Abstract:Inorder to investigate the protective effect of the Polygonatum kingianum polysaccharide and water extracts on Lactobacillus reuteri 1.2838 under different gastrointestinal stress conditions，the content of quorumsensing molecules autoinducers-2（AI-2）was measured.The activated L.reuteri 1.2838 was co-incubated with either the P.kingianum polysaccharide or water extract until OD600 nmreached 0.6-0.8.The treated probiotics were cultured for 1 h-3 h under gastrointestinal stress conditions to detect the production of AI-2.The results showed that the P.kingianum polysaccharide and water extracts could partially increase the production of L.reuteri 1.2838 AI-2 under different gastrointestinal stress conditions.However，the water extract exhibited a better protective effect on L.reuteri 1.2838 than that shown by the polysaccharide extract.