Corydalis decumbens
StarCorydalis decumbens
Synonyms: Corydalis kelungensis, Pistolochia decumbens, Corydalis amabilis, Corydalis gracilipes, Corydalis edulioides var. haimensis, Fumaria decumbens, Capnoides decumbens, Corydalis decumbens var. zhujiensis, Corydalis edulioides, Corydalis decumbens f. albescens
Safety at a glance
No rule in our tables for this herb: pregnancy, breastfeeding, incompatible pairs (十八反 / 十九畏), herb–drug, dose ceiling. This is not a safety clearance.
Not graded — No toxicity grade is recorded. Most herbs in the catalogue carry none.
Traditionally used for
- Pain & joints
Cautions & contraindications
- Heart conditions
- Seizure disorders
Western Herbalism Properties
Botanical Description
Corydalis decumbens (Papaveraceae), known in Chinese medicine as xia tian wu, is a small, delicate perennial herb that grows decumbent (creeping) along forest floors, meadows, and roadsides. It arises from a small subglobose tuber and produces slender, weak stems bearing finely divided, ternately compound leaves with narrow, blue-green segments. The small tubular flowers are pale, white tinged with pink and blue, borne in short racemes, and have the characteristic spurred form of the genus. The fruit is a slender capsule. The tuber differs from related Corydalis species in having a whitish, powdery cross-section rather than a bright-yellow waxy one. The species is native to lowland regions of southern and eastern China and Japan, where the tubers are dug in winter or early spring.
Active Constituents
Bicuculline
Phthalideisoquinoline alkaloidConcentration: One of four alkaloids routinely quantified in the tuber by HPLC for quality control, and confirmed by HPLC-MS as an active constituent of the crude drug
Bicuculline is the standard laboratory GABA-A receptor antagonist and a convulsant; it is the compound used to induce seizures experimentally. Its presence as a routinely assayed constituent of this drug is the single most safety-relevant fact in this monograph. Plant bicuculline is poorly brain-penetrant after oral dosing and no herb-induced seizure has been reported, but the drug should not be treated as pharmacologically inert in patients with a lowered seizure threshold.
Protopine
Protopine alkaloidConcentration: One of four alkaloids quantified in the tuber by the published HPLC quality-control method
A protopine-type alkaloid common to the Papaveraceae with sedative, antispasmodic and calcium channel activity. It is a quality marker for the drug rather than a compound whose contribution to the drug's effect has been separately demonstrated.
Tetrahydropalmatine
Tetrahydroprotoberberine alkaloidConcentration: One of four alkaloids quantified in the tuber by the published HPLC quality-control method
The same analgesic and sedative alkaloid that dominates Yan Hu Suo, present here as a minor rather than a principal constituent. Its presence is why this drug shares part of the Yan Hu Suo interaction profile, including additive sedation with central nervous system depressants.
Palmatine
Quaternary protoberberine alkaloidConcentration: One of four alkaloids quantified in the tuber by the published HPLC quality-control method, determined as the hydrochloride
A quaternary protoberberine used as a chromatographic marker for the drug. Being permanently charged it is poorly absorbed orally, so its analytical prominence overstates its systemic contribution.
alpha-Allocryptopine
Protopine-type alkaloidConcentration: Extracted from this species and developed as a cardiac-active compound; not part of the routine four-alkaloid assay
The cardiac-active alkaloid of this drug. It blocks the transient outward potassium current in rabbit ventricular myocytes with an IC50 of 37 micromolar, reducing transmural dispersion of repolarisation, suppresses isoproterenol-induced delayed afterdepolarisations and triggered activity in mouse cardiomyocytes, and blocks hERG with an IC50 of 49.65 micromolar. Potassium channel block cuts both ways: it is the basis of the antiarrhythmic claim and also the reason the drug warrants caution alongside QT-prolonging medication.
Phthalideisoquinoline hemiacetal alkaloids including alkyl derivatives of egenine and corydecumine G
Phthalideisoquinoline alkaloidsConcentration: Eight isolated from the tubers, six of them active in the calcium oscillation assay at low micromolar concentrations
The structural class that distinguishes this drug from other Corydalis tubers. Six of eight isolates suppressed spontaneous calcium oscillations in primary cultured neocortical neurons with IC50 values from 3.1 to 11.6 micromolar, which is a plausible mechanism for the drug's use in pain and neurological complaints. Corydecumine G, one of this class, reduced mechanical and thermal allodynia and spinal microglial activation in nerve-injured rats.
