Antioxidants from Plants Protect against Skin Photoaging

Abstract

Exposure to UV light triggers the rapid generation and accumulation of reactive oxygen species (ROS) in skin cells, with consequent increase in oxidative stress and thus in photoaging. Exogenous supplementation with dietary antioxidants and/or skin pretreatment with antioxidant-based lotions before sun exposure might be a winning strategy against age-related skin pathologies. In this context, plants produce many secondary metabolites to protect themselves from UV radiations and these compounds can also protect the skin from photoaging. Phenolic compounds, ascorbic acid and carotenoids, derived from different plant species, are able to protect the skin by preventing UV penetration, reducing inflammation and oxidative stress, and influencing several survival signalling pathways. In this review, we focus our attention on the double role of oxidants in cell metabolism and on environmental and xenobiotic agents involved in skin photoaging. Moreover, we discuss the protective role of dietary antioxidants from fruits and vegetables and report their antiaging properties related to the reduction of oxidative stress pathways.

Figure 1

Schematic representation of the cell antioxidant response following oxidative stress injury. Upon UV radiations, ROS levels increase and oxidative stress is induced. Endogenous antioxidants suppress ROS formation and exogenous and endogenous antioxidants cooperate to suppress propagation reactions. Cell damages are repaired by de novo enzymes. Finally, if the cooperation among these antioxidant-related networks is able to counteract oxidative stress injury, the cell will survive after an adaptation process; otherwise, in case of prolonged or excessive stress, the cell will undergo cell death.

Figure 2

Cartoon representing cellular responses to oxidative stress in the presence (red lines) or in the absence (blue lines) of antioxidants. After oxidative stress induction by UV radiations, there is an increase in free radicals, which, in turn, induces different responses in the cell, such as depletion in GSH, activation of MAPK cascade, increase in lipid peroxidation, inflammation, skin photoaging, and apoptosis. All these processes can be inhibited or counteracted by antioxidant's activity (reported in the red box).