
Chemistry of this pair. Indole and beta-carboline alkaloids act on monoamine storage, reuptake and oxidation, and several are tubulin poisons. Class mechanism. Botanical CYP3A4 and UGT1A1 modulation alters exposure to irinotecan, taxanes, vinca alkaloids and kinase inhibitors. High-dose antioxidant botanicals may also oppose the oxidative mechanism of some cytotoxics and of proteasome inhibitors. Expected Neutropenic sepsis and severe diarrhoea from over-exposure, or reduced antitumour effect; boronic-acid proteasome inhibitors are directly antagonised by polyphenols. Management No botanical should be taken during active cytotoxic therapy without oncology sign-off. Record all supplements in the chemotherapy chart. Onset unspecified Evidence D - in silico rule prediction only Find evidence for this pair Map this mechanism
Monoamine oxidase inhibitors CNS	4Contraindicated	PD-additive	predicted D	Hypertensive crisis, hyperpyrexia, serotonin syndrome, intracranial haemo…	why ▾
Chemistry of this pair. Indole and beta-carboline alkaloids act on monoamine storage, reuptake and oxidation, and several are tubulin poisons. Class mechanism. Beta-carboline (harmine, harmaline) and related botanical alkaloids are themselves reversible MAO-A inhibitors. Combined with a prescribed MAOI, or with tyramine-rich food or sympathomimetics, the pressor and serotonergic reserve is abolished. Expected Hypertensive crisis, hyperpyrexia, serotonin syndrome, intracranial haemorrhage. Management Absolute contraindication. Apply the full MAOI dietary and drug restriction list to the botanical as well. Onset rapid Evidence D - in silico rule prediction only Find evidence for this pair Map this mechanism
Antacids, PPIs and H2 blockers Gastrointestinal	2Moderate	PK-absorption	predicted D	Reduced or erratic absorption of alkaloids; heartburn and reflux from pre…	why ▾
Chemistry of this pair. Alkaloidal bases have pH-dependent absorption and commonly interact with hepatic CYP isoenzymes and efflux transporters. Class mechanism. Gastric pH elevation alters the dissolution and ionisation of alkaloidal and enteric-coated botanical products; menthol- and peppermint-oil products lose their enteric protection at high pH and can be released prematurely. Expected Reduced or erratic absorption of alkaloids; heartburn and reflux from premature release of volatile-oil preparations. Management Separate administration by 2 hours. Avoid non-enteric peppermint oil in reflux disease. Onset unspecified Evidence D - in silico rule prediction only Find evidence for this pair Map this mechanism

05 Hazard register

nomenclature - shares the common name "periwinkle" and the obsol

06 Confusable material

These entries could be mistaken for this one in trade, in the herbarium, or in a prescription. Powdered material is often indistinguishable, so the check is macroscopic, microscopic and chromatographic rather than nominal.

Vinca minor

Lesser Periwinkle

Apocynaceae

Shares the common name "periwinkle"

07 Mechanism map

Chemistry sorts to the left, pharmacology to the right. Dashed edges are predicted. Drag nodes, scroll to zoom, export at 3× for a figure.

species

chemical class

marker compound

drug class

expected effect

hazard

08 Open literature

Abstract-scoped query built from this binomial, its common names and its marker compounds, run live against Europe PMC, PubMed and OpenAlex, then ranked locally against an evidence hierarchy.

Checking openFDA spontaneous reports…

09 Isomechanistic neighbours

Species whose interaction profile overlaps this one, ranked by shared severity weight rather than by count — a shared contraindication counts for more than a shared minor signal. Practical use: these are the plants you should not stack with this one, because the mechanisms summate.

Species	Family	Shared classes	Jaccard
Rauvolfia serpentina Sarpagandha	Apocynaceae	6	1.00
Strychnos nux-vomica Nux Vomica	Loganiaceae	6	0.67
Alstonia scholaris Saptaparna	Apocynaceae	6	1.00
Physostigma venenosum Calabar Bean	Fabaceae	6	0.75
Peganum harmala Syrian Rue	Nitrariaceae	6	0.75
Vinca minor Lesser Periwinkle	Apocynaceae	6	0.75

10 References and notes

No citation is on record for this entry. That is itself the finding: the audit flagged it, and it is why the entry does not carry an A evidence grade.

Curator notes

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