No specific molecular targets (e.g., receptors, enzymes) for 2,4-D butyl ester are reported in the provided references. [1][2]

[2] 2,4-D butyl ester was completely degraded (100% removal within 96 h) by Acinetobacter sp. ZX02 in pure culture using mineral salts basal medium (MSM) with 300 mg/L of the compound as the sole carbon source. The degradation product was identified as 2,4-dichlorophenoxyacetic acid (2,4-D) by HPLC-MS, with a retention time of 40.77 min and m/z 161.2. Strain ZX02 could not further degrade 2,4-D. [2]

[2] The degradation of 2,4-D butyl ester by Acinetobacter sp. ZX02 was monitored by HPLC with a UV detector at 230 nm, using a C18 column and a methanol/water (95:5) mobile phase at 1.0 mL/min; retention times were 2.488 min for 2,4-D butyl ester and 4.484 min for 2,4-D. Metabolite identification was performed by HPLC-MS with ESI-negative mode, scanning m/z 100-2000, using a C18 column with a gradient of water and acetonitrile (both with 0.1% formic acid). [2]

[2] Bacterial growth and degradation of 2,4-D butyl ester by Acinetobacter sp. ZX02 were assessed in MSM with 300 mg/L of the compound. Samples were taken every 12 h; bacterial density was measured by OD550; degradation was monitored by extracting 1 mL culture with 1 mL ethyl acetate and 0.5 g NaCl, vortexing, concentrating the organic phase, and analyzing by HPLC. Antibiotic sensitivity of strain ZX02 was tested using the paper disc diffusion method with 30, 10, and 6 μg/disc of antibiotics; inhibition zone diameters were measured. The plasmid curing study was performed by growing ZX02 in LB broth with ethidium bromide (500 mg/L) at 40 °C for 24 h; plasmid loss was confirmed by agarose gel electrophoresis. [2]

[1] Male Wistar rats (approximately 200 days old) were administered 2,4-D butyl ester (formulated as a 50:50 mixture of n-butyl and iso-butyl esters) subcutaneously at 150 or 175 mg/kg/day for 10 consecutive days. The compound was emulsified in 20% Emulophor in sterile bacteriostatic water and injected in a volume of 1 mL/kg. Behavioral assessments (photocell locomotor activity and landing foot splay) were conducted 4 h post-injection. [1]
[2] For the degradation assay, Acinetobacter sp. ZX02 was cultured in 200 mL MSM with 300 mg/L 2,4-D butyl ester in 500 mL flasks at 29 °C on a rotary shaker at 160 rpm for 1 week; samples were taken every 12 h. For plasmid curing, strain ZX02 was cultured in LB broth with ethidium bromide (500 mg/L) at 40 °C for 24 h with shaking at 160 rpm. [2]

Absorption, Distribution and Excretion
Following oral administration of 2,4-D butyl ester to rabbits at doses of 150 or 490 mg/kg, the highest levels of 2,4-D were observed in the blood, kidneys, liver, spleen, lungs, heart, and urine within the first 24 hours after administration. Leaves most readily absorb the nonpolar (ester) form of 2,4-D. …2,4-D esters are not easily eluted from plants and are rapidly converted to acids by the plant. …After absorption by leaves, 2,4-D is transported within the phloem and may move with nutrients. After absorption by roots, it may be transported upwards with transpiration. The plant's growth status affects its transport. Herbicides accumulate primarily in the meristematic regions of stems and roots. /2,4-D/
After subcutaneous injection of 2,4-D, its butyl ester, and isooctyl ester into mice at a dose of 100 mg/kg, the esters were rapidly eliminated, with only 5-10% of 2,4-D remaining after 1 day. …In milk from dairy cows raised on pastures treated with 2,4-D, its butyl ester, or isooctyl ester, 2,4-D was eliminated.
/Relative/ Following a single subcutaneous injection of the compound at 100 mg/kg body weight into female C57BL/6 mice, the rate of disappearance of 2,4-D, its butyl ester, and isooctyl ester from plasma was: butyl ester > isooctyl ester > 2,4-D.
For more complete data on the absorption, distribution, and excretion of 2,4-D butyl esters (6 in total), please visit the HSDB records page.

