¹H and ¹³C NMR signal assignment of cucurbitacin derivatives from <i>Citrullus colocynthis</i> (L.) Schrader and <i>Ecballium elaterium</i> L. (Cucurbitaceae)

Abstract

2D NMR-derived 1H and 13C NMR signal assignments of six structurally closely related cucurbitacin derivatives are presented. The investigated 2-O-beta-D-glucopyranosylcucurbitacins I, J, K, and L were obtained from Citrullus colocynthis (L.) Schrader whereas the aglyca cucurbitacin E and I were isolated from Ecballium elaterium L.