Gou Teng
StarUncaria rhynchophylla (Miq.) Miq. ex Havil.
Traditionally used for
- Headaches
- Dizziness
- Mood & calm
- Nerves & recovery
- Blood pressure
☯ TCM Properties
Extinguishes Wind and Stops Spasms; Courses the Liver and Drains Heat; Calms the Liver and Subdues Yang
Traditional Chinese Uses
Gou Teng (gambir vine stem and thorns) is a cool herb that calms Liver Yang and clears Liver Heat, making it important for headache, dizziness, irritability, and hypertension from Liver Yang rising. It is one of the most important herbs for internally generated Wind — calming spasms, tremors, and convulsions in children and adults. Its ascending cooling nature makes it suitable for neurological conditions involving internal Wind and Heat.
Pharmacological Effects
- Hypotensive: Decoction, ethanolic extract, total alkaloids and rhynchophylline lowered blood pressure i.v. or orally without tachyphylaxis (e.g. 30-40% drop for 3-4 h in anesthetized rabbits/dogs; renal hypertensive rats lowered 12-18 mmHg after 15-20 days oral). Total alkaloids caused bradycardia and reduced peripheral resistance in dogs; rhynchophylline, corynoxeine and isomers were calcium antagonists on rat/rabbit aorta; 3α-dihydrocadambine and 3β-isodihydrocadambine were hypotensive i.v. in rats.
- Sedative and anticonvulsant: Decoction or ethanolic extract (0.1 g/kg i.p.) reduced spontaneous activity in mice for 3-4 h and antagonized caffeine, but had no hypnotic action; ethanolic extract (2 g/kg s.c.) suppressed experimental epilepsy in guinea pigs, with relapse 3 days after stopping.
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 525.
Used In Formulas (16)
Relationships
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Botanical Description
Uncaria rhynchophylla is an evergreen woody climbing liana in the family Rubiaceae, native to the broadleaved evergreen forests and forest margins of southern China, Taiwan, Japan, Korea, and parts of Southeast Asia. The plant climbs by means of paired, recurved, hooklike modified peduncles that develop in the leaf axils, giving rise to the common name gambir hook. Mature vines can extend 10 m or more, with slender greyish-brown stems bearing opposite, ovate-lanceolate leaves 5-12 cm long that are glabrous above and slightly pubescent on the veins beneath. Small yellowish flowers are densely packed into solitary, globose terminal heads about 2-3 cm in diameter, blooming in summer. The fruits are small capsules with winged seeds adapted to wind dispersal. The medicinal portion comprises the hook-bearing stem segments collected from older vines.
Active Constituents
Rhynchophylline
Tetracyclic oxindole alkaloid (monoterpenoid indole alkaloid)Concentration: total alkaloids of the hooked stem are reported at roughly 0.2%, of which rhynchophylline makes up about 28-50%; content is highest in bark, then stem, then hooked stem, then leaves
The principal alkaloid and the compound most of the neuropharmacology is built on. It is a non-competitive antagonist at NMDA-type ionotropic glutamate receptors, an inhibitor of EphA4 tyrosine kinase, and suppresses microglial inflammation by downregulating MAPK and NF-κB signalling; it also protects dopaminergic neurons in MPP+ models through the PI3K/Akt/GSK3β cascade acting on MEF2D.
Its stability is a practical dosing issue, not a footnote. Wu et al. (2015) measured thermal degradation and epimerisation directly: after 10 minutes at 50 degrees C rhynchophylline lost 4.4% and isorhynchophylline 2.3%, but after 10 minutes at 90 degrees C the losses were 41.4% and 18.8% respectively, and continued heating at 90 degrees C drives the pair to an equilibrium mixture in about 50 minutes. Rhynchophylline had a half-life of 0.81 days at 90 degrees C against 3.10 days for isorhynchophylline. This is the quantitative basis for the long-standing rule that Gou Teng is added late (hou xia) in the last few minutes of a decoction: a herb boiled with the rest of the formula for 30-40 minutes delivers a substantially degraded and re-equilibrated alkaloid fraction.
