Bai Xian Pi
StarDictamnus dasycarpus Turcz.
Traditionally used for
- Digestion
- Urinary & fluids
- Pain & joints
- Skin
- Liver & jaundice
Cautions & contraindications
- Liver conditions
☯ TCM Properties
Clears Heat and dries Dampness; Dispels Wind and Stops Itching; Resolves Toxicity; Clears Damp-Heat from the Skin; Clears Damp-Heat and Resolves Jaundice
Traditional Chinese Uses
Bai Xian Pi (白鲜皮) is the root bark of Dictamnus dasycarpus Turcz. (Rutaceae), Cortex Dictamni. It is bitter and cold, entering the Spleen, Stomach and Bladder channels. It clears Heat and dries Dampness, dispels Wind and stops itching, resolves toxicity, clears Damp-Heat from the skin, and resolves jaundice.
It is a leading herb for Damp-Heat skin disease: hot, red, weeping, intensely itchy eruptions, eczema, urticaria, scabies and sores with a purulent discharge — used both internally and as an external wash. Its reach into Damp-Heat also gives it a role in jaundice, and in Damp-Heat painful obstruction where the joints are hot, swollen and sore.
The fresh root bark has a strong goat-like odour, which is the origin of the drug's name. It is cold and bitter and is used with care where the Spleen and Stomach are deficient and cold.
Western Herbalism Properties
Relationships
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Botanical Description
Dictamnus dasycarpus (Bai Xian Pi, densefruit pittany) is a perennial herb in the Rutaceae family, growing 40 to 100 centimeters tall from a stout, branched, fleshy taproot whose cortex is the medicinal material. Stems are erect, sparsely branched, and beset with gland-dotted hairs especially in the upper parts. The alternate leaves are odd-pinnate with 9 to 13 ovate to elliptic leaflets, each 3 to 9 centimeters long, with finely serrate margins and conspicuous translucent oil glands that emit a strong, characteristic lemon-like aroma when bruised. From late spring into summer, terminal racemes bear showy flowers with five spreading pink to pale purple petals veined with darker purple, ten declinate stamens, and a glandular-hairy ovary that becomes a five-lobed capsule densely covered in stalked glands. Native to northern China, Korea, Mongolia, and parts of eastern Siberia. The peeled root bark is harvested in spring or autumn, sliced, and dried for use as a cooling, anti-inflammatory remedy in damp-heat skin disorders.
Active Constituents
Dictamnine
Furoquinoline alkaloidConcentration: the predominant alkaloid of the root bark
Both the main pharmacological alkaloid of the drug and its principal hepatotoxin. Its furan ring is bioactivated, chiefly by CYP3A4, to a reactive epoxide that binds hepatic protein; in mice a high dose raised AST, total and direct bilirubin and relative liver weight and produced hepatocyte vesicular steatosis around the lobules, with female animals more affected. This compound is the reason Cortex Dictamni is a documented cause of herb-induced liver injury.
Fraxinellone
Degraded limonoidOne of the two markers by which the Chinese Pharmacopoeia assays this drug, and one of its main limonoid constituents. Like dictamnine it carries a furan ring and undergoes cytochrome P450 bioactivation, and it has been implicated alongside dictamnine in Cortex Dictamni liver injury.
Obacunone
Limonoid (triterpenoid)The second pharmacopoeial quality marker for D. dasycarpus. It has anti-inflammatory, antioxidant and neuroprotective activity in preclinical work and is not among the constituents implicated in hepatotoxicity.
Limonin
Limonoid (triterpenoid)A bitter limonoid of the root bark, one of the compounds shown to protect cultured rat cortical cells against glutamate-induced neurotoxicity.
⚠ Drug Interactions
Any hepatotoxic drug (e.g. paracetamol, methotrexate, isoniazid, ketoconazole, statins) and alcohol
Cortex Dictamni is one of the best-documented causes of herb-induced liver injury in East Asia. In a systematic review of 97 Korean HILI cases, Dictamnus dasycarpus accounted for 37.1%, second only to Polygoni Multiflori Radix at 39.2%; 33 of the Dictamni Cortex cases (91.7%) had a cumulative RUCAM score above 7, meaning probable to highly probable causality. In UK users taking Chinese herbal preparations for chronic skin disease in the 1990s the drug was linked to acute hepatitis. Mechanistically the injury is driven by CYP-mediated metabolic activation of the furanoids dictamnine and fraxinellone to reactive intermediates. Classical texts list this herb as non-toxic; that classification is contradicted by modern pharmacovigilance and should not be relied on.
Clinical note: Do not combine with other hepatotoxins or with regular alcohol use. Avoid in existing liver disease. Check baseline liver enzymes before any course longer than a few weeks and recheck during treatment, and stop immediately on nausea, dark urine, pale stools or jaundice. Warn patients explicitly, since this herb is commonly prescribed for eczema and psoriasis, conditions treated over long periods.
CYP3A4 inducers (e.g. rifampicin, carbamazepine, phenytoin, St John's wort)
CYP3A4 is the enzyme that bioactivates dictamnine. Work in Frontiers in Pharmacology showed the toxicity of dictamnine is modulated by CYP3A4 activity: increasing CYP3A4 increased the injury and inhibiting it reduced the injury. Anything that induces CYP3A4 therefore shifts more of the alkaloid down the toxic activation route.
