1. Department of Biosciences, School of Science and Technology, Teikyo University, 1-1 Toyosatodai, Utsunomiya 320-8551, Japan, Graduate School of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan, Department of Natural Products, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenhe District, Shenyang 110015, China, and Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan