Canadine

Other Names

(R)-Canadine(R)-Tetrahydroberberine(S)-Canadine(S)-Tetrahydroberberine16,17-dimethoxy-5,7-dioxa-13-azapentacyclo[11.8.0.02,10.04,8.015,20]henicosa-2,4(8),9,15(20),16,18-hexaene5,8,13,13a-Tetrahydro-9,10-dimethoxy-6H-benzo[g]-1,3-benzodioxolo[5,6-a]quinolizine9,10-Dimethoxy-5,8,13,13a-tetrahydro-6H-[1,3]dioxolo[4,5-g]isoquinolino[3,2-a]isoquinolineBerberine, 9-deoxy-16,17-dihydro-Berberine, tetrahydro-Berbine, 9,10-dimethoxy-2,3-(methylenedioxy)-dl-Canadinedl-Tetrahydroberberinel-TetrahydroberberineNSC 36351NSC 94918TetrahydroberberineTetrahydroumbellatineTHBXanthopuccine

Synopsis

Canadine (Tetrahydroberberine): A Comprehensive Reference

1. Identity: Chemical and Botanical Profile

1.1 Names and Chemical Classification

Canadine, also known as (S)-tetrahydroberberine and xanthopuccine, is a benzylisoquinoline alkaloid (BIA), of the protoberberine structural subgroup, and is present in many plants from the family Papaveraceae, such as Corydalis yanhusuo and C. turtschaninovii. It is widely abbreviated in the scientific literature as THB (tetrahydroberberine). Additional synonyms include canadin, and it carries the IUPAC chemical names 16,17-dimethoxy-5,7-dioxa-13-azapentacyclo[11.8.0.02,10.04,8.015,20]henicosa-2,4(8),9,15(20),16,18-hexaene, with a molecular formula of C₂₀H₂₁NO₄ and a molecular weight of 339.39 Da. Its CAS number is 522-97-4 and it appears in PubChem as CID 34458.

The systematic IUPAC name of tetrahydroberberine is 9,10-dimethoxy-5,8,13,13a-tetrahydro-6H-benzo[g][1,3]benzodioxolo[5,6-a]quinolizine, and it has been crystallized as a racemic mixture about an inversion center. The crystal structure of racemic tetrahydroberberine shows intermolecular 1,3-benzodioxole –CH₂⋯OCH₃ and –OCH₃⋯OCH₃ interactions; it is a widely distributed naturally occurring alkaloid.

As a protoberberine, canadine belongs to the same structural family as berberine, palmatine, and coptisine, but is distinguished by having a fully reduced (saturated) D-ring, which confers distinct receptor pharmacology and significantly different biological properties compared to its oxidized counterpart, berberine.

1.2 Stereochemistry and Enantiomers

Metabolically, (S)-canadine is derived from (S)-reticuline, a pivotal intermediate in the biosynthesis of numerous BIA structural subgroups, through three enzymatic steps: (1) berberine bridge enzyme to (S)-scoulerine; (2) (S)-scoulerine 9-O-methyltransferase to (S)-tetrahydrocolumbamine; and (3) (S)-canadine synthase/CYP719A21 to (S)-canadine. In Corydalis cava, the enzyme berberine reductase converts berberine back to canadine but as the (R) enantiomer of the product — a type of stereochemical inversion that allows both enantiomers to be present in this species.

Metabolically, (S)-canadine is the immediate precursor of berberine, which is produced through the action of the enzyme tetrahydroberberine oxidase. It is also an intermediate in the biosynthesis of noscapine, which is likewise a benzylisoquinoline alkaloid, but of the phthalideisoquinoline structural subgroup.

