Optimization of pancreatic lipase inhibition by Cudrania tricuspidata fruits using response surface methodology

The fruits of Cudrania tricuspidata (Carr.) Bur. (Moraceae) significantly inhibited pancreatic lipase, which plays a key role in fat absorption. Optimization of extraction conditions with minimum pancreatic lipase activity and maximum yield was determined using response surface methodology with three-level-three-factor Box-Behnken design (BBD). Regression analysis showed a good fit of the experimental data and the optimal condition was obtained as ethanol concentration, 74.5%; temperature 61.9 °C and extraction time, 13.5 h. The pancreatic lipase activity and extraction yield under optimal conditions were found to be 65.5% and 54.0%, respectively, which were well matched with the predicted value of 65.8% and 47.1%. Further fractionation of C. tricuspidata extract resulted in the isolation of compound 1, which was identified as 5,7,4′-trihydroxy-6,8-diprenylisoflavone. It inhibited pancreatic lipase activity with IC₅₀ value of 65.0 μM. HPLC analysis suggested positive correlation between pancreatic lipase inhibition and 5,7,4′-trihydroxy-6,8-diprenylisoflavone of C. tricuspidata fruits.