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Metabolism of Fenitrothion and Conjugation of 3-Methyl-4-nitrophenol in Tomato Plant (Lycopersicon esculentum)

Fukushima, Masao, Fujisawa, Takuo, Katagi, Toshiyuki, Takimoto, Yoshiyuki
Journal of agricultural and food chemistry 2003 v.51 no.17 pp. 5016-5023
Solanum lycopersicum var. lycopersicum, cellobiose, esters, fenitrothion, glass, glucose, greenhouses, hydroponics, isomers, leaves, mass spectrometry, metabolism, metabolites, nuclear magnetic resonance spectroscopy, quartz, solar radiation, stems, tomatoes
The metabolism of 14C-labeled fenitrothion (Sumithion, [O,O-dimethyl-O-(3-methyl-4-nitrophenyl)phosphorothioate]) in tomato plant (Lycopersicon esculentum Mill., cv. Ponderosa) grown in the greenhouse equipped with quartz glass was conducted to investigate the effect of sunlight on the behavior of fenitrothion and to elucidate the detailed structure of conjugated metabolites. Tomato plants (BBCH 85) were topically treated with 14C-labeled fenitrothion twice with a 2 week interval between applications. At 15 days after the second application, more than half of the recovered 14C was detected as unaltered fenitrothion, glucose, and cellobiose esters of 3-methyl-4-nitrophenol (NMC) in extracts from tomato fruit. The photoinduced formation of the S-methyl isomer of fenitrothion via thiono−thiolo rearrangement was detected only in the surface rinse but at trace amounts. In the whole tomato fruit, fenitrothion, the S isomer, NMC-β-glucoside, and NMC cellobioside were detected at 34.16, 1.28, 7.47, and 15.07% of the recovered 14C, respectively. Trace amounts of the oxon analogue of fenitrothion were detected only on tomato leaves. The chemical structure of the cellobiose conjugate of NMC, 1-O-β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyl-3-methyl-4-nitrophenol, was determined by spectroscopic analyses (liquid chromatography−mass spectrometry, NMR), using the metabolite obtained from leaves and stems of tomato plant hydroponically grown with 14C-labeled NMC.