Naturally Occurring Polyhydroxylated Spirostanol Saponins, A Review of the Classification, Sources, Biosynthesis, Biological Activities, and Toxicity.

Polyhydroxylated spirostanol saponins, characterized by three or more hydroxy substitutions in the aglycone, have various interesting biological activities. In the present study, "steroids", "saponins", "polyhydroxylated", "spirostanol saponins", and "steroidal saponins" were used as search terms to screen the literature. Cited references were collected between 1950 and 2023 from the Web of Science, SciFinder, and China National Knowledge Internet (CNKI). A total of 407 polyhydroxylated spirostanol saponins were included in this review. These saponins were classified into three types, α, β, and γ. Polyhydroxylated spirostanol saponins have potential benefits, primarily anti-inflammatory, antimicrobial, cytotoxic, and cAMP phosphodiesterase inhibitory activities. These compounds were found in 11 plant families and 36 genera. The top three families containing the most saponins were Asparagaceae, Melanthiaceae, and Amaryllidaceae, and the top five genera were Trillium, Helleborus, Allium, Dracaena, and Paris. The top five plants were Trillium tschonoskii Maxim., Ypsilandra thibetica Franch., Paris polyphylla var. yunnanensis (Franch.)Hand.-Mazz., Helleborus thibetanus Franch., and Helleborus foetidus L. On the basis of their diverse biological activities, these saponins and related plant resources are worthy of further development and utilization.