Anxiolytic-Like Effect of baicalin and its additivity with other anxiolytics.
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 gamma-aminobutyric acid dl-THP: dl-tetrahydropalmatine.
Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.
Zhiwen
Z
Xu
Feng
F
Wang
Shui Ying
SY
Tsang
Kwan Hang
KH
Ho
Hui
H
Zheng
Chun Tak
CT
Yuen
Chun Yin
CY
Chow
Hong
H
Xue
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000494:pharmacology; D003975:Diazepam / Q000494:pharmacology; D004357:Drug Synergism; D005419:Flavonoids / Q000494:pharmacology*; D051379:Mice; D009465:Neuromuscular Agents / Q000494:pharmacology
D014151:Anti-Anxiety Agents; D001600:Berberine Alkaloids; D005419:Flavonoids; D009465:Neuromuscular Agents; C038044:baicalin; C014215:tetrahydropalmatine; D003975:Diazepam