ABSTRACT
From a methanolic extract of the leaves of Andira inermis (Fabaceae), andirol A and B, two compounds with a novel type of a rotenoid-related skeleton and andinermol, a new 2-aryl-3-hydroxymethyl-benzofuran could be isolated. Characterisation and structure elucidation of these compounds was achieved on the basis of their spectral data. In addition, the in vitro activities of the isolated compounds against both the chloroquine-sensitive strain PoW and the chloroquine-resistant clone Dd2 of Plasmodium falciparum have been evaluated.
Subject(s)
Fabaceae/chemistry , Heterocyclic Compounds, 4 or More Rings/chemistry , Plant Extracts/chemistry , Aldehydes/chemistry , Aldehydes/isolation & purification , Benzofurans/chemistry , Benzofurans/isolation & purification , Heterocyclic Compounds, 4 or More Rings/isolation & purification , Magnetic Resonance Spectroscopy , Methanol , Models, Molecular , Molecular Conformation , Plant Extracts/isolation & purificationABSTRACT
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.
Subject(s)
Butterflies/metabolism , Glycine/isolation & purification , Plants/chemistry , Animals , Crystallography, X-Ray , Feeding Behavior/physiology , Glycine/analogs & derivatives , Glycine/chemistry , Magnetic Resonance Spectroscopy , Molecular Conformation , Molecular Structure , Passiflora/chemistryABSTRACT
Different extracts from 11 West African plants traditionally used against malaria in Ghana were tested against both the chloroquine-sensitive strain PoW and the chloroquine-resistant clone Dd2 of Plasmodium falciparum. Due to the promising in vitro activity of the lipophilic extract [IC50: 10.5 microg/ml (PoW); 13.1 microg/ml (Dd2)], Microglossa pyrifolia (Lam.) Kuntze (Asteraceae) was chosen for further phytochemical investigation. From active fractions 13 compounds were isolated; their structures were established on the basis of spectroscopic methods. 1-Acetyl-6E-geranylgeraniol-19-oic acid and sinapyl diangelate represent new natural compounds. The two diterpenes E-phytol [IC50: 8.5 microM (PoW); 11.5 microM (Dd2)], and 6E-geranylgeraniol-19-oic acid [IC50: 12.9 microM (PoW); 15.6 microM (Dd2)] proved to be the most active constituents in our test system.
