Agnuside

Pharmacology & Research

Agnuside is an iridoid glucoside — p-hydroxybenzoyl aucubin ^{12Reference 12Kurüzüm-Uz A et al. · 2003Glucosides from Vitex agnus-castusView study →} — and, alongside casticin, one of the two HPLC standardisation markers of chaste-tree fruit. The load-bearing distinction mirrors casticin’s: agnuside is a QC marker, and Vitex agnus-castus’s human PMS/mastalgia/prolactin evidence belongs to the herb’s dopaminergic diterpene extract, not to agnuside. Two things separate it from casticin, though: its own isolate signal is anti-inflammatory/anti-arthritic (not anticancer — in the one Vitex chemoprevention screen the active was vitetrifolin D, not agnuside ^{9Reference 9Li S et al. · 2013Compounds from Vitex agnus-castus fruits in chemoprevention via NQO1 induction (active = vitetrifolin D, not agnuside)View study →}), and it has no antimitotic mechanism. Its literature is thin but coherent, and entirely preclinical.

1. Anti-inflammatory / anti-arthritic

The strongest and most reproducible part of the file: agnuside reduced PGE₂/LTB₄ and Th1/Th2 cytokines in rat polyarthritis (effect retained in adrenalectomised rats, so not HPA-mediated) ^{1Reference 1Pandey A et al. · 2012Anti-arthritic activity of agnuside mediated through downregulation of inflammatory mediators and cytokinesView study →}, suppressed HIF-1α and the NLRP3 inflammasome (caspase-1/ASC → IL-1β/IL-18) with reduced synovial fibrosis in knee-osteoarthritis rats ^{2Reference 2Zhang L et al. · 2021Agnuside alleviates synovitis and fibrosis in knee osteoarthritis through inhibition of HIF-1α and the NLRP3 inflammasomeView study →}, preferentially inhibited COX-2 in vitro (sparing COX-1) ^{4Reference 4Suksamrarn A et al. · 2002Iridoids with anti-inflammatory activity from Vitex peduncularis (agnuside preferential COX-2 inhibition)View study →}, and modulated NF-κB/PI3K-Akt/p38/Stat3, autophagy and Tregs in allergic-asthma mice ^{3Reference 3Tirpude NV et al. · 2022Agnuside mitigates OVA-LPS-induced perturbed lung homeostasis in allergic asthmaView study →}.

Gap: all animal/in-vitro with no human isolate data, and two of the studies use V. negundo rather than chaste-tree ^{1,2Reference 1Pandey A et al. · 2012Anti-arthritic activity of agnuside mediated through downregulation of inflammatory mediators and cytokinesView study →Reference 2Zhang L et al. · 2021Agnuside alleviates synovitis and fibrosis in knee osteoarthritis through inhibition of HIF-1α and the NLRP3 inflammasomeView study →}.

2. Analgesic

Analgesia is repeatedly described for agnuside and is embedded in the anti-arthritic/osteoarthritis models (paw inflammation, COX-2, vascular-permeability and leukocyte-migration inhibition) ^{1,2,4Reference 1Pandey A et al. · 2012Anti-arthritic activity of agnuside mediated through downregulation of inflammatory mediators and cytokinesView study →Reference 2Zhang L et al. · 2021Agnuside alleviates synovitis and fibrosis in knee osteoarthritis through inhibition of HIF-1α and the NLRP3 inflammasomeView study →Reference 4Suksamrarn A et al. · 2002Iridoids with anti-inflammatory activity from Vitex peduncularis (agnuside preferential COX-2 inhibition)View study →}.

Gap: no dedicated antinociceptive isolate assay surfaced — the signal is inferred from inflammation endpoints, plausibly secondary to the COX-2 action ^{1Reference 1Pandey A et al. · 2012Anti-arthritic activity of agnuside mediated through downregulation of inflammatory mediators and cytokinesView study →}.

3. Neuroprotective

In an AlCl₃-induced Alzheimer’s rodent study, agnuside improved neuronal survival and cognition via PI3K/AKT/mTOR, with antioxidant/anti-inflammatory/anticholinesterase readouts ^{7Reference 7Gnanarajan R et al. · 2025Agnuside enhances neuronal survival and cognitive function via PI3K/AKT/mTOR in AlCl₃-induced Alzheimer’s diseaseView study →}.

Gap: a single study in one model, from one group — hypothesis-generating only ^{7Reference 7Gnanarajan R et al. · 2025Agnuside enhances neuronal survival and cognitive function via PI3K/AKT/mTOR in AlCl₃-induced Alzheimer’s diseaseView study →}.

4. Metabolic / thermogenic

A 2026 mechanistic study found agnuside binds and stabilises the complex-I assembly factor NDUFAF6, reinforcing mitochondrial respiratory-complex assembly and demand-dependent brown/beige-fat thermogenesis ^{8Reference 8Zhao Q et al. · 2026Agnuside stabilises the complex-I assembly factor NDUFAF6 to reinforce mitochondrial efficiency and thermogenic responsivenessView study →}.

Gap: a single high-quality mechanistic paper on a novel target, with no translation and distinct from the anti-inflammatory literature ^{8Reference 8Zhao Q et al. · 2026Agnuside stabilises the complex-I assembly factor NDUFAF6 to reinforce mitochondrial efficiency and thermogenic responsivenessView study →}.

