Photoprotective and antioxidant properties of scytonemin isolated from Antarctic cyanobacterium Nostoc commune Vaucher ex Bornet & Flahault and its potential as sunscreen ingredient

In the cosmetic industry there is an increasing demand for substances obtained from natural sources that can replace synthetic ones. Due to consumer demand for a protective filter with (SPF) labels in sunscreens, moisturizers, face make-up, and lipsticks worldwide, they produce tonnes of such products every year. Many species of cyanobacteria live in extreme environments, including sites with excessive doses of sunlight and drought. To survive in such extreme conditions, they produce compounds that allow both protection against ultraviolet radiation (UV), as well as the substances that are responsible for reducing oxidative stress. The aim of this study was to isolate, identify, and test the biological potential of the secondary metabolite scytonemin from the cyanobacterium Nostoc commune Vaucher ex Bornet et Flahault collected in Antarctica. The photoprotective effect was evaluated by the measurement of the sun protection factor (SPF) and the antioxidant activity was determined by two different assays including superoxide anion scavenging activity and free radical scavenging activity based on the amount of substance. An estimated SPF value of 33.34 ± 0.02 demonstrated that scytonemin might serve as a topically applicable ingredient for natural UV sunscreen cream.