Comparison of ephedrine and pseudoephedrine contents in 34 Kampo extracts containing Ephedrae Herba used clinically in Japan.

Ephedrae Herba is among the important crude drugs prescribed in Kampo medicine for the treatment of cold, flue, rhinitis, nasal congestion, cough, and asthma. The active ingredients of Ephedrae Herba, ephedrine (E) and pseudoephedrine (PE), are potent sympathomimetic compounds that stimulate α-, ß1-, and ß2-adrenoceptors resulting in dilatation and alleviation of nasal mucosal hyperemia. Hypertension, palpitations, insomnia, and dysuria are the main adverse effects of E and PE, which can be avoided by determining the actual contents of these alkaloids in Kampo extracts containing Ephedrae Herba. However, the extraction efficiencies of E and PE from Ephedrae Herba contained in Kampo formulas in combination with other crude drugs remain unknown. Therefore, we comprehensively determined the E and PE contents of 34 Kampo extracts containing Ephedrae Herba used clinically in Japan. The E and PE contents per daily dosage in Kampo extracts were generally proportional to the compounding amount of Ephedrae Herba. In contrast, the extraction efficiencies of E or PE were not constant and not influenced by the pH of the extracts. We assume that the extraction efficiencies of E and PE may be independently affected by other constituent crude drugs. Thus, it is necessary to investigate the cause and mechanism in the future. In conclusion, these results show that the E and PE content of each Kampo formulation can be estimated from the compounding amount of Ephedrae Herba. Therefore, the amount of Ephedrae Herba should be carefully considered to ensure the safe use of Kampo formulations containing Ephedrae Herba.

Effect of Schisandrae Fructus on glycyrrhizin content in Kampo extracts containing Glycyrrhizae Radix used clinically in Japan.

Glycyrrhizae Radix is an important crude drug in Japan and is the most frequently prescribed drug in Kampo medicines for the treatment of a wide range of diseases. Glycyrrhizin (GL), the major active ingredient of Glycyrrhizae Radix, has various pharmacological actions but causes adverse effects such as pseudoaldosteronism. In a previous study, the GL content of shoseiryuto was found to be unexpectedly low, and Schisandrae Fructus in shoseiryuto reduced the pH value of the decoction and drastically decreased the extraction efficiency of GL from Glycyrrhizae Radix. In the present study, we investigated the extraction efficiency of GL from Glycyrrhizae Radix in decoctions comprising Glycyrrhizae Radix and five different fruit-derived crude drugs. Among the five fruit-derived crude drugs tested, Schisandrae Fructus markedly decreased both the pH value of the decoction and the extraction efficiency of GL. A comparison of the pH value of the decoction and the GL content of 12 Kampo prescriptions (containing at least Glycyrrhizae Radix and Schisandrae Fructus) showed that the GL content per daily dose was proportional to the compounding amount of Glycyrrhizae Radix, and that the extraction efficiency of GL from Glycyrrhizae Radix was strongly correlated with the pH value of the decoction. In addition, the pH value of the decoction was similar to the pH value documented in interview forms provided by pharmaceutical companies. These results suggested that the GL content in Glycyrrhizae Radix-containing Kampo products can be estimated from both the compounding amounts of Glycyrrhizae Radix and the pH value documented in their interview forms. Knowledge of GL content will help avoid adverse reactions due to Glycyrrhizae Radix.

Correction to: Comparison of glycyrrhizin content in 25 major kinds of Kampo extracts containing Glycyrrhizae Radix used clinically in Japan.

The article Comparison of glycyrrhizin content in 25 major kinds of Kampo extracts containing Glycyrrhizae Radix used clinically in Japan, written by Mitsuhiko Nose, Momoka Tada, Rika Kojima, Kumiko Nagata, Shinsuke Hisaka, Sayaka Masada, Masato Homma and Takashi Hakamatsuka, was originally published Online First without open access. After publication in volume 71, issue 4, page 711-722 the author decided to opt for Open Choice and to make the article an open access publication. Therefore, the copyright of the article has been changed to

Comparison of glycyrrhizin content in 25 major kinds of Kampo extracts containing Glycyrrhizae Radix used clinically in Japan.

Glycyrrhizae Radix is the most frequently used crude drug in Japan and is prescribed in Kampo medicine for the treatment of a wide range of diseases. The major active ingredient of Glycyrrhizae Radix, glycyrrhizin (GL), has been shown to possess various pharmacological actions, but is also known to cause adverse effects such as pseudoaldosteronism. To avoid the adverse effects of GL, precautions have been indicated on the package inserts of Glycyrrhizae Radix-containing formulas depending on the amount of Glycyrrhizae Radix they contain. However, it remains unknown whether the extraction efficiency of GL from Glycyrrhizae Radix is constant throughout the different combinations of crude drugs in Glycyrrhizae Radix-containing formulas. To confirm the basis of the safety regulation, in this study we comprehensively determined the GL content of 25 major kinds of Kampo extracts compounding Glycyrrhizae Radix. We found that the GL content per daily dosage in all Kampo extracts are generally proportional to the compounding amount of Glycyrrhizae Radix, except in the case of shoseiryuto (Sho-seiryu-To). We also found that Schisandrae Fructus in Sho-seiryu-To decoction caused a lowered pH condition and drastically decreased the extraction efficacy of GL from Glycyrrhizae Radix. Moreover, we were able to confirm that the extraction efficiency of GL from Glycyrrhizae Radix is dependent on the pH value of the extraction solvent. The extraction efficiency of GL in the 25 kinds of Kampo extracts was not constant but it correlates significantly with the pH value of the decoction. Furthermore, the GL contents are well correlated with pseudoaldosteronism incidence data obtained from the Japanese Adverse Drug Event Report (JADER) database on the 25 kinds of Kampo extracts. This suggests that the GL content is a better index to consider to avoid the adverse effects of Glycyrrhizae Radix-containing Kampo formulas.