Different effects of two types of Chimonanthus praecox scents on anxiety: β-Ocimene might be the key component...

Chimonanthus praecox (wintersweet), endemic to China, is traditionally consumed as appreciation and medicine using its flowers. While its floral scent is valued, its mental health benefits remain unexplored. This study investigated anxiety effects and mechanisms of two groups of C. praecox-Concolor Group (CSX) and Patens Group (CHX)-on anxiety-like behaviors in mice.

HS-SPME/GC-MS analysis showed CSX flowers were rich in linalool, while CHX flowers had a β-ocimene-rich aroma. Effects of acute and chronic exposure on anxiety (elevated plus maze [EPM], open field test [OF], light-dark box test [LDB], elevated zero maze [EZM]), and social behaviors (three-chamber social interaction test) were tested in ICR mice. Acute and chronic CSX exposure significantly increased open-arm exploration in the EPM and EZM tests (e.g., open-arm entries: 21.59 % vs 6.91 % in control; p < 0.01). Conversely, chronic low-concentration CHX impaired social behaviors (e.g., social preference: 30.92 % vs 59.38 %; p < 0.01). β-Ocimene consistently induced anxiogenic effects (LDB, EPM, three-chamber test), especially in female mice (e.g., reducing light box exploration [97.10 s vs 143.04 s, p < 0.05] and social preference [45 % vs 63 %; p < 0.001]). Chronic exposure further impaired social behavior and elevated hippocampal 5-HIAA/5-HT (negatively correlated with anxiolytic behavior: LDB r = -0.523, EPM r = -0.368), opposite to CSX. Only the linalool-rich CSX demonstrated significant anxiolytic effects, correlating with attenuated hippocampal 5-HIAA/5-HT.

The functional difference results from β-ocimene content levels, which emphasize volatile-specific anxiety modulation. Wintersweet's traditional use may extend to mental health applications through distinct aroma compounds.