Pectic oligosaccharide structure-function relationships: prebiotics, inhibitors of Escherichia coli O157:H7 adhesion and reduction of Shiga toxin cytotoxicity in HT29 cells

Di, R., Vakkalanka, M. S., Onumpai, C., Chau, H. K., White, A., Rastall, R. A., Yam, K. and Hotchkiss, A. T. (2017) Pectic oligosaccharide structure-function relationships: prebiotics, inhibitors of Escherichia coli O157:H7 adhesion and reduction of Shiga toxin cytotoxicity in HT29 cells. Food Chemistry, 227. pp. 245-254. ISSN 0308-8146 doi: 10.1016/j.foodchem.2017.01.100

Abstract/Summary

Shiga toxin (Stx)-producing, food-contaminating Escherichia coli (STEC) is a major health concern. Plant-derived pectin and pectic-oligosaccharides (POS) have been considered as prebiotics and for the protection of humans from Stx. Of five structurally different citrus pectic samples, POS1, POS2 and modified citrus pectin 1 (MCP1) were bifidogenic with similar fermentabilities in human faecal cultures and arabinose-rich POS2 had the greatest prebiotic potential. Pectic oligosaccharides also enhanced lactobacilli growth during mixed batch faecal fermentation. We demonstrated that all pectic substrates were anti-adhesive for E. coli O157:H7 binding to human HT29 cells. Lower molecular weight and deesterification enhanced the anti-adhesive activity. We showed that all pectic samples reduced Stx2 cytotoxicity in HT29 cells, as measured by the reduction of human rRNA depurination detected by our novel TaqMan-based RT-qPCR assay, with POS1 performing the best. POS1 competes with Stx2 binding to the Gb3 receptor based on ELISA results, underlining the POS anti-STEC properties.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/69158
Identification Number/DOI	10.1016/j.foodchem.2017.01.100
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences > Food Research Group
Publisher	Elsevier
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