In vivo and in vitro effects of tea extracts on enterotoxigenic Escherichia coli-induced intestinal fluid loss in animal models.
OBJECTIVE
Enterotoxigenic Escherichia coli (ETEC) infection is a major cause of dehydrating diarrhoea in infants and early-weaned piglets living under subhygienic conditions. We studied the effect of different tea types and subfractions on the intestinal fluid and electrolyte losses involved in ETEC diarrhoea.


METHODS
Jejunal segments of anaesthetised piglets were infected with ETEC or ETEC heat-labile toxin (LT) and subsequently perfused for 8 hours with control or tea solutions containing green or black tea extract (BTE) or 3 different BTE subfractions containing small-size, large-size or no phenolics. Changes in intestinal fluid and electrolyte net absorption were measured. To assess the antisecretory effects of tea, BTE was incubated before or after administration of the secretagogue forskolin in rat jejunal tissue placed in Ussing chambers and Cl- secretion measured as changes in short-circuit current (I(SC)).


RESULTS
Enterotoxigenic E. coli infection of piglet jejunal segments significantly reduced net absorption of fluid, Na+ and Cl- and increased net secretion of K+ compared with controls. Perfusion of the ETEC-infected segments with both 3 g/L green tea extract and BTE significantly inhibited these disturbances in fluid and electrolyte balance. The BTE subfraction rich in polymeric phenolics but not the other subfractions improved the fluid and electrolyte balance. Addition of forskolin to rat jejunal tissue induced a significant increase in I(SC). Pretreating but not posttreating the jejunal tissue with BTE inhibited the forskolin-induced increase in I(SC).


CONCLUSIONS
Tea may inhibit net fluid and electrolyte losses involved in secretory diarrhoea from ETEC.
Bruins
M J
MJ
Unilever Research and Development, Unilever Food and Health Research Institute, Vlaardingen, The Netherlands.
Cermak
R
R
Kiers
J L
JL
van der Meulen
J
J
van Amelsvoort
J M M
JM
van Klinken
B J W
BJ
D000818:Animals; D001826:Body Fluids; D005576:Colforsin / Q000494:pharmacology; D003681:Dehydration / Q000209:etiology; D004195:Disease Models, Animal; D004403:Dysentery / Q000188:drug therapy* / Q000382:microbiology; D004573:Electrolytes; D004927:Escherichia coli Infections / Q000150:complications / Q000188:drug therapy*; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D005765:Gastrointestinal Agents / Q000494:pharmacology; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000187:drug effects*; D007583:Jejunum / Q000187:drug effects* / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013552:Swine; D013662:Tea
D004573:Electrolytes; D005419:Flavonoids; D005765:Gastrointestinal Agents; D010936:Plant Extracts; D013662:Tea; D005576:Colforsin