Water-soluble intracellular extract of Desmodesmus sp.YT enhanced the antioxidant capacity of human skin fibroblast to protect the skin from UV damage

Abstract Ultraviolet (UV) radiation-induced oxidative stress damage is a significant catalyst for skin aging and can even contribute to the development of skin cancer. In this study, the mechanism of how water-soluble intracellular extract (WIE) of Desmodesmus sp.YT (YT) prevent human skin fibroblast (HSF) against the oxidative damage caused by UV radiation were explored. Results showed that YT-WIE exhibited great antioxidant activity. The potent scavenging ability activity was observed in DPPH (IC50 = 0.55 mg mL -1 ), ABTS (IC50 = 3.11 mg mL -1 ), ·OH (IC50 = 2.21 mg mL -1 ) and O 2 •- (IC50 = 0.98 mg mL -1 ). Additionally, the findings indicated that when compared to the control group, YT-WIE group exhibited an 89.30% enhancement in the viability of HSF and a 44.63% increase in the survival rate following UV irradiation. To investigate the underlying mechanism, comprehensive analysis of gene transcription and translation was conducted using RT-qPCR and Western blot. The results demonstrated a significant upregulation of antioxidant genes ( GCLC , GCLM , TXNRD1 , HMOX1 , NQO1 ) by YT-WIE treatment at a concentration of 400 µg mL -1 , with fold increases ranging from 1.13 to 5.85 times. Therefore, YT-WIE exhibited a great potential to serve as antioxidants that can protect human cells from excessive oxidative stress caused by outer stimulus, such as UV.