Lou Lu
StarRhaponticum uniflorum (L.) DC.
Traditionally used for
- Digestion
- Menstrual & women's health
- Pain & joints
- Skin
Cautions & contraindications
- Pregnancy
- Liver conditions
- Toxic — professional use only
☯ TCM Properties
Clears Heat and Resolves Toxicity; Reduces abscesses and disperses nodules; Promotes Lactation; Relaxes the Sinews and Unblocks the Collaterals
Traditional Chinese Uses
Lou Lu (漏芦) is the root of Rhaponticum uniflorum (L.) DC. (Asteraceae), Radix Rhapontici. It is bitter and salty and cold, entering the Stomach channel. It clears Heat and resolves toxicity, reduces abscesses and disperses nodules, promotes lactation, and relaxes the sinews to unblock the collaterals.
Its signature use is acute mastitis and breast abscess with hot, hard, painful swelling, where it both drains the Heat toxin and unblocks the breast to restore the flow of milk — it is the herb reached for when the breast is blocked and inflamed together. It is used more generally for carbuncles, scrofula and hot swollen sores, and its unblocking of the collaterals gives it a place in Wind-Damp painful obstruction with stiff, contracted sinews.
It is cold and downward-moving and is contraindicated in pregnancy and in patients whose Qi and Blood are deficient.
Western Herbalism Properties
Relationships
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Botanical Description
Rhaponticum uniflorum (Lou Lu, uniflower swisscentaury), formerly placed in Stemmacantha, is a perennial herb in the Asteraceae family, growing 30 to 80 centimeters tall from a stout, dark brown to blackish, often twisted woody root that constitutes the medicinal material. The stems are erect, simple, unbranched, and densely white-tomentose, especially in the upper portion. Basal leaves are large, oblong-elliptic, 10 to 30 centimeters long, deeply pinnatifid to pinnatisect with lobed segments, gray-green and softly woolly beneath; stem leaves diminish upward. Each stem terminates in a single large solitary capitulum 4 to 6 centimeters across, the involucre bowl-shaped with overlapping bracts bearing dry, scarious, brown to blackish appendages; the tubular florets are rosy purple to violet. Native to the steppes and dry montane slopes of northern China, Mongolia, Korea, and southern Siberia. The roots are harvested in spring or autumn, washed, sliced, and dried for use in formulas for heat-toxin sores and breast abscess.
Active Constituents
20-Hydroxyecdysone
PhytoecdysteroidConcentration: The dominant ecdysteroid. Chinese material contains about 0.45% in the root and up to 1.35% in the leaves; Russian raw material has been reported at 0.02-1.06%. Other ecdysteroids in the plant occur only at trace level.
The compound behind the plant's reputation as a stimulant and adaptogenic remedy in Chinese, Siberian and Mongolian practice. Root extracts standardised on it show anabolic effects in rats (increased physical endurance, working capacity, muscle ATP and skeletal muscle mass, with reduced metabolic acidosis) comparable to Rhaponticum carthamoides extract used as the reference. It is not the constituent responsible for the traditional heat-clearing indication.
Thiophene polyacetylenes (arctinal, arctinone b, arctic acid, 7-chloroarctinone b)
Dithiophene polyacetyleneConcentration: Twelve thiophenes have been isolated from the roots, mostly derivatives of 5'-(1-propynyl)-2,2'-dithiophene. Two chlorinated members, 7-chloroarctinone b and rhapontiynethiophene A, come specifically from roots of Chinese origin.
Sulphur-containing polyacetylenes that contribute to the anti-inflammatory activity of the root. They are the chemical feature Rhaponticum shares with the unrelated Echinops species also sold as Lou Lu, and are one reason the two drugs have been treated as interchangeable despite belonging to different genera.
Caffeoylquinic acids (chlorogenic acid, 1,3- and 3,5-di-O-caffeoylquinic acid)
Hydroxycinnamate esterConcentration: Seven caffeoylquinic acids identified, mainly in the herb and seeds rather than the root.
Antioxidant and anti-inflammatory phenolics. They dominate the phenolic profile of the aerial parts, which matters because much of the modern pharmacology on this species used flower and inflorescence extracts rather than the root that is the medicinal drug.
Arctiin
Lignan glycosideConcentration: 0.42-2.26% in the flowers, where it is the most abundant of the phenolics measured; other flower phenolics range down to 0.03-0.05% for chrysoeriol.
The major measurable lignan of the flowering parts and part of the anti-inflammatory phenolic fraction. Its concentration in the root, the part actually dispensed as Lou Lu, is not established.
Diosbulbin B
Furanoid norditerpene lactoneConcentration: Detected in Rhaponticum uniflorum roots; the amount present has not been quantified in the literature.
A safety-relevant finding rather than a therapeutic one. Diosbulbin B, first isolated from Dioscorea bulbifera, is an established hepatotoxin that causes oxidative damage to hepatocyte membranes, and it has been reported from the roots of this species. Since no human toxicology exists for Lou Lu, this is the one identified constituent that argues for caution in prolonged use or in patients with liver disease.
