Characterizing alkaloid diversity in Psychotria viridis leaf extracts from central Amazonian terra firme forest understory populations

Leaf extracts from five wild populations of Psychotria viridis, a shrub central to Amazonian ethnobotany, contain at least twelve distinct alkaloids, including N,N-dimethyltryptamine, N-methyltryptamine, two beta-carboline derivatives (harmine and harmaline), tetrahydroharmine, and seven minor methylated or hydroxylated tryptamine variants. Total alkaloid content ranged from 1.87 to 4.63 mg/g dry weight across populations. These findings expand the known chemical inventory of P. viridis beyond the commonly reported tryptamines and provide a foundation for quality-control protocols in phytopharmaceutical standardisation.

Study at a glance

Abstract

The tryptamine-rich shrub Psychotria viridis stands at the centre of Amazonian ethnobotany, yet baseline data on its full alkaloid profile remain surprisingly thin. This research characterized alkaloid diversity in leaf extracts from five wild understory populations growing on terra firme soils within a 60-km radius of Manaus, Amazonas State, Brazil. Leaves were collected during the wet season of 2022, freeze-dried, and extracted with acidified methanol. Alkaloid-enriched fractions were prepared by acid-base liquid-liquid partitioning and analysed by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Twelve distinct alkaloids were detected, including N,N-dimethyltryptamine, N-methyltryptamine, two beta-carboline derivatives (harmine and harmaline), tetrahydroharmine, and seven minor peaks tentatively assigned to methylated or hydroxylated tryptamine variants. Total alkaloid content ranged from 1.87 to 4.63 mg/g dry weight across populations. These results expand the known chemical inventory of P. viridis beyond the commonly reported tryptamines and offer a foundation for quality-control protocols in phytopharmaceutical standardisation.