title: Plant analysis by butterflies: occurrence of cyclopentenylglycines in Passifloraceae, Flacourtiaceae, and Turneraceae and discovery of the novel nonproteinogenic amino acid 2-(3'-cyclopentenyl)glycine in Rinorea.
abstract: Following records about feeding habits of nymphalid butterflies, a novel nonproteinogenic L-amino acid, (S)-2-(3'-cyclopentenyl)glycine (11), was discovered in Rinorea ilicifolia, a species where the presence of a cyclopentanoid natural product of this kind was neither known nor anticipated from the taxonomic point of view. Another novel amino acid, (2S,1'S,2'S)-2-(2'-hydroxy-3'-cyclopentenyl)glycine (12), the stereochemistry of which was determined by single-crystal X-ray diffraction, was shown to occur in species belonging to Flacourtiaceae, Passifloraceae, and Turneraceae. These species, many of which serve as hosts for nymphalid butterflies (Acraeinae, Heliconiinae, Argynninae), also produce 2-(2'-cyclopentenyl)glycine. Cyclopentenylglycines are proposed to be novel chemical recognition templates for plant-insect interactions. Ratios between the epimers of (2S)-2-(2'-cyclopentenyl)glycine, which co-occur in plants, were determined by (1)H NMR spectroscopy. Contrary to a previous report, the (2S,1'R) epimer always appears to predominate over the (2S,1'S) epimer. Stereochemical aspects of biosynthesis of natural cyclopentanoid cyanogenic glycosides are discussed in relation to these findings.
authors.affiliation: Department of Medicinal Chemistry, Royal Danish School of Pharmacy, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
authors.forename: Vicki
authors.initials: V
authors.lastname: Clausen
authors.forename: Karla
authors.initials: K
authors.lastname: Frydenvang
authors.forename: Ricarda
authors.initials: R
authors.lastname: Koopmann
authors.forename: Lise Bolt
authors.initials: LB
authors.lastname: Jørgensen
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Abbiw
authors.forename: Patrick
authors.initials: P
authors.lastname: Ekpe
authors.forename: Jerzy W
authors.initials: JW
authors.lastname: Jaroszewski
mesh_terms: D000818:Animals; D002080:Butterflies / Q000378:metabolism*; D018360:Crystallography, X-Ray; D005247:Feeding Behavior / Q000502:physiology; D005998:Glycine / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D029598:Passiflora / Q000737:chemistry; D010944:Plants / Q000737:chemistry*
chemical_list: C457144:2-(2'-hydroxy-3'-cyclopentenyl)glycine; C026228:cyclopentenylglycine; D005998:Glycine