Chlorohyssopifolins A and E
Chlorinated guaianolide sesquiterpene lactoneConcentration: Isolated from the herb and roots; minor constituents.
Chlorinated sesquiterpene lactones. Sesquiterpene lactones as a class are the usual cause of contact sensitisation to Asteraceae, which is relevant to topical use of the drug on abscesses.
beta-Sitosterol and daucosterol
Phytosterol and its glucosideConcentration: Present in both herb and roots; individually minor.
Common phytosterols contributing to the anti-inflammatory and hypolipidaemic activity reported for root extracts. They are not distinctive to this species.
⚠ Drug Interactions
Radix et Rhizoma Veratri (Li Lu, Veratrum nigrum), as a documented dispensing substitute for Lou Lu
Hong Kong's Chinese Medicine Regulatory Office lists Radix Rhapontici and Radix et Rhizoma Veratri as an easily confused pair and states plainly that poisoning cases have occurred in the past from incorrectly dispensing Radix et Rhizoma Veratri to patients as Radix Rhapontici. The two drugs are unrelated: Lou Lu is the root of Rhaponticum uniflorum in the Compositae, while Li Lu is the root and rhizome of Veratrum nigrum (or Veratrum schindleri) in the Liliaceae, whose steroidal alkaloids act on voltage-gated sodium channels. Veratrum has a narrow therapeutic window and is toxic to the cardiovascular and nervous systems; even external application causes burning of skin and mucosa, sneezing and lacrimation. Radix Rhapontici is listed in Schedule 2 of the Chinese Medicine Ordinance and in the Chinese Pharmacopoeia; Radix et Rhizoma Veratri is in Schedule 2 only. The confusion is driven by the shared 'Lu' element in the two names, not by any similarity of action.
Clinical note: Insist on species-verified Rhapontici Radix and check what actually arrives. Li Lu is also traditionally listed among the eighteen incompatibilities as antagonising the Shen herbs (ginseng and its relatives), Asarum and Paeonia, so a substituted batch can also silently break a formula's incompatibility rules. Any patient who develops vomiting with bradycardia and hypotension after a Lou Lu-containing prescription should be treated as a possible Veratrum poisoning and the dispensed material retained.
Echinopsis Radix (Yu Zhou Lou Lu, Echinops latifolius or Echinops grijsii), sold under the same pinyin name
Two unrelated genera in the Compositae have both been dispensed as Lou Lu. Rhaponticum uniflorum is Qi Zhou Lou Lu (Rhapontici Radix); the roots of Echinops latifolius and Echinops grijsii are Yu Zhou Lou Lu (Echinopsis Radix). Because the chemical composition and pharmacological action of Echinops differ from those of Rhaponticum, the Chinese Pharmacopoeia renamed the Echinops drug to separate them. The chemistries are genuinely different: Echinopsis Radix is dominated by thiophenes (49 of the 85 compounds reported from it) with antitumour, insecticidal and antifungal activity, whereas the Rhaponticum drug is defined by ecdysteroids and triterpenes among its 225 reported compounds. Modern research on one cannot be read across to the other.
Clinical note: Specify Rhapontici Radix or Echinopsis Radix by Latin pharmaceutical name on the prescription, never Lou Lu alone. When citing evidence for a clinical claim, check which genus the study used.
CYP3A4 substrates (e.g. ciclosporin, tacrolimus, statins, midazolam, many oncology agents)
In sandwich-cultured rat hepatocytes treated for 48 hours, Rhaponticum uniflorum inhibited CYP3A1, the rodent analogue of human CYP3A4, in a concentration-dependent way at both the enzyme and transcript level. Enzyme activity measured by erythromycin N-demethylase fell 26.4%, 44.2% and 65.4% at 15.6, 31.2 and 62.4 mg/mL, and CYP3A1 mRNA fell 29.4%, 49.8% and 56.0%. This is downregulation of expression as well as direct inhibition. There is no human study, and the concentrations used are high.
Clinical note: Treat as a plausible but unconfirmed inhibition signal. Avoid combining with narrow-index CYP3A4 substrates such as ciclosporin, tacrolimus or oral chemotherapy without monitoring drug levels.
Hepatotoxic drugs and other hepatotoxic herbs (e.g. paracetamol at high dose, methotrexate, isoniazid)
Rhaponticum uniflorum root extracts are themselves hepatoprotective in hydrogen peroxide-injured liver cells, and formal toxicity work places the extracts in the practically non-toxic group: no deaths after intragastric doses of 3.5-10 g/kg, intraperitoneal LD50 of 5.8 g/kg for the herb extract and 9.5 g/kg for the root extract, no adverse effect of long-term administration on central nervous, cardiovascular, urinary, gastrointestinal, metabolic, haematological or haemostatic parameters, and no local irritation or mutagenicity at 100 and 1000 mg/kg. Against that, the hepatotoxic furanoid norditerpene diosbulbin B has been detected in the roots, unquantified. The two observations are not reconciled in the literature.
