UVA radiation, blue light damages and hydroxytyrosol

Skin photoaging is mainly induced by ultraviolet (UV) irradiation and its manifestations include dry skin, coarse wrinkle, irregular pigmentation, and loss of skin elasticity. Dietary supplementation of nutraceuticals with therapeutic and preventive effects against skin photoaging has recently received increasing attention.

The major mechanisms of these dietary components to alleviate skin photoaging include the maintenance of skin moisture and extracellular matrix content, regulation of specific signaling pathways involved in the synthesis and degradation of the extracellular matrix, and antioxidant capacity. Taken together, the ingestion of food-derived functional components could be an attractive strategy to prevent skin photoaging damage.

The photoaging process and the underlying mechanisms are complex. Matrix metalloproteinases, transforming growth factors, skin adipose tissue, inflammation, oxidative stress, nuclear and mitochondrial DNA, telomeres, microRNA, advanced glycation end products, the hypothalamic-pituitary-adrenal axis, and transient receptor potential cation channel V are key regulators that drive the photoaging-associated changes in skin (“Boosting the Photoaged Skin: The Potential Role of Dietary Components” Ruixuan Geng et al; Nutrients 2021).

Studies have indicated that exposure to high concentrations of many environmental factors, such as ultraviolet (UV) radiation, outdoor air pollutants, including polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), particulate matter (PM), heavy metals, gaseous pollutants, such as carbon monoxide (CO), nitric oxides (NOx ), sulfur oxide (SO2 ), ozone (O3 ), and indoor air pollutants (solid fuels consumption), might interrupt the skin’s normal barrier function.

Air pollutants are believed to induce or exacerbate a range of skin conditions, such as aging, inflammatory diseases (atopic dermatitis, cellulitis, and psoriasis), acne, hair loss, and even skin cancers (mainly melanoma and Squamous Cell Carcinoma) through various mechanisms. The interaction between pollutants and the skin might differ based on each agent’s particular characteristics. Also, damaging the skin barrier seems to be closely related to the increased production of reactive oxygen species (ROS), induction of oxidative stress, activation of aryl hydrocarbon receptor (AhR), and inflammatory cytokines (“The impact of air pollution on skin and related disorders: A comprehensive review”; Ruhollah Abolhasani et al.; Dermatol Ther 2021).

Natural hydroxytyrosol is a potent antioxidant under the form of an ortho-diphenol that shows an elevated free radical scavanger activity.

The oxidative stress plays a major role in mediating the UVA-induced protein damage. Results suggest that hydroxytyrosol may exerts differential effects on melanoma cells according to the dose employed. (“Hydroxytyrosol, a natural antioxidant from olive oil, prevents protein
damage induced by long-wave ultraviolet radiation in melanoma cells”; Stefania D’Angelo et al; Free Radical Biology&Medicine 2005).

HT has a significant protective ability against UVB-induced DNA damage and that oxidative stress plays an important part in it (“The Protective Effects of Hydroxytyrosol Against UVB-induced DNA Damage in HaCaT cells; Wei Guo et al.; Phytotherapy Research 2009).

Recently it was established that the long-term exposure to light-emitting-diode-generated blue light (LED-BL) from electronic devices seems to have a relevant implication in the molecular mechanisms of premature photoaging. Hydroxytyrosol has demonstrated to protect keratinocytes and fibroblasts from LED-BL-induced damage. Thus, hydroxytyrosol might be proposed as an encouraging candidate for the prevention of BL-induced premature photoaging (“Hydroxytyrosol from olive fruits prevents blue-light-induced damage in human keratinocytes and fibroblasts”; Rosanna Avola; Journal of Cellular Physiology; 2018).