Three new triterpenoid saponins from the leaves and stems of Panax quinquefolium

Three new minor dammarane saponins, quinquenosides L10 (1), L14 (2), and L16 (3), were isolated from the leaves and stems of Panax quinquefolium L. By the combination of one- and two-dimensional NMR techniques and MS spectroscopic analysis, their structures were established as 20-O-(α-l-arabinopyranosyl-(1-6)-O-β-d-glucopyranosyl)-3-O-β-d-glucopyranosyl-dammar-24-ene-3,12, 20-triol (1), 20-O-α-l-arabinopyranosyl-3-O-(β-d-glucopyranosyl-(1-2)-O-β-d-glucopyranosyl)-dammar-24-ene-3,12,20-triol (2), 3-O-(β-d-glucopyranosyl-(1-2)-O-β-d-glucopyranosyl)-20-O-(β-d-glucopyranosyl-(1-6)-β-d-glucopyranosyl)-dammarane-3,12,20,24,25-pentaol (3). The content of artemisinin was significantly enhanced by 3.0 mg l− 1 of compounds 1, 2, and 3 in the callus of Artemisia annua.