High-performance liquid chromatography paired with UV photodiode array, electrospray MS-MS and thermospray MS detectors was investigated as a method for the analysis of alkaloids in different parts of Psychotria spp. collected in the Amazon. Nine products have been isolated from the vegetable material and their structures elucidated by spectroscopic means. These constituents indicate pyrrolidinoindoline and quinoline alkaloid classes. Minor components were also assigned through MS fragmentations. Place and period of collections of the plant materials are responsible for both qualitative and quantitative variations with respect to pyrrolidinoindoline and quinoline type alkaloids. (C) 1999 Elsevier Science B.V. All rights reserved.