Effects of Three Different Brazilian Green Propolis Extract Formulations on Pro- and Anti-Inflammatory Cytokine Secretion by Macrophages

Abstract

Propolis is known for its immunomodulatory properties. We investigated the effects of three recently developed propolis extract formulations: polar propolis fraction (PPF), soluble propolis dry extract (PSDE), and microencapsulated propolis extract (MPE), and some of their components, on pro- and anti-inflammatory cytokine production in a macrophage model. Bone marrow cell-derived macrophages (BMDM) in cell culture were E. coli lipopolysaccharide (500 ng/mL) stimulated for two hours and subsequently incubated for 20 hours with one of the three propolis extract formulations (1, 10, 25, 50, 100 and 300 µg/mL) or with isolated propolis components (caffeic acid, p-coumaric acid, artepillin C, or baccharin) (10, 25, 50 and 100 µg/mL) to determine how they affected secretion of the pro-inflammatory cytokines IL-6 and TNF-α, and the anti-inflammatory cytokine, IL-10. PPF increased IL-6 and IL-10 levels. PSDE increased IL-6 and IL-10 at lower concentrations, while at higher concentrations it increased TNF-α and decreased IL-10. MPE increased IL-10. Caffeic acid and PPF increased both IL-6 and IL-10. Artepillin C and PSDE decreased IL-10. Baccharin and MPE increased IL-10. Baccharin also decreased IL-6. p-coumaric acid did not affect secretion of these cytokines. Pro- and anti-inflammatory cytokine production by the different propolis extracts differed; however, all three propolis extract formulations have potential as immunomodulatory agents in food supplement and pharmaceutical products.