Urease Inhibition Assay

Evaluation of urease activity was carried out according to a previously published methodology (Tanaka et al., 2004). H. pylori and Canavalia ensiformis ureases (Jack Bean type IX urease; Sigma-Aldrich) were used, separately, in the assay mixture (25 μL, 4U) with 25 μL of different concentrations of GTE and its CPC fractions. Samples and urease were preincubated for 4 h at room temperature (for H. pylori urease, it was used at 37 °C) in a 96-well assay plate. After preincubation, 200 μL of 100 mM phosphate buffer at pH 6.8 containing 500 mM urea and 0.002% phenol red was added. The changes in absorbance at 570 nm were measured using Epoch Microplate Reader (BioTek).