In vitro anti-obesity activity by pancreatic lipase inhibition - Simple HPLC approach using EVOO as natural substrate

Background: Pancreatic lipase (PL) is a key lipolytic enzyme in humans for the digestion and absorption of dietary fats. Thereby, PL is a well-recognized target in the management of obesity and its inhibition attracts the interest of researchers globally. Thescreening of new natural PL inhibitors as alternative strategy to the synthesis of chemical ones represents nowadays a hot topicin research. The main challenge in this matter is the lack of a universal analytical method allowing the monitoring of PL activityand the reliable quantification of lipid digestion products. Results: The (normal phase)-high-performance liquid chromatography-evaporative light scattering detector [(NP)-HPLC-ELSD] method proposed in this work represents a direct and rapid strategy to simultaneously quantify the products obtained fromin vitroPL digestion. As one of the main novelties, the triacylglycerol (TAG) fraction from extra-virgin olive oil was selectedas natural substrate. The PL activity was measured by monitoring the levels of remaining TAGs and formed free fatty acids(FFAs), using Orlistat as known inhibitor. The method validation confirmed the adequacy of the analytical method for quanti-tative purposes, showing high recovery percentage values (between 99% and 103%) and low relative standard deviation (RSD%) values (between 2% and 7%) for triolein and oleic acid standard solutions, as well as appreciably low limit of detection (LOD)and limit of quantification (LOQ) values (respectively 58 and 177 ng mL−1 for triolein; 198 and 602 ng mL−1 for oleic acid). Finally, the developed HPLC-ELSD method was successfully applied to evaluate the inhibitory effect of a polyphenolic extractobtained from apple pomace. The results showed a comparable inhibition degree between a 4.0 mg mL−1 apple pomace solu-tion and a 1.0∼gmL−1 Orlistat solution. Conclusion: The proposed innovative method reveals highly sensitive and simple to follow the fate of PL digestion, thus open-ing the way to further investigations in the research of new potentially anti-obesity compounds.