Corydalis Yanhusuo Rhizome Extract
Also known as: Yanhusuo, Corydalis rhizome, Corydalis yanhusuo W.T. Wang, Corydalis yanhusuo
Overview
Corydalis yanhusuo rhizome extract is derived from the dried tuber of the plant, primarily used in Traditional Chinese Medicine (TCM) for pain relief and cardiovascular conditions. The extract is rich in isoquinoline alkaloids, including tetrahydropalmatine (THP), corydaline, and protopine, which are believed to be responsible for its pharmacological effects. It is commonly marketed as an analgesic and sedative dietary supplement. While preclinical animal studies consistently demonstrate its analgesic and anti-addiction properties, high-quality human randomized controlled trials (RCTs) are limited. The quality of evidence is mixed, with strong animal data but significant variability in the alkaloid content of commercial supplements and a lack of large-scale human clinical validation. This variability poses challenges for consistent dosing and efficacy.
Benefits
Corydalis yanhusuo extract exhibits several potential benefits, primarily in pain management and opioid-sparing effects. Animal studies consistently show significant analgesic effects, increasing mechanical and thermal pain thresholds across acute, inflammatory, and neuropathic pain models. Furthermore, preclinical research indicates an opioid-sparing effect, where the extract reduced morphine tolerance and dependence in mice, potentially allowing for lower opioid doses. Secondary benefits observed in preclinical models include sedative and anxiolytic effects, mainly attributed to tetrahydropalmatine, and potential cardioprotective and hepatoprotective properties. While these findings are promising, they are predominantly from animal studies, and human data are sparse, requiring further rigorous clinical trials to establish efficacy and effect sizes in humans. The strength of evidence for these benefits in humans is currently low.
How it works
The primary mechanisms of action for Corydalis yanhusuo's analgesic and anti-addiction effects are attributed to its isoquinoline alkaloids, particularly tetrahydropalmatine (THP) and corydaline. These alkaloids interact with multiple neurochemical systems, including dopaminergic, opioid, and potentially GABAergic pathways. By modulating these systems, the extract influences pain perception and reward pathways in the brain. Additionally, some alkaloids in the extract have been shown to regulate the expression of apoptosis-related proteins (e.g., Bcl-2 family), contributing to observed cardioprotective effects. While hepatic metabolism is involved, the full absorption and metabolic pathways of its various alkaloids are not yet completely elucidated, and bioavailability can vary significantly depending on the specific alkaloid content of the extract.
Side effects
While generally considered safe in animal studies at tested doses with no major toxicity reported, human side effects of Corydalis yanhusuo are not well documented due to limited clinical data. A significant concern is the wide variability in alkaloid content among commercial supplements, which can lead to inconsistent dosing and potential for adverse effects, especially if products are adulterated or highly enriched with specific alkaloids like tetrahydropalmatine. Drug interactions are not well studied, but caution is advised when combining with central nervous system (CNS) depressants or opioids due to potential additive sedative effects. Contraindications and data for special populations, such as pregnant or lactating individuals, or those with hepatic impairment, are lacking. Therefore, clinical caution is warranted in these groups. Users should be aware that the safety profile in humans is not fully established, and individual responses may vary.
Dosage
There is no standardized dosing for Corydalis yanhusuo established from human clinical trials. Preclinical animal studies have utilized extract doses ranging from 125 to 500 mg/kg for analgesic and opioid tolerance effects. However, translating these doses directly to humans is not straightforward. A major challenge in standardizing human dosage is the significant variability in alkaloid content (e.g., tetrahydropalmatine, corydaline) among commercial supplements, which can range from undetectable to approximately 11 mg/g. This inconsistency makes it difficult to ensure a consistent therapeutic dose. Optimal dose, timing, and formulation for human use require further clinical validation. Users should be aware that the efficacy and safety of a given product may depend heavily on its specific alkaloid profile, which is often not disclosed or standardized.
FAQs
Is Corydalis yanhusuo effective for pain?
Animal studies strongly support its analgesic effects across various pain types. However, high-quality human data are limited, so its effectiveness in humans is not yet definitively established.
Is it safe to combine with opioids?
Preclinical data suggest it may reduce opioid tolerance and enhance analgesia. However, human safety and interaction data are insufficient, so combining should be done with extreme caution and medical supervision due to potential additive sedative effects.
How soon does it work?
Animal studies show effects within days of administration. The onset of action in humans is not well defined due to a lack of clinical trials.
Are all Corydalis yanhusuo supplements equal?
No, there is significant variability in the alkaloid content of commercial supplements, which can greatly affect their efficacy and safety. Quality and standardization are critical concerns.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8540887/ – This preclinical RCT in mice demonstrated that Corydalis yanhusuo extract significantly reduced morphine tolerance and dependence while enhancing morphine's analgesic effects. The study was well-controlled and provides strong evidence for opioid-sparing potential in animal models.
- https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1518750/full – This systematic analysis of 14 commercial Corydalis yanhusuo products revealed significant variability in alkaloid content, with some products showing signs of adulteration. It highlights critical quality control issues and challenges for consistent dosing in human supplements.
- https://pdfs.semanticscholar.org/35f4/b12be1d95e574919d8d2f8d69962d1876155.pdf?skipShowableCheck=true – This literature review summarizes the analgesic, sedative, cardioprotective, and hepatoprotective effects of Corydalis alkaloids, detailing their proposed mechanisms of action. While comprehensive, it primarily draws from preclinical data and notes the limited number of human RCTs.
- https://journals.sagepub.com/doi/10.1177/1934578X231152309 – This study utilized network pharmacology and meta-analysis to identify molecular targets and pathways for Corydalis rhizome, particularly in the context of angina within Traditional Chinese Medicine. It provides useful mechanistic insights, though its focus is on combined herbal formulations and angina, not direct analgesic efficacy.