Isorhynchophylline (Uncaria Oxindole Alkaloid · Neuroprotective)
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Compound | Isorhynchophylline |
| Chemical class | Alkaloid — Indole (tetracyclic oxindole; heteroyohimbine-related) |
| CAS | 6859-01-4 |
| Primary source | Uncaria rhynchophylla (Gou Teng), stems with hooks |
| Key applications | Neuroprotective; antihypertensive; calcium-channel modulation; research context |
| Claim strength | Emerging |
| Typical form | Uncaria rhynchophylla extract standardised to oxindole alkaloids (availability on request) |
| Buy from Herbuno | Availability on request — request bulk pricing → |
Name origin: Isorhynchophylline is the iso- (stereoisomeric) form of rhynchophylline, both named for Uncaria rhynchophylla — the rhyncho- element ("beak" or "hook") referring to the plant’s characteristic curved, hook-bearing stems. It is a tetracyclic oxindole indole alkaloid, a structural type distinguished by its spiro-fused oxindole system. Traditional use: Uncaria rhynchophylla (Gou Teng, the "hook vine") is a classical Chinese materia medica herb, categorised as liver-pacifying and wind-extinguishing, and used in formulae for headache, dizziness, hypertension, convulsions, and conditions that today would be described in neurological and cardiovascular terms. The hooked stems are the part traditionally used, and isorhynchophylline is one of the oxindole alkaloids that account for part of the herb’s reputed activity. Research trajectory: Isorhynchophylline is a principal oxindole alkaloid of the plant and has drawn sustained attention for antihypertensive and neuroprotective activity; a dedicated review summarises its actions on the cardiovascular and central nervous systems and their proposed calcium-channel and autophagy-related mechanisms Zhou 2012. Bioassay-guided isolation identified isorhynchophylline, together with rhynchophylline, as a major active constituent protecting neurons against beta-amyloid-induced toxicity by reducing intracellular calcium overload and tau hyperphosphorylation Xian 2012. Commercial source: Isorhynchophylline-standardised Uncaria rhynchophylla extract is available from Herbuno on request; note that Herbuno’s Gambier (Uncaria gambir) products are standardised for catechins and tannins, not for the rhynchophylline-type oxindole alkaloids, so a distinct Uncaria rhynchophylla material is required.
Evidence for Isorhynchophylline Applications
Neuroprotection: In a well-established beta-amyloid neurotoxicity model in PC12 cells, isorhynchophylline (with rhynchophylline) significantly reduced neuronal cell death, intracellular calcium overload, and tau hyperphosphorylation, marking it as a major active neuroprotective constituent of Uncaria rhynchophylla identified through bioassay-guided fractionation Xian 2012. Claim strength: Emerging.
Cardiovascular activity: Isorhynchophylline shows antihypertensive, bradycardic, and antiarrhythmic effects in preclinical models, attributed largely to modulation of calcium ion channels, and these cardiovascular actions are a central focus of the reviewed pharmacology Zhou 2012. Claim strength: Emerging.
Autophagy and CNS mechanisms: Proposed mechanisms include the induction of autophagy and the protection of neural and neuroglial cells against beta-amyloid toxicity, of interest for research into vascular dementia and amnesia, though these remain preclinical findings Zhou 2012. Claim strength: Emerging.
Relationship to rhynchophylline: Isorhynchophylline and its isomer rhynchophylline co-occur in the plant and are frequently studied together as the principal bioactive oxindole alkaloids, with bioassay-guided work identifying both as the major contributors to the herb’s neuroprotective activity Xian 2012. Claim strength: Emerging.
Distinct from catechin-type Uncaria products: Isorhynchophylline is an oxindole alkaloid of Uncaria rhynchophylla, chemically unrelated to the catechins and tannins that are standardised in Uncaria gambir (Gambier) products, so material intended to deliver isorhynchophylline must be sourced and standardised specifically for the oxindole alkaloids rather than for catechin content Zhou 2012. Claim strength: Emerging.
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Dosage & Formulator Specification
Isorhynchophylline is at an early, preclinical stage of evidence, and no established human dose exists. Research uses have applied it in animal models at tens of milligrams per kilogram — for example, oral doses of 20 or 40 mg/kg in rodent cognition studies — but these do not translate to human supplement dosing and are cited only for scientific context, not as a dosing recommendation.
For formulators, the practical material is Uncaria rhynchophylla extract standardised to total oxindole alkaloids (rhynchophylline plus isorhynchophylline) by HPLC. This is a genuinely different ingredient from Uncaria gambir (Gambier) extracts, which are standardised for catechins and tannins and do not deliver the rhynchophylline-type alkaloids at all; conflating the two Uncaria species would be a sourcing error. Isorhynchophylline-standardised Uncaria rhynchophylla material is available from Herbuno on request.
Given the alkaloids’ cardiovascular activity — blood-pressure lowering and heart-rate effects in preclinical models — responsible formulation and labelling should reflect the early evidence base and avoid therapeutic claims. Standardisation to a defined total-oxindole-alkaloid content, with the rhynchophylline-to-isorhynchophylline ratio specified where an application requires it, is the appropriate commercial specification, and batch-level HPLC assay is advisable given natural variation in alkaloid content with plant source and part.
The distinction between the two Uncaria species is worth stating plainly because it is a genuine sourcing trap. Uncaria gambir and Uncaria rhynchophylla share a genus name but deliver entirely different chemistry: gambir is a catechin-and-tannin source used in leather-tanning and as a polyphenol ingredient, while rhynchophylla is the source of the neuroactive oxindole alkaloids discussed here. A buyer who specifies "Uncaria extract" without pinning down species and standardisation target could easily receive material with none of the isorhynchophylline the application requires, which is exactly why this monograph is explicit about the species and the oxindole-alkaloid specification.
This monograph documents isorhynchophylline as a formulator reference within the HerbIQ index, distinguishing the oxindole-alkaloid Uncaria rhynchophylla material from the catechin-standardised Gambier products, and positions the compound honestly as an early-evidence ingredient available on request rather than a finished, clinically validated product.
Frequently Asked Questions — Isorhynchophylline
What is isorhynchophylline?
Isorhynchophylline is a tetracyclic oxindole indole alkaloid from Uncaria rhynchophylla (Gou Teng), a hook-bearing vine used in traditional Chinese medicine. It is studied for cardiovascular and neuroprotective activity and is one of the plant’s principal bioactive oxindole alkaloids.
What is isorhynchophylline studied for?
Preclinical research reports antihypertensive effects and neuroprotection against beta-amyloid toxicity, mediated in part by modulation of calcium channels and by reduction of tau hyperphosphorylation; some studies also report induction of autophagy. Clinical evidence in humans is limited, so the claim strength is early-stage.
Can I source isorhynchophylline from Herbuno?
Isorhynchophylline-standardised Uncaria rhynchophylla extract is available on request. It is important to note that Herbuno’s current Uncaria products are Gambier (Uncaria gambir) extracts standardised for catechins and tannins, which do not deliver the rhynchophylline-type oxindole alkaloids; a distinct Uncaria rhynchophylla material is required.
How does isorhynchophylline differ from rhynchophylline?
They are isomeric oxindole alkaloids of Uncaria that co-occur in the plant and are frequently studied together. Both show neuroprotective and cardiovascular activity in preclinical models, and they differ in the configuration of the oxindole system, which can influence their relative potencies.
Related compounds: Rhynchophylline, Mitragynine, Yohimbine, Reserpine
Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.
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