Background: Valeriana officinalis is widely used as an herbal sedative and anxiolytic in alternative medicine. In this study, we investigate the effects of valerian root extracts on physical and psychological stress responses by utilizing a communication box.
Methods: Mice received oral administration of valerian root extracts or distilled water for 3 weeks prior to being subjected to physical or psychological stress.
Results: Plasma corticosterone levels were measured 1 h after the final stress conditions and were significantly increased in both the physical and psychological stress groups compared to the control group; these levels were predominantly higher in the physical stress group compared to the psychological stress group. The administration of valerian root extracts significantly reduced the plasma corticosterone levels in both the physical and psychological stress groups. In addition, compared to the control group, physical and psychological stress groups showed significantly increased levels of 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4) and 5-hydroxyindoleacetic acid (5-HIAA), metabolites of norepinephrine and serotonin, in the hippocampus and amygdala, respectively. The administration of valerian root extracts significantly suppressed the increase of MHPG-SO4 and 5-HIAA in the two stress groups.
Conclusion: These results suggest that valerian root extracts can suppress physical and psychological stress responses by modulating the changes in serotonin and norepinephrine turnover in the hippocampus and amygdala.