Herbicides protoporphyrinogen oxidase inhibitors

Durst, G.L. (1998). Comparative Molecular-Field Analysis (CoMFA) of Herbicidal Protoporphyrinogen Oxidase-Inhibitors Using Standard Steric and Electrostatic Fields and an Alternative LUMO Field. Quant.Struct.-Act.Relat., 17,419-426. 

Durst, G.L. (1998) Comparative molecular-field analysis (CoMFA) of herbicidal protoporphyrinogen oxidase-inhibitors using standard steric and electrostatic fields and an alternative LUMO field. Quant. Struct. -Act. Relat., 17, 419-426. 

F. E. Dayan, S. O. Duke, Phytotoxidty of Protoporphyrinogen Oxidase Inhibitors Phenomenology, Mode of Action and Mechanisms of Resistance, in Herbicide Activity Toxicology, Biochemistry and Molecular... 

Meazza G, Bettarini F, La Porta P, Piccardi P, Signorini E, Portoso D, Fomara L (2004) Synthesis and herbicidal activity of novel heterocyclic protoporphyrinogen oxidase inhibitors. Pest Manag Sci 60 1178-1188... 

Hao GF, Zuo Y, Yang SG, Yang GF (2011) Protoporphyrinogen oxidase inhibitor an ideal target for herbicide discovery. Chimia 65 961-969... 

Many photobleaching herbicides act by inhibiting the enzyme protoporphyrinogen oxidase (Protox), which catalyzes the last step in common between chlorophyll and heme biosynthesis. Usnic acid shares some structural features in common with these herbicides, such as the diphenyl ether scaffolding. The inhibitory activity of (-)-usnic acid on Protox was similar to that of the herbicide, acifluorfen, (I50 ca. 3 pM). However, these compounds did not displace acifluorfen from its binding site on Protox (data not shown), indicating that this natural product interacts with Protox differently than other photobleaching inhibitors. 

In addition, EC formulations were prepared using a few proprietary experimental herbicides, belonging to the protoporphyrinogen oxidase (PPO) inhibitors (Figure 10.7). Several safer solvents were tested and most formulations resulted in a generally increased efficacy, but only a select number of long-chained lactic acid esters were found to provide a significantly increased selectivity toward crops. 

Uracil derivatives can also function as herbicides by inhibition of the enzyme protoporphyrinogen-IX-oxidase (PRO), which is involved in the biosynthesis of chlorophyll <2006H(68)561>. Commercial examples of such PPO inhibitors include isocil 1104, bromacil 1105, terbacil 1106, flupropacil 1107, lenacil 1108, butafenacil 1109, and benzfendizone 1110 (Figure 9). 

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