New triterpenoid estersaponins from the root barks of Pittosporum verticillatum subsp. verticillatum and evaluation of cytotoxicities

The phytochemical investigation of the root barks of Pittosporum verticillatum Bojer subsp. verticillatum led to the isolation of three new triterpene saponins, 3-O-[β-d-glucopyranosyl-(1 → 2)]-[α-l-arabinopyranosyl-(1 → 3)]-[α-l-arabinofuranosyl-(1 → 4)]-β-d-glucuronopyranosyl-21-O-(2-acetoxy-2-methylbutanoyl)-R1-barrigenol (1), 3-O-[β-d-glucopyranosyl-(1 → 2)]-[α-l-arabinopyranosyl-(1 → 3)]-[α-l-arabinofuranosyl-(1 → 4)]-β-d-glucuronopyranosyl-21-O-(2-acetoxy-2-methylbutanoyl)-28-O-acetyl-R1-barrigenol (2), 3-O-[β-d-glucopyranosyl-(1 → 2)]-[α-l-arabinopyranosyl-(1 → 3)]-[α-l-arabinofuranosyl-(1 → 4)]-β-d-glucuronopyranosyl-21-O-β,β-dimethylacryloyl-22-O-angeloyl-R1-barrigenol (3), and one known saponin senaciapittoside B (4). Their structures were elucidated mainly by 1D- and 2D-NMR spectroscopy and HRESIMS. Compounds 1–4 were evaluated for their cytotoxicity against one human cancer cell line (SW480) and one rat cardiomyoblast cell line (H9c2).

Graphical abstractThree new triterpenoids (1–3) and one known triterpene saponin (4) were isolated from Pittosporum verticillatum subsp. verticillatum collected from Northern region of Madagascar. Cytotoxicity of these compounds was evaluated against SW480 and H9c2 cell lines. Among them, compound 3 showed a moderate cytotoxicity against SW480 and a weak cytotoxicity on H9c2 cell line, whereas the other compounds were inactive on both cell types.Figure optionsDownload full-size imageDownload high-quality image (276 K)Download as PowerPoint slide