Metabolite Profiling of Antiaddictive Alkaloids from Four Mexican Tabernaemontana Species and the Entheogenic African Shrub Tabernanthe iboga (Apocynaceae)

Introduction

Ibogaine is a monoterpenoid indole alkaloid (MIA) of the ibogan subclass that has been investigated for anti-addictive properties in animal models and used in diverse therapeutic and traditional contexts despite regulatory restrictions in many countries. Previous work has identified ibogaine and related ibogan-type alkaloids such as coronaridine, ibogamine and voacangine across species of the Apocynaceae family, notably Tabernanthe iboga from Central Africa and members of the pantropical Tabernaemontana genus. Interest in alternative sources of these alkaloids has grown because most ibogaine in circulation originates from plant material rather than total synthesis, and rising demand has raised concerns about sustainability and adulteration of T. iboga root bark. This study set out to compare quantitatively the alkaloid profiles of root and stem barks from four Mexican Tabernaemontana species (T. alba, T. amygdalifolia, T. arborea, T. donnell‑smithii) with root bark from Tabernanthe iboga. Using a microextraction protocol coupled with gas chromatography–mass spectrometry (GC/MS) and principal component analysis (PCA), Krengel and colleagues aimed to characterise interspecific and intraspecific variation in monoterpenoid indole alkaloid contents, evaluate the predominance of key ibogan-type compounds, and assess the potential of Mexican Tabernaemontana as alternative sources of anti‑addictive alkaloids.