Toll-like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD2) receptor complex [1]
Myeloid differentiation primary response 88 (MyD88) [1]
IL-1 receptor-associated protein kinase-4 (IRAK4) [1]
Nuclear factor-κB (NF-κB) [1]

In RAW 264.7 macrophages, DHP at concentrations ≤ 25 μM did not significantly affect cell viability. At 50 μM, viability decreased to 69.2 ± 0.6%. [1]
DHP inhibited the LPS-induced upregulation of pro-inflammatory mediator mRNA expression (iNOS, IL-12p35, TNF-α) in a concentration-dependent manner (0-25 μM). [1]
DHP significantly reduced LPS-induced nitric oxide (NO) production in a concentration-dependent manner, from 16.6 ± 0.4 μM (LPS only) to 13.1 ± 0.3, 10.8 ± 0.4, and 9.7 ± 0.1 μM at 6.25, 12.5, and 25 μM DHP, respectively. [1]
DHP significantly decreased LPS-induced IL-12 release from 1261.3 ± 13.8 pg/mL to 1072.4 ± 12.5, 1022.7 ± 5.6, and 878.4 ± 15.1 pg/mL at 6.25, 12.5, and 25 μM DHP, respectively. [1]
DHP significantly decreased LPS-induced TNF-α release from 1549.6 ± 14.9 pg/mL to 1291.5 ± 20.8, 1189.6 ± 16.7, and 897.0 ± 9.8 pg/mL at 6.25, 12.5, and 25 μM DHP, respectively. [1]
Molecular docking and dynamics simulations predicted that DHP binds stably to the hydrophobic pocket of MD2, with estimated ΔG of -6.52 kcal/mol (mouse) and -6.57 kcal/mol (human). The binding score with Mcule was -7.2 (mouse) and -7.4 (human). [1]
In RAW 264.7 macrophages, DHP (25 μM) attenuated TLR4 expression and dimerization on the cell membrane. [1]
DHP (0-25 μM) downregulated MyD88 expression and inhibited IRAK4 phosphorylation in a concentration-dependent manner. [1]
DHP (0-25 μM) inhibited the LPS-induced nuclear translocation of NF-κB p50 and p65 subunits in a concentration-dependent manner. [1]
DHP (0-25 μM) significantly decreased the LPS-induced depolarization of the mitochondrial membrane potential, reducing the proportion of cells with depolarized potential from 39.7 ± 2.0% (LPS only) to 3.7 ± 0.3% at 25 μM. [1]
DHP (0-25 μM) remarkably decreased LPS-induced mitochondrial reactive oxygen species (mtROS) production in a concentration-dependent manner. [1]

In zebrafish larvae, DHP at concentrations ≤ 25 μM showed no significant increase in mortality over 48 hours, while 50 μM and 100 μM caused 60% and 100% mortality, respectively. [1]
In LPS-microinjected zebrafish larvae, DHP (6.25, 12.5, 25 μM) decreased mortality and morphological abnormalities (swollen pericardial sac, cyrtosis, yolk crenulation) in a concentration-dependent manner. At 12.5 and 25 μM, DHP completely inhibited mortality. [1]
DHP (6.25, 12.5, 25 μM) recovered the LPS-induced decrease in heart rate, restoring it from 143.4 ± 1.2 beats/min (LPS only) to 161.8 ± 1.2, 180.5 ± 1.2, and 188.2 ± 0.9 beats/min, respectively. [1]
DHP (0-25 μM) reduced the migration of macrophages and neutrophils to the inflammatory site (yolk sac) in LPS-microinjected zebrafish larvae in a concentration-dependent manner, as shown by neutral red and Sudan Black staining. [1]
DHP (0-25 μM) decreased the expression of pro-inflammatory genes (iNOS, TNF-α, IL-12) in LPS-microinjected zebrafish larvae in a concentration-dependent manner. [1]
DHP (25 μM) attenuated LPS-induced mtROS production in zebrafish larvae, as shown by MitoSOX Red staining. [1]
DHP (25 μM) restored the LPS-induced decrease in heart rate (from 133.0 ± 1.6 to 175.5 ± 1.7 beats/min) in zebrafish larvae, an effect similar to the mitochondria-targeted antioxidant MitoTEMPO. [1]