1.3 Principal Botanical Sources

Canadine occurs across multiple plant genera, most prominently:

Corydalis yanhusuo W.T. Wang (Papaveraceae) — the most commercially and medicinally significant source. Also known as Rhizoma Corydalis (RC), YuanHu, YanHu, or XuanHu in China, it is a well-known traditional Chinese medicine prepared from the dried tubers of Corydalis yanhusuo. Tetrahydroberberine is among the protoberberine alkaloids obtained from the crude basic fraction of Corydalis species.
Hydrastis canadensis L. (Ranunculaceae/Buttercup family) — Goldenseal. The plant contains isoquinoline alkaloids such as hydrastine, berberine, berberastine, hydrastinine, tetrahydroberberastine, canadine, and canalidine; the three major alkaloids are berberine, hydrastine, and canadine.
Corydalis cava and related Corydalis spp. Canadine is a derivative of berberine isolated from Corydalis cava (Papaveraceae).
Berberis spp. Tetrahydroberberine, also known as canadine and xanthopuccine, is a naturally occurring alkaloid that occurs in widely distributed shrubs, both deciduous and evergreen, of the genus Berberis.

The Corydalis genus occurs in the northern hemisphere, and nearly 70 species have been used in traditional herbal medicines in China, Japan, and Korea.

1.4 Concentration in Plant Material

Canadine is an alkaloid found in goldenseal in lesser amounts compared to its principal alkaloids. Commercial samples of goldenseal yield 1.5–4% hydrastine and 0.5–6.0% berberine, with canadine present at lower concentrations. In Corydalis, 41 protoberberine compounds have been identified; the group includes tertiary amine bases such as tetrahydroberberine and quaternary ammonium bases such as berberine, all of which have significant analgesic effects.

1.5 Common Forms and Preparations

Canadine is encountered in several product forms:

Crude dried tuber or rhizome powder — The dried powder of tubers of Corydalis yanhusuo is used in traditional Chinese medicine to cure gastric and duodenal ulcers, cardiac arrhythmia diseases, rheumatism, and dysmenorrhea.
Vinegar- or wine-processed herbal preparations — Before being used in clinics, C. yanhusuo is traditionally processed through dry-frying or frying with vinegar, wine, or salt. In water decoctions, wine and vinegar processing increase the amount of tertiary alkaloids; the differences are more pronounced for certain formulas, in which the content of all tertiary alkaloids (including tetrahydroberberine) is increased by wine processing.
Water decoctions — prepared by boiling the tuber in water, a standard approach in TCM clinical practice.
Standardized extracts — modern preparations isolate or enrich for specific alkaloids; research preparations used in pharmacological studies employ isolated THB, typically as a racemic mixture or as the pure (S)- or levo-enantiomer.
Goldenseal root extract or tincture — standardized to total alkaloid content per the British Pharmacopoeia/European Pharmacopoeia. The BP/EP requires a minimum content of 2–5% (dried drug) for hydrastine and a minimum of 3.0% for berberine.

2. Traditional and Historical Use

2.1 Native American Traditions (Goldenseal)

Goldenseal is a plant native to the northeastern United States and southeastern Canada, with a bright yellow rhizome. Historically, Native Americans used goldenseal to treat a variety of conditions, such as digestive disorders, wounds, skin and eye conditions, and cancer. Native Americans have used goldenseal internally (for respiratory, immune system, and gastrointestinal ailments), and externally for inflammation.

Goldenseal was used by indigenous people as a medicine in North America before the arrival of the settlers; it was valued as a wash for eyes and as a digestive remedy. The early settlers of the United States learned of the medicinal uses of goldenseal from the indigenous people; the Cherokee used the plant as a stomachic, a remedy for sore eyes, and a yellow dye, and the plant quickly became a popular remedy with the pioneers for these uses.

Canadine, as a constituent alkaloid, would have been present in these preparations, though it was not identified as a distinct chemical entity until the era of alkaloid chemistry in the nineteenth and early twentieth centuries. The plant's name in several indigenous traditions reflects both its vivid yellow pigment and the "seal"-like scar pattern on its rhizomes. Other common names for Hydrastis canadensis include yellow or orange root, yellow puccoon, Indian paint, jaundice root, Ohio curcuma, Indian dye, eye balm, and yellow eye.

2.2 Traditional Chinese Medicine (Rhizoma Corydalis / Yanhusuo)

Corydalis yanhusuo was first reported in Lei Gong Pao Zhi Lun (Northern and Southern Dynasties, 618–907 AD) and has been used as an analgesic agent in traditional Chinese medicine for over 1,100 years, primarily for the treatment of chest pain.

