The Hydroxytyrosol posses the hability to destory the free radicals and inhibit their chain reactions. Hence, a large antioxidant capacity has been attributed to this compound. The antioxidant activity of the Hydroxytyrosol is the largest found compared with the other polyphenols. This antioxidant activity is even higher that the one found for the Vitamin E. Antioxidants are substances that protect the cell from the action of oxidants or free radicals, counteracting its harmful effect.

Free Radicals are molecules with a high oxidant activity and commonly they are the responsible of multiple oxidative chain reactions. The antioxidants act taking place into the oxidative chain reactions and then, they can remove the free radicals and stop the oxidative process.

Different in vitro and in vivo scientific studies pointed out that Hydroxytyrosol inhibit the oxidation of low density lipoproteins (LDL) which are the responsible for the parthenogenesis of arteriosclerosis. The peroxidation modifies the LDL creating fatty deposits that produce atheromas. The in vitro scientific reports clearly conclude that the mice feeded with Hydroxytyrosol presented more resistance to the lipidic peroxidation compared with mice feeded with other different diet.

Another recently published study by the "Instituto de Investigación Sanitaria del Hospital Universitario La Paz" (Madrid), has demonstrated that the Hydroxytyrosol consumption as food supplement contributed to a healthy aging with a cardioprotective effect on the endothelial function and atherogenic risk reduction.

The EFSA (European Food & Safety Authority) considered in 2012 all the polyphenols present in the olive tree as protective agents for LDL against the free radical oxidation and also prevents the vascular deterioration produced by the arteriosclerosis. This organization (EFSA) recommends a minimum consumption of 5 mg / day of Hydroxytyrosol.

Different scientific publications have demonstrated that Hydroxytyrosol posses powerful antibacterial properties. This fact makes this compound a really efficient antimicrobial agent against pathogenic bacteria in humans with a superior effectiveness compared with erythromycin and ampicillin.

Many different studies have demonstrated that Hydroxytyrosol posseses an outstanding anti-inflammatory effect. During the inflammatory processes that take places in the human body, free radicals are generated and antioxidants are reduced.

Hydroxytyrosol has the capacity to inhibit the cyclooxygenase enzymes (COX) and lipoxygenases (LOX) which are the responsible to produce the so-called prostaglandins from arachidonic acid, reducing the oxidative deteriorarion characteristic of inflammatory processes.

The chemoprevention is one of the main cancer treatments nowadays and the antioxidants play an important role in this field. Different scientific studies suggest that Hydroxytyrosol inhibits the cancer cell replication, especially in breast cancer and colon cancer. Specifically, Hydroxytyrosol is able to inhibit the initiation and promotion steps of carcinogenesis. This prevents the DNA damage induced by different genotoxic species and induces apoptosis (cell death) in different tumor lines. Studies conducted on the consumption of Extra Virgin olive oil and the prevalence of disases in the population, result in a lower incidence in cancer.

Hydroxytyrosol (and Tyrosol in less extend) protect against the cancer cell proliferation and the apoptosis in mammary epithelial cells (MCF10A) or cancel cells (MDA-MB-231 and MCF7). It has also been shown that oleuropein inhibits tumor necrosis factors, inducing an specific line of action in monocytes. Thus, for instance, a recent study has demonstrated that high oleuropein consumption inhibits cell proliferation in breast edenocarcinoma.

Ultraviolet radiation (UV) is an electromagnetic radiation with wavelenghts between 100 and 400 nm. In small amounts, UV radiation is beneficial for human health and plays an essential role in the production of vitamin D. However, the long exposure to the UV radiation is related to different types of skin cancer, sunburn, accelerated aging of the skin, cataracts and other eye diseases. It has also been proven that these radiations reduce the effectiveness of the immune system.

In order to help the skin to put up with the UV light day by day, a high Solar Protection Factor is required in the costmetics and solar protector products. Hydroxytyrosol increases this factor in almost a 19%. Moreover, it also prevents the degradation of the cosmetic product from long periods exposure of solar UV radiation.  Hydroxytyrosol prevents the damage caused by the UV radiation in the melanoma cells upon harmul UV radiation exposure. The presence of Hydroxytyrosol significantly reduces the breakage of DNA strands caused by UVB radiation by inhibiting the proliferation of reactive species caused by the incident radiation.

To conclude, Hydroxytyrosol protects against edema and erythema caused by excessive sun exposure.

Several epidemiological studies in vitro and in vivo indicate that the consumption of polyphenols reduces the risk of neurodegeneration and also of the cognitive decline associated with the age. Correlated studies revealed that the effects of cytoprotection in P12 cells are due to Hydroxytyrosol. The bran in its activity has a big energetic consumption because it consumes a large amount of oxygen. During this oxidative process free radicals are generated and they damage the cells.

As conclusion, Hydroxytyrosol protects the brain cells against peroxidation of lipids.

The ADM (Age-related Macular Degeneration) is a disease associated with the age and other harmful effects, such as smoking, and it causes blindness in people over 55 years old.

A study carried out by Silva, S et al (2014) demonstrated the anti-inflammatory power of Hydroxytyrosol reducing joing edema in rats. Hydroxytyrosol stimulates the production of chondrocytes by regenerating and reparing the articular cartilage. It also helps during the physical exercise it increases the production of Glutathione (endogenous antioxidant) and reduces the production of lactic acid and the consequent muscular atrophy.