Molecular docking simulations were performed to investigate the potential binding of DHP to the TLR4/MD2 receptor complex. The crystal structures of the mouse TLR4/MD2-lipid IVa complex (PDB ID: 3VQ1) and human TLR4/MD2-E. coli LPS Ra complex (PDB ID: 3FXI) were obtained. The chemical structure of DHP was obtained and minimized. The interaction between TLR4/MD2 (a monomer) and DHP was assessed using the web-based SwissDock and Mcule platforms. The binding poses were visualized. [1]
A molecular dynamics (MD) simulation was performed on the strongest binding pose between DHP and MD2 obtained from Mcule. The simulation was conducted under default conditions (0.15 M NaCl, 1 ns, 300 K). The root-mean-square deviation (RMSD) and root-mean-square fluctuation (RMSF) were analyzed to assess the stability of the MD2-DHP complex. [1]

RAW 264.7 macrophages were seeded and maintained in DMEM with 5% FBS. For cell viability, cells were treated with DHP (0-50 μM) for 2 h, then with LPS (500 ng/mL) for 24 h. MTT (0.5 mg/mL) was added for 30 min, formazan dissolved in DMSO, and absorbance measured at 570 nm. [1]
For NO assay, cells were pretreated with DHP (0-25 μM) for 2 h, then with LPS (500 ng/mL) for 24 h. NO production was measured using the Griess reagent assay. [1]
For RT-PCR, cells were treated with DHP (0-25 μM) for 2 h, then with LPS (500 ng/mL) for 6 h. Total RNA was extracted and reverse-transcribed. cDNA was amplified using specific primers for iNOS, TNF-α, IL-12p35, and GAPDH. [1]
For ELISA, cells were treated with DHP (0-25 μM) for 2 h, then with LPS (500 ng/mL) for 24 h. Supernatants were collected and IL-12 and TNF-α levels were quantified. [1]
For Western blotting, cells were treated with DHP (0-25 μM) for 2 h, then with LPS (500 ng/mL) for 20 min. Total, cytosolic, and nuclear proteins were extracted, separated by SDS-PAGE, transferred to membranes, and probed with antibodies against MyD88, p-IRAK4, p50, p65, β-actin, and nucleolin. [1]
For immunofluorescence staining, cells were seeded on coverslips, treated with DHP (0-25 μM) for 2 h, then with LPS (500 ng/mL) for 1 h. Cells were fixed, permeabilized, blocked, and incubated with anti-p65 or anti-TLR4 antibody, followed by Alexa Fluor 488-conjugated secondary antibody and DAPI nuclear staining. Images were captured. [1]
For mtROS detection, cells were treated with DHP (0-25 μM) or MitoTEMPO for 2 h, then with LPS (500 ng/mL) for 24 h. Cells were stained with MitoTracker Green and MitoSOX Red, and images were captured. [1]
For mitochondrial membrane potential analysis, cells were treated with DHP (25 μM), MitoTEMPO (10 μM), or TLR4-IN-C34 (10 μM) for 2 h, then with LPS (500 ng/mL) for 2 h. Cells were stained using the Muse MitoPotential Kit and analyzed by flow cytometry. [1]

Zebrafish (AB strain) larvae at 3 days postfertilization (dpf) were used. For toxicity assessment, larvae (n=20 per group) were exposed to various concentrations of DHP (0-100 μM) in E3 embryo medium for 48 h, and survival rate was measured. [1]
For endotoxemia studies, larvae (3 dpf, n=20 per group) were microinjected with 2 nL of LPS (0.5 mg/mL) into the yolk sac. They were immediately placed in E3 medium containing DHP (0-25 μM) and cultured at 28.5°C. Survival rate and phenotypic abnormalities were observed at 48 h post-injection (hpi). Heart rate was manually measured for 1 min at 24 hpi. [1]
For macrophage and neutrophil staining, larvae (n=20 per group) were microinjected with LPS and treated with DHP (0-25 μM). At 18 hpi, larvae were stained with neutral red (macrophages) or Sudan Black (neutrophils). For neutral red staining, larvae were incubated in neutral red solution at 28.5°C in the dark for 8 h. For Sudan Black staining, larvae were fixed with 4% paraformaldehyde for 2 h, washed, and incubated in Sudan Black solution for 40 min. [1]
For gene expression analysis in larvae, total RNA was extracted from larvae (n=20 per group) at 18 hpi and RT-PCR was performed for iNOS, TNF-α, and IL-12. [1]
For mtROS detection in larvae, larvae (n=20 per group) were microinjected with LPS, treated with DHP (25 μM) or MitoTEMPO (10 μM), and at 24 hpi, stained with MitoTracker Green and MitoSOX Red. Larvae were anesthetized and fixed on slides for imaging. [1]

