Shui Duo Nian
StarRhodomyrtus tomentosa (Aiton) Hassk.
Synonyms: Myrtus tomentosa Aiton, Rhodomyrtus tomentosa (Aiton) Hassk., 桃金娘根, 水哆哟
Traditionally used for
- Digestion
- Bowel health
- Menstrual & women's health
- Pain & joints
- Skin
- Liver & jaundice
☯ TCM Properties
Eliminates Dampness and dispels Wind; Controls bleeding; Alleviates pain
Traditional Chinese Uses
Sweet and sour with a neutral nature, Shui Duo Nian (rose myrtle root) eliminates Dampness and dispels Wind, controls bleeding and alleviates pain. It is used mainly for Wind-Damp painful obstruction (rheumatic joint and low-back or foot pain), and as a Blood-astringing herb for uterine bleeding (metrorrhagia), haemorrhoidal bleeding and other chronic haemorrhage. It also settles epigastric and abdominal pain from disharmony of the middle burner and is applied to hepatitis, chronic dysentery and diarrhoea. Externally the root or leaf decoction is used to wash and stanch bleeding wounds, and it features in folk remedies for snakebite and corneal injury. It is a southern-Chinese folk herb, typically decocted 6–15 g; the sour-astringent action suits leakage and bleeding patterns rather than acute excess-Heat.
Relationships
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Botanical Description
Shui Duo Nian (水哆哟) is the root of Rhodomyrtus tomentosa (Aiton) Hassk., the rose myrtle or downy myrtle (Myrtaceae). It is an evergreen shrub 1–2(–3) m tall with young branches, undersides of leaves and buds densely covered in soft grey-white tomentum. The opposite, leathery leaves are elliptic with three prominent longitudinal veins. Showy five-petalled flowers 2–4 cm across open rose-pink to purplish, followed by fleshy, dark purple, edible berry-like fruits crowned by the persistent calyx. The medicinal part is the woody root, dug year-round, washed, sliced and sun-dried; leaves and fruit are used secondarily. It thrives on acidic hill soils and can form dense thickets.
Sunny hill slopes, open pine woodland, heathy grassland and disturbed acidic soils at low to middle elevations in the humid subtropics.
Active Constituents
Betulinic acid
Lupane-type pentacyclic triterpeneConcentration: Isolated from the roots; not quantified in the root drug
One of thirteen compounds isolated from the roots of Rhodomyrtus tomentosa specifically, rather than from the better-studied leaf. Betulinic acid and the related lupeol, betulin and friedelin from the same root fraction showed inhibitory activity against SK-MEL-110 melanoma cells in MTT assay. It has broadly documented anti-inflammatory activity, which is consistent with the drug's traditional use for rheumatic pain.
Betulin, lupeol and friedelin
Pentacyclic triterpenesConcentration: Isolated from the roots; not quantified
Triterpene companions of betulinic acid in the root, all of which inhibited melanoma cell growth in the same in vitro screen. These are structural triterpenes of low oral bioavailability and their in vitro cytotoxicity should not be read as an anticancer indication.
2-alpha,3-beta,23-trihydroxyoleana-11,13(18)-dien-28-oic acid
Oleanane-type triterpene acidConcentration: Isolated from the roots; reported from this plant for the first time in 2016
An oleanane triterpene acid characterised from the root together with 3-beta,23-dihydroxyolean-18-en-28-oic acid, both showing inhibitory activity against melanoma cells in vitro. No in vivo or human data exist.
Gallic acid and methyl gallate
Phenolic acidsConcentration: Isolated from the roots; not quantified
Simple phenolics of the root fraction with astringent and antioxidant properties. Together with the tannin content they provide the most plausible chemical basis for the traditional haemostatic and anti-diarrhoeal uses of the root.
