Extraction of antioxidant compounds from different varieties of Mangifera indica leaves using green technologies

Supercritical Fluid Extraction (SFE) and Subcritical Water Extraction (SWE) from mango leaves were applied in order to obtain extracts with high phenolic content and potent antioxidant activity. The effects of extraction conditions on sub- and supercritical CO2 extraction were analyzed: temperature (35 and 55 °C), pressure (10 and 40 MPa), percentage of co-solvent (0 and 20%) and type of co-solvent (methanol/ethanol). The best condition (CO2 + 20% of ethanol at 10 MPa, 55 °C, 20 g/min and 3 h) was compared with SWE (4 MPa, 100 °C, 10 g/min, and 3 h) using seven mango cultivars. SWE was more efficient than subcritical CO2 + ethanol. The antioxidant activity was evaluated by DPPH assay, and the quantification of the main polyphenols of mango leaves by HPLC analysis. SWE showed global yields up to 35% for Kent variety, and extracts with antioxidant activities superior to (+)-α-tocopherol related with their high content on the polyphenols mangiferin and quercetin.