Bu Gu Zhi
StarPsoralea corylifolia L. (syn. Cullen corylifolium (L.) Medik.)
Traditionally used for
- Bowel health
- Urinary & fluids
- Fertility & vitality
- Pain & joints
- Energy & fatigue
- Skin
Cautions & contraindications
- Liver conditions
☯ TCM Properties
Tonifies Kidney Yang; Secures Essence and Stops Enuresis; Warms the Middle Burner and Stops Diarrhea; Aids the Kidneys in Grasping Qi; Dispels Wind-Heat from the Skin
Traditional Chinese Uses
Bu Gu Zhi (psoralea fruit, broken dish bone herb) is a warm herb used in Chinese medicine to warm Kidney and Spleen Yang, astringe to stop deficiency-type diarrhea, and promote the absorption of calcium for bone health. It is used for lower back pain from Kidney Yang deficiency, early-morning diarrhea from Kidney-Spleen Yang deficiency, urinary frequency, bedwetting, and impotence. Applied externally, it is a classical treatment for vitiligo and patchy hair loss, for which modern research has identified its photosensitizing compounds.
Western Herbalism Properties
Pharmacological Effects
- Bone calcification: Seed acetone-extract fractions (Ho-0, Ho-1) given orally raised serum inorganic phosphorus and promoted bone calcification in normal and rachitic rats.
- Cardiovascular: Corylifolinin (10^-5 to 10^-6 M) dilated coronary vessels in isolated hearts; 20 mg/kg i.v. in dogs increased coronary flow by 80% with high coronary selectivity; enhanced cardiac contractility.
- Anti-implantation and estrogenic: Corylifolinin and bakuchiol had anti-implantation action in mice (ED50 58 mg/kg and 0.37 ml/kg); bakuchiol showed strong estrogenic action in ovariectomized rats.
- Photosensitivity: Crude preparation given enterally or topically sensitized skin to UV light, causing pigmentation and in severe cases swelling and blistering.
- Antineoplastic and antimutagenic: Ethanolic extract (active: bakuchiol) cytotoxic to L929 and five human cancer cell lines in vitro; psoralidin cytotoxic to SUN-1 and SUN-16 stomach carcinoma lines (IC50 53 and 203 µg/ml); psoralen antimutagenic, especially vs benzo(a)pyrene.
- Other: Hemostatic in mice; extract inhibited penicillin-resistant Staphylococcus aureus and S. albus; psoralen analogs inhibited hexobarbital metabolism in mice.
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 609.
Relationships
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Botanical Description
Cullen corylifolium (syn. Psoralea corylifolia, Fabaceae), known as babchi or Bu Gu Zhi, is an erect annual herb 60-180 cm tall with glandular-pubescent stems and simple, broadly ovate to elliptic leaves 5-10 cm long bearing prominent dark resinous glands beneath. Dense axillary racemes 5-10 cm long carry numerous small pea-flowers with bluish-violet to whitish corollas. The single-seeded indehiscent pods are ovoid, 4-5 mm long, blackish-brown when ripe, and contain a flattened, kidney-shaped seed with a strongly aromatic, slightly bitter taste due to furanocoumarins (psoralen, isopsoralen) responsible for the herb's well-known phototoxic and pigmenting effects. Native to India and naturalized across China, Southeast Asia, and tropical Africa. (Sources: POWO; Wikipedia; Bensky)
Active Constituents
Psoralen
Linear furanocoumarinConcentration: Major coumarin; a Chinese Pharmacopoeia marker (with isopsoralen)
A photosensitising furanocoumarin underlying the herb's traditional topical use for vitiligo and psoriasis. It also activates the aryl-hydrocarbon receptor and induces CYP1A2, and is a principal contributor to dose- and duration-dependent hepatotoxicity.
Isopsoralen (angelicin)
Angular furanocoumarinConcentration: Major coumarin; co-marker with psoralen
Osteogenic and oestrogen-like activity reported; also implicated, with psoralen, in liver injury.
Bakuchiol
Meroterpene phenolConcentration: Major lipophilic constituent
Antibacterial, antioxidant and oestrogen-like; identified as a key hepatotoxic component acting through mitochondrial dysfunction and oxidative stress, particularly under immune/inflammatory stress.
Bavachin
FlavanoneConcentration: Major flavonoid
Phytoestrogenic and osteogenic (bone-forming) in preclinical models; can raise bilirubin and contributes to hepatotoxicity.
Isobavachalcone / bavachalcone
ChalconeConcentration: Characteristic flavonoid
Antibacterial, antioxidant and osteogenic; inhibits certain UDP-glucuronosyltransferases and contributes to the herb's hepatic effects.
Psoralidin
CoumestanConcentration: Characteristic constituent
Antioxidant and anticancer in vitro; also identified among the hepatotoxic constituents via mitochondrial dysfunction and apoptosis.
Corylifol A / corylin
Prenylated flavonoid / isoflavoneConcentration: Minor-to-moderate flavonoid
Osteogenic and oestrogen-modulating activity reported in preclinical bone and metabolic models.
Neobavaisoflavone
IsoflavoneConcentration: Minor flavonoid
Anti-inflammatory and osteogenic activity; investigated for CYP-mediated herb-drug interaction potential.
