Pancreatic Lipase Inhibition by Polyphenols in Persimmon Leaf Tea

Persimmon (Diospyros kaki) leaf tea is a traditional beverage rich in polyphenols and has been associated with various health benefits; however, its potential to inhibit dietary lipid digestion remains to be fully elucidated. This study evaluated the pancreatic lipase-inhibitory effect of hot-water extracts of persimmon leaves (persimmon leaf tea) using both a synthetic substrate (p-nitrophenyl palmitate, pNPP) and a physiologically relevant triacylglycerol substrate in an oil-in-water emulsion system. Persimmon leaf tea exhibited concentration-dependent inhibition in both assays, indicating lipase-inhibitory effects against both synthetic and physiologically relevant lipid substrates. The pNPP assay was therefore used for subsequent evaluations. High-performance liquid chromatography analysis identified astragalin and isoquercitrin as the predominant flavonol glycosides in the tea. Astragalin and isoquercitrin individually inhibited porcine pancreatic lipase activity in a concentration-dependent manner. Astragalin exhibited a slightly stronger lipase-inhibitory effect than isoquercitrin. When the two compounds were combined at concentrations corresponding to those in persimmon leaf tea, the mixture produced stronger inhibition than the tea itself, suggesting that matrix components may modulate flavonoid activity. Removal of polyphenols by polyvinylpolypyrrolidone treatment markedly reduced lipase-inhibitory effect and reconstitution with the two flavonoids substantially restored the effect, demonstrating that polyphenolic compounds are major contributors to the effect, although they may not fully account for the total inhibition. Although the tea exhibited lower maximal inhibition than the combined authentic standards, this difference is likely attributable to matrix effects from other constituents present in the tea. Compared with the pharmaceutical inhibitor orlistat, persimmon leaf tea showed milder inhibition, with IC₅₀ values several hundred times higher, which may be advantageous for long-term dietary use. These findings indicate that persimmon leaf tea suppresses lipid digestion through the combined actions of its major flavonoids and suggest its potential as a functional beverage for moderating dietary fat absorption.