Urease Inhibitors of Agricultural Interest Inspired by Structures of Plant Phenolic Aldehydes

Lívia Horta,Yane Mota,Taniri Braga,Luzia Modolo,Ivanildo Marriel,Ângelo De Fátima,Gisele Barbosa

doi:10.21577/0103-5053.20160208

Abstract

The plant phenolic natural products (PNPs) protocatechuic aldehyde, syringaldehyde and vanillin were used as platforms for obtaining four urease inhibitors. Urea (urease substrate) or thiourea (urease inhibitor) core was added to the structure of newly synthesized compounds to provide inhibitors up to 230-fold more active than the PNPs they originated from. The PNP derivatives are mixed inhibitors with higher affinity to urease active site. Two compounds were as efficient as N-(butyl)thiophosphoric triamide (NBPT) toward soil. Overall, PNPs derivatives are promising urease inhibitors for use as additive in urea-based fertilizers formulations.

Highlights

Nitrogen (N) is a key nutrient absorbed by plants mostly as nitrate (NO3−) and/or ammonium (NH4+)
Effect of phenolic aldehyde derivatives on the kinetic parameters of jack bean urease The inhibition profile exhibited by the natural product derivatives 2A7, 2A9, 2B10 and 2D2, synthesized in this study, was determined by incubating inhibitors at concentrations necessary to inhibit jack bean urease activity between 30 and 40% in reaction medium containing 20 mmol L-1 phosphate buffer, 1 mmol L-1 ethylene diamine tetra acetic acid (EDTA), urea and 12.5 mU urease
The derivatives 2A7 and 2B10, originated from protocatechuic aldehyde (PA), were the most potent urease inhibitors showing results (94% urease inhibition) comparable to that observed for the standard inhibitor hydroxyurea (HU; Figure 2)

Summary

Introduction

Nitrogen (N) is a key nutrient absorbed by plants mostly as nitrate (NO3−) and/or ammonium (NH4+). In vitro assays were performed with pure jack bean urease to check the potential of synthesized compounds as inhibitors of ureolytic activity and disclose the mechanism of action of promising molecules The effect of such phenolic aldehyde derivatives on soil ureases was addressed to confirm the potential of synthesized compounds for use as additives in urea-based fertilizers. Effect of phenolic aldehyde derivatives on the kinetic parameters of jack bean urease The inhibition profile exhibited by the natural product derivatives 2A7, 2A9, 2B10 and 2D2, synthesized in this study, was determined by incubating inhibitors at concentrations necessary to inhibit jack bean urease activity between 30 and 40% (from 0.3 to 1.6 mM) in reaction medium containing 20 mmol L-1 phosphate buffer (pH 7.0), 1 mmol L-1 EDTA, urea (ranging from 1 to 32 mmol L-1) and 12.5 mU urease. Data were subjected to analysis of variance (ANOVA) by general linear model (GLM) procedure and contrast analysis at 5% significance level using the software R (Software Foundation, Boston, MA, USA)

Results

Discussion

Conclusions