Glanduliferins A and B, two new glucosylated steroids from Impatiens glandulifera, with in vitro growth inhibitory activity in human cancer cells.

Impatiens glandulifera has been imported from Himalaya in Europe and is considered as an invasive alien plant whose spreading arouses increasing interest among scientific literature. Via anti-cancer bioguiding, two new glucosylated steroids, named glanduliferins A and B, were isolated from the dried stem of I. glandulifera plants, together with the well-known α-spinasterol and 2-methoxy-1,4-naphthoquinone, which are also isolated from roots and leaves. They were characterized as 17-(2-hydroxy-2-pentamethylcyclopropyl-ethyl)-10,13-dimethyl-2,3,4,5,6,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopents[a]phenathren-3-O-(4-O-acetyl)-α-D-glucopyranoside and 17-(4-ethyl-1,5-dimethyl-hex-2-enyl)-10,13-dimethyl-2,3,4,5,6,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopents[a]phenathren-3-O-(6-O-acetyl)-β-D-glucopyranoside using various NMR and HRESIMS techniques and chemical methods. In vitro determination of the growth inhibitory activity of the four isolated compounds using the MTT colorimetric assay revealed mean IC50 growth inhibitory value of ~30 μM for glanduliferin A while glanduliferin B and α-spinasterol were poorly active till 100 μM. 2-methoxy-1,4-naphthoquinone revealed to be active in the single micromolar digit range as previously described. Quantitative videomicroscopy analyses of the effects of glanduliferins A and B suggested cytostatic rather than cytotoxic activity in U373 glioblastoma (GBM) cells.