RESUMEN
The photoreaction of 2,3,4',5-tetrahydroxystilbene-2-O-ß-d-glucoside (TSG) has been investigated. Water-assisted/water-accelerated photodimerization of trans-TSG favored the formation of syn-head-to-tail [2 + 2] photocyclobutane under 365 nm irradiation as a result of hydrophobic association and a fluorescent solute-solute aggregate from their excited singlet states. In contrast, irradiation with 254 nm led to [2 + 2] photocycloreversion. The two cyclobutane dimers were first obtained through straightforward photoreaction and identified as multiflorumiside A and multiflorumiside C through the detailed analysis of high-resolution electrospray ionization mass spectrometry and one- and two-dimensional nuclear magnetic resonance. Therefore, trans-TSG should be protected from light and water.
Asunto(s)
Fallopia multiflora/química , Glucósidos/química , Extractos Vegetales/química , Estilbenos/química , Glucósidos/aislamiento & purificación , Glucósidos/efectos de la radiación , Luz , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/efectos de la radiación , Raíces de Plantas/química , Espectrometría de Masa por Ionización de Electrospray , Estilbenos/aislamiento & purificación , Estilbenos/efectos de la radiaciónRESUMEN
Six new 9,19-cycloartane triterpenes (1-6) were isolated from the aerial parts of Cimicifuga yunnanensis. The new chemical structures were determined by extensive analyses of 1D and 2D NMR spectroscopy. Compounds 1 and 2 are the first 9,19-cycloartane triterpenes characterized by CH3-18 shifting from C-13 to C-12 in the Cimicifuga spp. The evaluation of inhibition activity against human HL-60, SMMC-7721, A-549, MCF-7, and SW480 cell lines indicated that compounds 1-6 showed different levels of cytotoxic activities with IC50 values ranging from 1.2 to 27.8 µm.