In vitro anti-eimerial activity of several phytogenics

The control of coccidiosis, an infection of the intestinal tract, is a fundamental concern in poultry farming. In this study an in vitro model was used to simulate the first stage of an infection, the invasion of epithelial cells in the cecum by Eimeria tenella sporozoites. This model was applied to screen various phytogenic samples for their ability to inhibit cell invasion. Fluorescence-labeled sporozoites were co-cultured with Madin-Darby bovine kidney (MDBK) cells in the presence of samples, cell culture medium (negative control) or monensin sodium (positive control). After incubation fluorescent intracellular sporozoites were counted either by microscope or flow cytometer and relative inhibition rates were calculated. Monensin sodium showed a MIC₅₀ of 180 nM. Among the tested phytogenics quinine (1) (MIC₅₀=2.5–19.3µM) and cinchonidine (2) (MIC₅₀=2.7–21.2µM) performed best. Other Cinchona alkaloids showed less effect. A link between molecular configuration and anti-eimerial activity is assumed.