1. Department of Medicinal Chemistry, The University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, Utah 84108-1257, Mt. Albert Research Centre, The Horticulture and Food Research Institute of New Zealand Ltd., Private Bag 92 169, Auckland, New Zealand, and Department of Chemistry, Biochemistry, and Molecular Biology, Oregon Graduate Institute, 20000 NW Walker Road, Portland, Oregon 97291-1000