Isorhynchophylline
Tetracyclic oxindole alkaloid (C-7 epimer of rhynchophylline)Concentration: roughly 15% of the total alkaloid fraction
The C-7 stereoisomer of rhynchophylline, with a broadly similar but not identical profile - it differs in its pattern of MAPK phosphorylation, protects against amyloid beta-induced injury through PI3K/Akt/GSK-3β signalling, and inhibits tau hyperphosphorylation. The two epimers interconvert on heating, which means a decoction does not deliver the ratio present in the raw herb.
Corynoxeine and isocorynoxeine
Oxindole alkaloidsConcentration: minor alkaloids of the hooked stem; quantified together with the rhynchophylline pair in Pharmacopoeia-style four-alkaloid assays
The second epimeric pair of oxindole alkaloids in the drug. Together with rhynchophylline and isorhynchophylline they are the four alkaloids Lei et al. (2023) identified as pregnane X receptor activators, which is the mechanism behind the herb's CYP3A4 induction.
Corynoxine and corynoxine B
Oxindole alkaloidsConcentration: minor constituents; not routinely assayed in commercial material
Autophagy inducers. Corynoxine B promotes clearance of alpha-synuclein and amyloid precursor protein C-terminal fragments through Beclin-1 and HMGB1/2 binding; corynoxine acts through the Akt/mTOR pathway and TFEB/TFE3 activation. Both have limited brain permeability and low bioavailability in their native form, which is why the neuroprotection literature works with chemically modified derivatives - a caution against reading those findings straight across to a decoction.
Hirsutine and hirsuteine
Indole alkaloidsConcentration: minor alkaloids of the hooked stem
Non-oxindole indole alkaloids of the drug. Hirsuteine, together with the uncarialines, is reported to act as a 5-HT1A receptor agonist, which is relevant when considering combination with serotonergic drugs.
Geissoschizine methyl ether
Indole alkaloidConcentration: minor constituent of the hooked stem
An indole alkaloid of the Uncaria hook that is repeatedly identified as a central actor in the neuropsychiatric pharmacology of Uncaria-containing formulas. Like the other alkaloids it is heat-labile in decoction.
⚠ Drug Interactions
CYP3A4 substrates (ciclosporin, tacrolimus, midazolam, statins, many oral anticancer agents, some direct oral anticoagulants)
Lei et al. (2023) showed that Gou Teng extract activates the pregnane X receptor in a dose-dependent manner and induces CYP3A4 expression, and identified the responsible compounds as isocorynoxeine, rhynchophylline, isorhynchophylline and corynoxeine - the four main oxindole alkaloids of the drug. The direction of this interaction is induction rather than inhibition, so the practical risk is under-exposure to the co-administered drug rather than toxicity. The same paper examined Uncaria tomentosa (cat's claw), which is a different species with a different alkaloid profile and should not be assumed to behave identically.
Clinical note: Take particular care where loss of drug effect is dangerous: transplant immunosuppression, HIV protease inhibitors, oral anticancer agents, hormonal contraception and antiepileptics. Where a narrow-therapeutic-index CYP3A4 substrate is involved, either avoid Gou Teng or arrange drug-level monitoring, and re-check levels when the herb is stopped, since induction reverses over days to weeks.
Antihypertensives (calcium channel blockers, ACE inhibitors, ARBs)
Gou Teng is the alkaloid-bearing herb in Tianma Gouteng Yin, the formula most studied as an adjunct in essential hypertension. Wang et al. (2013) reviewed 22 randomised controlled trials of the formula added to conventional antihypertensives and found blood pressure improved in five subgroups, while noting that methodological quality was generally low and safety remained uncertain. Tai et al. (2020) pooled 14 trials with 1,537 patients comparing nifedipine plus Tianma Gouteng decoction against nifedipine alone and found a significantly higher total efficacy rate for the combination. Both are formula-level, not herb-level, evidence, and neither isolates the contribution of Uncaria.
Clinical note: Expect an additive effect rather than an independent one. Monitor blood pressure when Gou Teng or a Gou Teng formula is started alongside antihypertensive therapy, particularly in elderly patients, and warn about postural symptoms. Do not use it as a replacement for antihypertensive medication.
