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Cpy2.5

California Poppy Research

Mostly mechanism / observationalModerate safety

4 peer-reviewed studies

What the evidence says

Mostly mechanism / observational

Most California Poppy studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.

Most evidence is from medium-quality randomised trials published 2001–2016 with a typical study size of 264 participants.

Based on 4 studies · 1 RCT · 264 total participants

Confidence

Low

By outcome

Anxiety & stressModest anxiety reduction shown only as part of a fixed hawthorn + magnesium combination, not standalone · Weeks (in combination trial)
Too few graded studies1 study
Safety profile
Too few graded studies1 study

Older research base

Newest study from 2016

200120082016

1RCTn=264 · medium study2004

A fixed combination of hawthorn, California poppy, and magnesium was significantly more effective than placebo for mild-to-moderate anxiety, but the effect cannot be attributed to California poppy alone.

Hanus M, Lafon J, Mathieu M. · Curr Med Res Opin (2004)

264 patients with mild-to-moderate generalized anxiety (Hamilton 16-28), 3-month double-blind RCT
Total Hamilton anxiety dropped more on the combination than placebo (-10.6 vs -8.9, p=0.005)
Tested a fixed COMBINATION (Crataegus + Eschscholtzia + magnesium), so the standalone effect of California poppy is unknown

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2In Vitro2015

California poppy alkaloid (S)-reticuline acted as a positive allosteric modulator at several GABA-A receptor isoforms, providing a molecular basis for the herb's depressant effects.

Fedurco M, Gregorová J, Šebrlová K, et al. · Biochem Res Int (2015)

(S)-reticuline positively modulated alpha3, alpha5, and alpha6 GABA-A receptor isoforms
Supports a GABAergic mechanism for sedation
In-vitro recombinant-receptor study — not human efficacy

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3In Vitro2016

Ethanolic California poppy extract and its alkaloids inhibited several CYP enzymes and activated PXR in vitro, signalling herb-drug interaction potential, whereas the aqueous tea appeared safer.

Manda VK, Ibrahim MA, Dale OR, et al. · Planta Med (2016)

Ethanolic extract showed time-dependent inhibition of CYP3A4, CYP2C9, CYP2C19 and reversible CYP2D6 inhibition
Extract activated the pregnane X receptor (>2-fold)
Aqueous tea and its main alkaloid (californidine) did not affect CYPs or P-glycoprotein

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4Animal2001

The sedative and anxiolytic effects of California poppy extract in mice were suppressed by the benzodiazepine antagonist flumazenil, pointing to benzodiazepine-receptor involvement.

Rolland A, Fleurentin J, Lanhers MC, Misslin R, Mortier F. · Phytother Res (2001)

Extract showed sedative, anxiolytic, and peripheral analgesic effects in mice
Effects blocked by flumazenil, implicating the benzodiazepine receptor
No antidepressant, neuroleptic, or antihistaminic activity

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View in Research Library

California Poppy Research

Mostly mechanism / observational

Double-blind, randomised, placebo-controlled study to evaluate the efficacy and safety of a fixed combination containing two plant extracts (Crataegus oxyacantha and Eschscholtzia californica) and magnesium in mild-to-moderate anxiety disorders.

Modulatory Effects of Eschscholzia californica Alkaloids on Recombinant GABAA Receptors.

Modulation of CYPs, P-gp, and PXR by Eschscholzia californica (California Poppy) and Its Alkaloids.

Neurophysiological effects of an extract of Eschscholzia californica Cham. (Papaveraceae).