Antibacterial activities of Dipsacus sylvestris Huds. against Borrelia burgdorferi s.s. in vitro
Lyme borreliosis seems to be a new widespread disease of epidemic extent, controlled by a controversial discussed antibiotic based pharmacotherapy . In actual ethnobotanical approaches herbal medicines are involved, such as treatment with hydroethanolic extracts of teasel , obtained from the roots of Dipsacus sylvestris Huds., Dipsacaceae, although antibacterial effects of the european teasel have not been described before. In this context, solely grapefruit seed extract was tested in vitro against Borrelia burgdorferi without any relation to therapeutical use .
Fresh first year roots from Dipsacus sylvestris were extracted with 70% – ethanol, ethyl acetate as well as dichloromethane. The extracts were solubilized in water – the lipophilic extracts with addition of polysorbate 80– and tested in vitro on their activity against Borrelia burgdorferi s.s. over 8 days. The hydroethanolic extract showed no inhibition of growth whereas the two less polar fractions showed significant growth inhibiting activity. Strongest inhibition was found in the ethyl acetate extract (99.7±1.0% on day 4). The influence of polysorbate 80 on the bacterial growth was examined and found to be negligible (5.6±7.6% on day 4). All extracts were characterized by TLC and CZE (Capillary Zone Electrophoresis) as well as the crude drug itself, allowing the differentiation from the Traditional Chinese Medicine drug Dipsacus asperoides Cheng. Especially CZE (λ=234nm; borate buffer 45mmol/l; pH 9.6) yields a typical fingerprint electropherogram mainly consisting of iridoids and phenolic acids.
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3. Brorson, Ø., Brorson, S.H. (2007) Infection 35:206–208.