Synergistic Anti-Borreliae Efficacy of a Composition of Naturally-occurring Compounds: an In vitro Study

Background: Borrelia sp, which is a pathogenic agent of Lyme diseases in mammals, has become an increasing problem worldwide due to the emergence of persistence. In this study we investigated whether a defined composition of naturally occurring substances could display a broad and synergistic action in vitro against both active and persistent forms of Borrelia spp.Methods: A formulation of six plant-derived compounds combined at their 1/32-1/2 MIC values was tested in vitro against two species of Borrelia recognized as causative agents of Lyme disease in North America and Europe.Results: The results showed that a composition of baicalein, luteolin, rosmarinic acid, monolaurin, cis-2 decenoic acid, and iodine at their 1/8 MIC values has significant synergistic effect against the active and persisting latent forms. This composition revealed anti-oxidative properties affecting Borrelia’s membrane but not DNA. Finally, we observed its inhibitory effect on the release of IL-1α, IL-1β, and IL-6 by human CD14+ monocytes stimulated with live Borrelia sp.Conclusion: These results suggest that such a formulation of compounds might be considered and further explored for its significant pleotropic anti-Borreliae efficacy. Additional in vivo and human studies are warranted to validate this possibility.