Assessing residues of newly synthesized quinolone derivatives as antifungals for disease management and consumer safety in tomatoes

Abstract

Chemo-selective heterogeneous catalytic hydrogenation was employed to synthesise 6-amino-N-methyl-2-quinolone (AMQ) and 6-amino-N-ethyl-2-quinolone (AEQ) to establish its structure-activity relationship (SAR) by 1H NMR,13C NMR, FT-IR, LC-MS/MS. AMQ (MIC = 18.2, 16.5 mg/mL) and AEQ (MIC = 19.2, 20.5 mg/mL), were more effective against Aspergillus niger and Aspergillus flavous. Both were tested on tomato (Solanum lycopersicum L.) plants to assess residual profiles, dissipation patterns, and yield effects. Acetonitrile and methanol (9.5:0.5, v/v), and modified buffer QuEChERS were used for extraction and analysed by LC-MS/MS. For AMQ, LOD and LOQ were 0.0065 and 0.017 mg kg−1, respectively, whereas, for AEQ, 0.0031 and 0.017 mg kg−1. The 5-point calibration curves of both compounds were constructed with R2 in the range of 0.99. Average recoveries at LOQ and higher ranged from 82.50 -114.27%. According to first-order kinetics, the half-lives (T1/2) for the T1 and T2 of AMQ were 2.11, and 2.34 days, and for AEQ were 1.66 and 2.13 days, respectively. Estimated pre-harvest intervals (PHIs) for AMQ and AEQ were 8,6 days (T1), and 11,10 days (T2) respectively. Their application enhanced fresh tomato production 21.36–26.55%. Developed compounds have excellent in vitro and in vivo fungicidal action and could treat plant fungal infections.