Benzodiazepines, sedating antihistamines, opioids and other CNS depressants
The alkaloids of the drug act on CNS targets that overlap with sedative pharmacology - NMDA receptor antagonism by rhynchophylline, 5-HT1A agonism reported for hirsuteine and the uncarialines. No human interaction study has been performed, so this is a mechanistic expectation rather than a documented event.
Clinical note: Warn patients about drowsiness when Gou Teng is combined with sedatives, and take the usual care with driving. Be alert to serotonergic overlap if the patient is on an SSRI, SNRI or triptan, though no case of serotonin syndrome attributable to Gou Teng has been published.
Warfarin and antiplatelet agents
Huang et al. (2023) isolated five new alkaloids, uncarialines A-E, from Uncaria rhynchophylla and reported anticoagulant activity for them. This is isolated-compound in vitro work on minor constituents; there is no whole-herb coagulation study and no human data. Recorded so that an unexplained INR change in a patient on Gou Teng is not dismissed, not because the interaction is established.
Clinical note: No routine action required. If a patient on warfarin shows an unexplained INR rise after starting a Gou Teng formula, consider the herb among the possible causes rather than excluding it.
Uncaria tomentosa (cat's claw) and Uncaria guianensis - confusion of drugs sharing an English name
Uncaria rhynchophylla (Gou Teng, the hooked stem) and Uncaria tomentosa (cat's claw, the inner bark) are different species used for different purposes and containing different alkaloid mixtures. Lei et al. (2023) examined both in the same PXR study precisely because they are distinct botanicals sold under overlapping names. A patient's Western herbal cat's claw supplement is not a source of rhynchophylline, and evidence about one species should not be applied to the other.
Clinical note: Record the binomial, not the common name, in the notes. When a patient reports taking cat's claw, establish whether it is U. tomentosa or U. rhynchophylla before assessing interactions.
Other Uncaria species dispensed as Gou Teng (U. macrophylla, U. hirsuta, U. sinensis, U. sessilifructus)
Several Uncaria species are accepted as botanical sources of the Pharmacopoeia drug Gou Teng, so material dispensed under the pinyin name is not necessarily U. rhynchophylla. Alkaloid content also varies with the plant part supplied - Zhang et al. (2017) found rhynchophylline and isorhynchophylline highest in bark, then stem, then hooked stem, then leaves, and studies of U. macrophylla populations found alkaloid content varied significantly with growing-season rainfall. Material that is mostly stem or leaf rather than hook will differ in potency.
Clinical note: Specify the species and the plant part (hooked stem, not leaf or plain stem) when ordering, and expect potency to vary between suppliers. This is a dose-consistency issue rather than a toxicity one.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction (added late) | 3–12 g | Daily | — | — | 中国药典 2020 【用法与用量】3～12g，后下。 【性味与归经】甘，凉。归肝、心包经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Together they cool the liver and extinguish wind, arresting convulsions and spasms caused by extreme heat stirring liver wind.
High fever with convulsions in warm disease.
Core pair of a classical formula — Ling Jiao Gou Teng Tang, Tong Su Shang Han Lun (Yu Genchu)
The heavy, sinking action of one anchors ascendant liver yang while the other clears heat and extinguishes wind, together relieving headache, dizziness and tremor.
In this formula Tian Ma and Gou Teng are chief and Shi Jue Ming is a deputy.
Core pair of a classical formula — Tian Ma Gou Teng Yin, Za Bing Zheng Zhi Xin Yi (Hu Guangci)
Together they calm the liver and extinguish wind more strongly than either alone, addressing dizziness, headache and tremor from ascendant liver yang or internal wind.
