title: Antihyperglycemic action of sinapic acid in diabetic rats.
abstract: Sinapic acid is a hydroxycinnamic acid contained in plants. In an attempt to know the hyperglycemic effect of sinapic acid, this study applied streptozotocin (STZ) to induce type 1-like diabetic rats and fed fructose-rich chow to induce type 2-like diabetic rats. Sinapic acid dose-dependently reduced the hyperglycemia of STZ-diabetic rats (9.8 ± 1.8%, 11.6 ± 0.7%, and 19.4 ± 3.2% at 5 mg/kg, 10 mg/kg, and 25 mg/kg, respectively). Also, sinapic acid attenuated the postprandial plasma glucose without changing plasma insulin in rats. Repeated treatment of sinapic acid increased the gene expression of GLUT4 in soleus muscle of STZ-diabetic rats. Moreover, sinapic acid enhanced glucose uptake into isolated soleus muscle and L6 cells (337.0 ± 29.6%). Inhibition of phospholipase C (PLC) using U73122 (1.00 ± 0.02 μg/mg protein) or protein kinase C (PKC) using chelerythrine (0.97 ± 0.02 μg/mg protein) attenuated the sinapic acid-stimulated glucose uptake (1.63 ± 0.02 μg/mg protein) in L6 cells. Otherwise, the reduced glucose infusion rate (GIR) in fructose-rich chow-fed rats was also raised by sinapic acid. Our results suggest that sinapic acid ameliorates hyperglycemia through PLC-PKC signals to enhance the glucose utilization in diabetic rats.
authors.affiliation: Department of Anesthesiology, Shuang Ho Hospital , and Department of Anesthesiology, College of Medicine, Taipei Medical University , New Taipei City 10361, Taiwan.
authors.forename: Yih-Giun
authors.initials: YG
authors.lastname: Cherng
authors.forename: Cheng-Chia
authors.initials: CC
authors.lastname: Tsai
authors.forename: Hsien-Hui
authors.initials: HH
authors.lastname: Chung
authors.forename: Yun-Wen
authors.initials: YW
authors.lastname: Lai
authors.forename: Shu-Chun
authors.initials: SC
authors.lastname: Kuo
authors.forename: Juei-Tang
authors.initials: JT
authors.lastname: Cheng
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003373:Coumaric Acids / Q000008:administration & dosage*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001786:Blood Glucose; D003373:Coumaric Acids; D051275:Glucose Transporter Type 4; D007004:Hypoglycemic Agents; D009004:Monosaccharide Transport Proteins; C073734:sinapinic acid