RC was first recorded in the Shennong Herbal Classic and was listed as a medium-grade drug. RC is characterized as pungent, bitter, and warm, and associated with the spleen and liver meridians. In TCM, RC is believed to have functions such as activating blood, reinforcing vital energy, and relieving pain.

In traditional Chinese medicine, C. yanhusuo is believed to have the function of activating blood, moving "Qi" (vital energy), and relieving pain; therefore, Corydalis Rhizoma is used in clinics as a herbal medicine for the treatment of chest impediments, heart pain, amenorrhea and dysmenorrhea, postpartum stasis and obstruction.

Stir-frying with vinegar as a processing method converts the free alkaloids in the herb (including tetrahydroberberine) into water-soluble acetate salts; according to the theory of TCM processing, this reduces toxicity and enhances the effects of moving Qi and relieving pain.

Corydalis yanhusuo, a traditional medicinal plant in China, Japan, Korea, and other Asian countries, has been used for treating a wide range of medical conditions. Historically, the preparations were predominantly water decoctions or vinegar-processed powders taken orally, and the plant occupied a valued position as a non-opiate analgesic within the TCM pharmacopeia.

3. Key Constituents and Mechanisms of Action

3.1 Relationship to Berberine

Only more recently has recognition emerged that the fully reduced form of berberine — tetrahydroberberine — has significant pharmacological activity that differs from the parent berberine. In contrast to the cytotoxic effects of berberine, tetrahydroberberine has been reported to show little cytotoxicity toward several lines of cells, but instead to be effective as an antioxidant. This distinction is pharmacologically significant: the fully reduced nitrogen in THB is a tertiary amine rather than a quaternary ammonium, altering its membrane permeability, receptor affinity profile, and overall bioactivity.

3.2 Dopaminergic and Serotonergic Receptor Interactions

Tetrahydroberberine has micromolar affinity for dopamine D₂ (pKᵢ = 6.08) and 5-HT₁A (pKᵢ = 5.38) receptors but moderate to no affinity for other relevant serotonin receptors (i.e., 5-HT₁B, 5-HT₁D, 5-HT₃, and 5-HT₄; pKᵢ < 5.00). These receptor affinities form the basis for its effects on gastrointestinal motility, central nervous system sedation, and anxiolytic activity.

Accumulating lines of evidence indicate that the THPB (tetrahydroprotoberberine) family of molecules exhibit the effects of sedation, hypnosis, antinociception, anti-schizophrenia, antihypertension, and the prevention of drug addiction. Although extensive works have indicated that dopamine receptors (D1 and D2) are targets that mediate pharmacological effects of THPBs, other targets have also been reported to mediate THPBs' effects, including α-adrenergic receptor, serotonin 5-HT receptor, Ca²⁺ channels, and K⁺ channels.

3.3 Adrenergic Receptor Antagonism

Tetrahydroberberine (THB) competitively inhibited specific binding in rat cerebral cortex with pK₁ values of 6.01 ± 0.60, and inhibited phenylephrine-induced constrictions with pA₂ values of 5.45 ± 0.76; the results indicate that THB is a non-subtype-selective competitive antagonist for the α₁-adrenoceptor.

3.4 Calcium Channel Blockade

(S)-Canadine can block voltage-dependent calcium channels, but at a level significantly lower than that of verapamil. Studies have reported biological effects of tetrahydroberberine and its derivatives as a Ca²⁺ channel blocker, which enables the induction of vascular muscle relaxation and its use as antihypertension and anti-arrhythmia agents.

3.5 ATP-Sensitive Potassium (K_ATP) Channel Blockade

Tetrahydroberberine has been observed to block ATP-sensitive K⁺ ion channels that are associated with the pathogenesis of Parkinson's disease, indicating an important neuroprotective role. Further emerging evidence indicates that ATP-sensitive potassium (KATP) channels in the midbrain substantia nigra compacta (SNc) dopamine neurons promote pathogenesis in Parkinson's disease animal models; in addition to various brain neurons, KATP channels are also widely expressed in cardiovascular cells, muscle cells, and pancreatic β-cells.

