Research progress in mulberry leaf polysaccharide in treating diabetic nephropathy

Diabetic nephropathy(DN)is one of the most common complications of diabetes.It is an important cause of diabetes disability and death.DN is a systemic metabolic syndrome.In its pathogenesis,the interaction of various cell activities and a large number of cytokine biological activities,the activation of signal pathways and so on are involved in the development of DN.At present,the clinical treatment of DN is mainly Western medicine,but it has limitations such as strong toxicity,high side effects and poor compliance.Therefore,the discovery of natural anti-DN substances has also become an important means to treat DN.Mulberry leaves are the dry leaves of Morus alba L.It is not only a traditional Chinese medicine,but also a dual-purpose medicinal material for medicine and food.It has the effects of dispelling wind and clearing heat,cooling blood and brightening eyes,tonifying and so on.Mulberry leaf polysaccharide(MLP)is a kind of high molecular compound in mulberry leaves.It has many pharmacological effects,such as hypoglycemic,antioxidant,anti-stress,anti-virus and so on.Therefore,the pharmacological effects of mulberry leaf polysaccharides on diabetic nephropathy are reviewed in this paper,so as to provide references for further research and application.The pathogenesis of DN is complex,and the mechanism of renal injury has not been completely clarified.The current studies believe that DN is closely related to heredity,abnormal glucose metabolism,abnormal lipid metabolism,microcirculation disorder,cytokine action,oxidative stress and so on.Relevant studies show that the pharmacological effects of mulberry leaf polysaccharide in the prevention and treatment of DN mainly include:①Effect on transforming factor-β1(TGF-β1):TGF-β1 has become an important cytokine involved in the formation of renal fibrosis by regulating cell proliferation and differentiation and the production of extracellular matrix(ECM).MLP can significantly inhibit TGF-β1 protein,and then inhibit the synthesis of extracellular matrix by renal interstitial fibroblasts and inhibit the realization of fibrosis.②Effect on insulin receptor substrate(IRS-1):IRS-1 is an important signal molecule at the beginning of IR signal transduction.The decrease of IRS-1 gene expression or the decrease of expression can affect the effective transmission of IR signal and lead to the development and deterioration of diabetes. MPL can significantly increase the expression of IRS-1 mRNA in liver tissue of DN rats, so as to prevent and treat DN. ③ Effect on the expression of resistin protein in adipose tis sue. Resistin is a secretory polypeptide derived from adipose tissue and is specifically expressed in white adipose tissue and is closely related to type 2 diabetes mellitus (T2DM). Experimental studies show that MLP can effectively reduce the expression of resistin protein in white adipose tissue of T2DM rats, indicating that MLP may reduce the level of IR by inhibiting the expression of resistin in adipose tissue, thereby reducing the insulin resistance state of T2DM rats, so as to achieve the goal of treating diabetes. ④ Effect on adiponectin receptor 1 (AdipoR1): adiponectin can improve insulin resistance, reduce blood glucose and lipid. AdipoR1 is mainly expressed in skeletal muscle and kidney. Studies have shown that AdipoR1 is closely related to the occurrence and development of DN. The results showed that MLP could reduce the blood glucose and blood lipid level and up regulate the expression of AdipoR1 mRNA in DN rats, suggesting that MLP may delay the occurrence and development of DN. This article reviewed the pharmacological effects of mulberry leaf polysaccharides on diabetic nephropathy, and provided a useful basis for further development and utilization of mul berry leaf polysaccharides in the treatment of DN.

Preparation,structural characterization and bioactivities of polysaccharides from mulberry(Mori Fructus)

Mulberry(Mori Fructus),a highly promising functional food,has long exhibited multiple therapeutic effects as a tonic in traditional Chinese food and pharmacology.Polysaccharides have been regarded as the pivotal pharmacological ingredient in mulberry.In this study,structural characterization and bioactivities of polysaccharides from mulberry(PFM-3)were determined.The results showed that PFM-3 was a pyranose containing carboxyl group,which was mainly composed of glucose(Glc)and a small amount of mannose(Man)and fucose(Fuc).The molecular weight of PFM-3 was 96.17 kDa,and the surface of PFM-3 was compact and uniform crack.PFM-3 markedly decreased lipid accumulation,triglyceride(TG)and low density lipoprotein cholesterin(LDL-C)on hyperlipidemia human hepatocellular carcinoma(HepG2)cells.PFM-3 recovered nuclear morphometry and mitochondrial membrane potential(MMP),enhanced the activity of glutathione peroxidase(GPx)and decreased cell arrest in G2 phase on oxidative stress HepG2 cells.In addition,PFM-3 promoted the decline of tumor necrosis factor-α(TNF-α)and the augment of interleukin-10(IL-10)secretion on inflammatory mouse leukemia cells of monocyte macrophage(RAW 264.7).This work provides a certificate that PFM-3 could markedly improve cellular lipid accumulation,endogenous antioxidant defense capacity and inflammation levels to further use for treatment and amelioration of related diseases.