BIOACTIVE NATURAL-PRODUCTS FROM TRADITIONALLY USED MEXICAN PLANTS .5.ISOLATION AND STRUCTURAL CHARACTERIZATION OF NEW GLYCOLIPID ESTER-TYPE DIMERS FROM THE RESIN OF IPOMOEA TRICOLOR (CONVOLVULACEAE)

An extensive structural investigation using high field NMR spectroscop y and FAB mass spectrometry led to the characterization of tricolorins F-J, minor phytogrowth inhibitor glycolipids purified by recycling HP LC from the resins of Ipomoea bicolor Cav. (Convolvulaceae). The poten tial of various two-dimensional NMR techniques in deducing information about the saccharide substitution and the positions of acylation in t hese complex oligosaccharides is presented. Tricolorins F and G were f ound to be trisaccharides forming a macrolactone with the aglycone, (1 1S)-hydroxyhexadecanoic acid (jalapinolic acid). Tricolorins H, I and J consisted of three ester type dimers of either tricolorins F or G an d tricoloric acid C, a new hetero-trisaccharide of jalapinolic acid. ( C) 1997 Elsevier Science Ltd.