Glaucasides A–C, three saikosaponins from Atriplex glauca L. var. ifiniensis (Caball) Maire

From the roots of Atriplex glauca L. var. ifiniensis (Caball) Maire (syn. of Atriplex parvifolia Lowe var. genuina Maire), three new saikosaponins designated as glaucasides A–C ( 1–3 ) were isolated together with the known 3‐ O ‐ $\bf{\beta}$ ‐ D ‐glucopyranosyl‐(1 → 2)‐ $\bf{\beta}$ ‐ D ‐galactopyranosyl‐saikogenin F ( 4 ). The structures of the new compounds were elucidated by extensive analysis of one‐dimensional and two‐dimensional NMR spectroscopy, FABMS, HR‐ESIMS and chemical evidence as 13 $\bf{\beta}$ ,28‐epoxy‐16 $\bf{\beta}$ ,21 $\bf{\beta}$ ‐dihydroxyolean‐11‐en‐3 $\bf{\beta}$ ‐yl O ‐ $\bf{\beta}$ ‐ D ‐[2‐ O ‐sulfate]‐glucopyranosyl‐(1 → 2)‐ $\bf{\alpha}$ ‐ L ‐arabinopyranoside ( 1 ), 13 $\bf{\beta}$ ,28‐epoxy‐16 $\bf{\beta}$ ,21 $\bf{\beta}$ ‐dihydroxyolean‐11‐en‐3 $\bf{\beta}$ ‐yl O ‐ $\bf{\beta}$ ‐ D ‐[2‐ O ‐sulfate]‐glucopyranosyl‐(1 → 2)‐ $\bf{\alpha}$ ‐ L ‐arabinopyranosyl 21‐ O ‐{4‐(secbutylamido)‐butanoyl ester} ( 2 ) and 3‐ O ‐ $\bf{\beta}$ ‐ D ‐glucopyranosyl‐(1 → 2)‐ $\bf{\beta}$ ‐ D ‐galactopyranosyl saikogenin G ( 3 ). The cytotoxic activities of these compounds were evaluated against the HT‐29 and HCT 116 human colon cancer cell lines. Copyright © 2011 John Wiley & Sons, Ltd.