OBJECTIVE:To investigate the effects of cinnamaldehyde(CA),an active and major compound in cinnamon,on glucose metabolism and insulin resistance in C57BLKS/J db/db mice.METHODS:Sixteen male C57BLKS db/db mice were randomly divided into control and CA treatment groups.CA was given(20 mg.kg-1.day-1,p.o.) for 4 weeks.Pure water was given to control and db/+ mice.Subsequently,the levels of fasting blood glucose(FBG),fasting serum insulin,triglyeride,cholesterol,low-density lipoprotein-cholesterol(LDL-C),high-density lipoprotein-cholesterol(HDL-C),and free fatty acids(FFA),as well as the mRNA content of adiponectin and tumor necrosis factor(TNF)-α in adipose tissue,glucose transporter type 4(GLUT-4) in skeletal muscle,and protein expressions of Akt,phospho-Akt(Thr308),AMPKα,phospho-AMPKα(Thr172) in skeletal muscle were measured.RESULTS:1) CA decreased serum levels of FBG and insulin as well as body weight in db/db mice;2) CA increased serum HDL-C levels;3) CA significantly decreased the mRNA expression of TNF-α in adipose tissue and upregulated mRNA expression of GLUT-4 in skeletal muscle;4) protein expression of p-Akt was increased in CA-treated mice,but Akt,AMPKα and p-AMPKα showed no change.CONCLUSION:CA has antihyperglycemic and antihyperlipidemic actions in db/db mice and could be useful in the treatment of type-2 diabetes.