Olive (Olea europaea) leaf extract alters the cytokine profile of Leishmania major-infected macrophages: New insight into the underlying mechanism

Parasite Immunol. 2018 Apr;40(4):e12520. doi: 10.1111/pim.12520. Epub 2018 Mar 12.


This study aimed to identify the effects of olive leaf extract (OLE) on IFNγ, TNFα, TGFβ and nitric oxide (NO) resulted from macrophages infected with Leishmania major (L. major) amastigotes in the culture medium. High-performance liquid chromatography (HPLC) was used to analyse the level of Oleuropein in plant extract. To evaluate the immunomodulatory effects of OLE, the isolated BALB/c mice peritoneal macrophages were infected with L. major promastigotes and treated with 6.25, 12.5 and 25 μg/mL concentrations of OLE. To assess the cytokines, supernatants of cell cultures were harvested after 12, 24 and 48 hours. Cytokine production was evaluated by ELISA. Nitrite accumulation in the culture medium was assessed using the Griess reaction. The level of Oleuropein in the extract was 18.45% by HPLC. According to results, the production of IFNγ and TNFα was significantly increased when the infected and/or not infected macrophages with L. major promastigotes were affected by different concentrations of OLE. Conversely, the production of TGFβ was significantly decreased under the same conditions. Furthermore, the colorimetric determination of NO accumulation in the culture medium indicated that OLE has no effect on NO production. The study corroborates the immunomodulatory effects of OLE on L. major-infected macrophages.

Keywords: Leishmania major; Olea europaea; cytokine profile; macrophages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chromatography, High Pressure Liquid
  • Interferon-gamma / metabolism*
  • Iridoid Glucosides
  • Iridoids / analysis
  • Iridoids / pharmacology
  • Leishmania major / immunology*
  • Leishmaniasis, Cutaneous / drug therapy
  • Leishmaniasis, Cutaneous / immunology
  • Leishmaniasis, Cutaneous / parasitology
  • Macrophages / drug effects
  • Macrophages / immunology*
  • Macrophages / parasitology
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Nitric Oxide / metabolism*
  • Olea / chemistry*
  • Plant Extracts / pharmacology*
  • Transforming Growth Factor beta1 / metabolism*
  • Tumor Necrosis Factor-alpha / metabolism*


  • Iridoid Glucosides
  • Iridoids
  • Plant Extracts
  • Tgfb1 protein, mouse
  • Transforming Growth Factor beta1
  • Tumor Necrosis Factor-alpha
  • oleuropein
  • Nitric Oxide
  • Interferon-gamma