Tannins (including ellagitannins)
Hydrolysable and condensed polyphenolsConcentration: Documented in the plant; the root and root bark are the astringent parts used traditionally
Astringent polyphenols that precipitate surface proteins on mucosa and wound beds. They are the classical basis of the stops bleeding and treats dysentery indications, and they are also the source of the herb's only well-grounded interaction risk, since tannins chelate dietary and supplemental iron.
Rhodomyrtone
AcylphloroglucinolConcentration: Concentrated in the LEAF, not the root; leaf-derived rhodomyrtone has an MIC of 0.5-1 microgram/mL against most Gram-positive pathogens
The single most studied compound of this species and the reason it appears in the antibacterial literature. It is highly active against Gram-positive bacteria including biofilm-forming staphylococci and Streptococcus pneumoniae. The important qualification for this record is that rhodomyrtone is a leaf constituent: the phytochemical study of the root recovered triterpenes, sterols, phenylpropanoids and gallates, not rhodomyrtone. Antibacterial claims for Radix Rhodomyrti should not be inherited from leaf research.
Piceatannol
StilbeneConcentration: Described in reviews as a major phenolic of Rhodomyrtus tomentosa; not localised to the root in the primary root phytochemistry
A hydroxylated stilbene analogue of resveratrol with antioxidant and anti-inflammatory activity, repeatedly named among the principal phenolics of this species. As with rhodomyrtone, the reported distribution across plant parts is uneven and the root has not been shown to be a significant source.
beta-Sitosterol
PhytosterolConcentration: Isolated from the roots; not quantified
A ubiquitous plant sterol recovered from the root fraction. It is a marker of the lipophilic extract rather than an active in this context.
⚠ Drug Interactions
Oral iron salts and other divalent mineral supplements (calcium, zinc)
The root of Rhodomyrtus tomentosa is used traditionally as an astringent, and gallic acid, methyl gallate and tannins have been isolated from it. Hydrolysable tannins and gallates form insoluble complexes with non-haem iron and other divalent cations in the gut lumen, which is a general and well characterised property of tannin-rich astringent decoctions. There is no study of this specific herb with iron, so the interaction is inferred from constituent class rather than demonstrated for this drug.
Clinical note: Separate the decoction from iron, calcium or zinc supplements by at least two hours. This matters most in the herb's traditional indications of uterine bleeding and haemorrhoidal bleeding, where the patient may be iron-deficient and supplemented.
Antibiotics active against Gram-positive organisms (clindamycin, macrolides, beta-lactams)
Rhodomyrtone from the leaf is a potent Gram-positive antibacterial, and a randomised trial found 1% liposomal rhodomyrtone serum comparable to 1% clindamycin gel for inflammatory acne. Any additive effect would be pharmacodynamic and topical. This is flagged as theoretical for two reasons: no co-administration study exists, and the record here is the root, from which rhodomyrtone has not been reported.
Clinical note: No action is required, but do not assume the root carries the leaf's antibacterial activity, and do not substitute a root preparation where the evidence concerns leaf-derived rhodomyrtone.
No established human drug interactions
A deliberate negative entry. A search of the pharmacological literature for Rhodomyrtus tomentosa turns up no human pharmacokinetic or drug interaction studies of any kind, and none at all for the root. The species has no reported CYP or transporter interaction data, no anticoagulant interaction data, and no reported herb-drug adverse event reports. Claims to the contrary in secondary compilations should be treated as unsupported until a primary source is produced.
Clinical note: Record the absence of data as an absence, not as a safety finding. Systemic use during pregnancy, lactation or alongside narrow therapeutic index drugs cannot be supported on current evidence.
