Fluridone targets phytoene desaturase, a key enzyme in the carotenoid biosynthesis pathway. Carotenoids are essential for protecting chlorophyll from photo-oxidation and are necessary for photosynthesis. By inhibiting phytoene desaturase, fluridone prevents the formation of carotenoids, leading to the accumulation of phytoene and the bleaching of plant tissues. The compound is highly selective for plants and has low toxicity to animals.

In human activated ischemia, fluridone (0.5-50 μM) decreases proliferation and cytokine production while also inhibiting the proliferation of aortic smooth muscle cells for four days. Fluridone suppresses the expression of COX-2 in human monocytes that have been activated. Human monocytes that have been induced to produce acid are inhibited by fluridone [1].

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Fluridone is a systemic herbicide that inhibits carotenoid biosynthesis by blocking phytoene desaturase. It causes the bleaching of plant tissues and is effective against a wide range of aquatic weeds and algae. The compound is absorbed by plant roots and shoots and is translocated throughout the plant. Its specific IC50 values and detailed activity data are not extensively documented. Fluridone is used in aquatic weed management.

In mice treated with yeast, fluridone (8.25 mg/kg; i.p.; once) increases peritoneal regulatory factors [1].

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In vivo, fluridone is used as a systemic herbicide for the control of aquatic weeds and algae in ponds, lakes, and irrigation canals. It is applied to water bodies and is absorbed by aquatic plants, leading to the inhibition of carotenoid synthesis and plant death. The compound has low toxicity to fish and other aquatic animals. Specific in vivo efficacy data and application rates are determined based on the target species and environmental conditions.

The in vitro enzyme assay for fluridone typically involves measuring the inhibition of phytoene desaturase activity. The enzyme is incubated with varying concentrations of fluridone (typically 0.001-100 µM) in the presence of the substrate phytoene. The enzymatic activity is measured by monitoring the formation of carotenoids using HPLC or spectrophotometric methods. The IC50 value is determined by plotting the percentage of inhibition against compound concentration.

Cell proliferation assay [1]
Cell Types: Lymphocytes
Tested Concentrations: 0.5 μM, 2 μM, 5 μM, 50 μM
Incubation Duration: 4 days
Experimental Results: Inhibition of aortic smooth muscle cell proliferation.

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In vitro cellular assays for fluridone typically involve treating plant cell cultures or algae with the compound at concentrations ranging from 0.1 to 100 µM for 24-72 hours. Carotenoid levels are measured by HPLC or spectrophotometry. Chlorophyll levels and photosynthetic activity are assessed. Cell viability is assessed using standard plant cell viability assays. The compound is dissolved in DMSO and diluted in culture medium.

Animal/Disease Models: Male CD mice (20-22 g) treated with zymosan [1]
Doses: 8.25 mg/kg
Route of Administration: ip;
Experimental Results: Peritoneal inflammation was diminished in mice treated with zymosan.

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In vivo animal studies for fluridone are not typically performed for therapeutic purposes, as the compound is a herbicide rather than a therapeutic agent. The compound may be used in ecotoxicological studies to assess its effects on aquatic organisms. Fish and other aquatic animals are exposed to varying concentrations of fluridone, and survival, growth, and reproductive effects are assessed. The compound is not intended for human therapeutic use.

