Study of crosstalk between Kampo medicine and gut microbiota via gut immunity

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15287
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 47050:Environmental and natural pharmaceutical resources-related
• Research Institution: Fukuyama University
• Principal Investigator: Takayama Kento 福山大学, 薬学部, 講師 (60568559)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 大黄甘草湯 / レスポンダー・ノンレスポンダー / 腸内細菌叢 / 免疫グロブリンA / 短鎖脂肪酸

Outline of Final Research Achievements

So far, we clarified that the eating habits may influence the purgative activity of Daiokanzoto (DKT), thereby categorizing individuals as either responders or non-responders to DKT treatment. In this study, mice on the high-carbohydrate diet exhibited significantly high purgative activity with DKT. This correlated with increased Enterobacteriaceae abundance due to reduced immunoglobulin A regulation. However, the high-fiber diet greatly reduced DKT efficacy. Additionally, rhein 8-O-β-D-glucopyranoside, gallate, and tannin, which are DKT constituents, contributed to the difference between responders and non-responders.
The findings of the study may not only provide the scientific evidence regarding the mechanisms in responders and non-responders to Kampo medicines, but also enhance the significance of Kampo medicines as complex-component drugs the effects of which cannot be explained only based on the mechanism of action of the main components.

Free Research Field

漢方医薬学、生薬学

Academic Significance and Societal Importance of the Research Achievements

薬の効果には個人差のあることが一般的に知られているが、腸内細菌叢の違いが薬の効果にどのような影響を及ぼすのか探求する研究はほとんど行われていない。本研究では、腸内細菌との関わりが深い漢方薬について、緩下薬として頻用される大黄甘草湯の下剤効果と食習慣による腸内細菌叢の違いとの関連性について、腸管免疫応答とそれらを制御する短鎖脂肪酸の解析から一端を明らかにすることができた。また、本研究から漢方薬・腸内細菌叢・腸管免疫応答の３因子による複雑な関連性を紐解くことで、先人達の経験則に基づいた「証」の科学的解明に近づけると確信している。