Optimization of Extraction of Polyphenols and Flavonoids from Papaya Peel and Its Anti-tyrosinase and Anti-pancreatic Lipase

The extract process of polyphenols and flavonoids from papaya peel were optimized and their antioxidant activity, anti-tyrosinase and anti-pancreatic lipase were evaluated. On the basis of single factor experiment, orthogonal experiment was used to study the influence of ultrasonic temperature, ultrasonic time, ethanol concentration and solid-liquid ratio on the contents of polyphenols, flavonoids from papaya peel. The scavenging ability of papaya peel on DPPH free radicals and ABTS free radicals and its inhibitory activity on tyrosinase and pancreatic lipase were measured. The optimal extraction conditions were obtained: Ultrasonic temperature 40 ℃, ultrasonic time 60 min, 60% ethanol, solid-liquid ratio 1:25 g/mL. Under the optimal conditions, the contents of polyphenols and flavonoids from papaya peel reached (82.00±0.65) mg/g and (162.76±2.82) mg/g, respectively. The scavenging rates of papaya peel on DPPH free radicals and ABTS free radicals reached (94.79%±0.10%) and (96.94%±0.23%), respectively. The inhibition rate of papaya peel on tyrosinase with L-Tyr and L-Dopa as the substrate reached (83.33%±6.80%) and (67.12%±0.32%), respectively. The inhibition rate of papaya peel on pancreatic lipase reached (82.78%±1.28%), indicating that papaya peel had strong antioxidant capacity, tyrosinase and pancreatic lipase inhibitory activity.