Absorption, Distribution and Excretion
/In a rat metabolism study/...Preliminary study: Group A, 2 male (M) and 2 female (F) rats were given a single oral dose of [14C]fluridone (...radioactive purity 99.8%; [14C]fluridone was mixed with [12C]fluridone in the test solution, ...purity 100%; the test substance was suspended in 1% sodium carboxymethyl cellulose (CMC) solution), at a dose of approximately 10 mg/kg. Group B, 1 male (M) and 1 female (F) rats were given a single oral dose of approximately 1000 mg/kg. Urine, feces, and cage flushing fluid were collected daily for 7 consecutive days (further 14CO2 measurements were stopped because exhaled (retained) 14CO2 after 24 hours accounted for <1% of the dose). Final study: Group C, the carrier control group, 2 male/2 female mice were given a single oral dose of 1% sodium carboxymethyl cellulose (CMC). Group D: Five male/five female mice were given a single oral dose of approximately 7.4 mg/kg of CMC. Group E: Seven male/seven female mice were given approximately 10 mg/kg of unlabeled fluridinone once daily for 14 days, followed by an oral dose of approximately 10 mg/kg [¹⁴C]fluridinone on day 15. Group F: Five male/seven female mice were given a single oral dose of approximately 900 mg/kg of CMC. …Clinical symptoms (limited activity, abnormally rapid head movements, strabismus, loss of balance, and cage biting) appeared only after administration (Groups B and F) and subsided within 24 hours. Results: In Group A: After 7 days, 12.52%/12.89% (male/female) were excreted in urine and 72.76%/81.79% in feces. Group B: After 7 days, the excretion rate in urine was 4.83%/3.43%, and in feces it was 86.43%/86.31%. Group D: After 24 hours, the excretion rate in urine was 11.14%/10.44%, and in feces it was 72.46%/77.72%. After 7 days, the excretion rate in urine was 11.61%/10.93%, and in feces it was 79.19%/84.62%. After 7 days, the total excretion rate (including cage washing fluid) was 92.93%/98.74%. Group E: After 24 hours, the excretion rate in urine was 9.54%/8.51%, and in feces it was 70.69%/69.90%. After 7 days, 10.11%/9.14% of the drug was excreted in urine and 79.80%/81.79% in feces. The total excretion after 7 days (including cage rinsing) was 92.81%/94.21%. Group F: After 24 hours, 2.40%/2.43% of the drug was excreted in urine and 27.16%/27.18% in feces (therefore, fecal excretion was relatively delayed at the administered dose). After 7 days, 8.30%/8.07% of the drug was excreted in urine and 91.58%/90.09% in feces. The total excretion after 7 days (including cage rinsing) was 101.02%/99.62%. Total tissue residue was consistently less than 1% of the administered dose (Group DF). The highest drug concentration was observed in the liver under all conditions. The main metabolites are a variety of polar and nonpolar compounds, generated by aromatic hydroxylation and heteroaromatic N-demethylation reactions. The parent compound is the main component of feces within 72 hours after administration. In rat metabolic studies, fluridinone was rapidly and almost completely absorbed into the systemic circulation and excreted from male and female rats within 3 days. Within 3 days after administration, the total radioactivity recovered in urine and feces was 78-90% and 87-97% of the administered dose in male and female rats, respectively. Most (approximately 70%) of the radioactivity was excreted in feces. No tissue accumulation was observed. Rainbow trout and fourth-instar chironomid larvae absorbed fluridinone (14C) (1-methyl-3-phenyl-5-(3-trifluoromethylphenyl)-4-(1H)-pyridinone) from water at a much lower rate than other hydrophobic compounds tested under similar conditions… Chironomid larvae absorbed and cleared fluridinone more rapidly than rainbow trout. The bioavailability factor (BCF) of midge larvae was estimated at 128 (fluridone)... The highest accumulation of (14C)-fluridone residues was observed in the liver, intestines, and pylorus/cecum of adult rainbow trout... Most of the radioactive material was present in the form of fluridone or 4-hydroxyfluridone (1-methyl-3-(4-hydroxyphenyl)-5-(3-trifluoromethylphenyl)-4(1H)-pyridone) in fish tissues exposed to fluridone...

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Metabolism/Metabolites
The main metabolites are a variety of polar and nonpolar compounds, which are produced by aromatic hydroxylation and heteroaromatic N-demethylation. The parent compound is the main component in feces within the first 72 hours.
Most of the radioactive material was present in the form of fluridone or 4-hydroxyfluridone (1-methyl-3-(4-hydroxyphenyl)-5-(3-trifluoromethylphenyl)-4(1H)-pyridone) in fish tissues exposed to fluridone...

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Fluridone has a molecular weight of 329.28 g/mol and formula C19H14F3NO. It is a systemic herbicide that is applied to water bodies for aquatic weed control. The compound is absorbed by plant roots and shoots and is translocated throughout the plant. Detailed PK parameters are not applicable for this herbicide. The compound has low toxicity to animals and is relatively stable in the environment.

Toxicity Data
LC50 (Rat) > 2,130,000 mg/m³/1h

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10,000 mg/kg
LD50 (Mouse, oral) > 10,000 mg/kg
LD50 (Dog, oral) > 500 mg/kg
LD50 (Cat, oral) > 250 mg/kg
LD50 (Rabbit, dermal) > 5000 mg/kg

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Fluridone is intended for agricultural and research use only and is not approved for human therapeutic applications. As a herbicide, it has low toxicity to animals and is considered relatively safe for aquatic environments when used as directed. Appropriate safety precautions should be taken when handling the compound. Standard toxicity assessments would include acute toxicity studies in fish and other aquatic organisms.

[1]. Fluridone as a new anti-inflammatory drug. Eur J Pharmacol. 2013 Nov 15;720(1-3):7-15.

[2]. MYB41, MYB107, and MYC2 promote ABA-mediated primary fatty alcohol accumulation via activation of AchnFAR in wound suberization in kiwifruit. Hortic Res. 2020;7(1):86.

Fluridone is a phenylpyridine compound that acts as an inhibitor of carotenoid biosynthesis.

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Fluridone (CAS 59756-60-4) is a systemic herbicide used for the control of aquatic weeds and algae. It has a molecular weight of 329.28 g/mol and formula C19H14F3NO. Fluridone inhibits carotenoid biosynthesis by blocking phytoene desaturase, leading to the bleaching of plant tissues. The compound is used in aquatic weed management and has low toxicity to animals. Fluridone is not approved for human therapeutic use.

C19H14F3NO

329.3158

329.102

59756-60-4

43079

White to off-white solid powder

1.3±0.1 g/cm3

444.4±45.0 °C at 760 mmHg

154-155°C

222.6±28.7 °C

0.0±1.1 mmHg at 25°C

1.568

3.7

0

5

2

24

543

0

YWBVHLJPRPCRSD-UHFFFAOYSA-N

InChI=1S/C19H14F3NO/c1-23-11-16(13-6-3-2-4-7-13)18(24)17(12-23)14-8-5-9-15(10-14)19(20,21)22/h2-12H,1H3

1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]pyridin-4-one

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

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

DMSO : ~250 mg/mL (~759.14 mM)

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.)