1. Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand, FR 8.7, Pharmakognosie und Analytische Phytochemie, Universität des Saarlandes, 66041 Saarbrücken, Germany, and Plant Extracts Research Unit, New Zealand Institute for Crop & Food Research Limited, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand