Characterization and quantitation of hexadecyl, octadecyl, and eicosyl esters of p-coumaric acid in the vine and root latex of sweetpotato [Ipomoea batatas (L.) Lam.]

Methanol extracts of vine latex of four cultivars of sweetpotato [Ipomoea batatas (L.) Lam.] were analyzed for their chemical phenolic composition by reversed-phase HPLC. Major components were identified as hexadecyl, octadecyl, and eicosyl p-coumarates by an evaluation of data from UV spectra, hydrolysis, synthesis, and GC/MS of their trimethylsilyl derivatives. Both Z- and E-isomers of the phenolic acid were found, with the latter predominating. Trace quantities of hexadecyl (Z)- and (E)-ferulates were also identified in ester concentrates. Levels of octadecyl (E)-p-coumarate ranged from 0.7% fresh weight in cv