Nobiletin Inhibition of Lipase Activity

The RNs and UPNs were dissolved in deionized water at concentrations of 15.63, 31.25, 62.50, 125, 250, and 500 μg/mL, and a 0.22 μm filter was used after thorough ultrasonication. Six milligrams of porcine pancreatic lipase (PPL) was dissolved in 10 mL of buffered phosphate (0.1 M, pH 7.2). Then, as the reaction substrate, 8.4 μL of p-nitrophenylbutyrate (PNPB) was dissolved in 10 mL of acetonitrile. Different amounts of nobiletin sample solution (0.2 mL) were carefully mixed with 0.1 mL of PPL solution, and the mixture was then diluted to 2 mL with phosphate buffer. The samples were mixed evenly by ultrasonication and incubated at 37 °C for 30 min. An ultraviolet spectrophotometer was used to measure the absorbance at 410 nm, with orlistat serving as the positive control.