Vitex agnus-castus · PhytoNexus

01 Identity and provenance

Accepted binomial: Vitex agnus-castus
Common names: Chaste Tree
Family (APG IV): Lamiaceae
Part used: Fruit
Verification tier: Tier 2 · Verified Clinical columns reviewed and a source is on record.
Reviewer note (2026 audit): Front Endocrinol 2023;14:1269781. doi:10.3389/fendo.2023.1269781 | Drugs.com NPP Chaste Tree monograph | VERIFIED 2026 - synthetic analogue, application, interactions, side effects and references populated from retrieved primary/regulatory sources (see References). Interaction entries are labelled CLINICAL (case reports or trials in humans) vs THEORETICAL (in-vitro or animal only). Marketed-formulation column intentionally left blank. | INTERACTION

02 Constituent chemistry

Chemical class	Marker compound	Synthetic analogue in use
Iridoid glycosides	Agnuside Fruit	Bromocriptine, Cabergoline (FUNCTIONAL - dopamine D2 receptor agonism lowering prolactin). No structural analogue.

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: Premenstrual syndrome, PMDD, cyclical mastalgia, menstrual irregularity and latent hyperprolactinaemia. Clerodadienol-type diterpenes bind pituitary D2 receptors and suppress prolactin release.
Reported adverse effects: Gastrointestinal upset, headache, dizziness, acne, rash. Avoid in pregnancy and breastfeeding. Caution in hormone-sensitive conditions.

04 Interaction matrix

Source column, verbatim: CLINICAL: dopamine agonists and antagonists (antipsychotics, metoclopramide). HORMONAL - the Australian TGA issued a safety advisory (2 May 2019) on potential interaction with oral contraceptives; reduced contraceptive efficacy cannot be excluded. Health Canada carries warnings on hormone-containing medicines.
Normalised onto 2 canonical drug classes below.

Curated from the reviewed source

Drug class	Severity	Mechanism type	Provenance	Expected effect
Antipsychotics CNS	3Major	PD-additive + PK-CYP	curated A	Extrapyramidal symptoms, QT prolongation, excess sedation, or loss of ant…	why ▾
Class mechanism. Additive dopaminergic blockade, QT prolongation and sedation, plus CYP1A2, 2D6 and 3A4 modulation of clozapine, risperidone and quetiapine exposure. Expected Extrapyramidal symptoms, QT prolongation, excess sedation, or loss of antipsychotic control with inducers. Management ECG if other QT-prolonging agents are present. Consider clozapine level monitoring where inducers are stopped or started. Onset rapid Evidence A - human data with a cited source Matched on “antipsychotics” Find evidence for this pair Map this mechanism
Hormonal therapy, oral contraceptives and HRT Endocrine	3Major	PK-CYP3A4 induction + PD-oestrogenic	curated A	Breakthrough bleeding and contraceptive failure; unpredictable effect in …	why ▾
Class mechanism. CYP3A4-inducing botanicals accelerate ethinylestradiol and progestin clearance. Separately, isoflavone, lignan and coumestan phyto-oestrogens bind oestrogen receptors and may add to or compete with prescribed hormones. Expected Breakthrough bleeding and contraceptive failure; unpredictable effect in hormone-sensitive malignancy. Management Advise a second, non-hormonal contraceptive method. Avoid phyto-oestrogens in oestrogen-receptor-positive breast cancer without oncology advice. Onset delayed Evidence A - human data with a cited source Matched on “oral contraceptives” Find evidence for this pair Map this mechanism

05 Hazard register

hormonal - TGA advisory on oral-contraceptive efficacy.

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.

Vitex negundo

Nirgundi

Lamiaceae

Same genus (Vitex)

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
Serenoa repens Saw Palmetto	Arecaceae	1	0.25
Gymnema sylvestre Gurmar	Apocynaceae	1	0.25
Tribulus terrestris Gokshura	Zygophyllaceae	1	0.25
Achyranthes aspera Apamarga	Amaranthaceae	1	0.25
Sapindus mukorossi Reetha	Sapindaceae	1	0.25
Sesamum indicum Til (Sesame)	Pedaliaceae	1	0.25

10 References and notes

Source column: TGA safety advisory, 2 May 2019 (oral contraceptive interaction)

TGA safety advisory, 2 May 2019 (oral contraceptive interaction)

2019 manual

BibTeX for all 1 records

@article{anon2019,
  title = {TGA safety advisory, 2 May 2019 (oral contraceptive interaction)},
  year = {2019},
}

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