Three new minor steroidal glycosides were isolated from the whole plants of Hoya parasitica (Wall. ex Hornem.) Wight. Their structures were further elucidated as 3β,4α-dihydroxy-5β-spirost-(25)27-en-1β-yl O-α-L-arabinopyranoside (1), 3β-hydroxy-5β-spirost-25(27)-en-1β-yl O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (2), and (23S,24S,25S)-3β,4α,23,24-tetrahydroxy-5β-spirostan-1β-yl O-α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranoside (3) through interpretation of the spectroscopic data (one-dimensional and two-dimensional) and mass spectrometry (HR-ESI-MS). To the best of our knowledge, this is the first report of the isolation of spirostane-type steroidal saponins from the Hoya genus.
Keywords: Apocynaceae; Hoya parasitica (Wall. ex Hornem.) Wight; NMR; spectroscopic analysis; steroidal glycoside.