1. Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium, Department of Chemistry, “Al. I. Cuza” University of Iasi, Carol I Bvd. No 11, 700506 Iasi, Romania, and Laboratory of Ecophysiology, Biochemistry and Toxicology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium