Rhatany

Metadata

Approved Indications

Commission E (Germany)

• Approved: Inflammation of the mouth and pharyngeal mucosa
• The Commission E monograph recognizes rhatany root as an effective astringent for topical application in oral and throat conditions
• Published in the Complete German Commission E Monographs (Blumenthal et al., 1998)

ESCOP

• No ESCOP monograph has been published for Ratanhiae radix
• Although the ESCOP website lists a downloadable document on rhatany root (published 2017 as a supplement), it is not a full ESCOP therapeutic monograph in the standard sense. The therapeutic indications referenced in secondary sources for ESCOP — minor inflammations of the mouth and throat (stomatitis, gingivitis, pharyngitis) — appear to derive from a summary document rather than a formal ESCOP assessment equivalent to their standard monograph series
• This represents a notable gap in the European phytotherapy literature

EMA/HMPC

• Traditional use registration: Minor inflammation of the oral mucosa and gums
• Classification as a traditional herbal medicinal product based on long-standing use (minimum 30 years, including at least 15 years within the EU)
• The EMA monograph supports use of rhatany root preparations (tincture, decoction) for topical application in the oral cavity
• The indication is narrower than the Commission E approval, specifying oral mucosa and gums rather than including the broader pharyngeal mucosa

Agreement/Disagreement Between Bodies

Commission E and EMA are largely aligned on oral mucosal inflammation as the core indication. The Commission E monograph is somewhat broader, explicitly including pharyngeal mucosa (throat), while the EMA traditional use registration focuses specifically on oral mucosa and gums. The absence of a full ESCOP monograph is noteworthy, particularly given that ESCOP has published monographs for several other tannin-rich drugs (e.g., tormentil). This gap may reflect the limited clinical evidence base rather than any concern about efficacy or safety. All regulatory bodies that have assessed rhatany have approved it only for topical (local) application in the oral cavity, not for systemic internal use.

Conditions Treated

Primary

• Oral mucosal inflammation (stomatitis): The principal approved indication across regulatory bodies; tannin astringency provides direct mucosal protection
• Gingivitis: Inflammation of the gums; rhatany tincture and mouthwash applied directly to gingival tissue
• Minor oral mucosal lesions: Supportive care for aphthous ulcers, minor oral wounds, and irritation

Secondary

• Pharyngitis/sore throat: Included in the Commission E indication; gargling with rhatany decoction or diluted tincture
• Minor GI mucosal irritation: Historical use as an internal astringent for mild diarrhea and gastrointestinal complaints, though this indication is not supported by current regulatory approvals
• Minor oral bleeding: Astringent effect may help control minor bleeding from gums

Traditional/Historical

• South American indigenous uses: The Peruvian Indians used rhatany root for oral hygiene and dental care for centuries before European contact. In Lima during the 18th and 19th centuries, it was traditional for women to use the root to whiten their teeth during festivals and major events. The root was also chewed as a dental stick.
• European pharmaceutical history: Rhatany root was introduced to European medicine by the Spanish botanist Hipolito Ruiz Lopez (1754-1815) following his explorations of the Peruvian highlands. Ruiz observed indigenous women cleaning their teeth with rhatany root, recognized its hemostatic properties through practical experiments, and published his findings upon returning to Spain in 1797. The drug subsequently figured prominently in European and Euro-American medicine between approximately 1820 and 1920.
• Historical European preparations: Rhatany was official in the British Pharmacopoeia and the United States Pharmacopoeia throughout the 19th century. The powdered root was a frequent constituent of tooth powders, typically mixed with orris rhizome and charcoal. Infusions and decoctions were used as gargles, and the tincture was applied directly to bleeding gums and oral lesions. Lozenges containing rhatany (sometimes combined with cocaine in 19th-century practice) were used for sore throat.
• Dye and tanning: Indigenous communities of the Andes used the tannin-rich roots in leather tanning and as a natural red dye source.
• Hemorrhoids and wound care: Historical European herbals describe external application of rhatany decoctions for hemorrhoids, fissured anus, and minor wounds, exploiting the general astringent properties.

