Sangyod rice bran hydrolysate mitigates oxidative stress and inflammation in differentiated C2C12 cells and exerts protective effects in a middle-aged mouse model

Sangyod rice bran contains amino acids, flavonoids, and phenolic compounds with associated antioxidant effects that help mitigate oxidative stress-related disorders. However, the nutraceutical potential of Sangyod rice bran hydrolysate (HRB)—particularly its antioxidant and anti-inflammatory activities and its effects on muscle function in middle-aged individuals—remains underexplored. This study investigated the effects of HRB on oxidative stress and inflammation in an in vitro differentiated C2C12 cells and evaluated its impact in a middle-aged mouse model (10 months old). At non-toxic concentrations (50-100 μg/mL), HRB significantly reduced intracellular reactive oxygen species (ROS) and nitric oxide (NO) levels under hydrogen peroxide (H 2 O 2 )-induced oxidative stress. It also modulated inflammatory responses by downregulating pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1 beta (IL-1β), and IL-6) and upregulating the anti-inflammatory cytokine IL-10. HRB promoted myogenic repair through increased insulin-like growth factor 1 (IGF-1) expression and decreased levels of myostatin, myogenin, and glycogen synthase kinase-3 beta (GSK-3β). In vivo , although muscle mass and body weight remained unchanged, HRB supplementation markedly attenuated systemic oxidative stress and enhanced total antioxidant capacity in a middle-aged mouse model. Mechanistically, in the extensor digitorum longus (EDL) and tibialis anterior (TA) muscles, HRB enhanced myogenic differentiation and metabolic signaling via the extracellular signal-regulated kinase (ERK) and AMP-activated protein kinase (AMPK) pathways, supporting muscle maintenance without activating Akt-dependent signaling. In the gastrocnemius (GAS) and soleus (SOL) muscles, HRB promoted muscle function by activating the Akt, ERK, and AMPK signaling pathways. These findings position HRB, alone or in combination with whey protein, as a promising strategy for mitigating oxidative stress and inflammatory responses in middle-aged subjects, thereby warranting further molecular and long-term investigations.