title: Cucurbitacins fromCucurbita texana: Evidence for the role of isocucurbitacins.
abstract: In addition to cucurbitacins E andI, cucurbitacins D,1, 3-epi-isocucurbitacin D,2, and B,3, were isolated from the fruits ofCucurbita texana and structurally identified by UV, IR,(1)H NMR,(13)C NMR, and MS, and 2-O-Β-glucopyranosylcucurbitacin I was identified. These compounds have not been reported previously as constituents of this species. The isolation of 3-epi-isocucurbitacin D2 together with normal cucurbitacins suggests that isocucurbitacins occur naturally. Evidence is also discussed that isocucurbitacins are biosynthesized one step ahead of normal cucurbitacin.
authors.affiliation: Delaware Agricultural Experiment Station Department of Entomology & Applied Ecology College of Agricultural Sciences, University of Delaware, 19717-1303, Newark, Delaware.
authors.forename: F T
authors.initials: FT
authors.lastname: Halaweish