Xanthophyll esters are hydrolysed in the presence of recombinant human pancreatic lipase

Fruit-derived bioactive xanthophyll esters have to be cleaved in the human gastrointestinal tract before absorption of free xanthophylls is possible. One candidate for ester hydrolysis is human pancreatic lipase. For estimation of their activity, an in vitro assay using the recombinant enzyme human pancreatic lipase (rHPL) and porcine colipase was used. Extracts of fruits were incubated with rHPL/colipase for 21 h at 37 °C. Activity of rHPL was demonstrated by an increase of free xanthophylls formed during the incubation. An extremely low activity was detected with all substrates. HPLC–(APcI)MS studies proved that lutein diesters were preferentially cleaved at the β-ionone ring. This is the first report which shows that xanthophyll esters can be cleaved in the presence of rHPL, suggesting either an unexpected secondary ester bond hydrolysis occurring within rHPL active site or, more probably, a reaction induced by other amino acids of HPL such as observed earlier with p-nitrophenyl acetate.