The effect of Echinacea preparations in three laboratory tests of anxiety: comparison with chlordiazepoxide

Abstract

Echinacea preparations are traditionally used to treat upper respiratory infections and inflammations. No psychotropic effects of Echinacea have been reported so far, although some recently reported active constituents are behaviorally active. Prompted by these findings, the anxiolytic potential of five different Echinacea preparations was evaluated. Three of these decreased anxiety but two of them had a very narrow effective dose range. Only one extract decreased anxiety within a wide dose‐range (3–8 mg/kg). Anxiolytic effects were consistently seen in three different tests of anxiety, the elevated plus‐maze, social interaction and shock‐induced social avoidance tests. No locomotor suppressant effects were seen at any dose. Noteworthy, the doses that showed anxiolytic effects in the present study were much lower than those used in the laboratory models of the traditional indications. Chlordiazepoxide robustly decreased anxiety‐like behavior in all tests but suppressed locomotion at higher doses. Perceived and real risks of conventional medications increase the demand for alternative therapies, provided that these are safe and efficient. Earlier evidence shows that Echinacea preparations have an excellent safety profile, while our findings suggest for the first time that certain preparations have a considerable anxiolytic potential. Further research is required to identify factors that differentiate efficient and inefficient preparations. Copyright © 2010 John Wiley & Sons, Ltd.

Double‐blind placebo controlled trial of the anxiolytic effects of a standardized Echinacea extract

“…Assuming that alkamides are indeed responsible for the anxiolytic effects of Echinacea preparations, these findings suggest that anxiolysis depends largely on the alkamide composition of the preparation, which is highly dependent on various factors, including the species, plant part, habitat and climate (Kraus, Bae, Wu, & Wurtele, 2006;Wu et al, 2009). This assumption was experimentally supported by our earlier findings showing that the HPLC fingerprint of alkamides differentiated those extracts that did from those that did not affect anxiety (Haller et al, 2010).…”

“…The uniqely standardized Echinacea angustifolia root extract, specifically the one studied here (Anxiofit‐1), significantly decreased anxiety in four preclinical tests e.g. the elevated plus‐maze, social interaction, conditioned fear and social avoidance tests (Haller, Hohmann, & Freund, , 2013). In addition, the same preparation rapidly decreased anxiety in human subjects, an effect that was maintained for at least 7 days after stopping the one week‐long treatment (Haller et al, ).…”

“…We used an Echinacea angustifolia extract Anxiofit-1 in a tablet form (marketed as AnxioCalm in the US) that was characterized earlier in preclinical studies (Haller et al, 2010;Hájos et al, 2011;Hohmann et al, 2011) and used previously in a human trial (Haller et al, 2013). Ratio of herbal drug to native extract was 1: 8.…”

“…In this earlier human trial, however, no placebo control was employed, and sample size was small. To correct these deficiencies, here we performed a double‐blind, placebo‐controlled trial on a larger sample by using the preparation that proved effective in earlier studies .…”

Anxiofit‐1 and reduction of subthreshold and mild anxiety: evaluation of a health claim pursuant to Article 14 of Regulation (EC) No 1924/2006

“…Alkamides can act as cannabinomimetics at both the cannabinoid CB1 and CB2 receptors, and can also inhibit the anandamide-degrading enzyme fatty acid amid hydrolase (FAAH) (Haller et al, 2010). Alkamides can act as cannabinomimetics at both the cannabinoid CB1 and CB2 receptors, and can also inhibit the anandamide-degrading enzyme fatty acid amid hydrolase (FAAH) (Haller et al, 2010).…”