6,4′-Dihydroxy-7-methoxyflavanone Protects Against H2O2-induced Cellular Senescence by Inducing SIRT1 and Inhibiting Phosphatidylinositol 3-Kinase/akt Pathway Activation

6, 4′-Dihydroxy-7-methoxyflavanone (DMF) has been shown to possess anti-inflammatory, anti-oxidative, and neuroprotective activities. However, its effect on oxidative stress-induced aging remains undemonstrated. This study aimed at investigating the anti-senescence effect of DMF on hydrogen peroxide (H 2 O 2 )-induced premature senescence, and associated molecular mechanisms in human dermal fibroblasts (HDFs). The cells were DMF pretreated with small interfering RNA (siRNAs) of control or sirtuin 1 (SIRT1) before H 2 O 2 exposure, and western blot analysis, senescence-associated β-galactosidase (SA-β-gal) activity, cell counting, gene silencing, and SIRT1 activity assay were performed. Pretreatment with DMF inhibited H 2 O 2 -induced senescence phenotypes, which showed decreased SA-β-gal activity and increased cell growth in comparison with H 2 O 2 -treated HDFs. Meanwhile, the decreases in ac-p53, p21 Cip1/WAF1 , and p16 Ink4a and the increases in pRb and cyclin D1 were observed. DMF was also found to induce SIRT1 expression and activity level concentration- and time-dependently. Moreover, SIRT1 inhibition abrogated DMF senescence prevention. Additionally, Akt and ERK were activated with different kinetics after H 2 O 2 exposure, and Akt activity inhibition attenuated SA-β-gal activity augmentation. We also found that DMF inhibited H 2 O 2 -induced Akt phosphorylation. This study indicates that DMF effectively protects against oxidative stress-induced premature senescence through SIRT1 expression up-regulation and Akt pathway inhibition in HDFs. These results suggest that DMF can be a potential therapeutic molecule for age-related diseases, or a protective agent against the aging process.