Methanolic extract of Origanum vulgare ameliorates type 1 diabetes through antioxidant, anti-inflammatory and anti-apoptotic activity

Br J Nutr. 2015 Mar 14;113(5):770-82. doi: 10.1017/S0007114514004048. Epub 2015 Feb 11.


Type 1 diabetes (T1D), an autoimmune inflammatory disorder, develops as a consequence of pancreatic β-cell destruction and results in hyperglycaemia. Since current T1D therapy mainly involves insulin replacement, the aim of the present study was to evaluate the therapeutic potential of Origanum vulgare L. ssp. hirtum (Greek oregano) leaf extract rich in biophenols for the treatment of T1D. The phytochemical profile of methanolic oregano extract (MOE) and aqueous oregano extract (AOE) was determined by liquid chromatography/electrospray ion-trap tandem MS (LC/DAD/ESI-MSn), while their main compounds were quantified by HPLC with diode array detection. After establishing their potent in vitro antioxidant activity, the extracts were administered to C57BL/6 mice treated with multiple low doses of streptozotocin for diabetes induction. While prophylactic AOE therapy had no impact on diabetes induction, MOE reduced diabetes incidence and preserved normal insulin secretion. In addition, MOE scavenged reactive oxygen and nitrogen species and, therefore, alleviated the need for the up-regulation of antioxidant enzymes. MOE treatment specifically attenuated the pro-inflammatory response mediated by T helper 17 cells and enhanced anti-inflammatory T helper 2 and T regulatory cells through the impact on specific signalling pathways and transcription factors. Importantly, MOE preserved β-cells from in vitro apoptosis via blockade of caspase 3. Finally, rosmarinic acid, a predominant compound in MOE, exhibited only partial protection from diabetes induction. In conclusion, acting as an antioxidant, immunomodulator and in an anti-apoptotic manner, MOE protected mice from diabetes development. Seemingly, there is more than one compound responsible for the beneficial effect of MOE.

Keywords: T regulatory cells.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / adverse effects
  • Anti-Inflammatory Agents, Non-Steroidal / metabolism
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use*
  • Antioxidants / adverse effects
  • Antioxidants / metabolism
  • Antioxidants / therapeutic use*
  • Apoptosis
  • Cell Line
  • Cells, Cultured
  • Diabetes Mellitus, Type 1 / diet therapy
  • Diabetes Mellitus, Type 1 / immunology
  • Diabetes Mellitus, Type 1 / pathology
  • Diabetes Mellitus, Type 1 / prevention & control*
  • Dietary Supplements* / adverse effects
  • Dietary Supplements* / analysis
  • Hypoglycemic Agents / adverse effects
  • Hypoglycemic Agents / metabolism
  • Hypoglycemic Agents / therapeutic use*
  • Insulin / blood
  • Insulin / metabolism
  • Insulin Secretion
  • Insulin-Secreting Cells / metabolism
  • Insulin-Secreting Cells / pathology
  • Male
  • Methanol / chemistry
  • Mice, Inbred C57BL
  • Origanum / chemistry*
  • Oxidative Stress
  • Plant Extracts / adverse effects
  • Plant Extracts / chemistry
  • Plant Extracts / metabolism
  • Plant Extracts / therapeutic use*
  • Plant Leaves / chemistry
  • Solvents / chemistry
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocyte Subsets / metabolism
  • T-Lymphocyte Subsets / pathology


  • Anti-Inflammatory Agents, Non-Steroidal
  • Antioxidants
  • Hypoglycemic Agents
  • Insulin
  • Plant Extracts
  • Solvents
  • Methanol