Inhibitory effect of beta-glucosyl-phenolic hydroxamic acids against urease in the presence of microfloral beta-glucosidase.

Three glucosyl-phenolic hydroxamates, 4-O-(beta-D-glucopyranosyl) benzohydroxamic acid, 4-O-(beta-D-glucopyranosyl)hippuric hydroxamic acid, and 3-[4-O-(beta-D-glucopyranosyl)phenyl]propionohydroxamic acid (Glc-PPHA), were hydrolyzed to their corresponding aglycones by beta-glucosidase of intestinal flora of rat without any major adverse hydrolysis in vitro. Inhibitory potency of these glucosyl-hydroxamates on urease was recovered to the same extent as that of the corresponding aglycone hydroxamates by preincubation for 2h with rat intestinal flora. p-Hydroxyphenylpropionohydroxamic acid inhibited noncompetitively jack-bean urease activity and its glucose-ligated form, Glc-PPHA inhibited it competitively. A single oral dose of Glc-PPHA tended to inhibit urease activity in proximal colon contents of rat at 6 h after administration (p = 0.06). After 14C-urea was orally administered to rat, 14CO2 was collected for to measure the ureolysis in vivo. Expired 14CO2 was limited to 40% by a single oral dose of Glc-PPHA during 6 h, and 75% of intestinal ureolysis was repressed during the first 1 h in the breath test.