title: Decrease of hyperglycemia by syringaldehyde in diabetic rats.
abstract: Syringaldehyde is one of the active principles from the stems of Hibiscus taiwanensis (Malvaceae) that has been mentioned to lower hyperglycemia. However, the potential mechanisms for this action of syringaldehyde remain obscure. In the present study, we used streptozotocin to induce diabetic rats (STZ-diabetic rats) as type 1-like diabetic rats and fed fructose-rich chow to rats as type 2-like diabetic rats. Then, we performed the postprandial glucose test and applied the hyperinsulinemic euglycemic clamp to investigate the actions of syringaldehyde. Also, the changes of gene expressions of enzyme relating to glucose homeostasis in muscle and liver were characterized. Syringaldehyde significantly decreased the postprandial plasma glucose in rats, while the plasma insulin was not modified by syringaldehyde. The glucose infusion rate (GIR) in fructose chow-fed rats using hyperinsulinemic euglycemic clamp was markedly improved by syringaldehyde. Additionally, repeated administration of syringaldehyde for 3 days in STZ-diabetic rats resulted in a marked reduction of phosphoenolpyruvate carboxykinase (PEPCK) expression in liver and an increased expression of glucose transporter subtype 4 (GLUT 4) in skeletal muscle. Our results suggest that syringaldehyde may increase glucose utilization to lower hyperglycemia in diabetic rats.
authors.affiliation: Department of Ophthalmology, Chi-Mei Medical Center, Yong Kang, Tainan City, Taiwan.
authors.forename: S C
authors.initials: SC
authors.lastname: Kuo
authors.affiliation: Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan City, Taiwan.
authors.forename: H H
authors.initials: HH
authors.lastname: Chung
authors.affiliation: Department of Biological Science and Technology, Chung Hwa University of Medical Technology, Tainan, Taiwan.
authors.forename: C H
authors.initials: CH
authors.lastname: Huang
authors.affiliation: Department of Medical Research, Chi-Mei Medical Center, Yung Kang, Tainan City, Taiwan.
authors.forename: J T
authors.initials: JT
authors.lastname: Cheng
mesh_terms: D000818:Animals; D001547:Benzaldehydes / Q000494:pharmacology / Q000627:therapeutic use*; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000150:complications / Q000188:drug therapy* / Q000201:enzymology; D005632:Fructose; D015309:Glucose Clamp Technique; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D006943:Hyperglycemia / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D006946:Hyperinsulinism / Q000097:blood / Q000150:complications; D007333:Insulin Resistance; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000378:metabolism; D019518:Postprandial Period / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001547:Benzaldehydes; D001786:Blood Glucose; D051275:Glucose Transporter Type 4; C069665:syringaldehyde; D005632:Fructose; D010729:Phosphoenolpyruvate Carboxykinase (GTP)