Two unusual minor 18,19-seco-ursane glycosides from leaves of Ilex cornuta

The leaves of Ilex cornuta is traditionally used as a functional tea in China. Two new minor 18,19-seco-ursane glycosides, named cornutaoside A (1) and B (2), were isolated from leaves of I. cornuta, along with two known compounds (3 and 4). Their structures were elucidated as (3β,12β)-3-[β-d-glucopyranosyl-(1 → 2)-α-l-arabinopyranosyl]-12,21-dihydroxy-19-oxo-18,19-secours-13(18)-en-28-oic acid (1) and (3β,12β)-3-[β-d-glucopyranosyl-(1 → 2)-α-l-arabinopyranosyl]-12,19,21-trihydroxy-18,19-secours-13(18)-en-28-oic acid (2), by chemical methods, 1D and 2D NMR experiments, and by comparison with known analogues. This is the first report of E-seco triterpenoids and diterpene skeletons (4) from this plant. In a preliminary cytotoxic test against U937, L1210, and B16 cell lines, 1 and 2 had no significant activities as compared to controls, with concentrations up to 443.61 and 346.25 μM/plate, for 1 and 2, respectively.