Antioxidation and anti-aging activities of astaxanthin geometrical isomers and molecular mechanism involved in Caenorhabditis elegans

Astaxanthin (AST) exists trans/cis forms in food. Currently, the functional activities and molecular mechanisms of the geometrical isomers remain unclear. In this study, the anti-aging activities of isomers were studied in Caenorhabditis elegans. The median lifespan of C. elegans fed with 9-cis, 13-cis and all-trans isomers was observed to increase by 59.39%, 24.99%, and 30.43%, respectively. AST isomers didn't exert adverse effects on reproductive behavior, and could alleviate the decline in physiological function caused by senility in C. elegans. In addition, the decreased intracellular ROS accumulation was consistent with the life extension. RNA-seq analysis demonstrated that the lifespan extension was mediated primarily through the modulation of genes involved in the longevity regulating pathway, and was caused by the 9-cis (hsp-16.48, hsp-16.49) and all-trans (fat-5, pha-4) relative to the 13-cis. Furthermore, different isomers resulted in differences in anti-aging mechanisms through the regulation of the expression of specific differentially expressed genes.