Licorice extract studied for improving symptoms in stroke patients

Licorice is extracted from the root of the licorice plant (Glycyrrhiza glabria) with a long history of use as a herbal medicine.

Hundreds of antioxidant phytochemicals have been isolated from the licorice including Glycyrrhizic acid.

licorice rootNeuroprotective flavonoids have also been isolated including liquiritin, isoliquiritin, isoflavones and glabridin.
Stroke is a leading cause of disability with consequences that can included impaired neurological function.

In this clinical trial published in the Journal of Herbal Medicine a double blind randomized placebo controlled clinical trial tested licorice extract for improving neurological function in patients who experienced stroke.

Here’s a few details about the study:                        

  • 75 patients were randomized to two different doses of licorice extract or placebo
  • Licorice extract doses were 450 mg or 900 mg
  • NIHSS (National institute of Health Stroke Scale) was used to quantify neurological performance (e.g. consciousness state, gaze, visual function, motor system of face and limbs, gait, sensory function and language skills).  The lower the NIHSS score the better.

Here are the results:

  • The licorice extract appeared safe compared to placebo with no changes in serum levels of potassium and sodium, urea, or blood sugar
  • No changes in blood pressure were observed
  • NIHSS score improved from 10.68 to 6.4 with Licorice extract 450 mg
  • NIHSS score improved from 10.44 to 5.48 with Licorice extract 450 mg
  • NIHSS score improved from 8.36 to 5.64 with placebo
  • Licorce Extract significantly improved scores compared to placebo

Take home message:  This study provides evidence that licorice extract may be safe in patients who have suffered a stroke.  Larger trials will be helpful to determine if licorice extract should be used in stroke patients to improve neurological symptoms.

Jeremy Johnson, PharmD, PhD


Categories: Brain, Clinical Trials, Plant Extracts