Iranian Black Tea and Cowslip Extracts Induce Tumor Necrosis Factor-Alpha Secretion from Mouse Macrophage Cell Culture

Many species of tea (Camellia sinensis) and cowslip (Echium amoenum) are used in Iranian traditional medicine. The aim of this study was to conduct the survey on the ability of Iranian black tea and cowslip extracts on secretion of tumor necrosis factor-alpha (TNF-alpha) by non-infected and infected mouse macrophages. A macrophage infection model with Legionella pneumophila and enzyme linked immunosorbent assay (ELISA) technique was used in this study. Research showed that the concentrations of TNF-alpha in non-infected and infected macrophage culture supernatant treated with various concentrations of Iranian black tea and cowslip extracts was significantly higher than the control. Various concentrations of cowslip (0.5, 5 and 50 µg/mL) had significantly a great effect on the induction of TNF-alpha secretion in comparison with the Iranian black tea extract (P < 0.0001). In conclusion, we demonstrated the ability of Iranian black tea and cowslip on the induction of TNF-alpha, which can exert an anti-L. pneumophila activity on macrophages at a low dose. However, further studies to elucidate the mechanism(s) of the induction of macrophages by Iranian black tea and cowslip as well as their potential inhibitory effects on the growth of infected cells and their possible antitumor effects should be carried out in future works.