Berberine and jatrorrhizine
Protoberberine alkaloidsConcentration: Confirmed by HPLC-MS among the active ingredients of the crude drug in a 2025 network pharmacology study
Minor protoberberines identified in the crude drug alongside bicuculline and ferulic acid. Their presence means berberine-related interaction concerns apply to this drug in weaker form, but the quantities are far below those in Coptis and no berberine-specific interaction has been demonstrated with this herb.
Polysaccharides
PolysaccharideConcentration: Two polysaccharides characterised after extraction optimisation; no content specification established
Two structurally characterised polysaccharides with reported bioactivity. They are not the constituents behind the drug's traditional indications and are not used for quality control, but they do mean a water decoction differs materially from an alkaloid extract.
⚠ Drug Interactions
CYP1A2 and CYP3A4 substrates including theophylline, clozapine, olanzapine, midazolam, simvastatin and calcium channel blockers
A five-probe cocktail study in rats given this herb by gavage for seven days found inhibition of CYP1A2 and CYP3A4 activity, with no significant effect on CYP2C9 or CYP2D6. Inhibition of these two enzymes would raise plasma concentrations of drugs that depend on them for clearance. The study is in rats with a crude extract and has not been repeated in people, so the direction of the effect is better supported than its size.
Clinical note: Where a patient is on a narrow-therapeutic-index CYP3A4 or CYP1A2 substrate, monitor for exaggerated effect after starting this herb. Theophylline and clozapine levels deserve particular attention because both have narrow margins and are CYP1A2-dependent.
CYP2C19 substrates including omeprazole, voriconazole, clopidogrel and escitalopram
The same rat cocktail study found induction rather than inhibition of CYP2C19. Induction lowers exposure to CYP2C19 substrates, which would weaken acid suppression by omeprazole or antifungal cover by voriconazole. Clopidogrel is the exception: it is a prodrug activated by CYP2C19, so induction would be expected to increase rather than reduce its antiplatelet effect. Rat data with a crude extract; no human confirmation.
Clinical note: Consider loss of effect for CYP2C19-cleared drugs, and increased bleeding risk in the specific case of clopidogrel. Neither has been measured in people, so monitor clinical response rather than adjusting doses pre-emptively.
QT-prolonging drugs and class III antiarrhythmics including amiodarone, sotalol and macrolide antibiotics
alpha-Allocryptopine, an alkaloid of this species, blocks the transient outward potassium current in rabbit ventricular myocytes with an IC50 of 37 micromolar and the hERG current in transfected HEK293 cells with an IC50 of 49.65 micromolar, prolonging recovery from inactivation. The Chinese work frames this as the mechanism of an antiarrhythmic effect, and the compound does suppress delayed afterdepolarisations, but the same channel block is the mechanism of drug-induced QT prolongation. Micromolar in vitro potency and no human electrocardiographic data leave the clinical size unknown.
Clinical note: Avoid stacking with drugs that already prolong the QT interval, and be cautious in patients with known long QT syndrome, significant bradycardia or electrolyte disturbance. If the herb is used in a cardiac patient, an electrocardiogram before and during treatment is a reasonable precaution.
Antiepileptic drugs and drugs that lower the seizure threshold including tramadol, bupropion and clozapine
Bicuculline, a competitive GABA-A receptor antagonist used in the laboratory precisely because it reliably induces seizures, is one of the four alkaloids quantified for quality control in this drug and was confirmed by HPLC-MS as an active constituent. Antagonising GABA-A would in principle oppose the action of benzodiazepines and barbiturates and add to the seizure risk of proconvulsant drugs. Against this, orally administered plant bicuculline reaches the brain poorly and no seizure attributable to this herb has been reported. Absence of a reported case is not evidence that the risk is zero, particularly for concentrated extracts and injectable preparations.
Clinical note: Avoid in epilepsy and in patients on proconvulsant drugs, and do not use concentrated extracts in these patients at all. This is a precaution drawn from the drug's known composition rather than from any reported human event.