Clinical note: No documented human hepatotoxicity, so this is a watch item, not a contraindication. Reasonable to avoid open-ended courses in patients with existing liver disease or on hepatotoxic drugs, and to prefer defined treatment periods.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 5–9 g | Daily | — | — | 中国药典 2020 【用法与用量】5～9g。 【注意】孕妇慎用。 【性味与归经】苦，寒。归胃经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Evidence Tier
Moderate evidence · 5 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
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
5
2 verified · 3 unverified
Show 5 studies
- Effects of Rhaponticum uniflorum on activity and mRNA expression of CYP3A1 in rats hepatocytes
- Anti-tumor Effect of Rhaponticum uniflorum Ethyl Acetate Extract by Regulation of Peroxiredoxin1 and Epithelial-to-Mesenchymal Transition in Oral Cancer
- Ethanol extracts of Rhaponticum uniflorum (L.) DC inflorescence ameliorate LPS-mediated acute lung injury by alleviating inflammatory responses via the Nrf2/HO-1 signaling pathway
- Ethanol extracts of Rhaponticum uniflorum (L.) DC flowers attenuate doxorubicin-induced cardiotoxicity via alleviating apoptosis and regulating mitochondrial dynamics in H9c2 cells
- Rhaponticum uniflorum and Serratula centauroides Extracts Attenuate Emotional Injury in Acute and Chronic Emotional Stress
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
Effects of Rhaponticum uniflorum on activity and mRNA expression of CYP3A1 in rats hepatocytes
Sandwich-cultured rat hepatocytes treated with Rhaponticum uniflorum at 15.6, 31.2 and 62.4 mg/mL for 48 hours. CYP3A1 activity, measured as liver microsomal erythromycin N-demethylase, was inhibited 26.4%, 44.2% and 65.4%, and CYP3A1 mRNA fell 29.4%, 49.8% and 56.0%, both concentration-dependently. The authors concluded the herb both inhibits CYP3A1 enzyme activity and lowers its transcription.
Anti-tumor Effect of Rhaponticum uniflorum Ethyl Acetate Extract by Regulation of Peroxiredoxin1 and Epithelial-to-Mesenchymal Transition in Oral Cancer
Ethyl acetate extract of Rhaponticum uniflorum tested in oral cancer models, acting through peroxiredoxin 1 and suppression of epithelial-to-mesenchymal transition. One of the better-characterised antitumour reports for this species, and in vitro only.
Ethanol extracts of Rhaponticum uniflorum (L.) DC inflorescence ameliorate LPS-mediated acute lung injury by alleviating inflammatory responses via the Nrf2/HO-1 signaling pathway
Inflorescence ethanol extract at 100-400 mg/kg in oropharyngeal LPS-induced acute lung injury in BALB/c mice, against dexamethasone 5 mg/kg. It prevented pathological change in bronchoalveolar lavage fluid, lowered F4/80 expression and myeloperoxidase in lung tissue, and suppressed TNF-alpha, IL-6, NO and TLR4/MyD88/NF-kB and MAPK signalling, working through Nrf2/HO-1. Note this used the inflorescence, not the root that is dispensed as Lou Lu.
Ethanol extracts of Rhaponticum uniflorum (L.) DC flowers attenuate doxorubicin-induced cardiotoxicity via alleviating apoptosis and regulating mitochondrial dynamics in H9c2 cells
Flower ethanol extract at 12.5-800 micrograms/mL protected embryonic rat H9c2 cardiomyocytes against doxorubicin, against dexrazoxane as comparator, by lowering reactive oxygen species, Bax, cleaved caspase-3 and -9, cleaved PARP and NF-kB, and by normalising mitochondrial dynamics. Again a flower extract rather than the root drug.
Rhaponticum uniflorum and Serratula centauroides Extracts Attenuate Emotional Injury in Acute and Chronic Emotional Stress
Rodent study of Rhaponticum uniflorum extract in acute and chronic emotional stress models, supporting the traditional Siberian and Mongolian use of the plant as a stress-protective and stimulant remedy. Part of the ecdysteroid-linked adaptogenic literature rather than the heat-clearing indication.
Historical Texts
Shen Nong Ben Cao Jing
Han dynastyChinese Pharmacopoeia (Zhonghua Renmin Gongheguo Yaodian)
Modern, current editionsReferences
- Olennikov DN. The Ethnopharmacological Uses, Metabolite Diversity, and Bioactivity of Rhaponticum uniflorum (Leuzea uniflora): A Comprehensive Review . Biomolecules (2022) [DOI]
- Sun N, Wang Y, Ma S, Kang H, Zhou C, Jin L, Zhang X, Zhang Y, Yuan Y, Shu P. A Review of the Phytochemistry and Biological Activities of Echinopsis Radix . Molecules (2024) [DOI]
- Chinese Medicine Regulatory Office, Department of Health, Government of the Hong Kong Special Administrative Region. Identification of Easily Confused Species of Chinese Materia Medica in Hong Kong by Macroscopic and Microscopic Characteristics Project: Radix Rhapontici versus Radix et Rhizoma Veratri . Chinese Medicine Regulatory Office, Department of Health, Hong Kong SAR (2020)
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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