⚠ Drug Interactions
Hepatotoxic drugs (acetaminophen/paracetamol, methotrexate, isoniazid, statins)
Fructus Psoraleae is a recognised cause of drug-induced liver injury; psoralen, isopsoralen, bakuchiol, bavachin and psoralidin cause dose- and time-dependent hepatocellular damage and cholestasis via mitochondrial dysfunction, oxidative stress and CYP1A2 induction. Effects are amplified by overdose, prolonged use, raw (unprocessed) material and ethanol extracts, and under immune/inflammatory stress.
Clinical note: Avoid combining with other hepatotoxic agents; monitor liver function, limit duration, avoid high-dose raw/alcohol extracts, and stop at any sign of jaundice or transaminase rise.
Photosensitising agents and UV/PUVA therapy
The furanocoumarins psoralen and isopsoralen are potent photosensitisers that intercalate DNA and form cross-links on UVA exposure; combined with other photosensitising drugs or phototherapy they can cause severe phototoxic burns and increase long-term skin-cancer risk.
Clinical note: Counsel sun protection; avoid concurrent tetracyclines, fluoroquinolones, thiazides, retinoids and deliberate UV/PUVA unless supervised.
CYP3A4 substrates (e.g., midazolam, cyclosporine, certain statins)
Extracts and constituents (psoralen, isopsoralen) inhibit CYP3A4 in human recombinant enzyme and hepatocyte models, while psoralen also induces CYP1A2, so the herb can raise or lower plasma levels of CYP-metabolised drugs.
Clinical note: Monitor for altered response of narrow-therapeutic-index CYP3A4/CYP1A2 substrates.
Hormone-sensitive therapies (tamoxifen, aromatase inhibitors, oestrogens)
Bavachin, bakuchiol and corylin show oestrogen-like activity in preclinical models, which could theoretically oppose anti-oestrogen therapy or affect hormone-sensitive conditions.
Clinical note: Use caution in patients with hormone-sensitive cancers or on endocrine therapy.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 6–10 g | Daily | — | — | 中国药典 2020 【用法与用量】6～10g。外用20%～30%酊剂涂患处。 【性味与归经】辛、苦，温。归肾、脾经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Preparation Methods
Decoction (Tang)
Parts: dried ripe fruit
Typical adult dose 6-10 g of dried fruit decocted in water. Because of established hepatotoxicity, avoid high doses and prolonged uninterrupted use, prefer water decoctions over alcohol extracts, and monitor liver function.
Salt-processed (Yan Zhi)
Parts: dried ripe fruit
Frying with salt-water is the classic processing to direct the herb to the Kidney and temper its acrid dryness; salt-processed fruit is standard in kidney-yang and diarrhoea formulas (e.g., Si Shen Wan, Qing E Wan).
Topical tincture with controlled UVA (traditional/dermatologic)
Parts: dried ripe fruit
Historically applied topically for vitiligo and psoriasis to exploit the psoralen-plus-UVA (PUVA) photosensitising effect. Because of phototoxic burn and skin-cancer risk this should only be done under specialist supervision, never with uncontrolled sun exposure.
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Kidney yang is warmed while the lower back and knees are strengthened.
Kidney-deficiency low back pain.
Core pair of a classical formula — Qing E Wan, Tai Ping Hui Min He Ji Ju Fang
Kidney yang is warmed and the kidney helped to grasp qi, strengthening the lower back.
Core pair of a classical formula — Qing E Wan, Tai Ping Hui Min He Ji Ju Fang
Kidney yang is warmed while the spleen is warmed and the intestines astringed, stopping daybreak diarrhea.
Core pair of a classical formula — Er Shen Wan, Pu Ji Ben Shi Fang (Xu Shuwei)
Evidence Tier
Limited evidence · 1 studyRecorded 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
1
0 verified · 1 unverified
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
Five Constituents Contributed to the Psoraleae Fructus-Induced Hepatotoxicity via Mitochondrial Dysfunction and Apoptosis
Identified bakuchiol, bavachin, isobavachalcone, psoralidin and neobavaisoflavone as hepatotoxic constituents that damage hepatocytes through mitochondrial dysfunction and apoptosis, clarifying the mechanism of Bu Gu Zhi liver injury.
⚠ Safety & Contraindications
- Liver conditions
Contraindications
Its use is prohibited in patients with vigorous fire due to yin deficiency, or constipation.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 344–356.
Side Effects
- Crude preparation causes photosensitivity (see pharmacology).
- Bakuchiol given orally to mice for 1-4 weeks caused renal pathology, progressive at high dosage.
- Corylifolinin and isopsoralen at tested doses caused no significant organ or functional changes in rats, mice and dogs.
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 609.
Historical Texts
Kai Bao Ben Cao (Materia Medica of the Kaibao Era)
Northern Song dynasty (973 CE)Ben Cao Gang Mu (Compendium of Materia Medica), Li Shizhen
Ming dynasty (1578)Pu Ji Ben Shi Fang (Prescriptions of Universal Benefit), Xu Shuwei
Southern Song dynasty (1132)References
- Chen L, Chen S, Sun P, Liu X, Zhan Z, Wang J. Psoralea corylifolia L.: a comprehensive review of its botany, traditional uses, phytochemistry, pharmacology, toxicology, quality control and pharmacokinetics . Chinese Medicine (2023) [DOI]
- Wang Y, Zhang H, Jiang J, et al.. Five Constituents Contributed to the Psoraleae Fructus-Induced Hepatotoxicity via Mitochondrial Dysfunction and Apoptosis . Frontiers in 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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