The species Unonopsis duckei R. E. Fr. belongs to the Annonaceae family
and is found in the states of Amazonas, Pará and Rondônia. The genus to which
it belongs (Unonopsis) is described as neotropical consisting of trees and shrubs,
currently having 47 registered species, 25 of which are considered relatively new.
Its distribution in the national territory is endemic to the northern region with 15
species recorded for this region. From previous studies, isoquinoline alkaloids
were identified in this species. Due to the great pharmacological potential, the
interest and search for new alkaloids has become greater. For this reason, the
objective of this work was to investigate the presence of alkaloids not yet reported
in this species, based on the characterization of the alkaloid fraction of its bark
using mass spectrometry. The analyzes carried out allowed the preliminary
identification of 12 alkaloids. Among them, it was possible to classify them into
aporphine, oxoaporphine, tetrahydroprotoberberine and
benzyltetrahydroisoquinoline, namely: seven aporphine alkaloids, anonaine (1),
asimilobine (2), nornuciferine (3), isopiline (4), isocoridine (5), glaucine ( 6) and
boldine (7); three oxoaporphines, liriodenine (8), oxoputerine (9) and lisicamine
(10); a tetrahydroprotoberberine, tetrahydropalmatine (11) and a
benzyltetrahydroisoquinolinic phenol, 2-methoxy-5-[(5,6,7,8-tetrahydro-1,3-
dioxolo[4,5-g]isoquinolin-5-yl)methyl] - (9Cl, ACl) (12). Among these, the alkaloids
isopiline (4), isocoridine (5), boldine (7), oxoputerine (9) and tetrahydropalmatine
(11) stand out, reported for the first time in the species. Even more important is
the alkaloid benzyltetrahydroisoquinolinic phenol, 2-methoxy-5-[(5,6,7,8-
tetrahydro-1,3-dioxolo[4,5-g]isoquinolin-5-yl)methyl] - (9Cl - ACl) (12) which is
reported for the first time as a natural product. Such results reveal the
chemotaxonomic importance of the species and open spaces for new
explorations not only of the species, but also of the genus in question.
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