Kampo medicines induce formula-dependent changes in the intestinal flora of mice

Certain ingredients in Kampo medicines are known to be converted into the active form by bacterial flora in the intestine. Conversely, enteric microbiota is supposed to be affected by Kampo medicines, because the medicines comprise numerous compounds with prebiotic and/or antimicrobial properties. However, the effect of Kampo medicines on the bacterial flora has rarely been studied. In this study, the effects of different types of Kampo medicines on bacterial flora were investigated. Male IQI mice were orally treated with juzentaihoto, hochuekkito, kakkonto, and orengedokuto extract solutions (1 g/kg body weight) or water daily for 14 days. To examine the changes in the intestinal microflora, the terminal restriction fragment polymorphism (T-RFLP) method was used. Cluster analyses suggested that T-RFLP profiles of juzentaihoto/hochuekkito (“hozai”) and orengedokuto/kakkonto (“Shazai”) are classified into 2 different clusters in the dendrogram. To examine changes in 5 genera of common bacteria (Bifidobacterium, Lactobacillus, Clostridium, Escherichia coli, and Bacteroides fragilis), real-time PCR was performed. No large-scale changes were observed except for modest but significant decrease in Lactobacillus numbers by juzentaihoto as well as several hundred-fold increase in Escherichia coli numbers by hochuekkito. The present study indicates that DNA-based methods for the analysis of microbiota may pave the way for elucidation of the complicated and pleiotropic influences of the components of Kampo medicines on enteric flora.