High-resolution gas-chromatographic analysis of the secondary metabolites obtained by subcritical-fluid extraction from Colombian rue (Ruta graveolens L.)

Subcritical (CO2) extraction, carried out in a J&W Scientific High Pressure Soxhlet Extractor, was used to isolate secondary metabolites from leaves, flowers, stems and roots of Colombian rue (Ruta graveolens L.). The various extracts were analyzed by capillary chromatography, on an HP-5 (30 m) colu mn, using nitrogen-phosphorus, flame ionization, and mass selective detecti on systems. Kovats indexes and mass spectra (electron impact, 70 eV) were e mployed for compound identification. The extracts from the various parts of Ne studied had different compositions. The number of compounds detected at concentrations above 0.01% (w/w) in the extracts from leaves, flowers, ste ms and roots, was 78, 45, 25 and 24, respectively. 2-Nonanone (8.9%), 2-und ecanone (13.4%), chalepensin (13.0%), and geijerene (19.3%) were the main c onstituents found in the extracts from me leaves, flowers, stems and roots, respectively. Furanocoumarins, furoquinolines, hydrocarbons and benzodioxo l derivatives were the main compound families found in all extracts, at tot al concentrations between 3.7 and 33.9%, depending on the part of the plant . The extraction method used has low environmental impact and produced solv ent-free extracts in good yield with no pigments, waxes, resins, or high-mo lecular weight compounds which may interfere with the isolation and analysi s of the alkaloids responsible for rue's biological activity, which were ex tracted in relatively high yield. (C) 2000 Elsevier Science B.V. All rights reserved.