Yan Hu Suo (Corydalis yanhusuo tuber)
This species and Corydalis yanhusuo are the two best known Corydalis drugs in the Chinese Pharmacopoeia, and DNA barcoding work states plainly that authentication of these species remains problematic because of their high morphological variation, with several traditionally recognised Corydalis species collapsing into single genetic species under barcode gap analysis. The two drugs are not interchangeable: tetrahydropalmatine is the principal alkaloid of Yan Hu Suo but only a minor one here, while bicuculline and alpha-allocryptopine, which drive this drug's safety profile, are not the Yan Hu Suo story at all.
Clinical note: Confirm which Corydalis drug has been supplied before dispensing, and do not accept one against a prescription for the other. Morphological identification alone is not reliable for this genus.
Dosage Calculator
⚖ Dosage Calculator
A weight-based mathematical estimate for Corydalis decumbens. Not a prescription.
Evidence Tier
7 studies on recordRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
7
3 verified · 4 unverified
Show 7 studies
- Influences of Corydalis decumbens on the Activities of CYP450 Enzymes in Rats with a Cocktail Approach
- Phthalideisoquinoline Hemiacetal Alkaloids from Corydalis decumbens That Inhibit Spontaneous Calcium Oscillations, Including Alkyl Derivatives of (+)-Egenine That Are Strikingly Levorotatory
- Corydecumine G inhibits microglia activation via MAPK pathway in a rat model of neuropathic pain
- Structures, biomimetic synthesis, and anti-SARS-CoV-2 activity of two pairs of enantiomeric phenylpropanoid-conjugated protoberberine alkaloids from the rhizomes of Corydalis decumbens
- Effect of α-Allocryptopine on Transient Outward Potassium Current in Rabbit Ventricular Myocytes
- Allocryptopine and benzyltetrahydropalmatine block hERG potassium channels expressed in HEK293 cells
- Integrating network pharmacology and experimental validation via PPAR signaling to ameliorate rheumatoid arthritis: Insights from Corydalis Decumbentis Rhizoma (Xiatianwu)
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Influences of Corydalis decumbens on the Activities of CYP450 Enzymes in Rats with a Cocktail Approach
Rats received this herb by gavage for seven days, then a probe cocktail of phenacetin, omeprazole, metoprolol, tolbutamide and midazolam measured by validated UHPLC-MS/MS. The herb induced CYP2C19 and inhibited CYP1A2 and CYP3A4, with no significant effect on CYP2C9 or CYP2D6. The authors recommend monitoring and dose adjustment for co-administered drugs cleared by CYP1A2, CYP2C19 or CYP3A4. Rat study with a crude extract; no human herb-drug interaction study of this herb exists.
Phthalideisoquinoline Hemiacetal Alkaloids from Corydalis decumbens That Inhibit Spontaneous Calcium Oscillations, Including Alkyl Derivatives of (+)-Egenine That Are Strikingly Levorotatory
Six new and two known phthalideisoquinoline hemiacetal alkaloids were isolated from the tubers of this species, described in the paper as bulbs, and characterised by NMR, chemical degradation, X-ray crystallography and calculated ECD. Six of the eight suppressed spontaneous calcium oscillations in primary cultured neocortical neurons with IC50 values of 3.1 to 11.6 micromolar. The paper also warns that optical rotation and coupling constants alone can misassign absolute configuration in this alkaloid class. Isolated-compound in vitro work.
Corydecumine G inhibits microglia activation via MAPK pathway in a rat model of neuropathic pain
Corydecumine G, a phthalide isoquinoline from Corydalis Decumbentis Rhizoma, given intraperitoneally to rats with chronic constriction sciatic nerve injury, concentration-dependently reduced mechanical and thermal allodynia, suppressed p38 and ERK phosphorylation and spinal microglial activation, and lowered nitric oxide, iNOS, TNF-alpha and PGE2 in the dorsal horn; it also blunted LPS-induced BV2 microglial activation at 30 micromolar. A separate 2022 paper reporting analgesic effects of this herb in a mouse neuropathic pain model has since been retracted and should not be cited alongside this one.
