REQUIMTE, Serviço de Farmacognosia and Serviço de Bromatologia, Faculdade de Farmácia, Universidade do Porto, R. Aníbal Cunha, 4050-047 Porto, Portugal, and Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Science and Technology, CEBAS-CSIC, P.O. Box 164, E-30100 Espinardo, Murcia, Spain (At 2004-07-01)