3.6 Antioxidant Mechanisms

(S)-Canadine has displayed antioxidant activity: though it lacked any demonstrable cytotoxic effect in three unique cell cultures, it was observed to possess antioxidant activity against free radical-induced oxidative injury. Canadine elevated superoxide dismutase 1 and catalase and reduced malondialdehyde and reactive oxygen species levels in doxorubicin-treated H9C2 and PC12 cells; these results show that canadine ameliorates doxorubicin-induced cardiac and brain tissue damage by inhibiting oxidative stress.

3.7 Other Reported Molecular Interactions

In vitro, (S)-canadine stimulates myogenesis and inhibits muscle protein degradation, and it blocks K(ATP) channels in dopamine neurons. Canadine is also used in the synthesis of CPU 86017, a novel Class III antiarrhythmic agent with multiple actions at ion channels. Much remains to be learned about the physical and chemical underpinnings of the pharmacological activity of tetrahydroberberine; the capacity for tetrahydroberberine to act as both hydrogen-bond donor and acceptor suggests that this property should be considered as a key basis for some of its selective activity in vivo.

4. Scientific Evidence by Area of Use

4.1 Gastrointestinal Motility and Functional Dyspepsia

Evidence level: Preclinical (animal/in vitro); preliminary human-context pharmacokinetic data only — no completed controlled human trials for canadine alone.

Because delayed gastric emptying and impaired gastric accommodation are regarded as pathophysiological mechanisms underlying functional dyspepsia (FD), prokinetics and fundic relaxants have been suggested as new treatments for FD. THB isolated from Corydalis tuber has micromolar affinity for dopamine D₂ and 5-HT₁A receptors; oral administration of THB resulted in significantly accelerated gastric emptying of normal rats in a bell-shaped relationship, with a maximal efficacy at a dose of 30 μg/kg, and also restored the delayed gastric emptying caused by apomorphine, possibly mediated by an antidopaminergic effect.

Electromyography data indicated enhanced motor function of the upper gastrointestinal tract by THB, occurring through strengthening contractility and shortening the contraction interval; furthermore, in rats subjected to repeated restraint stress, a significantly higher shift in the pressure-volume curve by THB (10 μg/kg, p < 0.05) was inhibited by a 5-HT₁A antagonist and a nitric-oxide synthase inhibitor, but not a vasoactive intestinal peptide antagonist.

THB, with D₂ receptor antagonist and 5-HT₁A receptor agonist properties, has been assessed as having significant potential as a therapeutic for treatment of functional dyspepsia. THB has been incorporated as a component of DA-9701, a botanical gastroprokinetic agent studied for delayed gastric emptying. Although both THP and THB pass through the blood-brain barrier, as indicated by brain-to-plasma concentration ratios greater than unity (approximately 2–4), oral administration of DA-9701 at the effective dose in humans is not expected to lead to sufficient brain concentrations to exert central dopamine D₂ receptor antagonism. All prokinetic data for THB specifically remain at the animal stage; clinical trials for canadine in isolation do not yet exist.

4.2 Analgesia and Antinociception

Evidence level: Preclinical (animal, in vitro); TCM compound preparations studied in some clinical contexts, but not canadine in isolation.

Among the protoberberine alkaloids found in Rhizoma Corydalis, tetrahydroberberine (THB), corydaline, tetrahydropalmatine (THP), and berberine have significant analgesic effects. In TCM clinical practice, corydalis preparations containing THB have been used as analgesics for over a millennium, as noted above, but modern randomized controlled trials have generally studied whole extracts or multicomponent formulations, not isolated canadine. The mechanistic basis for analgesia is considered to involve dopaminergic modulation and, possibly, interaction with opioid-related pathways at the level of descending pain modulation — though these mechanisms have not been fully delineated in humans for THB specifically.

The crude extracts and purified compounds of C. yanhusuo have analgesic, antiarrhythmic, and antipeptic ulcer properties, along with hypnotic effects. Network pharmacology analyses have identified tetrahydroberberine as one of the compounds likely to regulate key targets relevant to pain and gastric ulcers. Specifically, tetrahydroberberine may regulate the expression of PTGS2, PTGS1, KCNH2, SCN5A, RXRA, CAMKK2, NCOA2, and ESR1, representing a potential treatment strategy against pain, gastric ulcers, inflammation, and cardiac arrhythmias. These analyses remain hypothesis-generating rather than clinically confirmed.

