Letter	Planta Med 2006; 72: 189-192 DOI: 10.1055/s-2005-873193
© Georg Thieme Verlag KG Stuttgart · New York
Anxiolytic-Like Effect of Baicalin and its Additivity with other Anxiolytics
Zhiwen Xu1, Feng Wang1, Shui Ying Tsang1, Kwan Hang Ho1, Hui Zheng1, Chun Tak Yuen1, Chun Yin Chow1, Hong Xue1
1 Department of Biochemistry, Hong Kong University of Science and Technology, Kowloon, Hong Kong, P. R. China

Abstract

Baicalin, a naturally occurring flavonoid, was previously reported to exert anxiolytic-like effects in the Vogel conflict test. In the present study, the anxiolytic effects of baicalin alone and in combination with other anxiolytics were tested in mice using the elevated plus-maze (EPM). Baicalin treatment (7.5 - 30 mg/kg) significantly increased entries into and time spent in open arms, indicative of an anxiolytic-like effect. Motor-depressive and myorelaxant side effects commonly associated with anxiolytics were not observed with baicalin at effective anxiolytic doses in the hole-board and horizontal wire tests, respectively. Co-administration of baicalin (3.75 mg/kg) with dl-tetrahydropalmatine (dl-THP; 0.25 mg/kg), an anxiolytic-hypnotic alkaloid, both at sub-effective doses, induced an additive effect resulting in considerable anxiolysis. Similarly, an additive anxiolytic-like effect was observed with baicalin (3.75 mg/kg) and diazepam (DZ; 0.5 mg/kg). Results obtained from this study demonstrate the potential of baicalin as a candidate anxiolytic and its possible application in multidrug therapy.

Abbreviations

BZS:benzodiazepine-binding site

EPM:elevated plus-maze

DZ:diazepam

GABA_A:type A γ-aminobutyric acid

dl-THP:dl-tetrahydropalmatine