Inhibitory effect of standardized Kaempferia parviflora extract on sarcopenia by improving protein metabolism pathways in aged C57BL/6J mice

Sarcopenia is a muscle disease typically characterized by an age-related loss of muscle mass and function, leading to the deterioration of health in older adults. The current study aimed to investigate the therapeutic potential of standardized Kaempferia parviflora extract (KPE) on sarcopenia and elucidate its underlying molecular mechanisms. To assess the inhibitory effects of KPE on sarcopenia, 18-month-old C57BL/6J mice were employed as an aged model. The mice were orally administered 100 and 200 mg/kg KPE daily for 8 weeks. KPE improved age-reduced grip strength and exercise endurance. It not only increased hindlimb muscle weight, volume, and myofiber cross-sectional area but also decreased abdominal fat volume and adipose tissue weight. KPE downregulated the mRNA expression of tumor necrosis factor alpha and interleukin-6 by inactivating nuclear factor kappa B protein expression and increasing the mRNA expression of anti-oxidant enzymes. Moreover, it significantly reduced the mRNA expression of muscle ring finger-1 and muscle atrophy F-box for proteolysis and stimulated the mammalian target of rapamycin pathway for protein translation by stimulating the phosphatidylinositol 3-kinase/Akt pathway. KPE also increased the relative mitochondrial DNA content by upregulating peroxisome proliferator-activated receptor gamma coactivator 1 alpha, nuclear respiratory factor 1, and mitochondrial transcription factor A mRNA expression. This study's findings demonstrate that KPE improves age-induced sarcopenia by regulating protein turnover and mitochondrial homeostasis. Therefore, KPE is potentially useful as a functional ingredient that inhibits or decelerates sarcopenia.