Discovery and characterization of pentacyclic triterpenoid acids in Styrax as potent and reversible pancreatic lipase inhibitors

•Styrax extract was found with strong pancreatic lipase (PL) inhibition activity.•Bioactivity and LC-MS guided fractionation strategy was used to identify naturally occurring PL inhibitors in Styrax.•Oleanonic acid (ONA) and betulonic acid (BNA) potently inhibit PL, with IC50 values less than 1.5 μM.•Inhibitory mechanisms of ONA and BNA against PL were investigated by inhibition kinetic analyses and in silico analysis.