Caffeoylquinic acids competitively inhibit pancreatic lipase through binding to the catalytic triad

Caffeoylquinic acid and its isomers inhibited porcine Pancreatic Lipase (PL) activity according to a competitive mode where binding and interaction with the catalytic triad of Ser153, His264 and Asp177 simultaneously occurred. The IC50 values under which 3-caffeoylquinic acid (CQA) and its isomers 4-, 5-CQA, 3,4-, 3,5- and 4,5-diCQA inhibited half of the porcine PL activity were 1.10, 1.23, 1.24, 0.252, 0.591 and 0.502 mM, respectively. The binding affinities in the range from −8.4 to −9.5 kCal/mol were well predicted from docking, which showed a high linear correlation coefficient of 0.893 and Spearman correlation of 1.0 with log(IC50) values. Caffeoylquinic acid and its isomers were stabilized by hydrogen bond and hydrophobic interaction in the binding pocket. This finding provided molecular mechanism of coffee and other natural food or drink containing caffeoylquinic acid and its isomers against lipase activity.