4.3 Central Nervous System: Sedation, Hypnosis, and Anxiolysis

Evidence level: Preclinical (animal); no controlled human trials for canadine/THB in isolation confirmed to date.

Accumulating lines of evidence indicate that the THPB family of molecules exhibit the effects of sedation, hypnosis, antinociception, anti-schizophrenia, antihypertension, and the prevention of drug addiction; morphological and biochemical experiments have also demonstrated that THPBs have neuroprotective effects. These properties are attributed primarily to dopamine receptor antagonism at D₁ and D₂ subtypes. In the context of the THPB family, tetrahydroprotoberberines (THPBs) are isoquinoline alkaloids isolated from the Chinese herb Corydalis yanhusuo, and l-tetrahydropalmatine (l-THP), the main active ingredient, has been used for more than 40 years in China as a treatment for chronic pain and anxious insomnia. While the research on related compounds such as l-THP and l-stepholidine is substantially more developed than that specifically on canadine, the compounds share mechanistic targets and general CNS effects.

4.4 Cardiovascular Effects: Antithrombotic, Antihypertensive, and Antiarrhythmic

Evidence level: Preclinical (in vitro and animal) — no human trials for canadine alone confirmed.

Platelet aggregation and thrombosis: Tetrahydroberberine (THB), an alkaloid extracted from Corydalis ambigua, inhibited rabbit platelet aggregation triggered by arachidonic acid (AA), ADP, and collagen with IC₅₀ values of 0.86, 1.31, and 1.10 mmol·L⁻¹, respectively; THB also reduced thromboxane B₂ (TXB₂) generation in rabbit platelet-rich plasma triggered by AA. THB at 30 mg·kg⁻¹·d⁻¹ intraperitoneally for 3 or 5 days restrained ADP-induced platelet aggregation in rats; THB at 15–30 mg·kg⁻¹ intravenously showed inhibition of venous thrombosis in rats; the results show that THB is a potent inhibitor of platelet aggregation in vitro and in vivo and is a promising antithrombotic drug.

Calcium channel blockade and vascular effects: Studies have reported biological effects of tetrahydroberberine and its derivatives as Ca²⁺ channel blockers, which enable the induction of vascular muscle relaxation and their use as antihypertension and anti-arrhythmia agents. Still other research has found an inhibitory effect upon platelet aggregation, suggesting an important role in protecting against thrombosis.

Antiarrhythmic utility: Canadine has been investigated as a scaffold for antiarrhythmic drug design. Canadine is used in the synthesis of CPU 86017, a novel Class III antiarrhythmic agent with multiple actions at ion channels. All clinical evidence remains indirect, derived from studies of whole Corydalis preparations in TCM, not from isolated THB in controlled human trials.

4.5 Neuroprotection

Evidence level: Preclinical (in vitro and animal) only.

THB possesses a broad range of pharmacological properties, including central nervous system inhibition, anti-cerebral ischemia, neuroprotection, antihypertensive, antiarrhythmic, antithrombotic, and anti-inflammatory properties, along with reported low toxicity. Morphological and biochemical experiments have demonstrated that THPBs also have neuroprotective effects, though the targets and underlying mechanisms of THPB-induced neuroprotection still remain elusive.

In animal models of Parkinson's disease, the blockade of K_ATP channels in dopaminergic neurons of the substantia nigra by THB has been proposed as a neuroprotective mechanism. Further emerging evidence indicates that ATP-sensitive potassium (KATP) channels in the midbrain substantia nigra compacta dopamine neurons promote pathogenesis in Parkinson's disease animal models. These findings have not been validated in clinical trials.

4.6 Anti-inflammatory Effects

Evidence level: In vitro and animal models only.

In contrast to the cytotoxic effects of berberine, tetrahydroberberine has been reported to show little cytotoxicity toward several lines of cells, but instead to be effective as an antioxidant; consequently, it holds promise as an anti-inflammatory agent. The antioxidant and anti-inflammatory properties are mechanistically linked, as reduction of reactive oxygen species burden downstream of K_ATP and calcium channel modulation is thought to dampen inflammatory signaling cascades. No randomized controlled trials in humans have evaluated canadine as a standalone anti-inflammatory agent.

