New cytotoxic principles from Datisca glomerata

Datisca glomerata has been systematically fractionated by following cellular toxicity in an effort to identify previously uncharacterized cytotoxic principles. Several new cucurbitacin glycosides, including datiscosides B(8), C(3), D(9), E(4), F(5), G(6), and H(10) and the known compound datiscoside (1), as well as cucurbitacins B(11), D(2), and F(7) have been isolated and characterized. Structures were assigned to the compounds on the basis of their high field 1H n.m.r., 13C n.m.r., high-resolution mass spectra (CI, EI, and FD) and chemical interconversions. The structure of datiscoside C(3) was independently established by single-crystal X-ray analysis at 193 and 293 K.