Three new labdane-type diterpene glycosides from fruits of Rubus chingii and their cytotoxic activities against five humor cell lines.

Three new labdane-type diterpene glycosides, 15,18-di-O-β-d-glucopyranosyl-13(E)-ent-labda-7(8),13(14)-diene-3β,15,18-triol (1), 15,18-di-O-β-d-glucopyranosyl-13(E)-ent-labda-8(9),13(14)-diene-3β,15,18-triol (2), and 15-O-β-d-apiofuranosyl-(1→2)-β-d-glucopyranosyl-18-O-β-d-glucopyranosyl-13(E)-ent-labda-8(9),13(14)-diene-3β,15,18-triol (3), were isolated from the fruits of Rubus chingii. Their structures were elucidated on the basis of spectroscopic data and chemical methods. The cytotoxic activities of compounds 1-3 were evaluated against five human tumor cell lines (HCT-8, BGC-823, A549, and A2780). Compounds 3 showed cytotoxic activity against A549 with an IC50 value of 2.32μM.