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 β-l- and β-d-arabinopyranoses by HPLC analysis of their thiocarbamoyl-thiazolidine 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 β-l-arabinopyranose from marine sources.