The Protective Role of Mangiferin and trans-Cinnamic Acid against Oxidative Stress in Wild Type and aak-2 Mutant Caenorhabditis elegans Strains

During cellular metabolism, reactive oxygen species and nitrogen species are produced which inherently results in oxidative damage of DNA and proteins. As a survival mechanism, these stressors modulate gene expression and various signalling pathways in C. elegans. The resistance to various forms of stress peaks in early adulthood and thereafter, decreases with age. In C. elegans, the gene aak-2 enables the adenosine monophosphate (AMP)-activated protein kinase activity which is involved in stress responses, germ cell cycle arrest during dauer formation, and maintenance of longevity. In this study, we evaluated the effects of mangiferin (MF) and trans-cinnamic acid (TCA) at concentrations of 10, 50, 100, and 200 µM on the survival rate, lifespan, and motility of C. elegans treated with hydrogen peroxide. The nematodes (wild type N2-Bristol and aak-2 mutant strains) were exposed to oxidative stress and then observed for the computation of percentage of survival (survival rate), motility, and maximum lifespan (ML). Treatment of wild-type C. elegans exposed to oxidative stress with TCA at concentrations of 50, 100, and 200 μM significantly (p < 0.05) increased the survival rate and ML of nematodes compared to the control. Furthermore, MF at all doses studied significantly (p < 0.05) increased the survival rate and extended the life span of H₂O₂-stressed wild-type nematodes fourfold. In the aak-2 mutant strain, the survival rate and ML were only increased in the nematodes treated with 100 and 200 µM of TCA. There was also a dose-dependent increase in survival rate and ML of nematodes treated with MF. MF at the concentration of 200 µM prolonged the lifespan of nematodes by 5 days and restored motility function in 30% of the total nematode population.