The specific molecular target of phenyl sulfate is not definitively identified in this study. However, it is shown to be a substrate for the human organic anion transporting polypeptide SLCO4C1 (OATP4C1). In an uptake study using SLCO4C1-overexpressing MDCKII cells, the uptake of phenyl sulfate was significantly increased, confirming it as a substrate for this transporter. Additionally, the SLCO4C1 inhibitor ritonavir inhibited the uptake of phenyl sulfate by human proximal tubular HK-2 cells. [1]
Phenyl sulfate is a substrate for the human organic anion transporting polypeptide SLCO4C1 (OATP4C1), as confirmed by uptake studies in SLCO4C1-overexpressing cells. The SLCO4C1 inhibitor ritonavir inhibits phenyl sulfate uptake in human proximal tubular HK-2 cells. Its pathogenic effects in the kidney are mediated through mechanisms involving oxidative stress and mitochondrial dysfunction, though the specific molecular target remains to be definitively identified.

Phenyl sulfate was shown to be toxic to differentiated human podocytes. Cell survival analysis revealed that phenyl sulfate induced significant cell toxicity at concentrations from 100 µM. [1]
Phenyl sulfate decreased glutathione levels in differentiated podocytes. Exposure to 30 µM phenyl sulfate caused a reduction in glutathione levels, which became significant at the 100 µM concentration. [1]
Phenyl sulfate impaired mitochondrial bioenergetics in cultured podocytes. Exposure to phenyl sulfate at concentrations ranging from 100 µM to 1 mM significantly decreased mitochondrial basal respiration, ATP production, proton leak, and maximum respiratory capacity. Phenyl sulfate also increased non-mitochondrial respiration, suggesting a compensatory respiration mechanism, while glycolysis (measured by extracellular acidification rate) remained unchanged. [1]

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In vitro, phenyl sulfate is toxic to differentiated human podocytes, inducing significant cell toxicity at concentrations of 100 µM and above. It decreases glutathione (GSH) levels in differentiated podocytes, with significant reduction observed at 100 µM. Phenyl sulfate impairs mitochondrial bioenergetics in cultured podocytes at concentrations of 100 µM to 1 mM, significantly decreasing basal respiration, ATP production, proton leak, and maximum respiratory capacity, while increasing non-mitochondrial respiration. Glycolysis remains unchanged.

In db/db mice (a model of type 2 diabetes), oral administration of phenyl sulfate (50 mg/kg) for 6 weeks significantly increased plasma phenyl sulfate levels by approximately 5-fold (to 27.3 ± 9.17 µM) and significantly increased albuminuria compared to control db/db mice. Electron microscopy revealed increased foot process effacement and glomerular basement membrane thickening in phenyl sulfate-treated db/db mice. [1]
In KKAy mice fed a high-fat diet (another DKD model), oral administration of phenyl sulfate (50 mg/kg) for 6 weeks significantly increased plasma phenyl sulfate levels (to 6.09 ± 3.18 µM) and increased albuminuria. Electron micrographs showed podocyte effacement, glomerular basement membrane thickening, and perivascular fibrosis in the treated group. [1]
In eNOS-knockout mice with the Akita mutation (a severe diabetes model), plasma phenyl sulfate levels were significantly higher in diabetic mice (15.4 ± 2.73 µM) compared to non-diabetic controls (5.97 ± 0.47 µM). Histological examination revealed significant glomerulosclerosis changes in the diabetic mice. [1]

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In vivo, oral administration of phenyl sulfate (50 mg/kg) for 6 weeks in db/db mice (type 2 diabetes model) significantly increased plasma phenyl sulfate levels (to 27.3 ± 9.17 µM) and significantly increased albuminuria. Electron microscopy revealed increased foot process effacement and glomerular basement membrane thickening. Similar effects were observed in KKAy mice fed a high-fat diet, with increased albuminuria, podocyte effacement, and perivascular fibrosis. These findings establish phenyl sulfate as a mediator of diabetic kidney disease progression.

In vitro enzyme/receptor binding experiments for phenyl sulfate typically involve transporter uptake assays. For example, MDCKII cells overexpressing SLCO4C1 are incubated with phenyl sulfate (e.g., 1-100 µM) in uptake buffer at 37°C for defined periods. Cells are washed, lysed, and intracellular phenyl sulfate levels are quantified by LC-MS/MS. Inhibition studies use the SLCO4C1 inhibitor ritonavir to confirm transporter specificity. These assays characterize the compound's interaction with organic anion transporters and its cellular uptake mechanisms.

