Anti-infective activities of Pelargonium sidoides (EPS® 7630): effects of induced NO production on Leishmania major in infected macrophages and antiviral effects as assessed in a fibroblast-virus protection assay.

EPs® 7630 is an aqueous-ethanolic extract of the roots of Pelargonium sidoides, employed in the treatment of upper respiratory tract infections. Its anti-infective activity is supposed to be associated with the activation of the nonspecific immune system. Using Leishmania major GFP-infected murine BMMΦ, the NO production of EPs® 7630-activated macrophages was correlated with the reduction of the GFP signal measured at single cell levels using flow cytometry. The anti-infectious effect of EPs® 7630 (3-10 µg/mL) on its own (NO production: 4-13 µM; signal reduction: 25-73 %) was less prominent than that in combination with IFN- γ (100 U/mL) (NO production: 20-27 µM; signal reduction: 35-78 %). Furthermore, supernatants of EPs® 7630-stimulated BMMΦ (10 µg/mL) significantly reduced the cytopathic effect of EMCV on L929 fibroblasts (antiviral activity 80 U/mL) when compared with an IFN- γ standard (100 U/mL). Direct addition of EPs® 7630 to L929 did not mediate cytoprotective effects. The antiviral components induced in BMMΦ by EPs® 7630 remain to be identified. Detection of any IFNs by ELISA was unsuccessful, which may be due to their very low concentrations in cell supernatants. The current data provide convincing support for the induction of anti-infectious responses by EPs® 7630.