Triterpene saponins from the halophyte Anabasis setifera exhibit anti-SARS-CoV-2 properties

Halophytes are well-known as a rich source of health-promoting phytochemicals. This study aimed to elucidate the chemical constituents and antiviral potential of the halophyte Anabasis setifera Moq., growing in the desert areas of Egypt. Six triterpenoid oleanane saponins (1-6) were purified using several chromatographic procedures and identified via HRMS and NMR spectroscopic analyses, with solysaponin B-D being reported for the first time. Additionally, three known triterpene saponins (4-6) were identified as spinacoside C (4), betavulgaroside IV (5), and (3β)-3-(β-d-glucuronopyranosyloxy)olean-12-en-23,28-dioic acid (6). The isolated triterpene saponins were able to inhibit the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2). Our study provides valuable insights into the promising antiviral activity of saponins 1, 2 and 4 with IC₅₀ values ranged between 2.339 and 6.837 μg mL^-1.