Isolation, spectroscopy and selective phytotoxic effects of polyphenols from vegetable waste waters

Abstract Catechol, 4-methylcatechol, tyrosol and hydroxytyrosol were isolated and characterized as the main polyphenols from olive oil mill waste waters. In addition, the corresponding acetates were prepared. In phytotoxicity assays carried out on tomato (Lycopersicon esculentum) and vegetable marrow (Cucurbita pepo) plants, the compounds were selectively toxic, except for 4-methylcatechol and its acetate. The vegetation waters remained phytotoxic even after total extraction of the polyphenols, suggesting that other chemical products contribute to the overall phytotoxicity.