Abstract:Urease inhibitors are key factors to increase the efficiency of urea usage through reducing urease activity. In order to find novel urease inhibitors, phenylgossypol Schiffbase (Gos-H), benzoyloxy gossypol Schiffbase (Gos-COOH), and sulfonatephenyl gossypol Schiffbase (Gos-SO3H) were synthesized through chemical modification from natural resource gossypol and their inhibitory effects on urease were studied. These compounds were applied to the red clay soil and the reduction of ammonia volatilization losses from urea with urease was determined. It was showed that gossypol and its derivatives had an excellent performance on inhibiting urease. IC50 values of gossypol and its derivatives to jack bean urease were: Gos, 2.61×10-5 mol·L-1; Gos-H, 9.93×10-5 mol·L-1; Gos-COOH, 1.49×10-4 mol·L-1, and Gos-SO3H, 1.85×10-4 mol·L-1. Schiffbases served as inhibitors for minimizing the ammonia volatilization losses from the red clay soil and their IC50 values were: Gos, 5.74×10-5 mol·L-1; Gos-H, 3.47×10-5 mol·L-1; Gos-COOH, 2.27×10-5 mol·L-1, and Gos-SO3H, 1.75×10-5 mol·L-1. In conclusion, the inhibition of Schiffbases was enhanced by the O-group modification from chemical treatments.
