The metabolism of (+-)-methylephedrine in rat and man

Biodegradation of Ephedrine Isomers by Arthrobacter sp. Strain TS-15: Discovery of Novel Ephedrine and Pseudoephedrine Dehydrogenases

The Gram-positive soil bacterium Arthrobacter sp. strain TS-15 (DSM 32400), which is capable of metabolizing ephedrine as a sole source of carbon and energy, was isolated. According to 16S rRNA gene sequences and comparative genomic analysis, Arthrobacter sp. TS-15 is closely related to Arthrobacter aurescens Distinct from all known physiological paths, ephedrine metabolism by Arthrobacter sp. TS-15 is initiated by the selective oxidation of the hydroxyl function at the α-C atom, yielding methcathinone as the primary degradation product. Rational genome mining revealed a gene cluster potentially encoding the novel pathway. Two genes from the cluster, which encoded putative short-chain dehydrogenases, were cloned and expressed in Escherichia coli The obtained enzymes were strictly NAD⁺ dependent and catalyzed the oxidation of ephedrine to methcathinone. Pseudoephedrine dehydrogenase (PseDH) selectively converted (S,S)-(+)-pseudoephedrine and (S,R)-(+)-ephedrine to (S)- and (R)-methcathinone, respectively. Ephedrine dehydrogenase (EDH) exhibited strict selectivity for the oxidation of the diastereomers (R,S)-(-)-ephedrine and (R,R)-(-)-pseudoephedrine.IMPORTANCE Arthrobacter sp. TS-15 is a newly isolated bacterium with the unique ability to degrade ephedrine isomers. The initiating steps of the novel metabolic pathway are described. Arthrobacter sp. TS-15 and its isolated ephedrine-oxidizing enzymes have potential for use in decontamination and synthetic applications.

Distribution Analysis via Mass Spectrometry Imaging of Ephedrine in the Lungs of Rats Orally Administered the Japanese Kampo Medicine Maoto

Maoto, a traditional Japanese Kampo medicine, has been used to treat various respiratory diseases, including respiratory infections and influenza. Ephedrine (EPD), the main ingredient in maoto, is also clinically used to treat respiratory diseases. However, the pharmacokinetics and distribution of EPD in the lungs after the administration of maoto have not been demonstrated. This study aimed to determine the concentrations, distribution, and pharmacokinetics of EPD and its precursor methylephedrine (MEPD) in the lungs of rats orally administered maoto (1 and 4 g/kg). We used liquid chromatography–electrospray ionization-tandem mass spectrometry to measure the ingredient concentrations. Both ingredients were detected in maoto-treated lung homogenates. Next, we examined the distribution of both ingredients in lung sections by using matrix-assisted laser desorption/ionization-mass spectrometry imaging, a powerful tool for the visualization of the distribution of biological molecules. The mass spectrometry imaging analysis detected only EPD and provided the first visual demonstration that EPD is distributed in the alveoli, bronchi, and bronchioles in the lungs of rats orally administered maoto (4 g/kg, three times at 2-h intervals). These results suggest that the pharmacological efficacy of maoto for the amelioration of respiratory symptoms is related to the distribution of EPD in the lung.

Current research and case work activities of criminalistics in Japan

The current research and case work activities of criminalistics in Japan are described. The selected forensic science disciplines are forensic osteology including specialized technology of skull identification, forensic serology, forensic DNA analysis of poisonous materials, forensic hair and fiber analysis, trace evidence analysis, document analysis, forensic psychology mainly concerned with the so-called lie-detector, forensic image analysis, voice print analysis, fire and explosion analysis, forensic engineering, firearm and toolmark analysis. The current activity of the Training Institute of Forensic Science at the National Research Institute of Police Science is also briefly described with special regard to the education and training course of forensic DNA typing analysis. Instruments for analytical and methodological use are listed according to the availability in evidence sample analyses.

N-oxidation and N-demethylation of methylephedrine by rat-liver microsomes

1. The metabolism of methylephedrine was studied using rat-liver microsomes; methylephedrine N-oxide and ephedrine were isolated as metabolites. 2. The formation of methylephedrine N-oxide was inhibited by methimazole or by preincubation of microsomes, but that of ephedrine was not; whereas the formation of ephedrine was inhibited by either SKF 525-A or CO, but the formation of the N-oxide was not. 3. Pretreatment of rats with phenobarbital increased N-demethylation, but decreased N-oxidation. Pretreatment with 3-methylcholanthrene did not influence either reaction. 4. The results indicate that the formation of the N-oxide was mediated by the flavin-containing monooygenase system and that of ephedrine was mediated by the cytochrome P-450 system.