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Zebrafish (AB strain) larvae at 3 days postfertilization (dpf) were used. For toxicity assessment, larvae (n=20 per group) were exposed to various concentrations of DHP (0-100 μM) in E3 embryo medium for 48 h, and survival rate was measured. [1]
For endotoxemia studies, larvae (3 dpf, n=20 per group) were microinjected with 2 nL of LPS (0.5 mg/mL) into the yolk sac. They were immediately placed in E3 medium containing DHP (0-25 μM) and cultured at 28.5°C. Survival rate and phenotypic abnormalities were observed at 48 h post-injection (hpi). Heart rate was manually measured for 1 min at 24 hpi. [1]
For macrophage and neutrophil staining, larvae (n=20 per group) were microinjected with LPS and treated with DHP (0-25 μM). At 18 hpi, larvae were stained with neutral red (macrophages) or Sudan Black (neutrophils). For neutral red staining, larvae were incubated in neutral red solution at 28.5°C in the dark for 8 h. For Sudan Black staining, larvae were fixed with 4% paraformaldehyde for 2 h, washed, and incubated in Sudan Black solution for 40 min. [1]
For gene expression analysis in larvae, total RNA was extracted from larvae (n=20 per group) at 18 hpi and RT-PCR was performed for iNOS, TNF-α, and IL-12. [1]
For mtROS detection in larvae, larvae (n=20 per group) were microinjected with LPS, treated with DHP (25 μM) or MitoTEMPO (10 μM), and at 24 hpi, stained with MitoTracker Green and MitoSOX Red. Larvae were anesthetized and fixed on slides for imaging. [1]

