A new monoterpenoid indole alkaloid N-oxide, 3.4-dihydro-1-(1-beta-D-glucopyranosyloxy-1,4a,5,7a-tetrahydro-4-methoxycarbonylcyclopenta[c]pyran-7-yl)-beta-carboline-N-2-oxide (3) and two known monoterpenoid indole alkaloids. croceaine A (1) and psychollatine (2), were isolated from Palicourea crocea (Rubiaceae) from Trinidad. The structures of 1-3 were determined on the basis of spectral and other physical data. Compounds I and 2 were previously isolated from plants of different genera viz. Palicourea crocea and Psychotria umbellato, respectively, both collected in Brazil. The results support the proposal that the genus Palicourea and the subgenus Heteropsychotria should be combined into a single genus. (c) 2008 Phytochemical Society of Europe Published by Elsevier B.V. All rights reserved.