4.7 Antitumor / Anticancer Activity

Evidence level: In vitro cell culture and animal models only — no human clinical trials.

Canadine is often known as tetrahydroberberine; two tetrahydroprotoberberine alkaloids possessing a transquinolizidine conformation displayed in vitro cytotoxicity against KB cells derived from a human epidermoid carcinoma. More recent in vitro research has examined its effects in specific cancer cell lines. One study focused on canadine's inhibition of epithelial-mesenchymal transformation (EMT) in cervical cancer; immunoblotting, wound healing, and tumor invasion experiments showed that low concentrations of canadine could inhibit the EMT process, proliferation, and migration of HT-3 cells (an HPV-negative cell line); combined with the GEO database, the expression levels of several genes highly expressed in cervical tumor tissues were found to be inhibited by canadine, especially MAGEA3.

All anticancer data remain at the in vitro or animal level. No human oncology trials have evaluated isolated canadine.

4.8 Musculoskeletal Effects

Evidence level: In vitro only.

(S)-Canadine in vitro stimulates myogenesis and inhibits muscle protein degradation. Research published via ResearchGate and associated databases has also examined tetrahydroberberine in the context of ovariectomy-induced bone loss, showing inhibition of RANKL-induced osteoclastogenesis in animal models, though these findings have not progressed to clinical trials.

5. Body Systems and Health Areas of Association

Gastrointestinal system: Prokinetic activity, gastric accommodation, functional dyspepsia, antiulcer potential (via Corydalis TCM tradition and preclinical pharmacology).
Central nervous system: Sedation, hypnosis, anxiolysis, antinociception — attributed to D₁/D₂ dopamine receptor antagonism, 5-HT₁A agonism, and K_ATP channel blockade in dopaminergic neurons.
Cardiovascular system: Antithrombotic (platelet inhibition), antihypertensive (Ca²⁺ channel blockade, α₁-adrenoceptor antagonism), antiarrhythmic (ion channel modulation).
Immunological/inflammatory system: Antioxidant activity, anti-inflammatory potential via reduction of ROS and downstream inflammatory mediators.
Oncological: In vitro cytotoxic and anti-EMT activity in specific cancer cell lines — preclinical only.
Musculoskeletal: Myogenic stimulation and protein degradation inhibition in vitro; potential bone-preserving effects in ovariectomy animal models.
Neuroprotective: Associated with protection against dopaminergic neuron injury through K_ATP channel mechanisms in animal models.

6. Dosage Forms and Reported Dosages

Canadine/THB has not received regulatory approval as a standalone pharmaceutical agent in most jurisdictions, and no consensus clinical dosing guidelines exist. The dosages below are drawn exclusively from identified research sources:

Gastric emptying (rat, oral): Maximal efficacy for accelerating gastric emptying was observed at 30 μg/kg orally.
Gastric accommodation (rat, oral): A dose of 10 μg/kg orally produced a significant shift in the pressure-volume curve under stress conditions (p < 0.05).
Antiplatelet effect (rat, intraperitoneal): THB at 30 mg·kg⁻¹·d⁻¹ intraperitoneally for 3 or 5 days restrained ADP-induced and AA-induced platelet aggregation in rats.
Antithrombotic effect (rat, intravenous): THB at 15–30 mg·kg⁻¹ intravenously showed inhibition of venous thrombosis in rats.
Hepatotoxicity study (mouse, oral): THB at 40 mg/kg by oral gavage increased mouse serum aspartate transaminase and total bilirubin, and liver malondialdehyde levels, and induced liver edema.
Pharmacokinetic study in rats (oral, multi-dose): The maximum concentrations of THB in brain following multiple oral DA-9701 for 7 days (150 mg/kg/d) was observed at 30 minutes after the last oral treatment: 6.97 ± 4.03 ng/g for THB.

No standardized human clinical dose for isolated canadine has been established in the literature reviewed. TCM preparations of Corydalis Rhizoma are dosed as a whole herb preparation according to traditional guidelines, not as measured quantities of individual alkaloids.

