Giardia duodenalis: Effects of an ozonized sunflower oil product (Oleozon®) on in vitro trophozoites

The ozonized sunflower oil product (Oleozon (R)) was investigated to explore its cytotoxic activity on Giardia duodenalis in vitro cultivated trophozites. Oleozon (R) produced inactivation of Giardia trophozoites in a dose- and cell density-dependent manner. Thirty microliter of Oleozon (R) with peroxide index value of 500 equivalent-mmol of activated oxygen per kilogram were used to achieve a 100% inhibition (<-4.00 log unit) of trophozoites from an initial inoculum of 15 x 104 cells. This potent effect was confirmed by transmission electron microscopy where morphological deterioration of superficial structures mainly in the ventral disc, and formation of a great number of micro vesicles in the cytoplasm were found. We concluded that a direct chemical-oxidation attack by the active substances from Oleozon (R) is one of the causes of the parasitocidal effect of this product. We suggest that the dose and cell density-de pendent effect must be taken into account when prescription of this product for giardiasis treatment in humans. (c) 2008 Elsevier Inc. All rights reserved.