Cytotoxicity and Immunomodulatory Effects of Propolis on Cancer and Normal Cells
Leukemia is a neoplastic proliferation of one kind of blood cells, characteristically a leukocyte. Leukemia is a set of malignant illnesses affecting the blood and blood-forming tissues including bone marrow, lymphatic system, and spleen. Propolis is a natural resinous product that honeybees collect from several plants and mix with beeswax and salivary enzymes. It contains a complex mixture of organic and non-organic compounds. Propolis has numerous uses in folklore medicine for healing many types of diseases. The objective of the current study was to determine the cytotoxic and immunomodulatory effect of aqueous and ethanolic extracts of propolis on cancer cells (lymphoma cell line) and normal cells (peripheral blood lymphocytes PBLs). The immunomodulatory effect was assessed by measuring the level of IL-4, IL-10, IL-17, and IFN-?.
Material and method: cancer (Raji cell line) and normal cells (PBLs) were treated with different concentrations (1000 to 31 µg/ml) of both aqueous and ethanolic extracts of propolis to determine the effect of propolis extracts on the viability of these cells by using MTT assay. ELISA assay kits were used to measure the level of IFN-?, IL-4, IL-10, and IL-17 in the supernatant of the cells.
Results: Higher concentration of ethanolic and aqueous extracts of propolis caused a decrement in the viability of the Raji cell line but did not affect the viability of the PBLs cells. Regarding the immunomodulatory effect of propolis' extracts, on the Raji cell line, aqueous extract at concentrations (50, 250 and 1000 µg/ml) and ethanolic extract at the concentration (1000 µg/ml) caused a decrease in the level of IL-4. Ethanolic extract at concentration 1000 µg/ml caused a decrease in the level of IL-10, while at concentration 50 µg/ml of the same extract caused an increase in the level of IL-10. All concentrations of both aqueous and ethanolic extracts of propolis caused a decrease in the level of IL-17 and IFN-?. Regarding the effect of propolis extracts on PBLs, both aqueous and ethanolic extracts of propolis in concentrations (250 and 50 µg/ml) caused an increment in the level of IL-4, and IL-17, while ethanolic extract at concentration 1000 µg/ml caused a decrease in the level of these cytokines. Propolis aqueous and ethanolic extracts at concentration 250 µg/ml caused a significant elevation in the level of IL-10. Aqueous extract at concentrations 50, 250 µg/ml and ethanolic extract at concentration 1000 µg/ml caused a significant increase in the level of IFN-?.
Conclusion: Propolis promotes PBLs proliferation and had an antiproliferative effect against the Raji cell line. It had a dose-dependent immunomodulatory effect.