Triterpene saponins from the roots of Acacia senegal (L.) Willd.

Six new triterpenoid saponins, named senegalosides A–F (1–6) were isolated from the seedpods and roots of Acacia senegal (Mimosaceae). Their structures were elucidated using 1D and 2D-NMR spectroscopic analysis and mass spectrometry. Compound 1 possesses an unusual sapogenin, 3β-hydroxy-21-oxo-olean-12-en-28-oic acid (machaeric acid), and was reported here in its natural form for the first time within the genus Acacia. Senegaloside A is the first example of a machaeric-type triterpenoid glycoside in the plant kingdom. The cytotoxic effect of isolated saponins was evaluated on the H4IIE rat hepatoma cell line. As a result, compounds 1, 3–6 were not significantly cytotoxic to H4IIE cells even at 200 μM. Compound 2 was suppressed cell viability at 50–200 μM.