Profiling of tyrosinase inhibitors in mango leaves for a sustainable agro-industry.

Although mango leaves are the main ingredients in some traditional Chinese medicine preparations and folk tea, they with considerable quantities are usually discarded as agricultural waste. Thus, to extend their potential, reverse ultrafiltration-HPLC-DAD-QTOF-MS/MS combining with key ion filtering strategy was proposed to efficiently fish and systematically identify tyrosinase inhibitors in ethyl acetate fraction of mango leaves, which has the highest total phenolic content (40.00 ± 0.84 mg GAE/g DW) and tyrosinase inhibition activity (IC50, 17.62 ± 1.26 μg/mL). Finally, 36 polyphenolic tyrosinase inhibitors were unambiguously characterized or tentatively identified, and three of them were found in mango leaves for the first time. Results suggested that the proposed strategy was powerful for effective identification of bioactive compounds in complex mixtures (e.g. food, agricultural and sideline products), and the findings would lay a foundation for potential applications of mango leaves in pharmaceutical, cosmetic, and food industrial fields.