1. Laboratory of Pharmacognosy and Phytochemistry, University of Geneva, CH-1211 Geneva 4, Switzerland, Laboratório de Química de Produtos Naturais, Universidade Federal da Paraíba, UFPB, cep 58000, João Pessoa, Paraíba, Brazil, and Laboratoire de Pharmacognosie, ISPB, Faculté de Pharmacie, Université Claude Bernard Lyon 1, 8 Avenue Rockefeller, Lyon, France