Optimization of microwave assisted extraction of Morus nigra L. fruits maximizing tyrosinase inhibitory activity with isolation of bioactive constituents

Morus nigra L. is a beneficial food due to rich phenolic components. While aiming higher yields for bioactive constituents, reduction in terms of raw material, solvent, time and energy gained more importance to provide a sustainable life for human and nature. Microwave assisted extraction (MAE) of Morus nigra fruits was optimized in order to elicit process parameters maximizing bioactive metabolites and tyrosinase inhibitory activity. Spectrophotometry and UPLC-DAD-ESI-MS/MS systems were utilized for quantitative analysis of total phenol, flavonoid and anthocyanin contents. Optimum conditions for MAE were determined as 500 W, 35% ethanol, 10 min yielding 12.63 mg/g cya-3-glu equiv. anthocyanin and IC50 value of 1.60 mg/ml for tyrosinase inhibitory activity. Microwave extracts prevailed better outcomes compared to conventional extraction methods (10.93 mg/g content with IC50 of 2.81 mg/ml). MAE could be considered as an advanced technique to obtain extracts from Morus nigra fruits with higher bioactive content and activity.