Evidence Tier
Moderate evidence · 4 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
1
0 verified · 1 unverified
Other clinical trial
0
Observational / case report
0
In vitro / animal
3
0 verified · 3 unverified
Show 3 studies
- Chemical Constituents from the Roots of Rhodomyrtus tomentosa
- Rhodomyrtus tomentosa (Aiton) Hassk. ethanol extract and rhodomyrtone: a potential strategy for the treatment of biofilm-forming staphylococci
- In vivo safety assessment of rhodomyrtone, a potent compound, from Rhodomyrtus tomentosa leaf extract
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 Rhodomyrtus tomentosa
The only substantial phytochemical study located that examines the root, which is the part this record specifies. Column chromatography of the roots yielded thirteen compounds: two oleanane triterpene acids, lupeol, betulin, betulinic acid, friedelin, beta-sitosterol, a diarylpropanol, evafolin B, beta-hydroxypropiovanillone, a bis-dihydroconiferyl diferuloylate, gallic acid and methyl gallate. Six of these were reported from the plant for the first time. Compounds 1 to 6, the triterpenes and sterol, inhibited SK-MEL-110 melanoma cells in MTT assay. Notably, rhodomyrtone, the compound that carries nearly all of this species' antibacterial reputation, was not among the root constituents recovered.
Rhodomyrtone as a New Natural Antibiotic Isolated from Rhodomyrtus tomentosa Leaf Extract: A Clinical Application in the Management of Acne Vulgaris
A randomised, double-blind controlled trial in 60 volunteers with mild to moderate acne compared a 1% liposomal encapsulated rhodomyrtone serum with a marketed 1% clindamycin gel, applied twice daily. Both groups showed significant reduction in total acne lesions from week 2 to week 8. At the end of the trial, inflamed acne counts fell by 36.36% with rhodomyrtone and 34.70% with clindamycin. A separate assessment of a commercial prototype in 45 volunteers found complete resolution of inflammatory acne in 68.89% and improvement in 28.89% after one week, with no irritation reported. The crucial qualification for this record is that the trial used rhodomyrtone isolated from the LEAF, not the root drug Radix Rhodomyrti that this entry describes.
Rhodomyrtus tomentosa (Aiton) Hassk. ethanol extract and rhodomyrtone: a potential strategy for the treatment of biofilm-forming staphylococci
An ethanol extract of Rhodomyrtus tomentosa and the isolated compound rhodomyrtone were assessed against biofilm-forming staphylococci, supporting their potential for treating staphylococcal biofilm infections. This is in vitro work on a leaf-derived extract and compound; it does not establish activity for the root preparation, and it does not establish clinical efficacy in any indication.
In vivo safety assessment of rhodomyrtone, a potent compound, from Rhodomyrtus tomentosa leaf extract
Rhodomyrtone was assessed in Galleria mellonella, zebrafish embryos, mice and human erythrocytes. Galleria showed 100% survival at 100 mg/kg over four days; at least 80% of zebrafish embryos survived 0.5 microgram/mL for three days; rhodomyrtone at 256 microgram/mL caused no observable haemolysis of human erythrocytes; and oral dosing of a rhodomyrtone formulation up to 5000 mg/kg for fourteen days produced no systemic toxicity in mice. Since the MIC against most Gram-positive pathogens is 0.5-1 microgram/mL, the authors argued for a wide safety margin. Again this concerns the leaf-derived isolate, and it is not a safety assessment of the root drug or of any whole-plant preparation.
Historical Texts
Sheng Cao Yao Xing Bei Yao
Qing dynasty (1711)Ling Nan Cao Yao Zhi
Modern era, twentieth century (Guangdong regional materia medica)References
- Zhao Z, Wu L, Xie J, Feng Y, Tian J, He X, Li B, Wang L, Wang X, Zhang Y, Wu S, Zheng X. Rhodomyrtus tomentosa (Aiton.): A review of phytochemistry, pharmacology and industrial applications research progress . Food Chemistry (2020) [DOI]
- Vo TS, Ngo DH. The Health Beneficial Properties of Rhodomyrtus tomentosa as Potential Functional Food . Biomolecules (2019) [DOI]
- Chen LY, Luo EE, Pan Y, Liang CQ, Yu MY, Qin XJ. Acetylcholinesterase inhibitory phloroglucinols from tropic Rhodomyrtus tomentosa . Phytochemistry (2024) [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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