The Mitra Project

Corynoxeine

CORYN · CAS 630-94-4

Oxindole alkaloid

Formula

C₂₂H₂₆N₂O₄

Molecular Weight

386.46 g/mol

Abundance in Leaf

0–2%

Last Reviewed

2026-03-12

What Is Corynoxeine?

Corynoxeine is a minor oxindole alkaloid found in small amounts in kratom. Unlike the primary indole alkaloids, corynoxeine does not act at opioid receptors — instead, research shows it inhibits an enzyme called acetylcholinesterase, which breaks down the neurotransmitter acetylcholine. This mechanism is similar to how some Alzheimer's medications work. Early preclinical research suggests potential neuroprotective and anti-inflammatory properties. Corynoxeine is not a primary driver of kratom's well-known effects, but it may contribute to some of the less opioid-like effects users report. It appears on COAs in trace amounts and is an active area of emerging research.

Dose-Dependent Effects

Receptor Activity

ReceptorKi (nM)Activity TypeWhat This Means
AcetylcholinesteraseInhibitorBlocks enzyme that breaks down acetylcholine. Similar mechanism to some Alzheimer's drugs.
Mu-opioid (MOR)InactiveDoes not meaningfully activate opioid receptors.

Safety & Adverse Effects

Research status

Corynoxeine is present only in trace amounts in kratom. Most pharmacological data comes from preclinical (in vitro and animal) studies. No direct adverse effects have been attributed to corynoxeine at the concentrations found in whole-leaf kratom.

Source: Kruegel et al. 2018; Begum et al. 2025

Drug Interactions

Cholinesterase inhibitors (donepezil, rivastigmine)

moderate

Theoretical additive acetylcholinesterase inhibition. Clinical significance at trace kratom concentrations is unknown.

COA Connection

Appears on Certificates of Analysis as: CORYN. Graded under Alkaloid Profile (Trace component).

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Cited Literature

[1]

Kruegel AC, Grundmann O (2018). The medicinal chemistry and neuropharmacology of kratom: A preliminary discussion of a promising medicinal plant and analysis of its potential for abuse. ACS Chem Neurosci.

DOI: 10.1021/acschemneuro.7b00579
[2]

Begum Y, et al. (2025). Phytochemical and pharmacological insights into Mitragyna speciosa: A comprehensive review. Kuwait J Sci.

DOI: 10.1016/j.kjs.2025.100381