Hydroxytrosol is an extract from olives that is a powerful antioxidant. Earlier research, published in the journal Circulation (2000;102:2169-2171) has shown it to protect from the oxidative stress found in second hand smoke. In that study, rats were exposed to smoke. Urine samples were taken and tested for 8-iso-PGF2 (alpha), which is a chemical that indicates oxidative stress. The smoke increased the level of the chemical; giving the rats hydorxytrosol prevented the increase in 8-iso-PGF2 (alpha).

In a recent study, published in the Journal of Agricultural and Food Chemistry (Vol. 55, No. 13, pp 5043 -5049) looked at the ability of hydroxytrosol to protect nerve tissue.  The researchers report that a 45% hydroxytyrosol extract increased resistance to oxidative stress in brain cells. Malondialdehyde is an end product of lipid oxidation—noxious to cells. The level of malonaldehyde was 25% lower when it was were administered in the presence of the olive extract. This indicates that hydroxytrosol may be protective of nerve tissue.