Significant longevity-extending effects of a tetrapeptide from maize on Caenorhabditis elegans under stress

A tetrapeptide (Leu-Asp-Tyr-Glu) from maize (TPM) is a bioactive peptide. Here we reported that TPM extended the lifespan of Caenorhabditis elegans under heat and oxidative stress. Specifically, TPM (10 mM) increased the average longevity of C. elegans by 36.9% and 27.6% under heat stress (35 °C) and oxidative stress, respectively. Further studies demonstrated that the significant longevity-extending effects of TPM on C. elegans could be attributed to its in vitro and in vivo free radical-scavenging effects and its up-regulation of stress-resistance-related proteins, including superoxide dismutase-3 (SOD-3) and heat shock protein-16.2 (HSP-16.2). Real-time PCR results showed that the up-regulation of ageing-associated genes such as daf-16, sod-3 and hsp-16.2, in addition to skn-1, ctl-1 and ctl-2, could also contribute to the stress-resistance effect of TPM. These results indicate that TPM can (or has the potential to) protect against external stress and extend lifespan under stress.