Chemical Synthesis of Two Series of Nerve Agent Model Compounds and Their Stereoselective Interaction with Human Acetylcholinesterase and Human Butyrylcholinesterase

The syntheses of three 1,2-dialkyl-sn-glycero-3-phosphates and one new 1,2-dialkyl-sn-glycerol are described. 1,2-Dioctadecyl-sn-glycero-3-phosphate was obtained by phosphorylation of 1,2-dioctadecyl-sn-glycerol with diphenylphosphorodichloridate and subsequent catalytic hydrogenolysis. 1,2-Dioctadecyl-sn-glycero-3-(methyl)phosphorylcholine was prepared by phosphorylation of the same dialkyl glycerol with methylphosphorodichloridate and subsequent reaction with choline iodide. 1,2-Dimethyl-sn-glycerol was prepared by treatment of 3-benzyl-sn-glycerol with methyl iodide and KOH followed by hydrogenolysis to remove the protecting group. This compound was then phosphorylated with phenylphosphorodichloridate, the product allowed to react with choline iodide, and the iodide-free product hydrogenated catalytically to yield 1,2-dimethyl-sn-glycero-3-phosphorylcholine which was characterized as the cadmium chloride complex. Some improvements in an established synthesis of 1,2-dioctadecyl-sn-glycerol are described.

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Catalytic detoxification of nerve agent and pesticide organophosphates by butyrylcholinesterase assisted with non-pyridinium oximes

Biochemical Journal ◽

10.1042/bj20121612 ◽

2013 ◽

Vol 450 (1) ◽

pp. 231-242 ◽

Cited By ~ 59

Author(s):

Zoran Radić ◽

Trevor Dale ◽

Zrinka Kovarik ◽

Suzana Berend ◽

Edzna Garcia ◽

...

Keyword(s):

Kinetic Analysis ◽

Hydroxy Group ◽

Ex Vivo ◽

Nerve Agent ◽

Oxime Group ◽

Quaternary Nitrogen ◽

Pyridinium Oximes ◽

Human Butyrylcholinesterase

In the present paper we show a comprehensive in vitro, ex vivo and in vivo study on hydrolytic detoxification of nerve agent and pesticide OPs (organophosphates) catalysed by purified hBChE (human butyrylcholinesterase) in combination with novel non-pyridinium oxime reactivators. We identified TAB2OH (2-trimethylammonio-6-hydroxybenzaldehyde oxime) as an efficient reactivator of OP–hBChE conjugates formed by the nerve agents VX and cyclosarin, and the pesticide paraoxon. It was also functional in reactivation of sarin- and tabun-inhibited hBChE. A 3–5-fold enhancement of in vitro reactivation of VX-, cyclosarin- and paraoxon-inhibited hBChE was observed when compared with the commonly used N-methylpyridinium aldoxime reactivator, 2PAM (2-pyridinealdoxime methiodide). Kinetic analysis showed that the enhancement resulted from improved molecular recognition of corresponding OP–hBChE conjugates by TAB2OH. The unique features of TAB2OH stem from an exocyclic quaternary nitrogen and a hydroxy group, both ortho to an oxime group on a benzene ring. pH-dependences reveal participation of the hydroxy group (pKa=7.6) forming an additional ionizing nucleophile to potentiate the oxime (pKa=10) at physiological pH. The TAB2OH protective indices in therapy of sarin- and paraoxon-exposed mice were enhanced by 30–60% when they were treated with a combination of TAB2OH and sub-stoichiometric hBChE. The results of the present study establish that oxime-assisted catalysis is feasible for OP bioscavenging.

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Catalytic Antioxidant therapy in a Rat Nerve Agent Model

Free Radical Biology and Medicine ◽

10.1016/j.freeradbiomed.2019.10.278 ◽

2019 ◽

Vol 145 ◽

pp. S104

Keyword(s):

Nerve Agent ◽

Antioxidant Therapy ◽

Agent Model ◽

Rat Nerve ◽

Catalytic Antioxidant

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Non-quaternary oximes detoxify nerve agents and reactivate nerve agent-inhibited human butyrylcholinesterase

Communications Biology ◽

10.1038/s42003-021-02061-w ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Gabriel Amitai ◽

Alexander Plotnikov ◽

Shira Chapman ◽

Shlomi Lazar ◽

Rellie Gez ◽

...

Keyword(s):

Small Molecules ◽

High Throughput Screening ◽

Reaction Rates ◽

Nerve Agents ◽

Nerve Agent ◽

The Novel ◽

Quaternary Compounds ◽

Toxicological Studies ◽

Pyridinium Oximes ◽

Human Butyrylcholinesterase

AbstractGovernment-sanctioned use of nerve agents (NA) has escalated dramatically in recent years. Oxime reactivators of organophosphate (OP)-inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) serve as antidotes toward poisoning by OPNAs. The oximes used as therapeutics are quaternary compounds that cannot penetrate the blood–brain barrier (BBB). There remains an urgent need for the development of next generation OPNA therapeutics. We have developed two high-throughput screening (HTS) assays using a fluorogenic NA surrogate, O-ethyl methylphosphonyl O-4-methyl-3-cyano-coumarin (EMP-MeCyC). EMP-MeCyC detoxification and EMP-BChE reactivation screening campaigns of ~155,000 small molecules resulted in the identification of 33 nucleophile candidates, including non-quaternary oximes. Four of the oximes were reactivators of both Sarin- and VX-inhibited BChE and directly detoxified Sarin. One oxime also detoxified VX. The novel reactivators included a non-quaternary pyridine amidoxime, benzamidoxime, benzaldoxime and a piperidyl-ketoxime. The VX-inhibited BChE reactivation reaction rates by these novel molecules were similar to those observed with known bis-quaternary reactivators and faster than mono-quaternary pyridinium oximes. Notably, we discovered the first ketoxime reactivator of OP-ChEs and detoxifier of OPNAs. Preliminary toxicological studies demonstrated that the newly discovered non-quaternary oximes were relatively non-toxic in mice. The discovery of unique non-quaternary oximes opens the door to the design of novel therapeutics and decontamination agents following OPNA exposure.

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