Pharmacophore-Oriented Discovery of Novel 1,2,3-Benzotriazine-4-one Derivatives as Potent 4-Hydroxyphenylpyruvate Dioxygenase Inhibitors

Abstract

4-Hydroxyphenylpyruvate dioxygenase (HPPD) is a functional protein existing in almost all aerobic organisms. In the field of agricultural chemicals, HPPD is acknowledged to be one of the crucial targets for herbicides at present due to its unique bio-function in plants. In the Auto Core Fragment in silico Screening (ACFIS) web server, a potential HPPD inhibitor featuring 1,2,3-benzotriazine-4-one was screened out via a pharmacophore-linked fragment virtual screening (PFVS) method. Molecular simulation studies drove the process of “hit-to-lead” optimization, and a family of 1,2,3-benzotriazine-4-one derivatives was synthesized. Consequently, 6-(2-hydroxy-6-oxocyclohex-1-ene-1-carbonyl)-5-methyl-3-(2-methylbenzyl)­benzo­[d]­[1,2,3]­triazin-4­(3H)-one (15bu) was identified to be the best HPPD inhibitor (IC50 = 36 nM) among the 1,2,3-benzotriazine-4-one derivatives, which had over 8-fold improvement of enzyme inhibition compared with the positive control mesotrione (IC50 = 289 nM). Crystallography information for the AtHPPD–15bu complex revealed several important interactions of the ligand bound upon the target protein, i.e., the bidentate chelating interaction of the triketone motif with the metal ion of AtHPPD, a tight π–π stacking interaction consisting of the1,2,3-benzotriazine-4-one moiety and two benzene rings of Phe-424 and Phe-381, and the polydirectional hydrophobic contacts consisting of the ortho-CH3-benzyl group of the core scaffold and some hydrophobic residues. Furthermore, compound 15bu displayed 100% inhibition against the five species of target weeds at the tested dosage, which was comparable to the weed control of mesotrione. Collectively, the fused 1,2,3-benzotriazine-4-one-triketone hybrid is a promising chemical tool for the development of more potent HPPD inhibitors and provides a valuable lead compound 15bu for herbicide innovation.

Discovery of Novel Pyrazole Derivatives with Improved Crop Safety as 4-Hydroxyphenylpyruvate Dioxygenase-Targeted Herbicides

“…Weeds compete with crop seedlings for sunlight, space, water, and nutrients, hindering the normal growth of crops and resulting in crop yield loss . The management and disposal of weeds are critical steps in maintaining agricultural production. , The use of herbicides can effectively enhance crop production; however, the extensive use of traditional herbicides has resulted in substantial environment damage and an increase in herbicide-resistant plants, presenting an opportunity for developing new herbicides. − Therefore, there is an urgent need for agricultural producers to develop new, effective, and low-risk herbicides. , 4-Hydroxyphenylpyruvate dioxygenase (HPPD) is one of the most important herbicide targets; HPPD-targeted herbicides cause abnormal photosynthesis by inhibiting the HPPD, following the unique bleaching symptom and eventually resulting in the death of weeds, and thus, HPPD-targeted herbicides have become a global research hot spot. − HPPD-targeted herbicides are broadly classified into three categories, including triketones, isoxazoles, and pyrazoles. Most commercial herbicides belong to the class of pyrazoles and triketones…”

Discovery of Subnanomolar Inhibitors of 4-Hydroxyphenylpyruvate Dioxygenase via Structure-Based Rational Design

“…As a result, structural modification has mainly focused on the introduction of different substituents on the 2-benzoylethen-1 core, 14,33 or introducing fused heterocycles, such as quinazolin-2,4-dione, isoindoline-1,3-dione, and 1,2,3-benzotriazine-4-one. 15,22,26,27 The best inhibitors showed a one-or two-digit nanomolar and even subnanomolar inhibitory K i values. 14 Therefore, further improvement of HPPD inhibitory potency requires a thorough understanding of the molecular mechanisms of inhibition at play.…”

“…In almost all aerobic organisms, 4-hydroxyphenylpyruvate dioxygenase (HPPD) is a conserved nonheme iron-dependent oxygenase, involved in the tyrosine metabolic pathway, , and responsible for catalyzing 4-hydroxyphenylpyruvic acid (HPPA) into homogentisic acid (HGA), a critical step in the pathway. − Aberration of the catalysis will lead to tyrosinemia in humans and failure of carotenoid and tocopherol biosynthesis in plants. − Therefore, many inhibitors targeting HPPD have been developed to treat the tyrosinemia type 1 disease or as herbicides. − …”

“…Fluorescent probes for visualizing HPPD in vivo also need ligands with high binding affinity. , Traditional HPPD inhibitors are mainly classified as triketone, pyrazole, and isoxazole derivatives. ,, In view of the inhibitor–HPPD interaction, optimization of the bidentate coordination with the metal ion and the π–π sandwich stacking with two phenylalanines are traditionally considered paramount for improving the binding affinity of HPPD inhibitors. As a result, structural modification has mainly focused on the introduction of different substituents on the 2-benzoylethen-1 core, , or introducing fused heterocycles, such as quinazolin-2,4-dione, isoindoline-1,3-dione, and 1,2,3-benzotriazine-4-one. ,,, The best inhibitors showed a one- or two-digit nanomolar and even subnanomolar inhibitory K i values . Therefore, further improvement of HPPD inhibitory potency requires a thorough understanding of the molecular mechanisms of inhibition at play.…”

Experimental and Computational Analysis of Newly Synthesized Benzotriazinone Sulfonamides as Alpha-Glucosidase Inhibitors

“…1,2,3-Benzotriazin-4(3 H )-one is known for its biologically active nucleus, and its derivatives have been reported as anti-inflammatory [ 24 ], anti-depressant [ 25 ], anticancer [ 26 ], anti-diarrheal [ 27 ], HIV inhibitor [ 28 ] and as anesthetics [ 29 ]. Some of its derivatives had been studied as enzyme inhibitors of 4-hydroxyphenylpyruvate dioxygenase [ 30 ], matrix metalloprotease [ 31 ], alpha-glucosidase [ 15 ], chorismate mutase [ 32 ], HepG2 [ 33 ] and acetylcholinesterase [ 34 ].…”