1. Division of Pharmacognosy, Department of Medicinal Chemistry, BMC, Uppsala University, Box 574, S-751 23 Uppsala, Sweden, Department of Medicinal Chemistry, AstraZeneca R&D Mölndal, S-431 83 Mölndal, Sweden, and GDECS Computational Chemistry, AstraZeneca R&D Mölndal, S-431 83 Mölndal, Sweden