Document Type

Poster Presentation

Publication Date



Background: The zebrafish species, Danio rerio, is a widely utilized model organism with well-characterized behaviors including anxiety-like behavior when placed into a novel environment. In addition, the fish can be treated with substances by immersion.

St. John’s Wort has been suggested as a plant-based treatment for depression and anxiety because it contains compounds that inhibit the serotonin transporter (SERT) among other effects. A number of St. John’s Wort supplements are commercially available.

The National Institute of Mental Health (NIMH) estimates that about 19% of US adults suffer an anxiety disorder each year and about 31% will experience an anxiety disorder in their lifetime. Clearly effective, inexpensive, and readily available treatments for anxiety represent an important area of research.

Objectives: Assess the ability of acute treatment with St. John’s Wort to reduce anxiety-like behavior in zebrafish.

Method: Zebrafish will be treated by immersion in a solution of St. John’s Wort supplements and assessed for anxiety in the Novel Dive Tank (NDT) Test.

Results: Acute treatment with St. John’s Wort supplements increased anxiety as measured using the NDT.

Conclusions: Acute treatment with the water-soluble constituents of St. John’s Wort supplements tested did not reduce apparent anxiety in the fish. Future studies will utilize a longer treatment time and more hydrophobic solvents.