Sesamin is a major lignan constituent of sesame and possesses various health-promoting effects. Previous studies have demonstrated that sesamin extends the lifespan of Drosophila and Caenorhabditis elegans and corrects oxidative damage-related tissue dysfunction in mammals. To understand its anti-aging effects, we aimed to determine whether sesamin restores tissue function hampered by oxidative damage and suppresses several aging-related phenotypes using Drosophila senescence-accelerated models.
We elucidated the anti-aging effects of sesamin on several aging-related phenotypes in the muscle, brain and midgut using the senescence-accelerated models (Sod1n1 mutant and Sod1-depleted flies) by immunostaining experiments. We determined the expression levels of several anti-oxidative and DNA repair genes using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). We also identified the metabolite of sesamin in Drosophila by LC-MS/MS.
We confirmed that sesamin (0.35 and 2 mg/ml) extended the lifespan of the fly models. As observed in mammals, it can be absorbed and metabolized by Drosophila adults. The sesamin feeding suppressed the age-dependent impairment of locomotor activity and inhibited the accumulation of reactive oxygen species (ROS) in their bodies. Sesamin delayed the age-dependent accumulation of damaged proteins in the muscle, partially suppressed the loss of dopaminergic neurons in adult brains displaying ROS accumulation, and suppressed the accumulation of DNA damage and hyperproliferation of intestinal stem cells. Four antioxidative genes and two DNA repair genes were simultaneously upregulated in sesamin-fed adults.  CONCLUSIONS: These observations represent the first direct evidence of the anti-aging effects of sesamin at the individual level. We propose that sesamin exerts anti-aging effects in the muscles, brain and midgut by inducing antioxidative and DNA repair genes, resulting in extended lifespan in flies.