Skullcap (Scutellaria lateriflora) and Anxiety: evidence and sources

Scutellaria lateriflora, a traditional herbal remedy for stress and anxiety, was tested on human volunteers for its effects on mood. In a placebo-controlled, double-blind, crossover study, 43 healthy participants were randomised to a sequence of three times daily S. lateriflora (350 mg) or placebo, each over two weeks. In this relatively non-anxious population (81% were mildly anxious or less, i.e. Beck Anxiety Inventory (BAI) scores ≤ 15), there was no significant difference between skullcap and placebo with BAI (p = 0.191). However, there was a significant group effect (p = 0.049), suggesting a carryover effect of skullcap. For Total Mood Disturbance measured by the Profile of Mood States, there was a highly significant (p = <0.001) decrease from pre-test scores with skullcap but not placebo (p = 0.072). The limitations of carryover effect, generally low anxiety scores and differences in anxiety levels between groups at baseline (p = 0.022), may have reduced the chances of statistical significance in this study. However, as S. lateriflora significantly enhanced global mood without a reduction in energy or cognition, further study assessing its putative anxiolytic effects in notably anxious subjects with co-morbid depression is warranted.

Scutellaria lateriflora is an herbal medicine with long-standing traditional use as a relaxing nervine. There has been controversy in the literature with regards to its efficacy, and this study was designed to clarify its effectiveness in reducing anxiety, one of the phytotherapeutic indications. A double blind, placebo-controlled study of healthy subjects demonstrated noteworthy anxiolytic effects. The use of phytomedicines for the treatment of anxiety is reviewed, as is the published literature on S. lateriflora and its putative toxicity.

The phytochemistry and biological activity of Scutellaria lateriflora L. (American skullcap) which has been traditionally used as a sedative and to treat various nervous disorders such as anxiety was studied. In vivo animal behaviour trials were performed to test anxiolytic effects in rats orally administered S. laterifolia extracts. Significant increases in the number of entries into the center of an "open-field arena"; number of unprotected head dips, number of entries and the length of time spent on the open arms of the Elevated Plus-Maze were found. The identification and quantification of the flavonoid, baicalin in a 50% EtOH extract (40 mg/g) and its aglycone baicalein in a 95% EtOH extract (33 mg/g), as well as the amino acids GABA in H2O and EtOH extracts (approximately 1.6 mg/g) and glutamine in a H2O extract (31 mg/g), was performed using HPLC. These compounds may play a role in anxiolytic activity since baicalin and baicalein are known to bind to the benzodiazepine site of the GABAA receptor and since GABA is the main inhibitory neurotransmitter.