Degradation of Allicin as Urease Inhibitor Affected by Soil Conditions and Its Effect on Kinetic Properties of Soil Urease

Abstract

ABSTRACT Allicin is an organosulfur compound from garlic that has shown potential as a soil urease inhibitor. However, little information was available on the degradation of allicin in different soil conditions and its effect toward kinetic properties of urease enzyme. Degradation of allicin was quantified by measuring the remaining concentration of allicin using high performance liquid chromatography (HPLC). The outcomes of the study showed allicin is able to retain longer than 24 h when moisture of soil was at 30% compared to 50 and 100% soil moisture levels. Meanwhile, when the temperature increased from 25 to 35ºC, the percentage of allicin decreased significantly. Contrary to this, as pH of soil increased to 6.5, the rate degradation of allicin was slower compared to pH 4.5 and 5.5. The Michaelis constant (Km ) is increased while the maximum enzyme reaction velocity (Vmax ) decreases after 24 h incubation compared to control showing inhibition of urease enzymes by allicin. Overall results revealed that the effectiveness of allicin as urease inhibitor was significantly related to its degradation rate in soil.