Extension of Drosophila Lifespan by Astragalus polysaccharide through a Mechanism Dependent on Antioxidant and Insulin/IGF-1 Signaling

Abstract

Historical literature and pharmacological studies demonstrate that <i>Astragalus polysaccharide</i> (APS) has anti-inflammatory and antioxidative effects. Studies into the longevity effects of APS are limited, and the molecular mechanism of lifespan extension by APS is not elucidated yet. Here, the longevity effect of APS was investigated in <i>Drosophila melanogaster</i> by feeding dose-dependent APS. APS significantly extended the lifespan and improved the reproduction. Meanwhile, APS increased locomotion, TAG level, and starvation resistance and reduced the mortality rate induced by hydrogen peroxide. The activities of superoxide dismutase (SOD) and catalase (CAT) were increased in flies treated with APS diet. Moreover, APS significantly enhanced expressions of antioxidant genes (<i>Sod1</i>, <i>Sod2</i>, and <i>Cat</i>), <i>dFoxO</i>, and 4<i>E</i> - <i>BP</i>, decreased the expressions of insulin-like peptides (<i>dilp2, dilp3</i>, and <i>dilp5)</i>, and longevity gene <i>MTH</i>. Together, these results indicate that APS can prolong the lifespan by regulating antioxidant ability and insulin/IGF-1 signaling and also enhance the reproduction ability in <i>Drosophila</i>. APS may be explored as a novel agent for slowing the aging process and improving reproduction.