Planta Med 2006; 72(2): 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
  • 1Department of Biochemistry, Hong Kong University of Science and Technology, Kowloon, Hong Kong, P. R. China
Further Information

Publication History

Received: April 6, 2005

Accepted: July 17, 2005

Publication Date:
05 December 2005 (online)


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.


BZS:benzodiazepine-binding site

EPM:elevated plus-maze


GABAA:type A γ-aminobutyric acid



  • 1 Macdonald R L, Olsen R W. GABAA receptor channels.  Annu Rev Neurosci. 1994;  17 569-602
  • 2 Atack J R. Anxioselective compounds acting at the GABA(A) receptor benzodiazepine binding site.  Curr Drug Targets CNS Neurol Disord. 2003;  2 213-32
  • 3 Medina J H, Viola H, Wolfman C, Marder M, Wasowski C, Calvo D. et al . Overview - flavonoids: a new family of benzodiazepine receptor ligands.  Neurochem Res. 1997;  22 419-25
  • 4 Hui K M, Wang X H, Xue H. Interaction of flavones from the roots of Scutellaria baicalensis with the benzodiazepine site.  Planta Med. 2000;  66 91-3
  • 5 Akao T, Kawabata K, Yanagisawa E, Ishihara K, Mizuhara Y, Wakui Y. et al . Baicalin, the predominant flavone glucuronide of scutellariae radix, is absorbed from the rat gastrointestinal tract as the aglycone and restored to its original form.  J Pharm Pharmacol. 2000;  52 1563-8
  • 6 Awad R, Arnason J T, Trudeau V, Bergeron C, Budzinski J W. Foster BC et al. Phytochemical and biological analysis of skullcap (Scutellaria lateriflora L.): a medicinal plant with anxiolytic properties.  Phytomedicine. 2003;  10 640-9
  • 7 Liao J F, Hung W Y, Chen C F. Anxiolytic-like effects of baicalein and baicalin in the Vogel conflict test in mice.  Eur J Pharmacol. 2003;  464 141-6
  • 8 Leung W C, Zheng H, Huen M, Law S L, Xue H. Anxiolytic-like action of orally administered dl-tetrahydropalmatine in elevated plus-maze.  Prog Neuropsychopharmacol Biol Psychiatry. 2003;  27 775-9
  • 9 Nolan N A, Parkes M W. The effects of benzodiazepines on the behaviour of mice on a hole-board.  Psychopharmacologia. 1973;  29 277-86
  • 10 File S E, Wardill A G. The reliability of the hole-board apparatus.  Psychopharmacologia. 1975;  44 47-51
  • 11 Hui K M, Huen M S, Wang H Y, Zheng H, Sigel E, Baur R. et al . Anxiolytic effect of wogonin, a benzodiazepine receptor ligand isolated from Scutellaria baicalensis Georgi.  Biochem Pharmacol. 2002;  64 1415-24
  • 12 Mohler H, Fritschy J M, Rudolph U. A new benzodiazepine pharmacology.  J Pharmacol Exp Ther. 2002;  300 2-8

Dr. Hong Xue

Department of Biochemistry

Hong Kong University of Science and Technology

Clear Water Bay

Hong Kong

People’s Republic of China

Phone: +852-2358-8707

Fax: +852-2358-1552