Correlation Between Phenolic Compounds Contents, Anti- tyrosinase and Antioxidant Activities of Plant Extracts

Abstract

Plants are a natural source of strategic bio-active chemicals able to inhibit tyrosinase and reduce reactive oxygen species helping to protect human body against diseases related to alterations in DNA and cancer. Anti-tyrosinase and antioxidant compounds are widely commercialized as components in foods, as well as in other products from pharmaceutical, cosmetics and health industries. Searching for plants containing natural antioxidants and bioactive compounds, we described a preliminary study in which eighteen extracts from thirteen plant species showed an interesting anti-tyrosinase potential. Schinus terebinthifolius was one of the most interesting plant species detected in the previous study. In this way, the present work aimed to evaluate the correlation between phenolic compounds contents and biological activities (anti-tyrosinase and antioxidant) of different extracts from S. terebinthifolius (barks and leaves). HPLC profile and antioxidant activities were determined for the extracts. Some secondary metabolites (caffeic and gallic acids as well as methyl gallate) were identified via HPLC and spectroscopic methods in S. terebinthifolius extracts. The in vitro anti-tyrosinase activity of these compounds was also evaluated and the extension of their activity was compared to the anti-tyrosinase activity of the crude extracts. Gallic and caffeic acid were found in both leaves and bark extracts. Gallic acid showed low anti-tyrosinase activity (30 %), in its pure form, but its presence waspositively associated with improved degrees of anti-tyrosinase (69-75 %) and antioxidant activities (inhibition concentration – IC) of the extracts (IC 50 % ABTS: 16.6 - 23.9 µg.mL-1 and IC 50 % DPPH: 295.2 – 392.4µg.mL-1). Schinus terebinthifolius extracts are, therefore, promising natural source of tyrosinase inhibitors (in bark extracts) and antioxidant agents (especially in leaves extracts), showing biotechnological potential to be used as functional food, nutraceutical or in cosmetic formulations.