Antioxidative, Anti-Inflammatory, and Anti-Aging Properties of Mycosporine-Like Amino Acids: Molecular and Cellular Mechanisms in the Protection of Skin-Aging

Abstract

Prolonged exposure to ultraviolet (UV) radiation causes photoaging of the skin and induces a number of disorders, including sunburn, fine and coarse wrinkles, and skin cancer risk. Therefore, the application of sunscreen has gained much attention to reduce the harmful effects of UV irradiation on our skin. Recently, there has been a growing demand for the replacement of chemical sunscreens with natural UV-absorbing compounds. Mycosporine-like amino acids (MAAs), promising alternative natural UV-absorbing compounds, are a group of widely distributed, low molecular-weight, water-soluble molecules that can absorb UV radiation and disperse the absorbed energy as heat, without generating reactive oxygen species (ROS). More than 30 MAAs have been characterized, from a variety of organisms. In addition to their UV-absorbing properties, there is substantial evidence that MAAs have the potential to protect against skin aging, including antioxidative activity, anti-inflammatory activity, inhibition of protein-glycation, and inhibition of collagenase activity. This review will provide an overview of MAAs, as potential anti-aging ingredients, beginning with their structure, before moving on to discuss the most recent experimental observations, including the molecular and cellular mechanisms through which MAAs might protect the skin. In particular, we focus on the potential anti-aging activity of mycosporine-2-glycine (M2G).

Keywords: UV-absorbing compound; anti-aging; anti-inflammation; anti-oxidation; anti-protein-glycation activity; mycosporine-2-glycine; mycosporine-like amino acids; sunscreen.

Figure 1

Removal of reactive oxygen species (ROS) by an antioxidant defense system consisting of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), thioredoxin oxidase (TRXR), and peroxiredoxin (PRDX). GSHred and GSSGox indicate reduced glutathione and oxidized glutathione, respectively. TRXred and TRXox indicate reduced thioredoxin and oxidized thioredoxin, respectively.

Figure 2

UV-B-induced inflammatory response. Nitric oxide (NO), inducible NO synthase (iNOS), prostaglandin E2 (PGE₂), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), and other cytokines, such as interleukin-1 (IL-1) and interleukin-6 (IL-6), are shown as mediators.

Figure 3

Chemical structures of the selected mycosporine-like amino acids (MAAs)—mycosporine-glycine, shinorine, porphyra-334, mycosporine-2-glycine, palythine, and euhalothece-362.