Cinnamon Extract Improves Insulin Sensitivity in the Brain and Lowers Liver Fat in Mouse Models of Obesity

• Published in: PloS one Vol. 9; no. 3; p. e92358
• Main Authors: Sartorius, Tina, Peter, Andreas, Schulz, Nadja, Drescher, Andrea, Bergheim, Ina, Machann, Jürgen, Schick, Fritz, Siegel-Axel, Dorothea, Schürmann, Annette, Weigert, Cora, Häring, Hans-Ulrich, Hennige, Anita M.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 18.03.2014; Public Library of Science (PLoS)
• Subjects: Acrolein - analogs & derivatives; Acrolein - pharmacology; Acrolein - therapeutic use; Adiposity - drug effects; Aldehydes; Analysis; Animal models; Animal tissues; Animals; Astrocytes; Astrocytes - drug effects; Biology and Life Sciences; Blood; Blood glucose; Brain; Brain - drug effects; Brain - metabolism; Cell Line; Cinnamaldehyde; Cinnamomum zeylanicum - chemistry; Cinnamon; Cortex; Diabetes mellitus; Energy expenditure; Energy Intake; Eugenol; Eugenol - pharmacology; Eugenol - therapeutic use; Glucose; Glucose tolerance; Glycogen; Glycogen - biosynthesis; Glycogen synthesis; Hepatocytes; Homeostasis; Humans; Insulin; Insulin - administration & dosage; Insulin - physiology; Insulin Resistance; Insulin secretion; Liver; Liver - drug effects; Liver - metabolism; Locomotion; Locomotor activity; Male; Medicine and Health Sciences; Mice; Mice, Inbred C57BL; Mice, Obese; Motor Activity - drug effects; Nutrition; Obesity; Obesity - drug therapy; Obesity - metabolism; Plant Extracts - pharmacology; Plant Extracts - therapeutic use; Research and Analysis Methods; Rodents; Secretion; Sensitivity; Signaling; Synthesis; Type 2 diabetes; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0092358

Treatment of diabetic subjects with cinnamon demonstrated an improvement in blood glucose concentrations and insulin sensitivity but the underlying mechanisms remained unclear. This work intends to elucidate the impact of cinnamon effects on the brain by using isolated astrocytes, and an obese and diabetic mouse model. Cinnamon components (eugenol, cinnamaldehyde) were added to astrocytes and liver cells to measure insulin signaling and glycogen synthesis. Ob/ob mice were supplemented with extract from cinnamomum zeylanicum for 6 weeks and cortical brain activity, locomotion and energy expenditure were evaluated. Insulin action was determined in brain and liver tissues. Treatment of primary astrocytes with eugenol promoted glycogen synthesis, whereas the effect of cinnamaldehyde was attenuated. In terms of brain function in vivo, cinnamon extract improved insulin sensitivity and brain activity in ob/ob mice, and the insulin-stimulated locomotor activity was improved. In addition, fasting blood glucose levels and glucose tolerance were greatly improved in ob/ob mice due to cinnamon extracts, while insulin secretion was unaltered. This corresponded with lower triglyceride and increased liver glycogen content and improved insulin action in liver tissues. In vitro, Fao cells exposed to cinnamon exhibited no change in insulin action. Together, cinnamon extract improved insulin action in the brain as well as brain activity and locomotion. This specific effect may represent an important central feature of cinnamon in improving insulin action in the brain, and mediates metabolic alterations in the periphery to decrease liver fat and improve glucose homeostasis.