Inhibition of bacterial urease by autoxidation of furan C‐18 fatty acid methyl ester products

Autoxidation products of synthetic methyl 9,12‐epoxy‐octadeca‐9,11‐dienoate (MEFA) were investigated by gas chromatography‐mass spectrometry analysis and tested for bacterial urease inhibition. A suspension of oxidized MEFA in 10% Tween 80 was an effective inhibitor for bacterial urease extract from Helicobacter pylori (I 50 =1.3 mM) and for commercial urease from Bacillus pasteurii (I 50 =0.06 mM). The urease inhibitory effect was cancelled by adding cysteine to the reaction mixture. The total content of biologically active oxidized products in the mixture was found to be 6.2%. Dioxo‐ene derivatives of MEFA on the thin‐layer chromatography plate surface were converted into more stable compounds, whose formation in the mixture reduced inhibition of B. pasteurii to about 2% of the former level. The mechanism of urease inhibition is supposed to involve the interaction of the thiol groups of the enzyme’s active center with the inhibitor molecules.