Berger A, Tanuhadi E, Brecker L, Schinnerl J, Valant-Vetschera K. Chemodiversity of tryptamine-derived alkaloids in six Costa Rican Palicourea species (Rubiaceae-Palicoureeae).
Phytochemistry 2017;
143:124-131. [PMID:
28806604 DOI:
10.1016/j.phytochem.2017.07.016]
[Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/27/2017] [Accepted: 07/31/2017] [Indexed: 06/07/2023]
Abstract
We report 14 harmala and tryptamine-iridoid alkaloids with various tri-, tetra- and pentacyclic cores from leaves and stem bark of six species of the large and complex neotropical genus Palicourea. Among them is the previously undescribed compound deoxostrictosamide which is related to strictosamide, a key intermediate in camptothecin biosynthesis. In addition, we describe the occurrence of 1,2,3,4-tetrahydronorharman-1-one for the first time within Rubiaceae and ophiorine A and B, two alkaloids with an unusual core bearing a betaine function and a zwitterion as new for the genus. Although the other compounds are already known from other species, their degree of structural diversity highlights the remarkable biosynthetic capabilities of the genus Palicourea. Furthermore, the present paper provides additional support for the hypothesis that tryptamine-iridoid alkaloids represent a distinct chemosystematic feature for the genus Palicourea.
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