GC-MS analysis of steroids and triterpenoids occurring in leaves and tubers of Tamus edulis Lowe

Abstract

Tamus edulis Lowe is an endemic perennial plant belonging to Dioscoreaceae family. The plant has long climbing stems, ovate leaves, flowers in spikes, fleshy red berries and long tuberous roots. Young shoots and tuberous roots of T. edulis were used traditionally for nourishment and as a herbal medicine. Leaves and roots analyzed in the present study were collected in the northwest of Madeira island. The GC–MS analysis allowed to detect several steroids in free forms in diethyl ether extracts; and diosgenin with its isomer, yamogenin, in hydrolyzates from methanolic extracts.The obtained results reveal that Tamus edulis has some features common with other Dioscorea species, e.g., the presence of steroidal saponins with diosgenin and yamogenin as aglycones, or the phytosterol composition with predominating sitosterol. However, some other traits, like the relatively high content of free steroids (more than 1 mg/g d.w.) and their profile rich in cholesterol derivatives, can distinguish Tamus edulis from other Dioscorea species studied previously for their steroid and triterpenoid profile.