Echinacea extract shows mild anti-anxiety effects in RCT
Scientists from Hungary investigated the potential anxiolytic (anti-anxiety) effects of an Echinacea angustifolia root extract standardized for alkamides. Data published in Phytotherapy Research indicated that Echinacea extract Anxiofit‐1, which is marketed in the US as AnxioCalm, produced statistically significant improvements in anxiety scores compared with placebo.
The potential benefits were observed after seven days of supplementation and were maintained after supplementation stopped, stated the researchers.
“These findings show that the standardized root extract of Echinacea angustifolia performed considerably better than placebo as it regards state anxiety and moderately better than placebo as it regards trait anxiety, likely because a trait is less responsive to treatments than a state,” they wrote. “The effect developed rapidly (within a few days) and was persistent as it did not vanish over the three weeks of washout.”
The scientists disclosed that lead researcher József Haller from the Institute of Experimental Medicine in Budapest is one of the authors of a US patent on the anxiety-reducing effects of Echinacea preparations.
A credible mechanism of action?
Commenting independently on the new systematic review and meta-analysis, Stefan Gafner, PhD, chief science officer of the American Botanical Council (ABC), told us that the results are quite good when compared to other clinical studies where botanical ingredients were evaluated using the STAI scale to measure anxiolytic effects.
“I was a bit surprised that the placebo effect was not more pronounced, but it seems to be in line with other publications. Nevertheless, this may be a point worth further discussion,” he added.
“What I found most compelling is that there are published data that may explain why echinacea would have an anxiolytic effect. The ability of some alkamides, which are a group of compounds found in Echinacea angustifolia roots (they also occur in other Echinacea spp. roots, in echinacea herb, and other plants besides echinacea), to elicit effects via the cannabinoid 1 (CB1) receptors, provides a credible mechanism by which the anxiolytic activity may be exerted. This is relevant since echinacea alkamides have been shown to cross the blood-brain barrier. However, the idea of a CB1-mediated anxiolytic effect of echinacea will need more robust science to be universally accepted.
Dr Gafner concluded: “Overall, this is a well-done study, showing a mild anxiolytic effect in people in temporary situations of perceived or actual stress/danger (state anxiety), e.g., a penalty shootout in a soccer final.
“However, as pointed out by the authors, ‘the sample size [number of patients enrolled] was well below those generally employed by studies on the efficacy of anxiolytic medications, and additional trials in larger study populations are required to support the validity of the findings reported here’.”
The researchers recruited 64 middle‐aged, physically healthy people living or studying in Budapest. The participants were randomly assigned to receive either 80 mg Echinacea or placebo every day for seven days. This was followed by a three-week washout period during which no tablets or capsules were taken. Anxiety was scored using the State‐Trait Anxiety Inventory (STAI). Participants also took the Beck Depression Inventory (BDI) and the Perceived Stress Scale (PSS).
Results showed that, in the Echinacea group, state anxiety scores decreased by approximately 11 points after seven days, compared with only 3 points in the placebo group, and that this was maintained over the washout period. However, no significant differences between the groups were observed for trait anxiety.
According to the University of California San Francisco: “State anxiety is defined as an unpleasant emotional arousal in face of threatening demands or dangers. A cognitive appraisal of threat is a prerequisite for the experience of this emotion. Trait anxiety, on the other hand, reflects the existence of stable individual differences in the tendency to respond with state anxiety in the anticipation of threatening situations.”
No impacts on depression or stress, as measured by the BDI or PSS, were recorded between the groups. The researchers also noted that no adverse effects were reported for the echinacea group.
“These findings suggest that particular Echinacea preparations have significant beneficial effects on anxiety in humans,” they wrote.
Commenting on the potential mechanism of action, Haller and his co-workers noted that alkamides may bind to the CB1 receptor, and thereby inhibit the activity of an enzyme called fatty acid amide hydrolase (FAAH). FAAH “degrades the endocannabinoid anandamide, and the inhibition of which increases anandamide levels in the brain, both of which were implicated in anxiety and are targets of anxiolytic drug development.
“Receptor binding and effects on FAAH may be due to the structural similarity between Echinacea alkamides and the endocannabinoid anandamide.”
Source: Phytotherapy Research
Published online ahead of print, doi: 10.1002/ptr.6558
“Double‐blind placebo controlled trial of the anxiolytic effects of a standardized Echinacea extract”
Authors: J. Haller et al.