The benzonitrile herbicides bromoxynil, chloroxynil, dichlobenil, and ioxynil have been used actively worldwide to control weeds in agriculture since 1970s. Even though dichlobenil is prohibited in EU since 2008, studies addressing the fate of benzonitrile herbicides in the environment show that some metabolites of these herbicides are very persistent. We tested the cytotoxic effects of benzonitrile herbicides and their microbial metabolites using two human cell lines, Hep G2 and HEK293T, representing liver and kidneys as potential target organs in humans. The cell viability and proliferation were determined by MTT test and RTCA DP Analyzer system, respectively. The latter allows real-time monitoring of the effect of added substances. As the cytotoxic compounds could compromise cell membrane integrity, the lactate dehydrogenase test was performed as well. We observed high toxic effects of bromoxynil, chloroxynil, and ioxynil on both tested cell lines. In contrast, we determined only low inhibition of cell growth in presence of dichlobenil and microbial metabolites originating from the tested herbicides.

• MeSH
• buněčná membrána účinky léků   MeSH
• buňky Hep G2 MeSH
• HEK293 buňky MeSH
• herbicidy toxicita   MeSH
• játra účinky léků   MeSH
• ledviny účinky léků   MeSH
• lidé MeSH
• nitrily toxicita   MeSH
• proliferace buněk účinky léků   MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• benzonitrile MeSH Prohlížeč
• herbicidy MeSH
• nitrily MeSH

The aim of this work was to determine the ability of rhodococci to transform 3,5-dichloro-4-hydroxybenzonitrile (chloroxynil), 3,5-dibromo-4-hydroxybenzonitrile (bromoxynil), 3,5-diiodo-4-hydroxybenzonitrile (ioxynil) and 2,6-dichlorobenzonitrile (dichlobenil); to identify the products and determine their acute toxicities. Rhodococcus erythropolis A4 and Rhodococcus rhodochrous PA-34 converted benzonitrile herbicides into amides, but only the former strain was able to hydrolyze 2,6-dichlorobenzamide into 2,6-dichlorobenzoic acid, and produced also more of the carboxylic acids from the other herbicides compared to strain PA-34. Transformation of nitriles into amides decreased acute toxicities for chloroxynil and dichlobenil, but increased them for bromoxynil and ioxynil. The amides inhibited root growth in Lactuca sativa less than the nitriles but more than the acids. The conversion of the nitrile group may be the first step in the mineralization of benzonitrile herbicides but cannot be itself considered to be a detoxification.

• MeSH
• amidohydrolasy metabolismus   MeSH
• amidy metabolismus   toxicita   MeSH
• benzamidy metabolismus   MeSH
• biotransformace MeSH
• dehydratasy metabolismus   MeSH
• herbicidy chemie   metabolismus   MeSH
• hydrolýza MeSH
• jodbenzeny metabolismus   MeSH
• kořeny rostlin účinky léků   růst a vývoj   metabolismus   MeSH
• nitrily chemie   metabolismus   toxicita   MeSH
• Rhodococcus metabolismus   MeSH
• salát (hlávkový) účinky léků   růst a vývoj   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2,6-dichlorobenzamide MeSH Prohlížeč
• amidase MeSH Prohlížeč
• amidohydrolasy MeSH
• amidy MeSH
• benzamidy MeSH
• benzonitrile MeSH Prohlížeč
• bromoxynil MeSH Prohlížeč
• chloroxynil MeSH Prohlížeč
• dehydratasy MeSH
• dichlobanil MeSH Prohlížeč
• herbicidy MeSH
• ioxynil MeSH Prohlížeč
• jodbenzeny MeSH
• nitrile hydratase MeSH Prohlížeč
• nitrily MeSH