1. Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 300, R.O.C., Department of Chemistry, National Cheng Kung University, Tainan, Taiwan 701, R.O.C., Department of Internal Medicine, National Cheng Kung University, Tainan, Taiwan 701, R.O.C., and, Department of Dentistry and Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan 701, R.O.C