Recovery and Characterization of Verbascoside, Isoverbascoside and Their Derivatives from Olive Mill Waste Water

Olive oil processing industries generate substantial quantities of phenolic-rich by-products, which could be valuable natural sources of antioxidants. This work is focused on the recovery and structural characterisation of antioxidant compounds from olive mill wastewater (OMWW), a polluting by-product of the olive oil production process. Phenolics were extracted from the waste material using a membrane technology coupled to a low-pressure gel filtration chromatography on a Sephadex LH-20. The LH-20 fraction was, in turn, characterized for its phenolic composition by HPLC-DAD-MS/MS analyses. Verbascoside, isoverbascoside, ?-hydroxyverbascoside, ?-hydroxyisoverbascoside, and various oxidized phenolics were identified. Uptake of verbascoside, purified from the LH-20 fraction, by HT-29 human colon carcinoma cell lines, an established model system for studying drug transport properties, was also assayed.