In vitro evaluation of antibacterial and immunomodulatory activities of Pelargonium reniforme, Pelargonium sidoides and the related herbal drug preparation EPs^® 7630

Abstract 

The importance of Pelargonium species, most notably Pelargonium reniforme and Pelargonium sidoides, in traditional medicine in the Southern African region is well documented. Nowadays, a modern aqueous-ethanolic formulation of the roots of P. sidoides (EPs^® 7630) is successfully employed for the treatment of ear, nose and throat disorders as well as respiratory tract infections. To provide a scientific basis of its present utilization in phytomedicine, EPs^® 7630, extracts and isolated constituents of the titled Pelargoniums with emphasis on P. sidoides were evaluated for antibacterial activity and for their effects on nonspecific immune functions. The samples exhibited merely moderate direct antibacterial capabilities against a spectrum of Gram-positive and Gram-negative bacteria. Functional bioassays including an in vitro model for intracellular diseases, a fibroblast-lysis assay (tumour necrosis factor (TNF) activity), a fibroblast-virus protection assay (IFN activity) and a biochemical assay for nitric oxides revealed significant immunomodulatory properties. Gene expression experiments (iNOS, IFN-α, IFN-γ, TNF-α, Interleukin (IL)-1, IL-10, IL12, IL-18) not only confirmed functional data, they also clearly showed differences in the response of infected macrophages when compared to that of noninfected cells. ELISA confirmed the protein production of TNF-α, IL-1α and IL-12, while FACS analyses reaffirmed the cytokines IL-1α and IL-12 at the singular cell level. The current data provide convincing support for the improvement of immune functions at various levels, hence, validating the medicinal uses of EPs^® 7630. Despite considerable efforts, the remedial effects cannot yet be related to a chemically defined principle.

Keywords: Pelargonium sidoides, Antibacterial activity, Immunomodulation, Nitric oxides, Cytokines, Gene expressions