Inhibitory effect of Zanthoxylum bungeanum maxim. and Capsicum annuum L. on the activities of pancreatic lipase and α‐amylase

Abstract

SummaryZanthoxylum bungeanum maxim. (ZBM) and Capsicum annuum L. (CAL) are popular condiments in China. In this study, the inhibition of pancreatic lipase and α‐amylase by ZBM and CAL extracts, as well as catechin, rutin, hydroxy‐α‐sanshool (from ZBM extract) and capsaicin (from CAL extract), was determined. The half maximal inhibitory concentration (IC50) values of ZBM extract, CAL extract, rutin, hydroxy‐α‐sanshool and capsaicin against pancreatic lipase were 82.1, 533.5, 583.8, 565.7 and 62.4 μg mL−1, respectively, while that against α‐amylase were 125.6, 1167.2, 213.2195.6 and 163.2 μg mL−1, respectively. Catechin had no detectible inhibition on the two enzymes even at 4 mg mL−1. The combination of hydroxy‐α‐sanshool and capsaicin against the two enzymes showed similar inhibition trends to that of ZBM and CAL extracts (synergism at low concentrations but antagonism at high concentrations), suggesting the two compounds were closely associated with the functions of the crude extracts. The results obtained from the in vitro digestion were similar but with a lower inhibition rate. Kinetic studies revealed that ZBM extract, hydroxy‐α‐sanshool and capsaicin showed mixed‐type inhibition for pancreatic lipase and α‐amylase. Molecular modelling suggested capsaicin had a higher affinity to the two enzymes, with glide scores of −8.18 and −7.87 kcal mol−1, respectively.