Optimization of extraction conditions of acorn pollen for tyrosinase inhibition using response surface methodology

Abstract

Bee pollen is a complex of flower pollen and nectar, collected by honey bees. It is rich in phenolic compounds including flavonoids, and has been used as a functional products such as dietary supplement. In our present study, the extract of acorn bee pollen inhibited tyrosinase activity, a key enzyme in melanin synthesis. For development as products, extraction procedure is indispensable and extraction conditions greatly affect the biological activity and chemical composition. Therefore, optimization of extraction conditions for maximum tyrosinase inhibition was determined using response surface methodology of Box-Behnken design (BBD) with three-level-three-factor such as extraction solvent (50, 75 and 100% EtOAc in MeOH), extraction time (19, 31 and 43h) and extraction temperature (10, 30 and 50 ° C). Regression analysis showed a good fit of the experimental data with F-value of 52.16 and p-value of 0.001 and showed the importance of extraction solvent for maximum tyrosinase inhibition with p-value of 0.001. The optimal condition was obtained as EtOAC concentration, 66.8%, extraction time, 19.0h, and extraction temperature 10.0 °C with 65.6% tyrosinase inhibition. Further analysis of flavonoid content and tyrosinase activity in the extract prepared from different extraction condition in response surface methodology suggested the positive correlation of flavonoid content and tyrosinase inhibition with R2 of 0.176. Taken together acorn pollen is a promising candidate for decrease in skin hyperpigmentation and food browning. In addition, optimized extraction condition for tyrosinase inhibition will provide useful information for the development of acorn bee pollen as functional products.