1. Department of Pharmacognosy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Tsushima, Okayama 700-8530, Japan; POLA Chemical Industries, Inc., Totsuka-ku, Yokohama 244-0812, Japan; and Faculty of Pharmaceutical Sciences, Matsuyama University, Bunkyo-cho, Matsuyama 790-8578, Japan