Effects of cinnamaldehyde on the glucose transport activity of GLUT1.
There is accumulating evidence that cinnamon extracts contain components that enhance insulin action. However, little is know about the effects of cinnamon on non-insulin stimulated glucose uptake. Therefore, the effects of cinnamaldehyde on the glucose transport activity of GLUT1 in L929 fibroblast cells were examined under both basal conditions and conditions where glucose uptake is activated by glucose deprivation. The data reveal that cinnamaldehyde has a dual action on the glucose transport activity of GLUT1. Under basal conditions it stimulates glucose uptake and reaches a 3.5 fold maximum stimulation at 2.0mM. However, cinnamaldehyde also inhibits the activation of glucose uptake by glucose deprivation in a dose dependent manner. Experiments with cinnamaldehyde analogs reveal that these activities are dependent on the α,β-unsaturated aldehyde structural motif in cinnamaldehyde. The inhibitory, but not the stimulatory activity of cinnamaldehyde was maintained after a wash-recovery period. Pretreatment of cinnamaldehyde with thiol-containing compounds, such as β-mercaptoethanol or cysteine, blocked the inhibitory activity of cinnamaldehyde. These results suggest that cinnamaldehyde inhibits the activation of GLUT1 by forming a covalent link to target cysteine residue/s. This dual activity of cinnamaldehyde on the transport activity of GLUT1 suggests that cinnamaldehyde is not a major contributor to the anti-diabetic properties of cinnamon.
Plaisier
Christina
C
Department of Chemistry and Biochemistry, Calvin College, 3201 Burton SE, Grand Rapids, MI 49546, USA.
Cok
Alexandra
A
Scott
Jordan
J
Opejin
Adeleye
A
Bushhouse
Kelsey T
KT
Salie
Mathew J
MJ
Louters
Larry L
LL
D000171:Acrolein / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D051272:Glucose Transporter Type 1 / Q000378:metabolism*; D051379:Mice; D013438:Sulfhydryl Compounds / Q000737:chemistry
D051272:Glucose Transporter Type 1; D013438:Sulfhydryl Compounds; D000171:Acrolein; D005947:Glucose; C012843:cinnamaldehyde