Absorption, Distribution and Excretion
Benzophenone-3 [2-hydroxy-4-methoxybenzophenone (HMB), oxybenzone, Spectra-Sorb UV-9 light absorber] is widely used as a UV absorber in various cosmetics and sunscreens. This study aimed to investigate the metabolism of orally administered HMB (100 mg/kg body weight). High-performance liquid chromatography (HPLC) analysis identified three metabolites: 2,4-dihydroxybenzophenone (DHB), 2,2'-dihydroxy-4-methoxybenzophenone (DHMB), and 2,3,4-trihydroxybenzophenone (THB), in both free and bound forms. HMB was rapidly absorbed and metabolized, and was detectable in plasma within 5 minutes of administration (in both free and protein-bound forms). Six hours later, the parent compound and its metabolites (both free and bound forms) were detectable in most tissues. DHB was present in most tissues, with the highest concentration in the liver. DHMB exists only in conjugate form in the liver, spleen, and heart. Trace amounts of THB have also been detected in biological samples. Urine is the primary route of excretion for HMB and its metabolites, while feces are a secondary route. This study reveals that O-dealkylation is the primary metabolic pathway for HMB. Benzophenone-3 (2-hydroxy-4-methoxybenzophenone, BZ-3) is a UV absorber widely used in pharmaceuticals, cosmetics, and industry as a sunscreen and color-fixing agent. Exposure routes for this chemical include skin and oral administration. Bioavailability via skin absorption differs from that via oral administration. This study investigated the in vivo distribution of BZ-3 after dermal administration of 100 mg/kg body weight to Sprague-Dawley rats. Blood samples were collected at different time intervals, and the parent compound and its metabolites were analyzed using high-performance liquid chromatography (HPLC). The parent compound and its metabolites were detectable in plasma within 5 minutes of administration, indicating rapid absorption. The absorption half-life (t1/2) was 3.45 hours, corresponding to an absorption rate constant of 0.2 hours⁻¹. Peak plasma concentration was reached 2.5 hours after administration, at 35 ± 4.5 μg/mL (mean ± standard error). Plasma clearance was biphasic, with different half-lives (1.3 hours for the α phase and 15.05 hours for the β phase), and the area under the plasma concentration-time curve was 211.1 ± 38.2 μg/mL/hr (mean ± standard error). BZ-3 and its metabolites are extensively bound to plasma proteins. Three metabolites were identified in plasma, with 2,4-dihydroxybenzophenone (DHB) and 2,2'-dihydroxy-4-methoxybenzophenone (DHMB) being the major metabolites detected, while 2,3,4-trihydroxybenzophenone (THB) was detected only in trace amounts. Tissue distribution studies showed that THB was the major metabolite in all tissues tested, followed by DHB (including both free and bound forms). The highest concentration was found in the liver, followed by the kidneys, spleen, and testes. Metabolism/Metabolites: The metabolism and cytotoxicity of 2-hydroxy-4-methoxybenzophenone (HMB) in isolated rat hepatocytes were investigated, as well as the alloestrogenous activity and estrogen receptor competitive binding assays of HMB and its metabolites in MCF-7 human breast cancer cells. Hepatocyte incubation with HMB resulted in a concentration- and time-dependent decrease in cell viability, accompanied by a reduction in intracellular ATP and adenine nucleotide pools. In hepatocyte suspension, low-toxicity concentrations (0.25 mM) of HMB were enzymatically converted to 2,4-dihydroxybenzophenone (DHB) and a hydroxylation intermediate, which was preliminarily identified by mass spectrometry-high performance liquid chromatography as an isomer of 2,2'' or trace amounts of dihydroxy-4-methoxybenzophenone (DHMB). Furthermore, both the parent compound and the two intermediates rapidly bind to glucuronide, while free, unbound DHMB and 2,3,4-trihydroxybenzophenone (THB) were identified as trace intermediates. In another experiment, DHB and THB competitively displaced 17β-estradiol bound to recombinant human estrogen receptor α in a concentration-dependent manner: the IC50 values of diethylstilbestrol and bisphenol A, known to have isoestrogenic activity, with DHB and THB being approximately 1 × 10⁻⁸, 1 × 10⁻⁵, 5 × 10⁻⁵, and 5 × 10⁻⁴ M, respectively. Moreover, concentrations of DHB from 10⁻⁸ to 10⁻⁶ M induced concentration-dependent proliferation of MCF-7 cells. Concentrations of DHMB and THB at 10⁻⁷ and 10⁻⁶ M also caused a slight increase in cell number, while concentrations of HMB at 10⁻⁹ to 10⁻⁴ M did not affect cell proliferation. Based on the relative IC50 values of competitive binding and the proliferative effect on MCF-7 cells, the order of estrogenic activity was DHB > THB > DHMB. These results indicate that certain hydroxylation intermediates (e.g., DHB) rather than the parent compound exert their alloestrogenic