Podocyte cell viability assay: Differentiated human urinary podocyte-like epithelial cells were cultured in 96-well collagen-coated plates. Phenyl sulfate was applied at final concentrations indicated (0, 3, 10, 30, 100, 300, 1000 µM), and cells were cultured for 72 hours. Cell viability was then measured. Results showed significant cell toxicity at concentrations from 100 µM. [1]
Glutathione measurement: Differentiated podocytes were exposed to phenyl sulfate (30 µM and 100 µM) for 72 hours. Glutathione levels were measured using a luminescent cell viability assay kit. Exposure to 30 µM phenyl sulfate decreased glutathione levels, with a significant reduction observed at the 100 µM concentration. [1]
Mitochondrial function measurement (Seahorse assay): Bioenergetic analysis of human cultured podocytes was carried out. Cells were cultured in a specialized assay medium without CO₂ for 60 minutes. After equilibration, oxygen consumption rate and extracellular acidification rate were measured using a Seahorse XF24 analyzer by sequentially injecting inhibitors of oxidative phosphorylation. Phenyl sulfate exposure (100 µM to 1 mM) significantly decreased mitochondrial basal respiration, ATP production, proton leak, and maximum respiration capacity. [1]

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In vitro cellular assays for phenyl sulfate use differentiated human urinary podocyte-like epithelial cells (HUPECs) or immortalized podocyte cell lines. Cells are treated with phenyl sulfate at concentrations ranging from 10 µM to 1 mM for 24-48 hours. Endpoints include cell viability (MTT assay), glutathione levels (colorimetric assay), mitochondrial function (Seahorse analyzer for oxygen consumption rate and extracellular acidification rate), and reactive oxygen species (ROS) measurement. These experiments characterize the compound's cellular toxicity and mechanisms of podocyte damage.

Oral administration in db/db mice: Phenyl sulfate was administered orally to db/db mice at a dose of 50 mg/kg/day for 6 weeks. Water intake was measured to estimate drug intake. Plasma phenyl sulfate levels were measured 1 hour after administration in a separate cohort (n=3) to confirm rapid absorption, showing a rise to 64.53 ± 5.87 µM. [1]
Oral administration in KKAy mice: Phenyl sulfate was administered orally to high-fat diet-fed KKAy mice at a dose of 50 mg/kg/day for 6 weeks. [1]
Streptozotocin-induced diabetic rat model: Diabetes was induced in 8-week-old SLCO4C1-Tg and wild-type rats by intraperitoneal injection of streptozotocin (50 mg/kg) dissolved in citrate-phosphate buffer (pH 4.2). Blood was collected on day 7, and rats with blood glucose levels greater than 300 mg/dl were selected for further analysis. [1]

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In vivo animal experiments for phenyl sulfate typically use diabetic mouse models including db/db mice and KKAy mice fed a high-fat diet. Phenyl sulfate is administered orally at 50 mg/kg daily for 6 weeks. Key endpoints include plasma phenyl sulfate levels (LC-MS/MS), urinary albumin excretion (ELISA), electron microscopy of kidney tissue for podocyte foot process effacement and glomerular basement membrane thickening, and histopathological assessment of renal fibrosis. These studies establish the role of phenyl sulfate in diabetic kidney disease pathogenesis.

After oral administration of phenyl sulfate (50 mg/kg) to db/db mice, the plasma concentration rose rapidly, reaching 64.53 ± 5.87 µM within 1 hour, and then decreased quickly. Following 6 weeks of oral administration in db/db mice, the plasma level was significantly increased by approximately 5-fold (to 27.3 ± 9.17 µM). [1]
In the human U-CARE diabetic cohort study, plasma phenyl sulfate levels in patients ranged from 0 to 68.1 µM. [1]

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Pharmacokinetic (PK) properties of phenyl sulfate have been characterized in animal models. Following oral administration of 50 mg/kg to db/db mice, plasma phenyl sulfate levels reached 27.3 ± 9.17 µM, representing approximately a 5-fold increase over baseline. In KKAy mice, oral administration achieved plasma levels of 6.09 ± 3.18 µM. Phenyl sulfate is a gut microbiota-derived metabolite, and its levels in plasma reflect the balance between microbial production, absorption, and renal clearance. As a uremic toxin, its clearance is dependent on kidney function.

