Conjugation of Hydroxytyrosol with Other Natural Phenolic Fragments: From Waste to Antioxidants and Antitumour Compounds

Hydroxytyrosol, a natural polyphenol that can be extracted from olive mill waste waters, was converted into a series of more complex and lipophilic analogues by conjugation with other naturally derived (poly)phenolic fragments. Ether and triazole linkers were employed. A small library of compounds was prepared, stressing step economy and operational simplicity. Some of these substances were proven to have activity equal or superior to that of the parent hydroxytyrosol in radical scavenging assays as well as in cytotoxicity tests against tumour cells.