effects through biotransformation. It is recommended to use sunscreens containing UV filters to reduce damage from solar ultraviolet radiation. In recent years, benzophenone (BP) UV filters have been widely used as UV stabilizers in moisturizing products and sunscreen lotions; however, information on the potentially harmful effects of long-term exposure to these compounds is scarce. Therefore, we investigated the toxicokinetics and metabolism of BP UV filters in rats using gas chromatography-mass spectrometry (GC-MS). To investigate the metabolism of BP-type ultraviolet filters, we analyzed the parent compound BP and 2-hydroxy-4-methoxybenzophenone (HMB). In rats, phenol (BP) is primarily converted to benzyl alcohol (BH) and 4-hydroxybenzophenone (HBP) (i.e., type A ultraviolet filters). In contrast, hexamethylbenzophenone (HMB) is converted to at least three intermediates, including 2,4-dihydroxybenzophenone (DHB) (formed via ortho-demethylation, subsequently to 2,3,4-trihydroxybenzophenone (THB)) and 2,2'-dihydroxy-4-methoxybenzophenone (DHMB) (formed via aromatic hydroxylation of HMB, i.e., type B ultraviolet filters). Furthermore, the toxicokinetics of BP showed that the peak concentration (Cmax) was reached approximately 4 hours after administration, at 2.06 ± 0.46 μg/mL. Following a single oral administration of HMB, its Cmax reached 21.21 ± 11.61 μg/mL (Tmax) within 3 hours, then rapidly decreased, showing a faster rate of decline compared to the toxicokinetics of BP. The concentrations of these metabolites in rat blood decreased much more slowly over time compared to the parent compound. Therefore, our results suggest that these metabolites may have more significant adverse effects in the long term than the parent compound. Benzophenone-3 (2-hydroxy-4-methoxybenzophenone, BZ-3) is a UV absorber widely used in pharmaceuticals, cosmetics, and industry as a sunscreen and color-fixing agent. The chemical can be exposed via skin and oral administration. Bioavailability via skin absorption differs from that via oral administration. This study investigated the in vivo distribution of BZ-3 after dermal administration of 100 mg/kg body weight (body weight) to Sprague-Dawley rats. Blood samples were collected at different time intervals, and the parent compound and its metabolites were analyzed by high-performance liquid chromatography (HPLC). The results showed that BZ-3 was rapidly absorbed, with the parent compound and its metabolites detectable in plasma within 5 minutes of administration. The absorption half-life (t1/2) was 3.45 hours, corresponding to an absorption rate constant of 0.2 hours⁻¹. Peak plasma concentrations were reached 2.5 hours after administration, at 35 ± 4.5 μg/mL (mean ± standard error). Drug clearance from plasma was biphasic, with different half-lives (1.3 hours for the α phase and 15.05 hours for the β phase), and the area under the plasma concentration-time curve was 211.1 ± 38.2 μg/mL/hr (mean ± standard error). BZ-3 and its metabolites were extensively bound to plasma proteins. Three metabolites were identified in plasma, with 2,4-dihydroxybenzophenone (DHB) and 2,2'-dihydroxy-4-methoxybenzophenone (DHMB) being the major metabolites detected, while 2,3,4-trihydroxybenzophenone (THB) was present only in trace amounts. Tissue distribution studies showed that THB was the major metabolite in all tissues examined, followed by DHB (both free and bound). The highest concentration was found in the liver, followed by the kidney, spleen, and testes. When benzophenone-3 (2-hydroxy-4-methoxybenzophenone; BP-3) was incubated with untreated rat liver microsomes in the presence of NADPH, a 5-hydroxylated metabolite, 2,5-dihydroxy-4-methoxybenzophenone (5-OH-BP-3), was generated, which is a major new metabolite of BP-3. The previously reported major in vivo metabolite of BP-3, 2,4-dihydroxybenzophenone (2,4-diOH-BP), was also detected; it is a 4-demethylated metabolite. However, the amount of 5-OH-BP-3 generated in vitro was approximately the same as that of 2,4-diOH-BP. SKF 525-A and ketoconazole inhibited the oxidase activity that generates 5-OH-BP-3, while quinidine and sulfamethoxazole also partially inhibited this activity. SKF 525-A, ketoconazole, and α-naphthylflavonoids inhibited the oxidase activity that generates 2,4-diOH-BP, and sulfamethoxazole also partially inhibited this activity. In rat liver microsomes treated with dexamethasone, phenobarbital, and 3-methylcholanthrene, the oxidase activity that generates 5-OH-BP-3 was enhanced. In rat liver microsomes treated with 3-methylcholanthrene and phenobarbital, the activity that generates 2,4-dihydroxy-BP was enhanced. Detection of recombinant rat cytochrome P450 isoenzymes catalyzing BP-3 metabolism revealed that 5-hydroxylation was catalyzed by P450 3A2, 1A1, 2B1, 2C6, and 2D1, while 4-demethylation was catalyzed by P450 2C6 and 1A1.

