Antidiabetic activity of perylenequinonoid-rich extract from Shiraia bambusicola in KK-Ay mice with spontaneous type 2 diabetes mellitus.
BACKGROUND
Bitter and cold traditional Chinese medicines (TCMs) have been long used to treat diabetes mellitus (DM) based on unique medical theory system since ancient China. As one of bitter and cold TCMs, the stromatas of Shiraia bambusicola have been used for the treatment of DM and exerted clinical effects to a certain extent. However, the corresponding active principles and antidiabetic mechanism of the TCM still remain unknown. Therefore, the aim of the present investigation was to evaluate the potential antidiabetic effect of the active Shiraia bambusicola EtOAc extract (SB-EtOAc) in vitro and in vivo, and elucidate its probable antidiabetic mechanism.


METHODS
A LC-PDA-ESIMS protocol was developed to determine the chemical principles of the active EtOAc extract rapidly and unambiguously. The effect of SB-EtOAc on the glucose transporter type 4 (GLUT4) translocation and glucose uptake in L6 cells was examined. SB-EtOAc was orally administration at the dose of 30, 60 and 120mg/kg/d in KK-Ay mice, for 21 days. Body weight, plasma glucose, oral glucose tolerance test, fasted blood glucose levels, oral glucose tolerance test and insulin tolerance test, serum insulin and blood-lipid indexes were measured. GLUT4 on L6 cells membrane and phosphorylation of the AMP-activated protein kinase (p-AMPK) expression in L6 cells were measured. The GLUT4 and p-AMPK expression in KK-Ay mice skeletal muscle were measured. Phosphorylation of the acetyl-CoA carboxylase (p-ACC) and p-AMPK were measured.


RESULTS
In vitro, SB-EtOAc exhibited a strong effect of stimulation on GLUT4 translocation by 3.2 fold in L6 cells compared with basal group, however, the selective AMPK inhibitor compound C can completely inhibit the AMPK pathway and prevent the GLUT4 translocation caused by SB-EtOAc. The further western blotting experiments showed that SB-EtOAc can stimulate AMPK phosphorylation in L6 cells and improve the expression of GLUT4. In vivo, SB-EtOAc can improve the KK-Ay mice insulin resistant and oral glucose tolerance to a certain extent. And the body weight, blood glucose levels and the serum TC, TG, FFA, AST, ALT and LDL-C were significantly reduced and HDL-C were increased after 3 weeks treatment. Mechanistically, phosphorylation of the AMPK and ACC had been improved obviously and the levels of AMPK phosphorylation and GLUT4 had been also enhanced.


CONCLUSIONS
In vitro, SB-EtOAc exhibited a strong effect of stimulation on GLUT4 translocation and improved significantly the glucose uptake. In vivo, SB-EtOAc significantly improved oral glucose tolerance and the insulin resistant as well as glucolipid metabolism. In this study, SB-EtOAc displayed promising positive antidiabetic activity in vitro and in vivo, partly by modulating AMPK-GLUT4 and AMPK-ACC signaling pathways.
Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei province, South-Central University for Nationalities, Wuhan 430074, PR China.
Mi
M
Huang
Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei province, South-Central University for Nationalities, Wuhan 430074, PR China.
Ping
P
Zhao
Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei province, South-Central University for Nationalities, Wuhan 430074, PR China.
Mingrui
M
Xiong
Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei province, South-Central University for Nationalities, Wuhan 430074, PR China.
Qi
Q
Zhou
Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei province, South-Central University for Nationalities, Wuhan 430074, PR China.
Sijian
S
Zheng
Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei province, South-Central University for Nationalities, Wuhan 430074, PR China.
Xinhua
X
Ma
Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei province, South-Central University for Nationalities, Wuhan 430074, PR China.
Chan
C
Xu
Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei province, South-Central University for Nationalities, Wuhan 430074, PR China.
Jing
J
Yang
Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei province, South-Central University for Nationalities, Wuhan 430074, PR China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China. Electronic address: xzyang@mail.scuec.edu.cn.
Xinzhou
X
Yang
College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China. Electronic address: tony@tust.edu.cn.
Tong-Cun
TC
Zhang
D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000085:Acetates / Q000737:chemistry; D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000818:Animals; D001203:Ascomycota / Q000737:chemistry*; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D015153:Blotting, Western; D002460:Cell Line; D002853:Chromatography, Liquid; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D007928:Lethal Dose 50; D008055:Lipids / Q000097:blood; D008297:Male; D032448:Myoblasts, Skeletal / Q000187:drug effects / Q000378:metabolism; D010569:Perylene / Q000302:isolation & purification / Q000494:pharmacology*; D010766:Phosphorylation; D021381:Protein Transport; D051381:Rats; D031787:Sasa / Q000382:microbiology*; D015398:Signal Transduction / Q000187:drug effects; D012997:Solvents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013997:Time Factors
D000085:Acetates; D015415:Biomarkers; D001786:Blood Glucose; D051275:Glucose Transporter Type 4; D007004:Hypoglycemic Agents; D007328:Insulin; D008055:Lipids; C495694:Slc2a4 protein, rat; D012997:Solvents; D010569:Perylene; C007650:ethyl acetate; D055372:AMP-Activated Protein Kinases; D000103:Acetyl-CoA Carboxylase
AMPK; Antidiabetic; GLUT4; KK-Ay mice; Shiraia bambusicola