Traditionally used for
- Cough & breathing
- Skin
☯ TCM Properties
Disperses swelling; Antimalarial
Traditional Chinese Uses
Mao Zhua Cao is the small tuberous root of Ranunculus ternatus (Radix Ranunculi Ternati), named for its resemblance to a cat's claw and entering the Liver and Lung channels. Its best-documented use is to dissipate Phlegm nodules and reduce swellings while resolving toxicity: it is a principal herb for scrofula (cervical lymph-node tuberculosis) with hard, swollen nodes, and is also applied to simple goiter, toxic sores, boils and abscesses, and swelling from snakebite. Traditional texts additionally note an antimalarial use.
It is usually decocted at fairly high dose (roughly 15-30 g), and the fresh or powdered root may be applied topically to nodules and sores; it is frequently combined with other Phlegm-softening and toxicity-clearing herbs. As a buttercup-family plant, the fresh material is locally irritant, so the prepared root is used under professional guidance.
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Botanical Description
Mao Zhua Cao is the tuberous root of Ranunculus ternatus, a small perennial buttercup of the family Ranunculaceae native to central and eastern China. The plant arises each spring from a cluster of slender, fleshy, spindle-shaped tuberous roots resembling tiny clawed fingers, which is the part collected for medicinal use and gives the herb its colloquial Chinese names. Slender erect stems 5 to 20 centimetres tall bear basal leaves on long petioles that are ternately divided into three rounded, lobed or toothed leaflets, while upper stem leaves are simpler and more linear. Solitary, glossy, bright yellow, five-petalled flowers about 1 centimetre across appear in early spring, followed by small heads of achenes. The species favours moist meadows, ditches, and grassy slopes below 1000 metres elevation.
Active Constituents
Methyl (R)-3-[2-(3,4-dihydroxybenzoyl)-4,5-dihydroxyphenyl]-2-hydroxypropanoate
BenzophenoneA benzophenone first described from the tuberous root and the most active anti-tubercular constituent isolated from this drug, inhibiting Mycobacterium tuberculosis at an MIC of 41.67 micrograms/mL. Combined 1:1 with gallic acid the MIC improved to 20.83 micrograms/mL, suggesting the root works as a mixture rather than through a single agent.
n-Butyl (R)-3-[2-(3,4-dihydroxybenzoyl)-4,5-dihydroxyphenyl]-2-hydroxypropanoate
BenzophenoneThe butyl homologue of the methyl ester above, also new to science from this root but far weaker against M. tuberculosis at an MIC of 266.67 micrograms/mL.
Gallic acid
Phenolic acidA known phenolic acid of the root with an anti-tubercular MIC of 66.67 micrograms/mL, which acts synergistically with the principal benzophenone, halving its MIC when combined in equal parts.
Vanillic acid
Phenolic acidA known root constituent with modest activity against M. tuberculosis at an MIC of 83.33 micrograms/mL.
Ternatolide
LactoneOne of the two compounds used as a quantitative marker in quality control of Radix Ranunculi ternati, alongside a pyrrole butanoic acid. Its presence is what distinguishes correctly identified root material in routine assay.
4-[Formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl]butanoic acid
Pyrrole alkaloidThe second designated quantitative marker for this drug. Alkaloids are a minor class here, only six of the 103 reported constituents.
Total saponins of Ranunculus ternatus
Triterpenoid saponin fractionThe standardised saponin fraction of the root, characterised by LC-MS and studied for antitumour activity in breast cancer models. It is a fraction rather than a single constituent.
Ranunculus ternatus alkaloid fraction
Mixed alkaloid fractionThe alkaloid fraction of the root has been reported to attenuate colorectal cancer metastasis through suppression of epithelial-mesenchymal transition. Note that ranunculin and protoanemonin are not among the 103 constituents catalogued from this drug: the vesicant lactone chemistry of the genus is not what is being used here.
⚠ Drug Interactions
First-line anti-tuberculosis therapy (isoniazid, rifampicin, pyrazinamide, ethambutol)
This root is used in China for pulmonary and cervical tuberculosis and does have measurable in vitro activity against M. tuberculosis, but the MICs of its isolated constituents are in the tens to hundreds of micrograms per mL, orders of magnitude weaker than rifampicin or isoniazid. Anything that inclines a patient to reduce, delay or interrupt standard four-drug therapy risks treatment failure and acquired drug resistance, which is a far greater harm than any pharmacokinetic effect.
Clinical note: Use only as an adjunct alongside a supervised standard regimen, never as a substitute, and confirm with the treating TB service that the patient remains fully adherent. Monitor liver function, since the standard regimen is already hepatotoxic.
Uncaria tomentosa (Western "cat's claw") - confusion of common names
Mao Zhua Cao is sold in English as "cat's claw herb" or "catclaw buttercup root", a name it shares with Uncaria tomentosa, the South American cat's claw of Western herbalism. The two are unrelated: Uncaria carries oxindole alkaloids with immunostimulant activity and documented CYP3A4 effects and is generally avoided with immunosuppressants, while this drug is a Ranunculaceae tuberous root used for scrofula and tuberculous lymphadenitis. A patient or supplier reading only the English name can easily supply one for the other.
Clinical note: Always confirm the binomial on the label. "Cat's claw" alone is not an identification.
Mao Gen (Ranunculus japonicus) - substitution within the genus
Mao Zhua Cao is the dried tuberous root of R. ternatus, taken by decoction, and reviews report low acute oral toxicity with maximum tolerated doses above 20 g/kg and no apparent adverse effects. Mao Gen is the fresh whole plant of R. japonicus, whose ranunculin releases the vesicant protoanemonin when the tissue is crushed and which is a topical blistering agent. Because the pinyin names are similar and both are Ranunculus, misidentification in the supply chain would put protoanemonin-generating fresh tissue into an oral preparation, causing blistering of the mouth and gut, salivation and bloody diarrhoea.
