Potent antioxidant biophenols from olive mill waste

Olive mill waste (OMW) is rich in biophenols that can be extracted and applied as natural antioxidants for the food and pharmaceutical industries. Bioactivity-guided fractionation combines the use of bioassay and chromatographic separation for isolation of potent bioactive compounds from highly complex plant extracts, such as OMW, and avoids tedious purification and identification of inactive phytochemicals. Antioxidant activity-guided fractionation and sub-fractionation of Correggiola variety OMW extract, using semi-preparative HPLC and multidimensional antioxidant screening, followed by isolation of the screening hits are described. Activity-guided fractionation using four different bioscreens revealed verbascoside and 3,4-dihydroxyphenylethyl alcohol–deacetoxyelenolic acid dialdehyde (3,4-DHPEA–DEDA) as the most potent antioxidants in Correggiola OMW extracts.