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Metabolism/Metabolites
Castor seed powder contains an esterase that hydrolyzes 2,4-D butyl ester…
The metabolic pathway of 2,4-dichlorophenoxyacetic acid (2,4-D) n-butyl ester in rats has not been fully studied. In this study, four male Wistar rats were subcutaneously injected with a dose of 100 mg/kg of 2,4-D butyl ester, and the presence of butyl ester and its metabolites in urine samples was detected using three analytical techniques. The results showed that 2,4-D butyl ester is rapidly hydrolyzed in vivo to 2,4-D acid. Within 48 hours after injection, 95% of the administered dose was excreted in the urine as free acid, while only a small amount (5%) was excreted in the subsequent 48 hours. No amino acid conjugates or parent 2,4-D butyl ester were detected in the urine of the tested rats. A trace metabolite (≤2% of the dose) was detected by gas chromatography-mass spectrometry analysis of urine samples. This compound appears to be a side-chain metabolite of 2,4-D butyl ester. Some chemical properties of this metabolite were characterized, and the structure of 2,4-D hydroxyethyl ester was proposed. The formation mechanism of this trace metabolite is unclear. Plants hydrolyze 2,4-D esters to 2,4-D, the active herbicide. …Further metabolism… occurs through three mechanisms: side-chain degradation, aromatic ring hydroxylation, and binding to plant components. /2,4-D esters/
The herbicidal activity of esters, nitriles, amines (and of course, salts) is similar to, or even identical to, the parent acid. This is clearly due to the presence of hydrolytic enzymes in plants and soil microorganisms that can convert these derivatives into the parent acid. /2,4-D esters/
For more complete data on the metabolism/metabolites of 2,4-D butyl esters (7 in total), please visit the HSDB record page.

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Biological half-life
These herbicides do not accumulate in animals. They are not widely metabolized but are actively excreted in urine…Their plasma half-life in humans is approximately 1 day. /Chlorophenoxy compounds/
...In rats, after oral or intravenous administration of 2,4-D, it is primarily excreted in the urine with a half-life of approximately 2 hours. /SRP: Unspecified salts or esters of 2,4-D/
The hydrolysis half-life of 2,4-D n-butyl ester in neutral water was determined to be 100 hours, much shorter in water-soluble soil suspensions. Smith (1976) reported that 2,4-D n-butyl ester was almost completely hydrolyzed to 2,4-D in moist soil in less than 24 hours. Similar results were obtained for the hydrolysis of 2,4,5-T n-butyl ester and isooctyl ester to 2,4,5-T. 2,4-D esters were completely hydrolyzed to 2,4-D in lake water within 9 days. Therefore, the rate of biological hydrolysis appears to be greater than that of chemical hydrolysis.

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[1] After three daily subcutaneous injections of 2,4-D butyl ester (150 mg/kg/day, as either n-butyl or mixed butyl esters), blood and brain concentrations of 2,4-D acid were measured four hours after the third injection. For 2,4-D-n-butyl ester: blood 333.89 ± 53.17 μg/mL; brain 45.99 ± 9.22 μg/g. For 2,4-D mixed butyl esters: blood 308.07 ± 53.99 μg/mL; brain 57.95 ± 16.97 μg/g. No 2,4-D esters were detectable. The extent of ester hydrolysis was similar for both formulations. [1]
[2] 2,4-D butyl ester was degraded by Acinetobacter sp. ZX02, with 55% decrease within 48 h and complete removal (from 300 mg/L to undetectable) by 96 h. The metabolite 2,4-D was identified; the organism could not further degrade 2,4-D, suggesting it utilized n-butanol as the carbon source. [2]

