Identification of higenamine in Radix Aconiti Lateralis Preparata as a beta2-adrenergic receptor agonist1.
OBJECTIVE
To screen beta2-adrenergic receptor (beta2-AR) agonists from Radix Aconiti Lateralis Preparata (RALP) as potential drug leads for asthma using a sensitive cell-based agonist assay.


METHODS
The beta2-AR gene was stably expressed by Chinese hamster ovary (CHO) cells also stably expressing a cyclic adenosine monophosphate (AMP) response element-linked enhanced green fluorescent protein reporter gene. The cells were used to screen agonists from high-performance liquid chromatographic fractions of an extract of RALP. The fraction with the highest activity was selected for further compound isolation and the study of the structure-activity relationship. Its active compound was further identified by chromatography and mass spectrometry.


RESULTS
Bioactivity-directed fractionation of the crude extract of RALP led to the isolation and characterization of the effective compound, namely hignamine. It could dose-dependently relax the isolated guinea pig trachea strip precontraction with acetylcholine with EC(50) value of (2.60+/-0.36)x10(-5) mol/L. Further in vivo studies also displayed that hignamine could protect experimental asthma model induced by histamine in guinea pigs to prolong the latent periods of asthma.


CONCLUSIONS
Hignamine, as a beta2-AR agonist existing in the extract of RALP, is the key compound contributing to the successful relief of the bronchoconstriction.
Bai
Gang
G
College of Life Sciences, Nankai University, Tianjin 300071, China. gangbai@nankai.edu.cn
Yang
Yang
Y
Shi
Qian
Q
Liu
Ze
Z
Zhang
Qi
Q
Zhu
Yuan-yuan
YY
D031841:Aconitum / Q000737:chemistry*; D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists / Q000737:chemistry* / Q000494:pharmacology*; D000470:Alkaloids / Q000737:chemistry* / Q000494:pharmacology*; D000818:Animals; D001249:Asthma / Q000139:chemically induced / Q000188:drug therapy; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D006632:Histamine; D066298:In Vitro Techniques; D008024:Ligands; D009126:Muscle Relaxation / Q000187:drug effects; D051381:Rats; D044005:Tetrahydroisoquinolines / Q000737:chemistry* / Q000494:pharmacology*; D014132:Trachea / Q000187:drug effects; D014162:Transfection
D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists; D000470:Alkaloids; D008024:Ligands; D044005:Tetrahydroisoquinolines; D006632:Histamine; C012348:higenamine