Anxiolytic effects of chronic treatment with Hypericum perforatum (St John’s Wort) tincture in male and female rats. (2020)
Type of ContentElectronic Thesis or Dissertation
Degree NameMaster of Science
PublisherUniversity of Canterbury
AuthorsShen, Jie Huashow all
Given high prevalence of anxiety disorders, it is important to identify effective alternative treatments due to the current limitations of pharmacological and psychological interventions. Worldwide, Hypericum perforatum (HP) products have become some of the best-selling herbal remedies. However, empirical evidence supporting their anxiolytic effects and investigations of dose levels are highly scarce. To begin empirical enquiry in this field, the present study sought to explore treatment effects of HP following chronic oral administration of an HP tincture in male and female rats. Several anxiety-related responses of 74 adult rats (35 males and 39 females) were studied in four behavioural testing apparatuses, including the open field test, the light/dark box, the y maze, and the elevated zero maze. Withdrawal responses were also investigated upon acute (72 hours) and chronic (14 days) HP treatment- free periods utilising the open field paradigm. Differences in anxiety responses were examined across sex and HP doses (0/mg/kg, 250mg/kg, 500mg/kg, and 750mg/kg). Results demonstrated evidence of anxiolytic effects of HP tincture and found that the 250mg/kg dose produced the greatest anxiolytic effect and the fewest withdrawal responses. Possible withdrawal responses were evident during the acute HP tincture treatment withdrawal period, pointing to possible anxiogenic effects upon acute discontinuation. Findings also showed sex differences, however, insufficient evidence was obtained from the present study with respect to a possible interaction between dose and sex. Despite the discussed limitations, the present study marked an important first step in initiating research into anxiolytic effects of commercially-popular herbal remedies and provides a foundation for further research into dose explorations, as well as dose and sex relationships.