Erylosides G-J (1-4), four new triterpenoid saponins, were isolated from th
e sponge Erylus nobilis collected from Jaeju Island, Korea. On the basis of
the results of combined chemical and spectral analyses, the structures of
the aglycones were determined to be lanostane-based, modified penasterols.
The oligosaccharide portions were composed of one unit each of L-arabinose,
D-galactose, and 2-N-acetyl-D-glucosamine (1 and 3) or two units of L-arab
inose and one unit of 2-N-acetyl-D-glucosamine (2 and 4). These compounds e
xhibited moderate cytotoxicty against a human leukemia cell line.