Anti‐Aging Effects of Schisandrae chinensis Fructus Extract: Improvement of Insulin Sensitivity and Muscle Function in Aged Mice

Abstract

Schisandrae chinensis Fructus has a long history of medicinal use as a tonic, a sedative, and an antitussive drug. In this study, we investigated the beneficial effects of Schisandrae chinensis Fructus ethanol extract (SFe) on metabolism in an aged mouse model. Sixteen-month-old C57BL/6J mice were fed with a diet supplemented with SFe for 4 months. Insulin sensitivity was lower at 20 months of age than at 16 months of age; however, the decrease in insulin sensitivity was less in SFe-fed mice. SFe supplementation also appeared to improve glucose tolerance. Body weight gain was lower in SFe-fed mice than in mice fed the control diet. Body fat mass was lower and the lean mass was higher in SFe-fed mice. In addition, the grip strength was enhanced in SFe-fed mice. Histological analysis of the tibialis anterior muscle showed that the size of myofiber and slow-twitch red muscle was increased by SFe supplementation. The expression of proteins related to muscle protein synthesis such as phospho-Erk1 and phospho-S6K1 was increased by SFe supplementation. The mRNA expression of genes related to myogenesis and their encoded proteins such as MyoD, Myf5, MRF4, myogenin, and myosin heavy chain, was increased, whereas that of genes related to muscle degradation, such as atrogin-1, MuRF-1, and myostatin, were decreased relative to control mice. These results suggest that SFe supplementation might have beneficial effects for the improvement of insulin sensitivity and inhibition of muscle loss that occur with aging.

Preventive Effects of Schisandrin A, A Bioactive Component of Schisandra chinensis, on Dexamethasone-Induced Muscle Atrophy

“…Previously, we found that the ethanolic extract of the Schisandra fruit significantly improved muscle strength and increased muscle mass in aged mice [27]. In addition, the extract significantly downregulated myostatin expression in muscle tissues [8,27]. However, the bioactive component of Schisandra responsible for this biological activity remains undetermined.…”

“…The fruits of S. chinensis have been used in traditional medicine in Korea and China and are known to be effective in the treatment of the cardiovascular diseases, fatigue and weakness, and insomnia [17,26]. Previously, we found that the ethanolic extract of the Schisandra fruit significantly improved muscle strength and increased muscle mass in aged mice [27]. In addition, the extract significantly downregulated myostatin expression in muscle tissues [8,27].…”

A subset of microRNAs in the Dlk1‐Dio3 cluster regulates age‐associated muscle atrophy by targeting Atrogin‐1

“…[27][28][29] Relative to other muscular disorders, the regulatory mechanism of E3 ligase expression in aging muscle remains largely unknown. Transcriptional levels of MuRF1 and Atrogin-1 have been determined in aged muscle of mouse, rat, and human, [30][31][32][33][34][35][36][37][38][39][40][41][42][43] but the results obtained to date are controversial. Here, we have focused on elucidating the mechanism underlying the regulation of Atrogin-1 expression by miRNAs during the muscle aging process.…”

Schisandrae chinensis Fructus Extract Ameliorates Muscle Atrophy in Streptozotocin-Induced Diabetic Mice by Downregulation of the CREB-KLF15 and Autophagy–Lysosomal Pathways

“…Similar to a previous report [ 44 ], we found that the STZ_Vehicle group exhibited a decrease in average CSA of type I, IIa, and IIb fibers compared with the CON_Vehicle group in the GA muscle, and the decrease in average CSA of type II fibers (type IIa and IIb) in the STZ_Vehicle group was higher than that of type I fibers. It was previously reported that SFe increases the percentage of slow fibers and induces the expression of myosin heavy chain 1 mRNA in the TA muscle of aged mice [ 20 ]. Similarly, our data showed that the administration of SFe strongly inhibited STZ-induced degradation in GA muscle slow fibers, compared with fast fibers ( Figure 3 E).…”

“…The known pharmacological effects of SF include antioxidant, antitumor, hepatoprotective, chondroprotective, antiseptic, anti-inflammatory, antiatherosclerotic, and antidiabetic activities [ 14 , 15 , 16 , 17 ]. SF extract has beneficial effects on dexamethasone-, disuse-, and aging-induced muscle wasting [ 18 , 19 , 20 ]. However, no study has investigated the effect of SF extract on muscle wasting in type 1 diabetes.…”