Isolation and structure of cytostatic steroidal saponins from the african medicinal plant balanites aegyptica

Bioactivity-guided separation of a CH₂Cl₂/MeOH extract of Balanites aegyptica afforded four new cytostatic saponins, named balanitins 4 [1], 5 [2], 6 [3], and 7 [4]. On the basis of enzymatic hydrolyses and glycosidation nmr chemical shifts employing the peracetates, structures 1–4 were established as yamogenin 3β-0-β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2) -β-d- glucopyranoside [1], yamogenin 3β-0-α-l-rhamnopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)] -β-d-glucopyranoside [2], yamogenin 3β-0-β-D-glucopyranosyl-(1→4)-[α-L-rham-nopyranosyl-(1→2)] -β-d--glucopyranoside [3], and diosgenin 3β-0-β-D-xylopyranosyl-(1→3)-β-d-glucopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)] -β-d-gIucopyranoside [4].