Chemopreventive Action by Ethanol-extracted Brazilian Green Propolis on Post-initiation Phase of Inflammation-associated Rat Colon Tumorigenesis

In Vivo. 2017 Mar-Apr;31(2):187-197. doi: 10.21873/invivo.11044.


Background/aim: Propolis has since long been utilized in numerous folk medicines with a variety of medicinal properties. In this study, the effects of ethanol-extracted (EEP) and water-extracted (WEP) Brazilian green propolis on the post-initiation phase of inflammation-associated rat colon tumorigenesis were directly compared.

Materials and methods: Male F344 rats at 6 weeks of age were subcutaneously injected with 1,2-dimethylhydrazine (DMH) at 40 mg/kg body weight twice during the first week, followed by 1% dextran sodium sulfate (DSS) in drinking water for one week. After a 1-week no-treatment period, animals were administered either basal Oriental MF powdered diet, or 1% EEP or 1% WEP in the basal diet until week 32.

Results: Post-initiation treatment with EEP significantly reduced the multiplicity of colorectal carcinomas compared to the control (0.40±0.13/rat vs. 2.29±0.84/rat, respectively, p<0.05), and EEP also reduced the tumor volume. Immunohistochemically, expression of inflammation-associated proteins inducible nitric oxide synthase, tumor necrotic factor alpha, nuclear factor kappa B and glutathione peroxidase-2 were significantly diminished in colorectal tumors from EEP-treated rats.

Conclusion: Suppression of inflammation and oxidative stress, which had been triggered by DMH and promoted by DSS, was a primary mechanism by which EEP suppressed carcinogenesis.

Keywords: Ethanol-extracted propolis; colon cancer; dextran sodium sulfate; dimethylhydrazine; inflammation; oxidative stress; rat.

MeSH terms

  • 1,2-Dimethylhydrazine
  • Animals
  • Carcinogens
  • Cell Transformation, Neoplastic / drug effects*
  • Cell Transformation, Neoplastic / metabolism
  • Cell Transformation, Neoplastic / pathology
  • Colitis / chemically induced
  • Colitis / prevention & control*
  • Colon / drug effects*
  • Colon / metabolism
  • Colon / pathology
  • Colonic Neoplasms / metabolism
  • Colonic Neoplasms / pathology
  • Colonic Neoplasms / prevention & control*
  • Dextran Sulfate
  • Ethanol / chemistry
  • Glutathione Peroxidase / metabolism
  • Immunohistochemistry
  • Male
  • NF-kappa B / metabolism
  • Nitric Oxide Synthase Type II / metabolism
  • Propolis / isolation & purification
  • Propolis / pharmacology*
  • Rats, Inbred F344
  • Time Factors
  • Treatment Outcome
  • Tumor Necrosis Factor-alpha / metabolism


  • Carcinogens
  • NF-kappa B
  • Tumor Necrosis Factor-alpha
  • Ethanol
  • Propolis
  • Dextran Sulfate
  • Glutathione Peroxidase
  • glutathione peroxidase 2, rat
  • Nitric Oxide Synthase Type II
  • 1,2-Dimethylhydrazine