1. Natural
Products Research Institute, College of Pharmacy, Seoul National University, San 56-1,
Sillim, Gwanak, Seoul 151-742, Korea
2. Department
of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, San 56-1, Sillim, Gwanak, Seoul 151-921, Korea
3. Department
of Biological Science, College of Life Science and Nano Technology, Hannam University, 461-6
Jeonmin, Yuseong, Daejeon 305-811, Korea