Isolation and Characterization of the ‘Flavonoid Crystals’ of Three Species of Prosthechea: Chemotaxonomic Considerations of the Genera Prosthechea and Encyclia

The isolation of fragnettin, the so called ‘flavonoid crystals’, from three species of Prosthechea, namely P. fragrans, P. vespa and P. caetensis, and its characterization as 8-C-β-D-quinovopyranosyl apigenin is described. The possibility of fragnettin (8-C-β-D-quinovopyranosyl apigenin), the ‘flavonoid crystals’ absent in the genus Encyclia, being the marker of the genus Prosthechea is suggested.