Toxicity Summary
Identification and Uses: 2,4-Dihydroxybenzophenone (BP1) is a solid. It is used as a UV absorber, particularly in paints and plastics. Human Studies: Benzophenone (BP) derivatives possess anti-androgenic activity. Treatment with BP1 (10⁻⁵ - 10⁻⁷ M) promotes the proliferation of MCF-7 breast cancer cells by regulating cell cycle-related genes. BP1 may promote prostate cancer progression by regulating cell cycle and metastasis-related genes through the androgen receptor signaling pathway. Animal Studies: Application to the intact and abraded skin of albino rabbits showed minimal irritation; application to the rabbit eyes showed mild to moderate irritation. 40 rats were fed BP1 at doses of 0–1.9 g/kg for 90 consecutive days. The results showed that rats in the 0.6 and 1.9 g/kg dose groups exhibited inhibited growth and development, and liver and kidney damage. According to a uterine nutrition study in ovariectomized rats, BP1 is a weak estrogenic compound. It was non-mutagenic against Salmonella Typhimurium strains TA100, TA98, TA1535, TA1537, and TA1538. Ecotoxicity studies: BP1 exhibits estrogenic activity in fish and acts as a pure or partial estrogen receptor α agonist.

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Interactions
/This study aims to/investigate the protective effect of 2,4-dihydroxybenzophenone (BP-1) against cocaine-induced acute hepatotoxicity and neurotoxicity in mice and its possible mechanisms.
Male ICR mice were pretreated with BP-1 (100, 200, 400 mg/kg, by gavage, for 4 days), and on day 4, 30 minutes after BP-1 administration, cocaine (75 mg/kg) was injected. Twenty-four hours after cocaine injection, the activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) were detected using a HITACHI-7170A fully automated biochemical analyzer. Simultaneously, malondialdehyde (MDA), reduced glutathione (GSH), and oxidized glutathione (GSSG) levels were measured, and the GSH/GSSG ratio was calculated. Histopathological analysis was then performed. Male ICR mice were pretreated with BP-1 (100, 200, and 400 mg/kg, administered by gavage for 3 days). On day 3, cocaine (20 mg/kg) was injected 30 minutes after BP-1 administration. Motor activity of each mouse was recorded immediately after cocaine injection for 0–180 minutes. Compared with the corresponding solvent group, after cocaine administration, the activities of ALT [(1571±1161) IU/L vs. (30±16) IU/L, P<0.05], AST [(408±226) IU/L vs. (101±12) IU/L, P<0.05] and LDH [(3963±1431) IU/L vs. (1935±287) IU/L, P<0.05] were significantly increased; the GSH/GSSG ratio [(5.11 +/- 0.63) vs. (6.88 +/- 1.13), P<0.05] decreased; and the MDA content [(1.97 +/- 1.36) umol/g vs. (0.07 +/- 0.06) umol/g, P<0.01] was significantly increased. Compared with the cocaine treatment group, serum ALT [(112±96) IU/L, (54±20) IU/L, (35±15) IU/L, P<0.05], AST [(130±33) IU/L, (107±5) IU/L, (99±9) IU/L, P<0.05] and LDH [(1667±564) IU/L, (1507±365) IU/L, (1249±349) IU/L, P<0.01] were significantly reduced after BP-1 pretreatment, and the GSH/GSSG ratio [(7.33±1.84), (9.28±0.67), (10.5±1.20)] was also significantly reduced. [P<0.05] Increased MDA content [(1.82 ± 1.19) μmol/g, (0.49 ± 0.31) μmol/g, (0.35 ± 0.30) μmol/g, P<0.05]. Liver histopathology in the BP-1 treatment group was also significantly improved. BP-1 pretreatment significantly reduced cocaine (20 mg/kg)-induced activity counts in mice, and shortened the time required for activity counts to return to normal. BP-1 has a protective effect against cocaine-induced acute hepatotoxicity and neurotoxicity in mice. Its mechanism of action may be related to its antioxidant activity. This study aimed to investigate the effect of 2,4-dihydroxybenzophenone (BP-1, a benzophenone derivative used as a UV absorber) on acetaminophen (APAP)-induced hepatotoxicity in C57BL/6J mice. Four days prior to administration of a hepatotoxic dose of APAP (350 mg/kg body weight), mice were orally administered BP-1 at doses of 200, 400, and 800 mg/kg body weight, respectively, every morning. Twenty-four hours after APAP intoxication, serum enzymes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH), were measured, and liver histopathological changes were examined. Results showed that BP-1 administration significantly reduced serum ALT, AST, and LDH levels. Liver histopathological examination revealed that BP-1 administration antagonized APAP-induced liver pathological damage in a dose-dependent manner. Further experiments showed that BP-1 pretreatment significantly reduced APAP-induced hepatic lipid peroxidation and markedly improved glutathione depletion. BP-1 effectively protected C57BL/6J mice from APAP-induced hepatotoxicity, and reducing oxidative stress may be part of its protective mechanism.