Structures, biomimetic synthesis, and anti-SARS-CoV-2 activity of two pairs of enantiomeric phenylpropanoid-conjugated protoberberine alkaloids from the rhizomes of Corydalis decumbens
Two pairs of enantiomeric phenylpropanoid-conjugated protoberberine alkaloids, decumicorine A and epi-decumicorine A, were isolated from the rhizomes and resolved by chiral HPLC; their biosynthesis by Diels-Alder cycloaddition between jatrorrhizine and ferulic acid was confirmed by biomimetic synthesis. One enantiomer blocked SARS-CoV-2 pseudovirus entry by interfering with spike binding to ACE2 on engineered cells. Pseudovirus and cell-line work; this is not evidence that the herb treats COVID-19.
Effect of α-Allocryptopine on Transient Outward Potassium Current in Rabbit Ventricular Myocytes
Whole-cell patch clamp in isolated rabbit left ventricular myocytes showed alpha-allocryptopine reducing the transient outward potassium current concentration-dependently from 1 to 100 micromolar with an IC50 of 37 micromolar, shortening inactivation time constants and reducing transmural dispersion of the current from 11.2 to 4.7 pA per pF at 30 micromolar. The authors read this as the mechanism of an antiarrhythmic effect. Isolated myocyte study of a single alkaloid, not of the herb.
Allocryptopine and benzyltetrahydropalmatine block hERG potassium channels expressed in HEK293 cells
Allocryptopine, stated in the paper to be extracted from Corydalis decumbens, reversibly suppressed hERG current amplitude and density in transfected HEK293 cells concentration- and voltage-dependently with an IC50 of 49.65 micromolar, and lengthened recovery from inactivation, without shifting steady-state inactivation. It reduced current density in the late phase of the action potential waveform. Patch-clamp study of an isolated alkaloid, at concentrations well above anything a decoction is likely to achieve.
Integrating network pharmacology and experimental validation via PPAR signaling to ameliorate rheumatoid arthritis: Insights from Corydalis Decumbentis Rhizoma (Xiatianwu)
In a TNF-alpha-stimulated cell model of rheumatoid arthritis, this herb dose-dependently lowered IL-6, IL-1beta, interferon-gamma, MMP-2, malondialdehyde and reactive oxygen species and raised PPAR-gamma protein, an effect reversed by the PPARG antagonist GW9662. Network pharmacology nominated RXRA, PPARG and PPARA as targets, and HPLC-MS confirmed bicuculline, ferulic acid, berberine and jatrorrhizine as constituents of the extract. Cell-culture work with computational target prediction; no animal or human arthritis endpoint.
Historical Texts
Pharmacopoeia of the People's Republic of China, Corydalis Decumbentis Rhizoma
Modern, current editionsChinese folk medicine of the southeastern provinces
Pre-modern folk use, formalised in the twentieth centuryReferences
- Y. Shen, C. Han, B. Xia, Y. Zhou, C. Liu, A. Liu. Determination of four alkaloids in Corydalis decumbens by HPLC . China Journal of Chinese Materia Medica (2011) [DOI]
- Jin-Sheng Zhang. Isoquinoline alkaloids, decumbenine B and C, from Corydalis decumbens . Phytochemistry (1995) [DOI]
- Lu Jiang, Meihui Li, Fengxi Zhao, Shanshan Chu, Liangping Zha, Tao Xu, Huasheng Peng, Wei Zhang. Molecular Identification and Taxonomic Implication of Herbal Species in Genus Corydalis (Papaveraceae) . Molecules (2018) [DOI]
- Bin Xu, Yicheng Fu, Li Liu, Kun Lin, Xiaojing Zhao, Yu Zhang, Xi Chen, Zhongqi Cai, Yun Huang, Yang Li. Effect of α-Allocryptopine on Delayed Afterdepolarizations and Triggered Activities in Mice Cardiomyocytes Treated with Isoproterenol . Evidence-Based Complementary and Alternative Medicine (2015) [DOI]
- Zhaojing Wang, Dianhui Luo. Extraction optimization, structure features, and bioactivities of two polysaccharides from Corydalis decumbens . PLOS ONE (2023) [DOI]
- Shanmin Huang, Xuehua Zheng, Weiguo Dong, Yao Lin, Shu Jiang, Haiyin Zheng, Changhui Qian. Corydalis decumbens Alleviates the Migration, Phagocytosis, and Inflammatory Response of Macrophages . Evidence-Based Complementary and Alternative Medicine (2023) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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