Antioxidation and anti-ageing activities of different stereoisomeric astaxanthin in vitro and in vivo

•There were significant differences among three stereoisomeric AST both in vitro and in vivo.•S AST exhibited the strongest antioxidation and anti-ageing activities.•Anti-ageing activities of three stereoisomeric AST do not cause adverse effects on the physiological functions of C. elegans. Astaxanthin (AST) is a potent antioxidant with different stereoisomers in nature. However, there have been no reports about the functional activities of different stereoisomers so far. In this study, the antioxidant and anti-ageing activities of 3S,3'S (S), 3R,3'R (R), and mixture (M) AST were evaluated in chemical-based assays, cellular antioxidant assays (CAA), and an organism-based model. S AST exhibited the strongest activity in chemical assays and CAA. The median lifespan of Caenorhabditis elegans fed with S, R and M AST was found to increase by 27.61%, 25.25% and 22.69%, respectively. The three stereoisomeric AST did not cause adverse effects on the physiological functions of C. elegans. A decreasing trend of intracellular ROS accumulation caused by AST treatment was accompanied by the prolonged lifespan. Our results provided mechanistic information on the antioxidation and anti-ageing activities of different stereoisomeric AST, which is useful for rational utilization of AST in functional food.