Mechanism of Action

1. Proanthocyanidin Tannin Astringency (Primary Mechanism)

• Oligomeric proanthocyanidins constitute the major active compound class (approximately 10-15% of the dried root)
• Scholz and Rimpler (1989) characterized these proanthocyanidins as consisting of 2-14 flavanol units with predominantly 2,3-cis configuration
• The propelargonidin:procyanidin ratio is 65:35, which is an unusual composition among medicinal plant tannins
• The predominant interflavan linkage is [4,8], with [4,6]-bonds present in higher oligomers forming branched chain structures
• Astringency is maximal for proanthocyanidins with degrees of polymerization from 5-10, and these oligomers are the primary astringent compounds in both rhatany tea and tincture
• The mechanism of astringency involves:
  • Protein precipitation: Tannins bind to and cross-link proteins on the mucosal surface, forming an insoluble tannin-protein complex
  • Mucosal barrier formation: The precipitated protein layer creates a protective coating over inflamed or damaged mucosa
  • Reduced permeability: The barrier decreases the passage of irritants, pathogens, and inflammatory mediators across the mucosal surface
  • Anti-exudative effect: Reduced secretion and fluid loss from inflamed tissues
  • Sensory nerve shielding: The protective layer reduces irritation of exposed sensory nerve endings, providing a local analgesic-like effect

2. Anti-inflammatory Activity (Neolignan-Mediated)

• In addition to the nonspecific anti-inflammatory effects of tannin astringency, rhatany contains neolignans and benzofuran derivatives with specific molecular anti-inflammatory targets
• Atanasov et al. (2011) isolated 11 lignan derivatives from the dichloromethane extract of K. lappacea roots and demonstrated:
  • Topical antiedematous activity comparable to indomethacin in a mouse ear in vivo model (ID50 values of 0.31-0.60 micromol/cm2)
  • Two compounds — 2-(2-hydroxy-4-methoxyphenyl)-5-(3-hydroxypropyl)benzofuran and (+)-conocarpan — showed activity profiles similar to hydrocortisone over a 48-hour time course
  • NF-kB inhibition: All 11 lignan derivatives significantly reduced NF-kB-dependent luciferase activity, with four compounds achieving low micromolar IC50 values (1.4-6.4 microM)
  • COX-1 and COX-2 inhibition: Several compounds inhibited cyclooxygenase enzymes with IC50 values of 2.7-7.6 microM, matching indomethacin potency
  • 5-Lipoxygenase inhibition: Compounds including (+)-conocarpan demonstrated inhibition (IC50 18.4 microM)
  • Microsomal prostaglandin E2 synthase-1 (mPGES-1) inhibition: Two compounds with IC50 values of 5.3 and 7.4 microM
  • Significant reduction of leukocyte infiltration (myeloperoxidase activity reduced 24-44%) at all observation times
• These findings demonstrate that the anti-inflammatory activity of rhatany root is not solely attributable to nonspecific tannin astringency but involves defined molecular targets in the arachidonic acid cascade and NF-kB signaling pathway

3. Antimicrobial Activity

• Tannins exhibit broad-spectrum antimicrobial activity by denaturing bacterial surface proteins and disrupting microbial cell membranes
• Scholz and Rimpler (1989) reported significant antimicrobial effects for the proanthocyanidin-rich extract in pharmacological screening
• Neolignans also contribute to inhibition of bacterial and fungal proliferation
• The combination of physical barrier formation (tannin astringency) and direct antimicrobial action provides a dual protective mechanism on oral mucosal surfaces

4. Antioxidant and Photoprotective Activity

• Five lignan derivatives from rhatany root exhibited antioxidant activity with IC50 values ranging from 22-42 microM, comparable to ascorbic acid (IC50 24.2 microM)
• Neolignans from K. triandra roots have demonstrated photoprotective activity in vitro
• Antioxidant activity correlates with ortho-positioned methoxy or hydroxy groups on the benzofuran scaffold

5. Additional Pharmacological Activities (Exploratory)

• PTP1B inhibition: Ratanhiaphenol III has been identified as an inhibitor of protein tyrosine phosphatase 1B (PTP1B), with an IC50 of 20.2 microM. It dose-dependently increased insulin receptor phosphorylation and insulin-stimulated glucose uptake in cultured myotubes. This represents the first documented antidiabetic potential for a rhatany root constituent, but it remains entirely at the in vitro stage.
• Anticoccidial properties: A 2024 study reported anticoccidial effects of K. lappacea root extract with coordinated modulation of CD4 T cells for IL-10 production and antioxidant activity, suggesting potential veterinary applications.

