Naturally occurring plant-derived sulfonated and sulfated saponins from 1983 to 2024

A substantial number of molecules have been already characterized from various organisms, such as plants, fungi, bacteria, and other animals; but just few have been already subjected to pharmacological assays. This is one of the reasons why reviewing previous studies will direct future investigations. The continuous chemical investigations of medicinal plants have been leading to a plethora of saponins. Some of these compounds carry one or more sulfonyl or sulfate groups. Such association rarely occurs in the plant kingdom. Till now, no report has summarized these sulfonated saponins isolated from medicinal plants. There is still a gap between the sulfonyl function and biological activities of these saponins. The present review encompasses the naturally occurring saponins containing the sulfonyl group either on the sapogenin or on the sugar moiety. The biosynthetic routes, their spectroscopic characteristics to shed more light on future structure elucidation and their biological activities are reported. It resulted that 141 saponins associating SO₃H or SO₃^- groups were reported from medicinal plants largely distributed within Zygophyllaceae and Asparagaceae families. Some of these compounds exhibited interesting biological activities including anticancer, antibacterial, anti-inflammatory and antiviral. It emerges from this review that many sulfonated saponins have been characterized, but just a few have been subjected to biological studies. The mechanism of action of these compounds remains understudied and further investigations need to be undertaken to understand how they act. This review covers reported data from 1983–2024.