Toona sinensis Roem (Meliaceae) leaf extract alleviates hyperglycemia via altering adipose glucose transporter 4.
In this study we tested the effects of Toona sinensis leaf extracted with water (TSL1) on alloxan-induced (50 mg/kgBwt, i.v.) diabetic Long-Even rats. Diabetic rats given TS leaf with water (TSL1), with 50% alcohol (TSL3) or with H2O extract (TSL5) showed lower levels of plasma glucose. Normal rats given Glibenclamide (GC) had lower levels of plasma glucose, but TSL1 administration showed no significant effect on plasma glucose. By contrast, TSL1 or GC given to alloxan-induced diabetic rats showed a 40% reduction in plasma glucose compared to diabetic rats. Diabetic rats had lower levels of insulin. Interestingly, TSL1 or GC given to diabetic rats showed improvements in plasma insulin levels. Diabetic rats had lower expressions of glucose transporter 4 (GLUT4) mRNA (RT-PCR) and GLUT4 protein (Western blot) in brown and white adipose tissues; in contrast, diabetic rats given TSL1 or GC showed a significant increase in both GLUT4 mRNA and protein levels. Moreover, the expressions of GLUT4 mRNA in red and white muscles were not significantly different among diabetic rats, diabetic rats given TSL1 or GC, and the normal rats. Compared to diabetic rats, diabetic rats given TSL1 or GC had lower levels of GLUT4 protein in white muscle but not in red muscle. Conclusively, T. sinensis Roem (Meliaceae) leaf possesses the hypoglycemia effect underlying an increment of insulin to mediate the adipose glucose transporter 4 mechanism.
Wang
Pei-Hwei
PH
Department of Physiology, Kaoshiung Medical University, Kaoshiung, Taiwan.
Tsai
May-Jywan
MJ
Hsu
Chia-Yu
CY
Wang
Chia-Yi
CY
Hsu
Hseng-Kuang
HK
Weng
Ching-Feng
CF
D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D019540:Area Under Curve; D001786:Blood Glucose / Q000032:analysis / Q000187:drug effects; D015153:Blotting, Western; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D005786:Gene Expression Regulation; D005951:Glucose Tolerance Test; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D006943:Hyperglycemia / Q000188:drug therapy*; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000032:analysis / Q000097:blood; D029582:Meliaceae / Q000737:chemistry*; D008517:Phytotherapy; D010936:Plant Extracts / Q000627:therapeutic use*; D018515:Plant Leaves / Q000737:chemistry; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D020318:Rats, Long-Evans; D020133:Reverse Transcriptase Polymerase Chain Reaction
D001786:Blood Glucose; D051275:Glucose Transporter Type 4; D007004:Hypoglycemic Agents; D007328:Insulin; D010936:Plant Extracts; D012333:RNA, Messenger