Key Active Constituents Summary

Clinical Evidence Summary

Randomized Controlled Trials

No clinical trials have been conducted on rhatany root preparations for any indication. This is the most significant gap in the evidence base and the primary reason for the D rating. Despite over 200 years of continuous pharmaceutical use in Europe and regulatory approval by both Commission E and EMA, no researcher has undertaken a randomized, controlled, or even an uncontrolled clinical study of rhatany in human subjects with oral mucosal inflammation or any other condition.

Pharmacological Basis in Lieu of Clinical Data

The therapeutic plausibility of rhatany rests on:

1. Well-characterized tannin pharmacology: The astringent mechanism of proanthocyanidin tannins on mucosal surfaces is well-established in pharmacognosy. The protein-precipitation and barrier-formation effects are direct physicochemical phenomena that do not require receptor-mediated activity and are therefore highly predictable from the phytochemical profile.
2. In vivo anti-inflammatory evidence: Atanasov et al. (2011) provided robust in vivo evidence that lignan derivatives from K. lappacea inhibit acute inflammation in a mouse ear edema model at potencies comparable to indomethacin, with defined molecular targets (NF-kB, COX-1/2, 5-LOX, mPGES-1).
3. In vitro antimicrobial data: Antibacterial and antifungal effects demonstrated in pharmacological screening support the traditional use in oral hygiene.
4. Analogy to other tannin drugs: Tormentil (Potentilla erecta), which has a comparable tannin profile, demonstrated clinical efficacy in a small RCT for rotavirus diarrhea (Huber et al., 2007), lending indirect support to the pharmacological plausibility of tannin-rich drugs for mucosal conditions.

Evidence Assessment

The evidence base for rhatany is among the weakest of any herb that holds dual regulatory approval (Commission E + EMA). The approval rests entirely on the length and consistency of traditional use documentation and the pharmacological plausibility of tannin astringency. While the in vivo and in vitro pharmacological data (particularly Atanasov et al., 2011) are methodologically sound and provide mechanistic support, they do not substitute for human clinical trials. The absence of even pilot-level clinical studies in the 21st century is notable and limits confidence in specific therapeutic claims.

European vs US/Anglophone Consensus

Notable commercial presence: Weleda Ratanhia Toothpaste is the most visible rhatany product worldwide, marketed as a natural oral care product containing krameria root extract alongside myrrh and essential oils of peppermint and spearmint. Dr. Hauschka cosmetics also uses rhatany extract. These anthroposophic/natural cosmetic companies have maintained commercial demand for rhatany root, which in turn sustains the wild harvesting supply chain from Peru.

Safety Profile

Contraindications

• Hypersensitivity to Krameria lappacea or any preparation components
• Known allergy to rhatany — rare allergic reactions affecting the lining of the mouth and throat have been reported

Drug Interactions

• No clinically documented drug interactions for topical oral use (which is the approved route of administration)
• Theoretical concern for internal use: Tannins can bind to and precipitate proteins and alkaloids in the gastrointestinal tract, potentially reducing absorption of concomitantly administered oral medications. This is a class effect of all high-tannin preparations, not specific to rhatany. If rhatany is taken internally (an unapproved but traditional use), a separation interval of at least 1 hour from other medications is recommended.
• Tannins may theoretically reduce bioavailability of iron supplements and certain antibiotics if taken simultaneously by mouth

Side Effects

• Generally well tolerated at recommended doses for topical oral use
• Rare allergic reactions in the lining of the mouth and throat have been reported
• Stomach upset is possible if preparations are swallowed
• Nausea may occur with internal use, particularly at higher doses, due to the high tannin content
• Prolonged topical use in the mouth may theoretically irritate mucosal surfaces, though this is not well-documented

Pregnancy/Lactation

• Pregnancy: Insufficient safety data. Not recommended during pregnancy due to lack of safety studies.
• Lactation: Insufficient safety data. Not recommended during breastfeeding.

