摘要
Roasted burdock root tea(BT),rich in inulin and chlorogenic acid,is currently being established as a tea beverage in Japan and a wider area.This study aimed to clarify the effects of BT on the gut environment and host health.BT was prepared using 5%(w/v)dried burdock root,and its effect on ammonia production was investigated using human faecal culture and Institute of Cancer Research mice fed with a high-sucrose and low-dietary fibre diet for 14 days.In human faecal cultures established using a medium prepared with BT,the pH significantly decreased from 6.5 to 4.6±0.1.In vitro,BT significantly suppressed the production of ammonia and indole(p<0.05).In vivo,BT increased the caecal acetate level from 34±3μmol/g to 49±4μmol/g and n-butyrate level from 5.1±0.7μmol/g to 14±1μmol/g and reduced the caecal pH from 7.0±0.1 to 6.6±0.1.Despite no significant changes in caecal ammonia levels,plasma ammonia levels in BT-treated mice decreased from 0.74±0.07 to 0.50±0.07μmol/mL.Moreover,16S rDNA(V4)amplicon sequencing of faeces revealed that BT increased the short-chain fatty acid-producing gut commensals Muribaculaceae and Clostridia UCG-014.These results suggest that BT has desirable functional properties correlated with short-chain fatty acid production and pH-lowering effects that inhibit ammonia production and absorption in the gut.
