[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 & Life Science,
Seoul National University, San 56-1, Sillim, Gwanak, Seoul 151-921, Korea
[3
]Marine
Natural Products Laboratory, Korea Institute of Ocean Science & Technology,
P.O.
Box 29, Seoul 425-600, Korea
[4
]Department
of Biological Science, College of Life Science and Nano Technology, Hannam
University, 461-6 Jeonmin, Yuseong, Daejeon 305-811, Korea