Interactions
In static bioassays on rainbow trout fry, 1 mg/L carbaryl reduced the LC50 of 2,4-D butyl ester from 30 mg/L to 11 mg/L. Salmo clarki was treated with mixtures of six different herbicides: dicamba, thiamethoxam, 2,4-D butyl ester, 2,4-D isooctyl ester, and 2,4-D propylene glycol butyl ether. Except for 2,4-D isooctyl ester, the LC50 values of the mixtures of 2,4-D esters and thiamethoxam were all lower than the LC50 values of these herbicides tested individually. Dicamba and 2,4-D isooctyl ester showed the lowest toxicity when used alone, and mixing dicamba or 2,4-D isooctyl ester with other tested herbicides did not increase toxicity. These results indicate that a mixed exposure approach is crucial in determining the biological significance of the co-existence of multiple herbicides in surface water. This study aimed to determine the contribution of different components in herbicide formulations to the overall toxicity of the formulation. Three relevant herbicide formulations were selected. The first was Agent Orange, consisting only of butyl esters of 2,4,5-T and 2,4-D. The second was a dilution of Agent Orange with diesel fuel. The third formulation was a tree and blackberry killer composed of butyl esters of 2,4,5-T, ethyl esters of 2,4-D, diesel fuel, and two surfactants. This study assessed the potential toxicity of the three formulations by determining their inhibitory effect on the oxidative function of submitochondrial particles in bovine heart mitochondria. Effective concentrations at which the three formulations inhibited submitochondrial particle activity by 50% were determined. In assessing the toxicity of the individual components of these formulations, the so-called “inert” components, namely diesel fuel and surfactants, were found to account for approximately 50% of the total toxicity of the complete formulation. Therefore, the results confirm the importance of assessing the toxicity of the complete formulation, not just focusing on the active ingredient. While cellular and subcellular assays cannot explain pharmacokinetic and pharmacodynamic changes that may affect the toxicity of exogenous substances, submitochondrial particle assays can serve as a preliminary screening method.

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Non-human toxicity values
Mice oral LD50: 380 mg/kg
Rat oral LD50: 920 mg/kg
Chicken (male, female) oral LD50: 2000 mg/kg (1350-2960 mg/kg), acid equivalent 1503 mg/kg /Data from table, 2,4-D butyl ester/
Rat oral LD50: 600 mg/kg
For more non-human toxicity values (complete data) for 2,4-D butyl esters (8 types in total), please visit the HSDB record page.

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[1] 2,4-D butyl ester (mixed butyl esters) at 150-175 mg/kg/day SC caused significant depression of photocell locomotor activity in rats, with tolerance developing at 150 but not 175 mg/kg. No increase in landing foot splay (ataxia) was observed with mixed butyl esters, unlike pure n-butyl ester. Food deprivation decreased sensitivity to the compound. [1]
[2] 2,4-D butyl ester is highly toxic to fish: 5 mg/L caused almost complete mortality in chum salmon fry; 1 mg/L was lethal to coho salmon fry and fingerlings of sockeye salmon, Dolly Varden trout, and rainbow trout. In contrast, 2,4-D acid at <50 mg/L produced no mortality in these species. It also caused reduced mortality of fertile hen eggs and decreased total lipids in liver and microsomes. [2] The compound has low soil adsorption (log Koc = 0.8) and leaches into groundwater. [2]
Antibiotic sensitivity: Strain ZX02 (Acinetobacter sp.) was susceptible to tetracycline (zone diameter 21-23 mm at 30 μg/disc), resistant to amoxicillin, trimethoprim, and chloramphenicol (zone diameters 11-12 mm). The plasmid-cured derivative ZX021 lost resistance to polymixin B sulfate. [2]

[1]. Formulation and food deprivation affects 2,4-D neurobehavioral toxicity in rats. Neurotoxicol Teratol. Sep-Oct 1987;9(5):363-7.

[2]. Isolation and Characterization of 2,4-D Butyl Ester Degrading Acinetobacter sp. ZX02 from a Chinese Ginger Cultivated Soil. J Agric Food Chem. 2017 Aug 30;65(34):7345-7351.

