Growth inhibiting activity of lipophilic extracts from Dipsacus sylvestris Huds. roots against Borrelia burgdorferi s. s. in vitro

Fresh first year roots from Dipsacus sylvestris HUDS. were extracted with 70% ethanol, ethyl acetate as well as dichloromethane. Extracts were solubilized in water (lipophilic extracts with addition of polysorbate80) and tested for their activity against Borrelia burgdorferi sensu stricto in vitro during an eight-day period using amoxicillin as standard. The hydroethanolic extract showed no growth inhibition whereas significant growth inhibiting activity could be shown in the two less polar fractions for the first time. Strongest inhibition was found in the ethyl acetate extract. The effect of polysorbate 80 on bacterial growth was examined and found to be negligible. As the nature of bioactive constituents has not been clarified yet, a micellar electrokinetic capillary chromatography fingerprint analysis for a methanolic extract was applied including loganin, chlorogenic acid, cantleyoside and caffeic acid as marker substances.