Identification of steroidal saponins from Tribulus terrestris and their in silico docking studies

Tribulus terrestris is known to possess many pharmacological properties, most notably its anticancer activities, owing to its rich steroidal saponin contents. Even though many reports are available elucidating the anticancer potential of the herb, we, for the very first time have attempted to isolate and identified the active compound present in seed crude saponin extract and confers its in silico docking ability with various cellular targets proteins. High performance thin layer chromatography confirms the presence of active saponins in leaf and seed saponin extracts which were further fractionated by silica gel column chromatography. Fractions collected were assessed for cytotoxicity on human breast cancer cells. High resolution liquid chromatography and mass spectroscopy was employ to identify the active components present in fraction with highest cytotoxicity. Intriguingly, Nautigenin type of steriodal saponin was identified to present in the active fraction of seed extract (SF11) and the identified compound was further analyzed for its in silico docking interaction using PyRx AutodockVina. Docking studies revealed the high binding affinity of Nuatigenin at significant sites with apoptotic proteins Bcl-2, Bax, caspase-3, caspase-8, p53 and apoptosis inducing factor along with cell surface receptors estrogen receptor, projesterone receptor, epidermal growth factor receptor, and human epidermal growth factor receptor-2. Thus, the conclusions were drawn that saponin fraction of Tribulus terrestis possesses active compounds having anticancer property and specifically, Nuatigenin saponin can be considered as an important therapeutic drug for the breast cancer treatment.