Protective effects of microalgal carotenoids against glycosylation-induced collagen degradation in skin

[Display omitted] •High-purity carotenoids were prepared from crude algal extracts.•Astaxanthin esters in H. pluvialis was quantified.•Microalgae-derived astaxanthin esters and lutein exhibited anti-glycosylation activities in fibroblast cell model.•Collagen degradation was induced by high sugar treatment and was ameliorated via downregulating MMP-2. Long-term high sugar accelerates skin ageing via glycosylation. In this study, microalgae-derived active compounds were investigated for their potentially beneficial effects on skin ageing. Two carotenoids, namely astaxanthin (in the form of either monoester or diester) and lutein, were separated from the green alga Haematococcus pluvialis. These carotenoid fractions significantly attenuated the high glucose (HG)-induced cell injury and oxidative stress. They also inhibited the formation of Nε-Carboxymethyllysine (CML), a typical product of glycosylation. The degradation of collagen I and III caused by HG was substantially recovered, in which astaxanthin monoester exhibited the most prominent effect. This was attributed to the down-regulation of matrix metalloproteinase (MMP)-2 mRNA expression. Through proteomics analyses, six hub proteins were identified, which work as highly connected nodes in the protective effects of astaxanthin monoester against HG stress. These findings strongly suggest the benefits of microalgae-derived carotenoids in alleviating HG-induced skin ageing.