Anti-Escherichia coli O157:H7 Properties of Purple Prairie Clover and Sainfoin Condensed Tannins

Molecules

Xiu-Li Liu¹  Yong-Qing Hao¹  Long Jin¹  Zhong-Jun Xu¹  Tim A. McAllister¹ 

[1] ¹Department of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot 010020, China ²Lethbridge Research Centre, Agriculture and Agri-Food Canada, P.O. Box 3000, Lethbridge, AB T1J 4B1, Canada

关键词: condensed tannins;    E. coli;    outer membrane;    cell aggregation;    protein precipitation;   

DOI  :  10.3390/molecules18022183

来源: mdpi

【 摘 要 】

Condensed tannins (CT) from purple prairie clover (PPC; Dalea purpurea Vent.) and sainfoin (SF; Onobrychis viciifolia) were assessed for anti-Escherichia coli activity by comparing their ability to react with proteins and liposome, cause cell aggregation, and alter outer membrane (OM) morphology and permeability. The PPC CT had greater (P < 0.01) protein-precipitating capacity than SF CT using either bovine serum albumin or ribulose 1,5-disphosphate carboxylase as model proteins. Minimum inhibitory concentration of PPC CT for two strains of E. coli and five strains of E. coli O157:H7 was four to six times lower than that of SF CT. E. coli exposed to 10 µg/mL of both CT had higher (P < 0.05) OM permeability than controls and was greater (P < 0.05) for PPC than for SF CT. Addition of both CT at 50 and 200 µg/mL caused cell aggregation which was more evident (P < 0.05) for PPC than for SF CT. Transmission electron microscopy showed electron dense material on the cell surface when cells were exposed to 50 µg/mL of PPC CT. The greater anti-E. coli activity of PPC than SF CT was due to its enhanced ability to precipitate protein that increased OM permeability and promoted cell aggregation.

【 授权许可】

CC BY   
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.