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Non-human toxicity values
Mice intravenous LD50: 85 mg/kg
Mice intraperitoneal LD50: 100 mg/kg
Rat oral LD50: 8600 mg/kg

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In vitro: In RAW 264.7 macrophages, DHP at concentrations of 6.25, 12.5, and 25 μM did not significantly affect cell viability (98.1 ± 2.6%, 97.3 ± 0.7%, and 98.0 ± 0.2%, respectively). At 50 μM, viability decreased to 69.2 ± 0.6%. The total viable cell count was also significantly decreased at 50 μM. No floating cells, apoptotic bodies, or cell debris were observed microscopically, even at 50 μM. [1]
In vivo: In zebrafish larvae, exposure to 100 μM DHP led to complete mortality within 24 h. Treatment with 50 μM DHP resulted in a 40% mortality rate at 24 h, which increased to 60% at 48 h. Concentrations of 25 μM or lower showed no significant increase in mortality rates over 48 h. [1]

[1]. 2,4'-Dihydroxybenzophenone: A Promising Anti-Inflammatory Agent Targeting Toll-like Receptor 4/Myeloid Differentiation Factor 2-Mediated Mitochondrial Reactive Oxygen Species Production during Lipopolysaccharide-Induced Systemic Inflammation. ACS Pharmacol Transl Sci. 2024 Apr 27;7(5):1320-1334.

[2]. Effect of Substituent Groups on the Strength of Intramolecular Hydrogen Bonds in 2,4-Dihydroxybenzophenone UV Absorbers. Molecules. 2023 Jun 27;28(13):5017.

2,4-Dihydroxybenzophenone is a type of benzophenone compound. Previous studies have reported the presence of 2,4-dihydroxybenzophenone in Arabidopsis thaliana, and relevant data are available. Mechanism of Action: Epithelial-mesenchymal transition (EMT) is an important process in embryonic development, cancer progression, and metastasis. EMT is influenced by the endogenous estrogen 17β-estradiol (E2). Benzophenone-1 (2,4-dihydroxybenzophenone, BP-1) and 4-tert-octylphenol (OP) are considered potential endocrine disruptors (EDCs) because they may possess estrogenic activity. This study investigated whether BP-1 and OP can induce EMT in BG-1 ovarian cancer cells expressing estrogen receptors (ERs). To investigate the effects of BP-1 and OP on BG-1 cell migration and the expression of EMT-related genes and proteins, we performed wound healing assays and Western blotting experiments. The results showed that both BP-1 (10⁻⁶ M) and OP (10⁻⁶ M) significantly enhanced the migration ability of BG-1 cells, and the cell monolayer wound area was significantly reduced compared with the control group, with effects similar to E2 (10⁻⁹ M). However, when BG-1 cells were co-treated with the estrogen receptor antagonist ICI 182,780, the wound area recovered to a level comparable to the control group. After treatment with BP-1 and OP, the expression levels of N-cadherin, Snail, and Slug proteins increased, while the expression level of E-cadherin decreased. However, after co-treatment with ICI 182,780, the expression level of E-cadherin decreased. In summary, these results suggest that the potential endocrine disruptors BP-1 and OP may induce ovarian cancer metastasis by regulating the expression of EMT markers and the migration of ER-expressing BG-1 ovarian cancer cells. 2,4-Dihydroxybenzophenone (benzophenone-1; BP-1) is a UV stabilizer primarily used to prevent polymer degradation and quality decline due to UV exposure. Recent reports indicate that BP-1 can be absorbed through the skin and accumulate in the human body, potentially inducing health problems including endocrine disorders. In this study, we examined the xenobiotic effect of BP-1 on BG-1 human ovarian cancer cells expressing the estrogen receptor (ER) and their associated xenograft animal models, comparing it with 17β-estradiol (E2). In in vitro cell viability assays, BP-1 (10⁻⁸-10⁻⁵ M), like E2, significantly promoted the growth of BG-1 cells. The mechanism of BG-1 cell proliferation was confirmed to be related to the upregulation of the cell cycle progression factor cyclin D1 by either E2 or BP-1. Both BP-1 and E2 induced cell growth, and the upregulation of cyclin D1 could be reversed by the ER antagonist ICI 182,780, suggesting that BP-1 may, like E2, mediate cancer cell proliferation through an ER-dependent pathway. On the other hand, although E2 downregulated the expression of p21, a regulator of the G1 phase of the cell cycle, BP-1 did not alter p21 expression. In xenograft mouse models transplanted with BG-1 cells, tumor volume significantly increased within 8 weeks compared to the control group (corn oil). Histopathological analysis showed abundant cell aggregation, high cell density, and disordered arrangement in tumor sections from the E2 and BP-1 groups. Increased BrdUrd-positive nuclei and overexpression of cyclin D1 further supported these findings. In summary, these results indicate that BP-1 is an endocrine disruptor (EDC) that exerts an allosteric-like effect by stimulating the proliferation of BG-1 ovarian cancer cells through the cell cycle-related estrogen receptor (ER) signaling pathway, with a mechanism of action similar to E2. Prostate cancer (PCa) is a major challenge to men's health worldwide. In recent years, endocrine disruptors (EDCs) have been found to potentially promote cancer progression as an exogenous factor. Triclosan (TCS) and 2,4-dihydroxybenzophenone (BP-1) have been reported to accumulate in the body through skin absorption. However, there is currently insufficient evidence to suggest that intervention with endocrine disruptors (EDCs) may promote the progression of prostate cancer (PCa). This study aimed to verify the risk of TCS and BP-1 for PCa progression; therefore, we examined the proliferation and migration of LNCaP prostate cancer cells. The results showed that TCS and BP-1, like dihydrotestosterone (DHT), promoted the proliferation and migration of LNCaP cells. Treatment with the known androgen receptor (AR) antagonist bicalutamide reversed this phenomenon, indicating that TCS and BP-1 mimic the role of DHT through the AR signaling pathway, exerting allogeneic androgenic effects in LNCaP cells. Western blotting was used to detect changes in the translational levels of cell growth and metastasis-related markers (such as c-fos, cyclin E, p21, and cathepsin D genes). The results showed that DHT, TCS, and BP-1 all upregulated the expression of genes related to the G1/S phase transition and metastasis, while simultaneously reducing the expression of p21 protein, which is responsible for cell cycle arrest. In summary, these results suggest that TCS and BP-1 may promote prostate cancer progression by regulating cell cycle and metastasis-related genes through the AR signaling pathway.

