الفهرس 
TitleOnly 14 pages are availabe for public view
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Abstract
Diabetes mellitus (DM) is a chronic disease that is characterized by hyperglycemia. It is evident that the prevalence of diabetes mellitus is rising in different regions of the world. The cost of treating diabetes using synthetic medications is high and there is an increased chance of adverse effects. The discovery of phytochemicals from medicinal plants offers a promising possibility for the creation of novel therapies for diabetes mellitus. A traditional flavoring agent made from cinnamon trees and other members of the genus Cinnamomum, cinnamaldehyde is now generating more interest due to its glucose lowering effect thus, preventing the progression of diabetes and its complication.
By destroying and recycling organelles, autophagy is a key process in maintaining cellular homeostasis. Impairment of the autophagic pathway in pancreatic β cells results in the development of type 2 diabetes. Cinnamaldehyde has been shown to induce autophagy by either upregulating or downregulating the gene expression of certain autophagic biomarkers.
Our study aimed to explore the effect of cinnamaldehyde on the hepatic expression of some autophagy regulated genes in HFD/STZ-diabetic rats compared to metformin.
The study was conducted on fifty male Wistar rats which were divided into five groups, ten rats each; the first group was the control group. The second group was diabetic untreated group. The third group received metformin in a dose of 200mg/kg while the fourth group received cinnamaldehyde in a dose of 40mg/kg. The fifth group received combination of metformin and cinnamaldehyde in doses of 200mg/kg and 40mg/kg, respectively. For all treated groups, the drugs were administrated orally for one month.
After the last day of treatment, blood samples were collected for the assessment of the following: fasting glucose, insulin, HOMA-IR, lipid profile, AST, ALT, urea, creatinine, MDA and total antioxidant capacity. Animals were then sacrificed by deep anesthesia, liver was dissected out for the determination of the gene expression of the following parameters: mTOR, miR30a, LC3Ⅱ and Beclin-1.
Cinnamaldehyde normalized the fasting blood glucose in the diabetic rats. Furthermore, it increased insulin levels compared to untreated rats. Interestingly, cinnamaldehyde treatment resulted in the induction of autophagy by upregulating the gene expression of Beclin-1 and LC3II and by downregulating the gene expression of mTOR and miR30a. Surprisingly, using cinnamaldehyde in combination with metformin had shown better improvement in glucose homeostasis parameters, lipid profile and autophagic genes expression.
Summary & Conclusion
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from the above-mentioned discussion, it can be concluded that:
1. Cinnamaldehyde is a promising natural glucose and lipid lowering agent that has vital role as anti-diabetic treatment.
2. Cinnamaldehyde induces autophagy via upregulating gene expression of Beclin-1 and LC3II and downregulating the expression of miR30a and mTOR.
3. Cinnamaldehyde decreases the oxidative stress which indicated by the decreased MDA level and by increased TAC level.
4. Cinnamaldehyde could be used as an adjuvant therapy with metformin for boosting the treatment efficacy and for decreasing the unwanted effect of metformin.
5. Further studies are necessary to explore the exact mechanism (s) of cinnamaldehyde on the autophagic pathway in diabetes.