Tea fungus/kombucha, an acetic acid flavoured fermented tea beverage, is widely consumed in various parts of the world and has more recently become a fad in the United States. This is due in part to the fact that it can be produced in the home, and it is reported to be medicinal, effective against arthritis, psoriasis, chronic fatigue, constipation, indigestion and metabolic diseases. Among 264 references from 1852 to 1961, there are reports of.antibiotic activity against Agrobacterium tumefaciens and medicinal value against a variety of diseases. The medicinal value appears to be related to that attributed to vinegar, one of our most ancient foods. We decided to test tea fungus/ kombucha for its antibiotic activity against Helicobacter pylori, a primary cause of gastritis related to peptic ulcers and gastric carcinoma, Escherichia coli, Staphylococcus (Micrococcus) aureus and Agrobacterium tumefaciens. Tea containing 4.36 g of dry tea per litre and 10% of sucrose and fermented with the tea fungus showed no antibiotic activity in the beverage beyond that caused by acetic acid, a primary product of the fermentation.
Swine were treated with cimetidine in order to quantify the reduction of nitrate to nitrite and the gastric formation of N-nitrosotrimethylurea (NTMU) under conditions similar to those in the achlorhydric human stomach. Gastric-fistulated swine were instilled with 6.0 mmol of nitrate in 50 ml water, after which gastric nitrate, nitrite and pH were monitored. Trimethylurea, 250 mumol in 50 ml water, was instilled via the fistula 10 min following the peak gastric nitrite concentration. Similar experiments were conducted with pentagastrin-stimulated animals, in order to quantitate the effect of gastric pH and microflora on the presence of nitrate, nitrite and NTMU formation. The stomachs of cimetidine-treated pigs (elevated pH) were colonized by nitrate reductase organisms to levels of 10(4)-10(7)/ml gastric fluid. Gastric nitrite concentration in cimetidine-treated animals reached a maximum of 370-2085 microM, 60 min following the nitrate dose. Trimethylurea was only marginally nitrosated (less than 0.1 mumol/l gastric fluid) in cimetidine- or pentagastrin-stimulated animals. The low yield of NTMU at elevated pH, in the presence of substantial nitrite, suggests that the nitrate-reducing bacteria present in the porcine stomach did not catalyze trimethylurea nitrosation in vivo.
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