Steroids Glycosylated with Both D- and L-Arabinoses from the South China Sea Gorgonian Dichotella gemmacea

Three new 19-hydroxy steroidal glycosides, namely, junceellosides E-G (2-4), were isolated together with the known analogue junceelloside C (1) from the South China Sea gorgonian Dichotella gemmacea. The structures of these compounds were elucidated by a combination of detailed spectroscopic analyses, chemical methods, and comparison with reported data. These glycosides are found to have sugar moieties of both beta-L- and beta-D-arabinopyranoses by HPLC analysis of their thiocarbamoylthiazolidine derivatives and those of authentic D- and L-arabinoses, leading to the structure revision of junceelloside C (1). This is the first report of steroidal glycosides from the gorgonian D. gemmacea and the first report of glycosides with beta-L-arabinopyranose from marine sources.