2,4-D n-Butyl ester is a colorless to light brown transparent liquid. (NTP, 1992)

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Mechanism of Action
After application of registered or soon-to-be-registered herbicides for ranching, the total alkaloid concentration, water content, crude protein, and neutral detergent fiber in white lupin (Lupinus leucophyllus) were monitored for 3 weeks. …2,4-D n-Butyl ester…caused the death of most white lupin plants, and as the plants dehydrated, the total alkaloid concentration, crude protein, and water content decreased. Herbicides that effectively kill lupins reduce alkaloid content, thereby reducing the risk of livestock poisoning.
…/Chlorophenoxy compounds (including 2,4-D esters)/ exert their herbicidal effect by acting as growth hormones in plants. /Chlorophenoxy compounds/
Chlorophenoxy acid derivatives are metabolized through the involvement of the hepatic microsomal mixed-function oxidase system. Therefore, administration of 2,4-D amine salts and their butyl esters to rats can induce enzyme systems (aminopyrine demethylase and aniline hydroxylase), although the induction is much lower than that of phenobarbital. Long-term administration of 2,4-D amine salts (0.1 LD50) can produce cumulative effects, reflected in changes in clinical and biochemical parameters. Stimulation of mixed-function oxidase systems may be one way to reduce the toxicological effects of such compounds. /2,4-D Butyl Ester/
Before incubation, 2,4-dichlorophenoxyacetic acid butyl ester (2,4-D be) (3.1 mg/egg) was administered to eggs from fertilized hens. Chicks hatched from the treated eggs exhibited motor dysfunction, abnormal posture, and muscle edema. Electromyography showed muscle weakness, prolonged distal motor latency, and muscle rigidity. Biochemical analysis of the leg and complex muscles showed… measured in 1-day-old chicks. Following treatment, glycogen levels in the leg muscles were significantly reduced (24%). A slight increase in sarcoplasmic proteins was observed in leg muscles (15%), while the 20 kDa protein content in myofibril proteins of the complex muscle increased. Although total lipid content remained unchanged, 2,4-D treatment led to a decrease in sterol esters (20%) and phosphatidylcholine (11%) in leg muscles, while increasing the content of phosphatidylserine (61%), triglycerides (37%), and free fatty acids (FFA) (448%). Increased levels of phosphatidylethanolamine (16%), sterols (58%), and FFA (267%) were detected in the complex muscle. Unsaturated FFAs, such as oleic acid, linoleic acid, and arachidonic acid, showed a significant increase (700–1500%). This phenomenon was observed. Considering lipid metabolism in avian embryos, the accumulation of free fatty acids and triglycerides is presumed to be due to their inability to be metabolized in mitochondria.

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[1] 2,4-D butyl ester is a phenoxy herbicide and a component of Agent Orange (mixed with 2,4,5-T). Its n-butyl ester formulation increases volatility for aerial application. The compound's neurobehavioral toxicity differs between formulations: mixed butyl esters do not produce ataxia (increased landing foot splay) unlike pure n-butyl ester. This difference is not explained by hydrolysis rates, as similar 2,4-D acid concentrations were found in blood and brain. Differences may be due to the type of alcohol released upon hydrolysis (n-butanol vs iso-butanol), with n-butanol being more neurotoxic. [1]
[2] 2,4-D butyl ester is a typical phenoxy herbicide widely used for controlling dicotyledonous weeds for over 80 years. It affects plant growth by stimulating RNA and protein synthesis similarly to natural auxin. Substantial exposure can cause health problems including dizziness, kidney failure, birth defects, malignant tumors, and may affect children's behavior and intelligence quotient. A 23 kb plasmid in Acinetobacter sp. ZX02 encodes the degradation gene for converting 2,4-D butyl ester to 2,4-D, and also carries resistance to polymixin B sulfate. [2]

C12H14CL2O3

277.14

276.032

94-80-4

7206

Colorless to light yellow liquid

1.2±0.1 g/cm3

343.9±27.0 °C at 760 mmHg

9ºC

132.0±22.7 °C

0.0±0.8 mmHg at 25°C

1.518

4.25

0

3

7

17

236

0

O=C(COC1C(Cl)=CC(Cl)=CC=1)OCCCC

CCEFMUBVSUDRLG-IDKOKCKLSA-N

InChI=1S/C10H16O/c1-7(2)8-4-5-10(3)9(6-8)11-10/h8-9H,1,4-6H2,2-3H3/t8-,9?,10?/m0/s1

(4S)-1-methyl-4-(prop-1-en-2-yl)-7-oxabicyclo[4.1.0]heptane

FEMA No. 4656 L-1,2-Epoxylimonene Limonene oxide, (-)-

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)