Plants' steroidal saponins - A review on its pharmacology properties and analytical techniques

The plant is a rich repository of useful secondary metabolites with profound medicinal potential. Saponins, one type of bioactive compound, are amphitheatric glycosides with one and more hydrophilic sugar and hydrophobic steroidal and terpenoid part. The former is known as steroidal saponin, and the latter is called terpenoid saponins. Steroidal saponin is mostly distributed among monocotyledon families such as Asparagaceae, Amaryllidaceae, Dioscoreaceae, Smilacaceae, and Liliaceae. Even though it is unusual, it could also be detected to some extent by dicotyledonous angiosperms, such as Plantaginaceae, Zygophyllaceae, Fabaceae, Asteraceae, and Solanaceae. It exhibits diverse pharmacological ability including antimicrobic, anti-inflammatory, cAMP phosphodiesterase inhibitory, antiadipogenic, bactericide, cardioprotective, antitumor, antidiabetic, cytotoxic activity, antifungal, antiviral, antioxidant, and hepatoprotective. Steroidal saponin timosaponin AIII from Anemarrhena asphodeloides has been found to possess antitumor activity. Diosgenin, another steroidal sapogenin, has the potential of preventing neurological diseases by affecting different signaling pathways, increasing bone formation, and increasing antithrombotic activity. Spicatoside A from Liriope platyphylla possesses anti-inflammatory, antiasthma, and antiosteoclastogenic activities. TTB2 from Trillium tschonoskii exhibits anticancer potential. The cell cycle arrest and ROS-dependent autophagy are induced by polyphyllin I. These diverse biological activities of steroidal saponins are attributed to the variability of their structural features. Analysis of steroidal saponins in plant materials mainly utilizes classically and advances thin layer chromatography (TLC) on normal and reverses-phase (high-performance thin-layer chromatography, densitometric TLC), gas chromatography, LC, UPLC, ultra-high-performance liquid chromatography (HPLC), supercritical fluid chromatography, and HPLC coupled to ultraviolet detector and diode array detector. HPLC coupled with MS and Nuclear magnetic resonance is used for online identification of separated saponins. The present review aims to furnish a comprehensive account of the recent advances in analytical methods of determination and medicinal applications of steroidal saponins.