Bioactivity of Ephedra: Integrating Cytotoxicity Assessment with Real-Time Biosensing

Abstract

Ephedrine-type alkaloids (ETA) are major active ingredients of Ephedra, a traditional Chinese medicinal herb used to treat asthma and nasal congestion. Until recently, large amounts of Ephedra were used in dietary supplements for weight loss and athletic performance enhancement. However, indiscriminate consumption of ETA-containing products has resulted in more than 1,000 reported cases of adverse effects. The objective of this study is to evaluate bioactivity of ETA. The toxicities of (-)-ephedrine and (+)-pseudoephedrine were measured using MTT assay on human neuroblastoma (SH-SY5Y) and rat myoblastoma (H9c2 (2-1)), while the stress responses of a panel of biosensing bioluminescent Escherichia coli strains were analyzed. SH-SY5Y showed similar sensitivity to (-)-ephedrine and (+)-pseudoephedrine, while H9c2 (2-1) could differentiate the cytotoxicity of (-)-ephedrine and (+)-pseudoephedrine. The biosensing of the E. coli strains was highly sensitive to the toxicity of ETA and could yield instantaneous response. The RLU ratios dependent on the construct of strains gave unique fingerprintingm pattern of ETA.