Core pair of a classical formula — Tian Ma Gou Teng Yin, Za Bing Zheng Zhi Xin Yi (Hu Guangci)
Evidence Tier
Strong 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
2
0 verified · 2 unverified
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
3
0 verified · 3 unverified
Show 3 studies
- Structural Stabilities and Transformation Mechanism of Rhynchophylline and Isorhynchophylline by Ultra Performance Liquid Chromatography/Time-of-Flight Mass Spectrometry (UPLC/Q-TOF-MS)
- Identification of PXR Activators from Uncaria Rhynchophylla (Gou Teng) and Uncaria Tomentosa (Cat’s Claw)
- Chemical and biological comparison of different sections of Uncaria rhynchophylla (Gou-Teng)
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
Structural Stabilities and Transformation Mechanism of Rhynchophylline and Isorhynchophylline by Ultra Performance Liquid Chromatography/Time-of-Flight Mass Spectrometry (UPLC/Q-TOF-MS)
The thermal behaviour of rhynchophylline and isorhynchophylline was measured across temperatures and heating times. At 50 degrees C for 10 minutes losses were 4.4% and 2.3% respectively; at 90 degrees C for 10 minutes they were 41.4% and 18.8%. Continued heating drove interconversion to an equilibrium of roughly 7:3 after about 50 minutes at 90 degrees C, 100 minutes at 80 degrees C or 150 minutes at 70 degrees C. Half-lives at 90 degrees C were 0.81 days for rhynchophylline and 3.10 days for isorhynchophylline, with activation energies of 87.01 and 81.26 kJ/mol. The authors concluded that lower temperatures and shorter heating better preserve both compounds. This is the quantitative evidence behind the practice of adding Gou Teng late in the decoction.
Identification of PXR Activators from Uncaria Rhynchophylla (Gou Teng) and Uncaria Tomentosa (Cat’s Claw)
Gou Teng extract activated the pregnane X receptor dose-dependently and induced CYP3A4 expression. Activity-guided fractionation identified isocorynoxeine, rhynchophylline, isorhynchophylline and corynoxeine as the PXR activators responsible. The study gives a defined molecular mechanism for a herb-drug interaction with CYP3A4 substrates, and distinguishes U. rhynchophylla from the separately examined U. tomentosa.
Tianma Gouteng Yin as Adjunctive Treatment for Essential Hypertension: A Systematic Review of Randomized Controlled Trials
Twenty-two randomised controlled trials of Tianma Gouteng Yin added to conventional antihypertensive therapy. Blood pressure improved in five subgroups, and Chinese medicine syndrome scores improved in the ACE inhibitor, calcium channel blocker and combined ACE inhibitor plus calcium channel blocker groups. The reviewers judged methodological quality generally low and stated that the safety of the formula remains uncertain. This is evidence about an eleven-herb formula containing Uncaria rhynchophylla, not about the herb alone.
Randomized Controlled Trials of Tianma Gouteng Decoction Combined with Nifedipine in the Treatment of Primary Hypertension: A Systematic Review and Meta-Analysis
Fourteen trials with 1,537 patients (769 receiving nifedipine plus Tianma Gouteng decoction, 768 receiving nifedipine alone) were pooled. The combination showed a significantly improved total efficacy rate over nifedipine alone. As with the 2013 review, this is formula-level evidence in which Uncaria rhynchophylla is one of eleven ingredients, and the included trials are predominantly Chinese-language with the methodological limitations typical of that literature.
Chemical and biological comparison of different sections of Uncaria rhynchophylla (Gou-Teng)
Different anatomical sections of Uncaria rhynchophylla were compared chemically and biologically. Rhynchophylline and isorhynchophylline content was highest in the bark, followed by stem, hooked stem and leaves. This matters for dispensing, because the official drug is the hooked stem and material padded with plain stem or leaf will carry a different alkaloid load than the assay on the bark-rich fraction would suggest.
⚠ Safety & Contraindications
Contraindications
It is not suitable for the weak and patients without fire.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 313–318.
Historical Texts
Ming Yi Bie Lu
Six Dynasties (attributed to Tao Hongjing, c. 500 CE)Ben Cao Gang Mu
Ming dynasty (1596)References
- Leilei Chen, Yingjuan Liu, Junxia Xie. The beneficial pharmacological effects of Uncaria rhynchophylla in neurodegenerative diseases: focus on alkaloids . Frontiers in Pharmacology (2024) [DOI]
- Ke-Pu Huang, Li-Li Xu, Sheng Li, Yin-Ling Wei, Lian Yang, Xiao-Jiang Hao, Hong-Ping He, Yu Zhang. Uncarialines A-E, new alkaloids from Uncaria rhynchophylla and their anticoagulant activity . Natural Products and Bioprospecting (2023) [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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