Elucidation of Chemical Interactions between Crude Drugs Using Quantitative Thin-Layer Chromatography Analysis.

Naohiro Oshima,Kana Ueki,Maho Saito,Yuki Hiraishi,Mina Niino,Noriyasu Hada,Takashi Hakamatsuka,Kazuki Okoshi

doi:10.3390/molecules27030593

Naohiro Oshima, Kana Ueki + Show 6 more

Open Access

https://doi.org/10.3390/molecules27030593

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Abstract

To elucidate the interactions between crude drugs in Kampo medicines (traditional Japanese medicines), it is important to determine the content of the constituents in a cost-effective and simple manner. In this study, we quantified the constituents in crude drug extracts using thin-layer chromatography (TLC), an inexpensive and simple analytical method, to elucidate the chemical interactions between crude drugs. We focused on five crude drugs, for which quantitative high-performance liquid chromatography (HPLC) methods are stipulated in the Japanese Pharmacopoeia XVIII (JP XVIII) and compared the analytical data of HPLC and TLC, confirming that the TLC results corresponded with the HPLC data and satisfied the criteria of JP XVIII. (Z)-ligustilide, a major constituent in Japanese Angelica Root, for which a method of quantification has not been stipulated in JP XVIII, was also quantitatively analyzed using HPLC and TLC. Furthermore, Japanese Angelica Root was combined with 26 crude drugs to observe the variation in the (Z)-ligustilide content from each combination by TLC. The results revealed that combinations with Phellodendron Bark, Citrus Unshiu Peel, Scutellaria Root, Coptis Rhizome, Gardenia Fruit, and Peony Root increased the (Z)-ligustilide content. Quantifying the constituents in crude drug extracts using the inexpensive and simple TLC method can contribute to elucidating interactions between crude drugs in Kampo medicines, as proposed by the herbal-pair theory.

Highlights

Kampo medicine is a traditional Japanese medicine that consists of an appropriate combination of multiple crude drugs
All crude drugs analyzed using each method satisfied the criteria of the marker compounds, and there was not a significant difference between the thin-layer chromatography (TLC) and highperformance liquid chromatography (HPLC) results
This study shows that constituents in two extracts that were prepared according to the modified JP XVIII and decocted in hot water can be quantitatively analyzed by TLC, based on the comparison of HPLC analytical data of five crude drugs and the quantitative

Summary

Introduction

Kampo medicine is a traditional Japanese medicine that consists of an appropriate combination of multiple crude drugs. During the decoction process of Kampo medicines, multiple crude drugs are co-decocted and expected to exert synergistic effects. We have pioneered the elucidation of the interactions among the crude drugs in orengedokuto, a Kampo medicine, and revealed the chemical interactions [1,2] that elicited anti-inflammatory effects [3,4]. These studies indicated the importance of determining the content of the constituents in the extract. For continuous research and development regarding the interactions between crude drugs, a simple and inexpensive method of quantification is required because not all research institutions have expensive analytical equipment, such as highperformance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry

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Discussion

Conclusion