Toxicology

• No reports of serious toxicity in the published literature
• The long history of pharmaceutical use (over 200 years in Europe) without reports of systemic toxicity provides some reassurance for topical oral use
• Chronic toxicity and mutagenicity data are lacking

Conservation Concern

• Krameria lappacea is an endangered, slow-growing shrub that is destructively harvested from wild populations in the Andean semi-deserts of Peru, southern Ecuador, Bolivia, northern Argentina, and Chile
• The plant is a root hemiparasite, making cultivation difficult
• Commercial harvesting involves uprooting the entire plant, which is destructive and non-sustainable
• The species is becoming increasingly rare and is reportedly commercially extinct in parts of its range
• Sustainable sourcing and adequate management strategies should have high priority
• Practitioners and consumers should seek products from suppliers that can document sustainable or responsibly managed sourcing

Clinical Dosage

Topical Oral Use (Approved Indication)

Historical Internal Use (Not Currently Approved)

Preparation Notes

• Decoction is required rather than simple infusion: the high tannin content and the dense, woody nature of the root bark necessitate boiling for adequate extraction. A simple hot water infusion will not extract sufficient active compounds.
• The tincture (Tinctura Ratanhiae) is the most commonly used pharmaceutical preparation in European practice and is listed in the European Pharmacopoeia.
• For oral mucosal inflammation, topical application (swishing, gargling, or direct painting) is essential; the preparation must have adequate contact time with the affected tissue.
• Do not use in iron vessels: Tannins react with iron salts, forming dark-colored precipitates and reducing the effectiveness of the preparation. Use glass, porcelain, or stainless steel for preparation.

Duration

• Topical oral use: Up to 1-2 weeks for minor oral inflammation
• If symptoms do not improve within one week, medical or dental consultation is advised
• Long-term daily use as a toothpaste ingredient (e.g., Weleda Ratanhia) is generally accepted in practice, though formal safety data for this duration are lacking

Sources

• Commission E Monograph: Ratanhiae radix (Rhatany Root). Published in: Blumenthal M, Busse WR, Goldberg A, et al., eds. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Austin, TX: American Botanical Council; 1998.
• EMA/HMPC Community Herbal Monograph on Krameria triandra Ruiz & Pavon, radix (traditional use registration)
• European Pharmacopoeia: Ratanhiae radix monograph
• Scholz E, Rimpler H. Proanthocyanidins from Krameria triandra root. Planta Med. 1989;55(4):379-384.
• Atanasov AG, Blunder M, Fakhrudin N, et al. Lignan derivatives from Krameria lappacea roots inhibit acute inflammation in vivo and pro-inflammatory mediators in vitro. J Nat Prod. 2011;74(8):1779-1786.
• Behl HM, Sidhu OP, Kumar S, et al. Quantitative analysis of anti-inflammatory lignan derivatives in Ratanhiae radix and its tincture by HPLC-PDA and HPLC-MS. J Pharm Biomed Anal. 2011;56(3):471-476.
• Baumgartner L, Sosa S, Atanasov AG, et al. Ratanhiaphenol III from Ratanhiae radix is a PTP1B inhibitor. Planta Med. 2011;77(16):1822-1827. [PMC3523387]
• Simpson BB. The past and present uses of rhatany (Krameria, Krameriaceae). Econ Bot. 1991;45(3):397-409.
• Carini M, Aldini G, Bombardelli E, et al. Antioxidant and photoprotective activity of a lipophilic extract containing neolignans from Krameria triandra roots. Planta Med. 2002;68(3):193-197.
• Grieve M. A Modern Herbal (1931). Rhatany entry. [botanical.com]
• Wichtl M (ed). Herbal Drugs and Phytopharmaceuticals. 3rd ed. Stuttgart: Medpharm; 2004.
• ESCOP supplement document on Ratanhiae radix (2017)
• Weleda AG. Ratanhia Toothpaste product information. [weleda.com]

Connections

• Compare tannin-mediated astringent mechanism with Tormentil, which has a similar high-tannin profile (15-22%) and overlapping indication for oral mucosal inflammation, but which additionally holds approved indications for diarrhea and has limited clinical trial data
• For oral and pharyngeal inflammation, compare with Sage, which is approved by Commission E, ESCOP, and EMA for the same indication but acts through a different mechanism (essential oil and rosmarinic acid rather than tannin astringency)
• For wound healing and mucosal repair, compare with Calendula, which is used topically for oral and skin inflammation through different anti-inflammatory pathways
• Rhatany belongs to the broader European tradition of “tannin drugs” (Gerbstoffdrogen) alongside tormentil, agrimony, and oak bark, all of which share the fundamental mechanism of mucosal protein precipitation and barrier formation
• The conservation status of wild rhatany contrasts with the easy cultivability of most European astringent herbs, raising ethical sourcing questions for practitioners