# Activation of Sirtuin3 by 6,4′-Dihydroxy-7-methoxyflavanone Against Myoblasts Senescence by Attenuating D-Galactose-Induced Oxidative Stress and Inflammation

## TL;DR

This study shows that a flavonoid called DMF can reduce muscle cell aging by activating SIRT3, which helps combat oxidative stress and inflammation.

## Contribution

The study identifies DMF as a novel SIRT3 activator that attenuates myoblast senescence through the SIRT3-SOD2 pathway.

## Key findings

- DMF reduces D-galactose-induced senescence by decreasing DNA damage and senescence markers.
- DMF activates SIRT3, which deacetylates SOD2 to reduce mitochondrial oxidative stress and improve ATP production.
- DMF suppresses NF-κB signaling, reducing inflammation and promoting myogenic differentiation.

## Abstract

Background/Objective: Cellular senescence is increasingly recognized as a key mechanism underlying sarcopenia, an age-related muscle disorder with no effective therapeutic. 6,4′-Dihydroxy-7-methoxyflavanone (DMF), a flavonoid isolated from Dalbergia odorifera T. Chen, has shown anti-senescence potential. This study aimed to investigate the protective effects of DMF against myoblasts senescence and elucidate the underlying molecular mechanisms. Method: A cellular model of senescence was established in C2C12 myoblasts using D-galactose (D-gal). The effects of DMF pretreatment were evaluated by assessing senescence phenotypes, myogenic differentiation, and mitochondrial function. The role of Sirtuin3 (SIRT3) was confirmed using siRNA-mediated knockdown. Results: DMF Pre-treatment effectively attenuated D-gal-induced senescence, as indicated by restored proliferation, reduced senescence-associated β-galactosidase activity, decreased DNA damage, and the downregulation of p53, p21Cip1/WAF1 and p16INK4a. Furthermore, DMF rescued myogenic differentiation capacity, enhancing the expression of Myoblast determination protein 1, Myogenin, Myosin heavy chain and Muscle-specific regulatory factor 4, and promoting myotube formation. Mechanistically, DMF was identified as a SIRT3 activator. It enhanced SIRT3 expression and activity, leading to the deacetylation and activation of the mitochondrial antioxidant enzyme superoxide dismutase 2. This consequently reduced mitochondrial reactive oxygen species, improved mitochondrial membrane potential and ATP production, and suppressed the NF-κB pathway by inhibiting IκBα phosphorylation and p65 acetylation/nuclear translocation. Crucially, all the beneficial effects of DMF—including oxidative stress reduction, mitochondrial functional recovery, anti-inflammatory action, and ultimately, the attenuation of senescence and improvement of myogenesis—were abolished upon SIRT3 knockdown. Conclusions: Our findings demonstrate that DMF alleviates myoblasts senescence and promotes myogenic differentiation by activating the SIRT3-SOD2 pathway, thereby reducing oxidative stress and NF-κB-driven inflammation responses. DMF emerges as a promising therapeutic candidate for sarcopenia.