Phenyl sulfate administration induced podocyte damage. Electron microscopy revealed increased foot process effacement and glomerular basement membrane thickening in phenyl sulfate-treated db/db and KKAy mice. [1]
Phenyl sulfate was directly toxic to differentiated human podocytes in vitro, with significant cell toxicity observed at concentrations of 100 µM and above. [1]
Phenyl sulfate decreased glutathione levels in differentiated podocytes, rendering cells vulnerable to oxidative stress, with a significant reduction at 100 µM. [1]
Phenyl sulfate impaired mitochondrial function in podocytes, significantly decreasing basal respiration, ATP production, and maximum respiratory capacity at concentrations of 100 µM to 1 mM. [1]

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Phenyl sulfate functions as a uremic toxin that accumulates in renal failure and contributes to the progression of chronic kidney disease. In experimental models, it induces podocyte damage and albuminuria. It reduces glutathione levels and induces mitochondrial dysfunction in podocytes. Phenyl sulfate may serve as a disease marker and future therapeutic target for diabetic nephropathy. In diabetic patient cohorts, phenyl sulfate levels significantly correlate with basal and predicted 2-year progression of albuminuria, particularly in patients with microalbuminuria.

[1]. Gut microbiome-derived phenyl sulfate contributes to albuminuria in diabetic kidney disease. Nat Commun. 2019 Apr 23;10(1):1835.

Phenylacetyl hydrogen sulfate is an aryl sulfate ester, a phenolic compound with an O-sulfonyl substituent. It is a human heterologous metabolite, functionally related to phenolic compounds, and is the conjugate acid of phenyl sulfate esters. Aryl sulfate esters are found in or produced by Escherichia coli (K12 strain, MG1655 strain). Phenylacetyl hydrogen sulfate has also been reported in Trypanosoma brevicornu, and relevant data are available for reference.

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Role in disease: Phenyl sulfate is identified as a gut microbiota-derived metabolite that contributes to albuminuria and podocyte damage in diabetic kidney disease (DKD). In a diabetic patient cohort (U-CARE study, n=362), plasma phenyl sulfate levels significantly correlated with baseline albuminuria (urinary albumin-to-creatinine ratio) and predicted 2-year progression of albuminuria, particularly in patients with microalbuminuria. Among known risk factors, phenyl sulfate was the only factor that served as a predictor of 2-year albuminuria progression in microalbuminuric patients. [1]
Source and metabolism: Phenyl sulfate is produced from dietary tyrosine. Gut bacterial tyrosine phenol-lyase converts tyrosine to phenol, which is then absorbed and metabolized to phenyl sulfate in the liver. [1]
Therapeutic targeting: Inhibition of the bacterial enzyme tyrosine phenol-lyase (using inhibitors such as 2-aza-tyrosine or L-meta-tyrosine) reduced plasma phenyl sulfate levels and ameliorated albuminuria and renal damage in diabetic mice, suggesting a potential therapeutic strategy. [1]

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Phenyl sulfate is a research tool compound used to study the role of gut microbiota-derived metabolites in kidney disease. It is an orally bioactive metabolite that induces albuminuria and podocyte damage in experimental models of diabetes. The compound is classified as an endogenous metabolite and a uremic toxin. It has potential as a disease marker and therapeutic target for diabetic nephropathy. It is not a drug and has no approved therapeutic indications, serving purely as a research compound for understanding diabetic kidney disease pathogenesis.

C6H6O4S

174.17

173.999

937-34-8

1733-88-6 (potassium salt)

74426

White to off-white solid at room temperature

1.949

1

4

2

11

197

0

O=S(OC1C=CC=CC=1)(O)=O

CTYRPMDGLDAWRQ-UHFFFAOYSA-N

InChI=1S/C6H6O4S/c7-11(8,9)10-6-4-2-1-3-5-6/h1-5H,(H,7,8,9)

phenyl hydrogen sulfate

phenyl hydrogen sulfate; Phenylsulfate; Phenol sulfate; 937-34-8; Sulfuric acid, monophenyl ester;

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)

H2O: ~250 mg/mL (1435.4 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.)