Clinical note: Avoid Bai Xian Pi in patients on strong CYP3A4 inducers. If it must be used, keep the course short and monitor liver enzymes.
CYP3A4 inhibitors (e.g. ritonavir, clarithromycin, grapefruit juice)
The same CYP3A4 dependence works in reverse: inhibiting the enzyme lowered dictamnine-induced hepatotoxicity in the Frontiers in Pharmacology model. This does not make the combination safe, because it raises exposure to unmetabolised dictamnine and to whatever alternative routes handle it, and the human dose-response is not characterised.
Clinical note: Do not treat a CYP3A4 inhibitor as protective or as a licence to use the herb more freely. The interaction is a reason to expect unpredictable exposure, not a safety measure.
Immune-activating states and drugs (infection, LPS-type immune challenge, immunostimulants)
The Journal of Pharmacy and Pharmacology review notes that D. dasycarpus hepatotoxicity is stress-dependent and manifests under immune challenge, which is the pattern of idiosyncratic rather than dose-predictable injury. Subchronic mouse dosing produced disturbances of haematopoiesis and of liver and kidney function even at behaviourally tolerated doses, and high-dose ethanol extract at 60 g/kg caused severe dose- and time-dependent hepatocellular necrosis.
Clinical note: Suspend the herb during acute infection or systemic inflammatory illness, and be aware that an uneventful earlier course does not predict safety on re-exposure.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction, or powder/pills | 5–10 g | Daily | — | — | 中国药典 2020 【用法与用量】5～10g。外用适量，煎汤洗或研粉敷。 【性味与归经】苦，寒。归脾、胃、膀胱经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Evidence Tier
Strong evidence · 6 studiesRecorded 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
1
1 verified · 0 unverified
Show the study
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
5
0 verified · 5 unverified
Show 5 studies
- Subchronic Toxicity Studies of Cortex Dictamni Extracts in Mice and Its Potential Hepatotoxicity Mechanisms in Vitro
- The Modulatory Role of CYP3A4 in Dictamnine-Induced Hepatotoxicity
- Cortex dictamni-induced liver injury in mice: The role of P450-mediated metabolic activation of furanoids
- Multi-Omics Integration to Reveal the Mechanism of Hepatotoxicity Induced by Dictamnine
- Exploring the Mechanism of Hepatotoxicity Induced by Dictamnus dasycarpus Based on Network Pharmacology, Molecular Docking and Experimental Pharmacology
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
Systematic review on herb-induced liver injury in Korea
Reviewed 97 identified cases of herb-induced liver injury in Korea. Injury was hepatocellular in 74.7%, cholestatic in 10.8% and mixed in 14.5%. Dictamnus dasycarpus was implicated in 37.1% of cases, the second most frequent herb after Polygoni Multiflori Radix at 39.2%. This is the strongest human evidence that Bai Xian Pi causes clinically significant liver injury.
Subchronic Toxicity Studies of Cortex Dictamni Extracts in Mice and Its Potential Hepatotoxicity Mechanisms in Vitro
Subchronic oral dosing of Cortex Dictamni extracts in mice produced hepatotoxicity, with accompanying in vitro work on the mechanism. Establishes that the whole-drug extract, not only isolated dictamnine, injures the liver on repeated dosing.
The Modulatory Role of CYP3A4 in Dictamnine-Induced Hepatotoxicity
Showed that CYP3A4-mediated metabolic activation governs dictamnine hepatotoxicity: raising CYP3A4 activity increased injury and inhibiting it reduced injury. This is the basis of the CYP3A4 inducer and inhibitor interactions recorded for this herb.
Cortex dictamni-induced liver injury in mice: The role of P450-mediated metabolic activation of furanoids
Attributed Cortex Dictamni liver injury in mice to cytochrome P450-mediated bioactivation of the drug's furan-containing constituents, identifying the furanoid class rather than any single compound as the hazard.
Multi-Omics Integration to Reveal the Mechanism of Hepatotoxicity Induced by Dictamnine
Integrated omics in mice showed that a high dose of dictamnine raised serum AST, total bilirubin and direct bilirubin and increased relative liver weight and the liver-to-brain weight ratio in females, with histology showing hepatocyte vesicular steatosis around the liver lobules. Documents a sex difference in susceptibility.
Exploring the Mechanism of Hepatotoxicity Induced by Dictamnus dasycarpus Based on Network Pharmacology, Molecular Docking and Experimental Pharmacology
Combined network pharmacology, molecular docking and bench pharmacology to map candidate targets of D. dasycarpus hepatotoxicity. Computational in origin and hypothesis-generating, but consistent with the metabolic-activation account established in the animal work.
Historical Texts
Shen Nong Ben Cao Jing
Han dynastyBen Cao Gang Mu
Ming dynastyReferences
- Yu Qin, Hong-Feng Quan, Xi-Rong Zhou, Shu-Juan Chen, Wen-Xin Xia, Hang Li, Huan-Ling Huang, Xue-Yan Fu, Lin Dong. The traditional uses, phytochemistry, pharmacology and toxicology of Dictamnus dasycarpus: a review . Journal of Pharmacy and Pharmacology (2021) [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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