7. Safety Considerations and Drug Interactions

7.1 Hepatotoxicity Signal in Animal Studies

Toxicological studies showed that THB at 40 mg/kg by oral gavage increased mouse serum aspartate transaminase and total bilirubin, and liver malondialdehyde levels, and induced liver edema. The real-time PCR results showed that THB induced Cyp1a2, Cyp3a11, and Cyp2e1 mRNA expression, while tetrahydropalmatine (THP) inhibited Cyp1a2 mRNA expression. Liver toxicity and oxidative damage were detected in THB-treated mice. These findings are from animal studies at relatively high oral doses and their direct translatability to humans requires further investigation.

7.2 Cytochrome P450 Enzyme Induction and Drug Interactions

The real-time PCR results showed that THB induced Cyp1a2 (1.66 ± 0.34 fold), Cyp3a11 (1.57 ± 0.24 fold), and Cyp2e1 (1.75 ± 0.97 fold) mRNA expression; the western blot results confirmed that the expression of CYP1A2, CYP3A, and CYP2E1 proteins in the mouse liver was induced by THB. These results provide information on the toxicity of THB and THP, and their related drug–drug interactions.

CYP1A2, CYP3A, and CYP2E1 are enzymes responsible for the metabolism of a wide range of therapeutic drugs. Induction of these enzymes by THB — if occurring in humans — could reduce plasma concentrations of co-administered drugs metabolized by these pathways. Research conducted on goldenseal as a whole also indicates CYP enzyme interaction: studies in human subjects have demonstrated that goldenseal supplementation inhibits CYP3A activity in vivo. This is primarily attributed to alkaloid constituents collectively, though the relative contribution of canadine versus hydrastine or berberine in these human studies is not yet fully delineated.

7.3 Blood-Brain Barrier Penetration

Although THB passes through the blood-brain barrier, as indicated by brain-to-plasma concentration ratios greater than unity (approximately 2–4), oral administration of DA-9701 at the effective dose in humans is not expected to lead to sufficient brain concentrations to exert central dopamine D₂ receptor antagonism. At higher doses or with more potent preparations, central dopaminergic effects cannot be excluded.

7.4 Platelet Aggregation and Anticoagulant Interactions

THB is a potent inhibitor of platelet aggregation in vitro and in vivo. Given this antiplatelet activity demonstrated in preclinical models, caution regarding combination with other antiplatelet or anticoagulant agents would be scientifically warranted, though this has not been studied in human clinical trials.

7.5 Cardiovascular and CNS Drug Interactions

Given the multi-receptor pharmacology of canadine — including D₁/D₂ dopamine receptor antagonism, α₁-adrenoceptor antagonism, Ca²⁺ channel blockade, and 5-HT₁A agonism — pharmacodynamic interactions with dopaminergic drugs (e.g., antipsychotics, anti-Parkinson agents, dopaminergic prokinetics), antihypertensives, antiarrhythmics, and serotonergic agents are mechanistically plausible. These interactions remain uncharacterized in controlled human studies.

7.6 Conservation Status of Source Plants

Goldenseal is listed as an endangered species because of overharvesting and habitat loss. Goldenseal is endangered in the wild due to over-harvesting and habitat loss; most commercial goldenseal is now cultivated. For Corydalis yanhusuo, sustainable cultivation exists, particularly in Zhejiang, Jiangxi, and Anhui provinces of China.

7.7 Evidence Limitations and Overall Assessment

The substantial majority of evidence for canadine/THB derives from in vitro cell culture experiments and animal (rodent) pharmacological studies. Human pharmacokinetic data exist only from studies examining whole-plant preparations (such as DA-9701 containing multiple alkaloids) rather than isolated canadine. No completed, peer-reviewed randomized controlled trials in human subjects evaluating health outcomes for isolated canadine have been identified in the literature reviewed. The evidence base for each application area — while mechanistically plausible and well-grounded in preclinical science — must accordingly be characterized as preliminary and not yet sufficient to support clinical recommendations.

References

Health Conditions

Health conditions that Canadine may help support.

No conditions available.

Body Systems

Body systems that Canadine may help support.

No body systems available.