Water Extract of Lotus Leaf Alleviates Dexamethasone-Induced Muscle Atrophy via Regulating Protein Metabolism-Related Pathways in Mice

Abstract

Muscle atrophy is an abnormal condition characterized by loss of skeletal muscle mass and function and is primarily caused by injury, malnutrition, various diseases, and aging. Leaf of lotus (Nelumbo nucifera Gaertn), which has been used for medicinal purposes, contains various active ingredients, including polyphenols, and is reported to exert an antioxidant effect. In this study, we investigated the effect of water extract of lotus leaf (LL) on muscle atrophy and the underlying molecular mechanisms of action. Amounts of 100, 200, or 300 mg/kg/day LL were administered to dexamethasone (DEX)-induced muscle atrophy mice for 4 weeks. Micro-computed tomography (CT) analysis revealed that the intake of LL significantly increased calf muscle volume, surface area, and density in DEX-induced muscle atrophy mice. Administration of LL recovered moving distance, grip strength, ATP production, and body weight, which were decreased by DEX. In addition, muscle damage caused by DEX was also improved by LL. LL reduced the protein catabolic pathway by suppressing gene expression of muscle atrophy F-Box (MAFbx; atrogin-1), muscle RING finger 1 (MuRF1), and forkhead box O (FoxO)3a, as well as phosphorylation of AMP-activated kinase (AMPK). The AKT-mammalian target of the rapamycin (mTOR) signal pathway, which is important for muscle protein synthesis, was increased in LL-administered groups. The HPLC analysis and pharmacological test revealed that quercetin 3-O-beta-glucuronide (Q3G) is a major active component in LL. Thus, Q3G decreased the gene expression of atrogin-1 and MuRF1 and phosphorylation of AMPK. This compound also increased phosphorylation levels of mTOR and its upstream enzyme AKT in DEX-treated C2C12 cells. We identified that LL improves muscle wasting through regulation of muscle protein metabolism in DEX-induced muscle atrophy mice. Q3G is predicted to be one of the major active phenolic components in LL. Therefore, we propose LL as a supplement or therapeutic agent to prevent or treat muscle wasting, such as sarcopenia.

Korean Red Ginseng exerts anti-inflammatory and autophagy-promoting activities in aged mice

“…Mice (7 mice/group) were orally treated with KRG-WE (200 mg/kg), or metformin (200 mg/kg) once a day for 30 days. Dose of KRG-WE was decided by previous animal experiments carried out with crude extracts [ 27 , 28 ]. Metformin as anti-aging drug was used according to previous report [ 29 ].…”

Antioxidant Activity of Valeriana fauriei Protects against Dexamethasone-Induced Muscle Atrophy

“…The muscle UPS regulates muscle proteostasis and an increase of muscle-specific E3 ligases, such as Atrogin-1 and MuRF1, are related to muscle atrophy. DEX administration in mice increased E3 ligases, resulting in reduced muscle mass, strength, and muscle area [ 32 ]. Overexpression of Atrogin-1 in myotubes induces atrophy, and mice lacking MuRF1 are protected from DEX-induced muscle atrophy [ 33 ].…”

Phytochemical Diversity and Antioxidant Potential of Natural Populations of Nelumbo nucifera Gaertn. throughout the Floristic Regions in Thailand

“…Several parts of this lotus species have been investigated, i.e., the antioxidant effect from stamen methanolic extract [ 12 ], the seed hydroalcoholic extract [ 18 ], epicarp extract [ 15 ], embryo extract [ 16 , 19 ], as well as leaf extract [ 8 , 11 ]. In addition, the anti-obesity activity [ 20 ], anti-inflammatory activity [ 21 , 22 ], enhancement of sleeping quantity and quality [ 23 ], potential to improve muscle wasting [ 24 ], as well as UV-protection and anticancer potential [ 25 ] of N. nucifera leaf extract were also reported by previous research works. The therapeutic effect of N. nucifera methanolic extract on pathological cardiomyocyte hypertrophy was also evaluated [ 26 ].…”