Mechanisms

Target / pathway	Effect	Relevant to
COX-2 (preferential; spares COX-1)	inhibited in vitro	anti-inflammatory / analgesic
PGE₂, LTB₄; vascular permeability; leukocyte migration	reduced	anti-arthritic
HIF-1α; NLRP3 inflammasome (caspase-1, ASC) → IL-1β, IL-18	suppressed	osteoarthritis synovitis/fibrosis
NF-κB, PI3K/Akt, p38, Stat3; autophagy; Tregs	modulated	allergic asthma / immune
PI3K/AKT/mTOR; acetylcholinesterase	pro-survival; inhibited	neuroprotection
NDUFAF6 → mitochondrial complex-I assembly	stabilised → thermogenesis	metabolic
P-glycoprotein ATPase	inhibited in vitro	theoretical herb–drug interaction
Fe²⁺/ascorbate lipid peroxidation	enhanced (pro-oxidant)	antioxidant caveat

Pharmacokinetics

Agnuside is a typical poorly-absorbed iridoid glucoside. The only isolate pharmacokinetic study (mice) reports absolute oral bioavailability ~0.7%, with greatest accumulation in the intestine ^{5Reference 5Ramakrishna R et al. · 2016AnimalPlasma pharmacokinetics, bioavailability and tissue distribution of agnuside in mice by LC-MS/MSView study →}; as an aucubin-type glucoside it is subject to intestinal β-glucosidase hydrolysis — agnuside is p-hydroxybenzoyl aucubin, so hydrolysis liberates aucubin plus p-hydroxybenzoic acid (the latter co-quantified in QC assays ^{13Reference 13Shah S et al. · 2013Validated HPLC method for p-hydroxybenzoic acid and agnuside in Vitex negundo and V. trifolia (QC marker)View study →}) — consistent with very low intact systemic exposure. It inhibits P-glycoprotein ATPase in vitro ^{11Reference 11Najar IA et al. · 2010Modulation of P-glycoprotein ATPase activity by some phytoconstituents (agnuside inhibitory)View study →}. Human data are limited to a single-volunteer plasma-assay demonstration (an analytical method paper, not an efficacy study) ^{6Reference 6Egeli D et al. · 2025Quantification of agnuside in human plasma with a novel HPLC method and a single-volunteer pharmacokinetic studyView study →}, and at herb-relevant intake (~0.09 mg/day marker quantity) systemic agnuside is negligible.

Clinical trials

There are no efficacy trials of the isolate. Agnuside has never been given to humans as a single compound therapeutically; the only human exposure on record is a single-volunteer plasma-assay demonstration ^{6Reference 6Egeli D et al. · 2025Quantification of agnuside in human plasma with a novel HPLC method and a single-volunteer pharmacokinetic studyView study →}. All human Vitex agnus-castus trials (PMS, mastalgia, cyclical breast pain, hyperprolactinaemia, PCOS) tested the whole standardised fruit extract, with effects attributed to the dopaminergic diterpene fraction — agnuside serves only as an HPLC standardisation marker there ^{14Reference 14Wuttke W et al. · 2003Chaste tree (Vitex agnus-castus) — pharmacology and clinical indicationsView study →}.

Last checked: July 2026.

Toxicity & Safety

Agnuside is repeatedly characterised as a nontoxic iridoid glucoside — no cytotoxicity against Vero cells, oral efficacy at low doses (~6.25 mg/kg in rodents), and trivial human marker exposure (~0.09 mg/day) — supporting a [low] flag, and unlike casticin it has no antimitotic/tubulin mechanism and so no intrinsic cytotoxic-class concern. Two honest caveats keep the rating from being “none”: a pro-oxidant signal (enhanced Fe²⁺/ascorbate lipid peroxidation) in one direct assay ^{10Reference 10Najar IA et al. · 2016Effect of some phytoconstituents on Fe²⁺/ascorbate-induced lipid peroxidation (agnuside pro-oxidant)View study →}, so “antioxidant” should be read as an indirect disease-model observation rather than a direct scavenging property; and in-vitro P-glycoprotein inhibition ^{11Reference 11Najar IA et al. · 2010Modulation of P-glycoprotein ATPase activity by some phytoconstituents (agnuside inhibitory)View study →} implying a theoretical herb–drug-interaction potential.

Pregnancy & lactation

Avoid. The caution rests on the source herb rather than an intrinsic agnuside mechanism: chaste-tree is hormonally active (dopaminergic, prolactin-lowering) and is itself cautioned in pregnancy and lactation, and there are no reproductive-safety data for the isolate.

Dosage

There is no established human dose — agnuside has never been given to humans as an isolate for therapy, and all dosing is preclinical (µM in vitro; ~6.25 mg/kg oral in rodents ^{2Reference 2Zhang L et al. · 2021Agnuside alleviates synovitis and fibrosis in knee osteoarthritis through inhibition of HIF-1α and the NLRP3 inflammasomeView study →}) that does not translate. As a chaste-tree constituent, incidental intake is ~0.09 mg/day from a standardised daily dose — a QC-marker quantity, not a therapeutic one.

References