Functional evaluation of perilla leaf tea as a pancreatic lipase inhibitor: roles of rosmarinic acid and emulsion structure

Obesity is a growing global concern, and pancreatic lipase inhibitors have emerged as potential targets for antiobesity strategies. This study evaluates the potential of Perilla frutescens (L.) Britton var. frutescens leaf tea as a pancreatic lipase inhibitor for managing dietary fat absorption. Perilla leaf tea significantly inhibited the pancreatic lipase-mediated hydrolysis of emulsified triglycerides, depending on its polyphenol and rosmarinic acid (RA) contents. However, the inhibitory effect diminished at higher concentrations, which coincided with the increased emulsion particle size. Perilla leaf tea did not inhibit the hydrolysis of solubilized p-nitrophenyl palmitate, whereas authentic RA reduced lipase activity against both substrate types. These findings suggest that perilla leaf tea and RA have different lipase inhibition mechanisms. This study implies that RA contributes to the lipase-inhibiting properties of perilla leaf tea and emulsion structure plays a pivotal role in modulating the ability of the tea to inhibit lipase activity.