New Insights in the bioavailability and molecular mode of action of Echinacea preparations

Echinacea is a widely used herbal remedy for prevention and treatment of the common cold. Recently a lot of new insights concerning the molecular mode of action of the main lipophilic constituents, the alkamides, have renewed interest in this plant [1–3]. Alkamides have recently been shown to be quite fast absorbed and nanomolar quantities have been detected by LC-MS/MS in the blood after oral application of different Echinacea preparations in randomized open, single-dose, crossover studies. Due to the structural similarity of the alkamides with anandamide, an endocannabinoid, we have evaluated their ability to bind to cannabinoid receptors CB1 and CB2. Each of the alkamides was recognized by both the CB1 and CB2 receptors and can therefore be considered as a new class of cannabinomimetics. There is also evidence that alkamide containing Echinacea preparations trigger effect on the pro-inflammatory cytokine TNF-α and chemokine IL-8 in an ex vivo study and therefore not only bind but also activate these CB2 receptors. However, due to a lot of new cognitions the effects are not exclusively related to CB binding.

References: 1. Woelkart, K. et al. (2005), Planta Med. 71:701–705. 2. Gertsch J. et al. (2004), FEBS Lett. 577:563–569. 3. Raduner, S. et al. (2006), J. Biol. Chem. 281:14192–14206.