Identification of higenamine in Radix AconitiLateralis Preparataas a beta2-adrenergic receptor agonist¹

Abstract

Aim: To screen beta2-adrenergic receptor (β 2 -AR) agonists from Radix Aconiti Lateralis Preparata (RALP) as potential drug leads for asthma using a sensitive cell-based agonist assay. Methods: The β 2 -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)×10-5 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. Conclusion: Hignamine, as a β 2 -AR agonist existing in the extract of RALP, is the key compound contributing to the successful relief of the bronchoconstriction.

The relaxation effect and mechanism of action of higenamine in the rat corpus cavernosum

“…So considering this phenomenon, it is suggested that b-adrenoceptors activated by higenamine increased the cAMP. 6,7 We do not have any data regarding the results of this study that higenamine has some PDE5 inhibitor activity. We guess that action mechanisms of higenamine and PDE-5 inhibitor showed synergistic effect have two signal pathways.…”

“…Higenamine mediates cardiotonic, 5,6 vascular relaxation, 7 bronchodilator 8 and anti-thrombotic effects, 9,10 and reduces apoptotic cell death in vivo, 11 suggesting that higenamine has various actions on the cardiovascular system and that it may have an effect on penile erection.…”

The synergistic anti-asthmatic effects of glycyrrhizin and salbutamol

“…During the experiment, animals were manipulated as previously described [12] . Briefly, the animals were placed in an inhalation cage, and each animal was exposed to atomized 0.1% histamine solutions for 20 s at the rate of 0.8 mL/min.…”

“…Briefly, this cell line The isolated guinea pig tracheal strips relaxation model Hartley strain guinea pigs were sacrificed with an overdose of pentobarbital (75 mg/kg, ip). Tracheal strips were removed and manipulated as previously described [12] . Acetylcholine (ACh) was added to the organ bath to induce the contraction of smooth muscle.…”

“…cAMP-regulated reporter gene assay The CHO-β 2 -AR-CRE-EGFP cell line was constructed and cultured as previously described [12] . Briefly, this cell line The isolated guinea pig tracheal strips relaxation model Hartley strain guinea pigs were sacrificed with an overdose of pentobarbital (75 mg/kg, ip).…”