Clinical note: Check that what is supplied is a dried tuberous root, not dried or fresh aerial parts. Reject any Ranunculus material sold for internal use that is not the tuber.
Levothyroxine and antithyroid drugs
Among the clinical applications reported for this drug in China are Hashimoto's thyroiditis and goitre, so patients using it are likely to be on thyroid replacement or antithyroid therapy at the same time. No pharmacokinetic or pharmacodynamic study of that combination has been published, so any effect on thyroid status would be detected only by monitoring.
Clinical note: Check thyroid function about six weeks after starting or stopping the herb in any patient on levothyroxine or carbimazole, and do not adjust their dose on the basis of symptoms alone.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 15–30 g | — | — | — | ChP 2025. 单味药可用至120g — up to 120 g when used as a single herb. Corrected from a generic 6-15g filler value generated from tcm_category; note the filler was too LOW here, not too high. |
Evidence Tier
Moderate 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
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
6
2 verified · 4 unverified
Show 6 studies
- Chemical Constituents from the Roots of Ranunculus ternatus and their Inhibitory Effects on Mycobacterium tuberculosis
- Ranunculus ternatus Thunb extract attenuates renal fibrosis of diabetic nephropathy via inhibiting SMYD2
- Network pharmacology and transcriptomic profiling elucidate the therapeutic effects of Ranunculus ternatus Thunb on liver fibrosis via MK3-NF-κB inhibition
- Cell death induction by Ranunculus ternatus extract is independent of mitochondria and dependent on Caspase-7
- Mechanism of total saponins of Ranunculus ternatus Thunb. in treatment of breast cancer based on liquid chromatography–mass spectrometry and network analysis
- Ranunculus ternatus Thunb. alkaloids attenuate colorectal cancer metastasis through EMT suppression
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
Chemical Constituents from the Roots of Ranunculus ternatus and their Inhibitory Effects on Mycobacterium tuberculosis
Two new benzophenones were isolated from the roots along with vanillic acid and gallic acid, and tested against Mycobacterium tuberculosis. MICs were 41.67, 266.67, 83.33 and 66.67 micrograms/mL respectively, and a 1:1 mixture of the most active benzophenone with gallic acid was better than either alone at 20.83 micrograms/mL. The paper records the traditional use of the plant for tuberculosis, faucitis and neck scrofula.
Ranunculus ternatus Thunb extract attenuates renal fibrosis of diabetic nephropathy via inhibiting SMYD2
An extract of Ranunculus ternatus reduced renal fibrosis in a diabetic nephropathy model, with the effect attributed to inhibition of the methyltransferase SMYD2. This is an indication with no basis in the classical use of the drug for scrofula and swellings.
Network pharmacology and transcriptomic profiling elucidate the therapeutic effects of Ranunculus ternatus Thunb on liver fibrosis via MK3-NF-κB inhibition
Network pharmacology combined with transcriptomics identified MK3-NF-kappaB signalling as the route by which Ranunculus ternatus reduced experimental liver fibrosis. As with the renal fibrosis work, this is a computationally guided preclinical finding and has not been tested in patients.
Cell death induction by Ranunculus ternatus extract is independent of mitochondria and dependent on Caspase-7
An extract of Ranunculus ternatus induced cell death by a caspase-7-dependent route that did not require mitochondrial involvement, which is unusual for a plant extract and distinguishes its cytotoxic mechanism from the common mitochondrial apoptosis pathway.
Mechanism of total saponins of Ranunculus ternatus Thunb. in treatment of breast cancer based on liquid chromatography–mass spectrometry and network analysis
The total saponin fraction of the root was characterised by LC-MS and its antitumour targets in breast cancer predicted by network analysis and then tested experimentally. It supports the traditional use of the drug for breast lumps and nodules but does not establish a clinical dose.
Ranunculus ternatus Thunb. alkaloids attenuate colorectal cancer metastasis through EMT suppression
The alkaloid fraction of Ranunculus ternatus reduced colorectal cancer metastasis, the authors attributing the effect to suppression of epithelial-mesenchymal transition. Alkaloids are a minor constituent class in this drug, only six of the 103 constituents catalogued.
References
- Changlin Wang, Jieqiong Wang, Mingzhou Gao, Peng Gao, Dongmei Gao, Hao Zhang, Xiangyu Mu, Mingqi Qiao. Radix Ranunculi ternati: review of its chemical constituents, pharmacology, quality control and clinical applications . Journal of Pharmacy and Pharmacology (2022) [DOI]
- Jing-Kui Tian, Feng Sun, Yi-Yu Cheng. Chemical Constituents from the roots of Ranunculus ternatus . Journal of Asian Natural Products Research (2006) [DOI]
- Yun-Lei Dai, Qing-Zhi Liu, Jian Wang, Meng Sun, Feng-Jv Niu, Hao-Cheng Wei, Chang-Zheng Zhou, Li Zhang. The genus Ranunculus L. (Ranunculus) in Asia: a review of its botany, traditional uses, phytochemistry, pharmacology, toxicity, and pharmaceutical preparations . Journal of Pharmacy and Pharmacology (2024) [DOI]
- Betelhem Sirak, Misgana Aragaw, Solomon Tadesse. Ranunculin, Protoanemonin, and Anemonin: Pharmacological and Chemical Perspectives . Current Medicinal Chemistry (2025) [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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