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The mechanism of action involves DHP binding to the hydrophobic pocket of MD2, which is predicted to block the dimerization of TLR4 and the subsequent binding of LPS to the TLR4/MD2 receptor complex. This inhibition leads to the downregulation of the downstream MyD88-IRAK4-NF-κB signaling pathway, reducing the expression of pro-inflammatory mediators (iNOS, TNF-α, IL-12). Furthermore, DHP inhibits the production of mitochondrial reactive oxygen species (mtROS), which are known to exacerbate the inflammatory response. [1]
The study suggests DHP has potential as a therapeutic agent for treating inflammatory conditions and endotoxemia by targeting the TLR4/MD2-mediated mtROS production. [1]

C13H10O3

214.2167

214.062

131-56-6

2,4-Dihydroxybenzophenone-13C6; 2731164-01-3; 2,4′-Dihydroxybenzophenone-d5; 91586-06-0; 2,4′-Dihydroxybenzophenone; 131-56-6

8572

Needles from hot water
Light-yellow, crystalline solid

1.3±0.1 g/cm3

409.0±14.0 °C at 760 mmHg

144.5-147 °C(lit.)

215.3±16.6 °C

0.0±1.0 mmHg at 25°C

1.648

3.17

2

3

2

16

246

0

OC1=CC(O)=C(C(C2=CC=CC=C2)=O)C=C1

ZXDDPOHVAMWLBH-UHFFFAOYSA-N

InChI=1S/C13H10O3/c14-10-6-7-11(12(15)8-10)13(16)9-4-2-1-3-5-9/h1-8,14-15H

(2,4-dihydroxyphenyl)-phenylmethanone

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)

DMSO: ~200 mg/mL (~933.6 mM; with ultrasonication)

Solubility in Formulation 1: ≥ 5 mg/mL (23.34 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween-80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), Clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of DMSO stock solution (50.0 mg/mL) to 400 μL of PEG300 and mix well; then add 50 μL of Tween-80 and mix well; finally add 450 μL of physiological saline and adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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