title: Effect of mulberry leaf (Folium Mori) on insulin resistance via IRS-1/PI3K/Glut-4 signalling pathway in type 2 diabetes mellitus rats.
abstract: BACKGROUND
  Folium Mori, the leaf of Morus alba L. (Moraceae), has been used in traditional Chinese medicine (TCM) for treating diabetes. However, it is unclear which components in the mulberry leaf are effective for the treatment of type 2 diabetes mellitus (T2DM).
  
  
  OBJECTIVE
  To investigate the flavonoids and polyphenols in mulberry leaves and their antihyperglycemic and antihyperlipidemic effects in T2DM rats.
  
  
  METHODS
  Male Sprague-Dawley rats were divided into five groups: normal control (NC), diabetic control (DBC), diabetic group with 0.3 mg/kg b.w./day rosiglitazone (RSG), diabetic group with 7 g/kg b.w./day TCM formula and diabetic group with 2 g/kg b.w./day Folium Mori extract (FME). After 4 weeks, the rats were sacrificed; biochemical parameters, gene and protein expression were measured.
  
  
  RESULTS
  The FBG level was significantly lower in the FME group than in the DBC group (p < 0.05). In oral glucose tolerance test, the AUC was significantly lower in the FME group (p < 0.05). The HOMA-IR level was significantly decreased in the FME group (p < 0.05). FME decreased the total cholesterol (TC), triglyceride (TG) and low density lipoprotein (LDL) levels (p < 0.05). FME increased the mRNA and protein expression of IRS-1, PI3K p85α and Glut-4 increased significantly (p < 0.05). Histological analysis revealed amelioration of lipid accumulation following FME treatment. Additionally, immunohistochemical analysis displayed stronger staining of Glut-4 in the FME group compared to the DBC group.
  
  
  CONCLUSIONS
  FME could decrease the body weight, blood glucose, TG, TC and LDL levels, and improve insulin resistance. FME possessed significant antihyperglycemic and antihyperlipidemic activities via the IRS-1/PI3K/Glut-4 signalling pathway.
authors.affiliation: a Beijing University of Chinese Medicine , Beijing , P.R. China.
authors.forename: Shengyu
authors.initials: S
authors.lastname: Cai
authors.affiliation: b Key Laboratory of the Health-Cultivation of the Ministry of Education , Beijing University of Chinese Medicine , Beijing , P.R. China.|c Beijing Key Laboratory of the Health-Cultivation , Beijing , P.R. China.|d Beijing International Technology Cooperation Base for Prevention and Treatment of Diabetes Mellitus with Chinese Medicine , Beijing , P.R. China.
authors.forename: Wen
authors.initials: W
authors.lastname: Sun
authors.affiliation: e Department of Science and Technology , Beijing University of Chinese Medicine , Beijing , P.R. China.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Fan
authors.affiliation: f Dongfang Hospital Affiliated to Beijing University of Chinese Medicine , Beijing , P.R. China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Guo
authors.affiliation: f Dongfang Hospital Affiliated to Beijing University of Chinese Medicine , Beijing , P.R. China.
authors.forename: Guangyuan
authors.initials: G
authors.lastname: Xu
authors.affiliation: g School of Chinese Pharmacy , Beijing University of Chinese Medicine , Beijing , P.R. China.
authors.forename: Tunhai
authors.initials: T
authors.lastname: Xu
authors.affiliation: f Dongfang Hospital Affiliated to Beijing University of Chinese Medicine , Beijing , P.R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Hou
authors.affiliation: h Scientific Research Experiment Center, Beijing University of Chinese Medicine , Beijing , P.R. China.
authors.forename: Baosheng
authors.initials: B
authors.lastname: Zhao
authors.affiliation: i Beijing Shijitan Hospital, Capital Medical University , Beijing , P.R. China.
authors.forename: Xingzhong
authors.initials: X
authors.lastname: Feng
authors.affiliation: b Key Laboratory of the Health-Cultivation of the Ministry of Education , Beijing University of Chinese Medicine , Beijing , P.R. China.|c Beijing Key Laboratory of the Health-Cultivation , Beijing , P.R. China.|d Beijing International Technology Cooperation Base for Prevention and Treatment of Diabetes Mellitus with Chinese Medicine , Beijing , P.R. China.
authors.forename: Tonghua
authors.initials: T
authors.lastname: Liu
mesh_terms: D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000502:physiology*; D055504:Insulin Receptor Substrate Proteins / Q000502:physiology*; D007333:Insulin Resistance; D050356:Lipid Metabolism / Q000187:drug effects; D008297:Male; D031625:Morus; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D051275:Glucose Transporter Type 4; D055504:Insulin Receptor Substrate Proteins; C526296:Irs1 protein, rat; D010936:Plant Extracts; D019869:Phosphatidylinositol 3-Kinases; D005947:Glucose
keywords: Antihyperglycemic effect; antihyperlipidemic effect; flavonoids; polyphenols; skeletal muscle