Monnieria trifolia L. is an herb that grows throughout northeastern Brazil. The leaves of this plant have been used in popular medicine as a diaphoretic, antipyretic, febrifuge, and an antiinflammatory agent (1). Several alkaloids, typical of the family Rutaceae, have been isolated (2-4) from the leaves of M. trifolia. Our interest in the medicinal plants of northeastern Brazil led us to investigate this herb, and we have reported the structures of two furoquinoline alkaloids (5), montrifoline (1) and delbine (2), from the leaves of M. trifolia. In this communication, we wish to report the isolation of these alkaloids, along with kokusaginine (3), γ-fagarine (4), skimmianine (5), evoxine (6), and arborinine (7) from the whole plant. This is the first report of the isolation of kokusaginine and γ-fagarine from this source. The isolation of montrifoline, skimmianine, and arborinine was effected without the use of chromatography. The spectral properties of montrifoline are very similar to those of kokusaginine, except that the former shows the presence of an isopentoxy group in place of a OCH3 group. Upon KOH fusion, montrifoline furnished delbine with the loss of a C5-unit (C5H10O2). That this C5-unit is a (CH3)2C(OH)CH(OH)CH2 side-chain, is indicated by the pmr, ms (see below), and by biogenetic considerations. Delbine gives kokusaginine upon methylation, and as delbine has a OCH3 group at C-4 (3H singlet at 4.37 ppm), it must be either 6-hydroxy-7-methoxydictamnine (2) or 7-hydroxy-6-methoxydictamnine (8). However, structure 8 represents heliparvifoline, mp 245-247°, an alkaloid isolated from Helietta parvifolia (6) and proved to be different from delbine by direct comparison with an authentic sample. Therefore, structure 2 should represent delbine, and, consequently, structure 1 should be assigned to montrifoline (5).