Characterization of sinapyl derivatives in pineapple (Ananas comosus [L.] Merill) juice.

Three previously unidentified phenolic compounds were found in pineapple (Ananas comosus [L.] Merill) juice in substantial concentrations and were isolated by semipreparative reverse phase HPLC. The structures were elucidated from UV spectra, acid hydrolysis, and subsequent amino acid analysis, mass spectrometry, and two-dimensional NMR spectroscopy. The compounds are identified as S-sinapyl-L-cysteine, N-L-gamma-glutamyl-S-sinapyl-L-cysteine, and S-sinapylglutathione.