DEHYDROACETIC ACID

Dehydroacetic acid (DA) and benzoic acid (BA) are used as preservative agents in cosmetics in Korea at maximum concentrations of 0.6% and 0.5%, respectively. Prior to conducting the percutaneous absorption study, analytical methods were developed and validated for the quantification of DA and BA in various matrices including swab (SW), stratum corneum (SC), full-thickness skin (dermis + epidermis, SK), and receptor fluid (RF). These methods demonstrated excellent linearity (r 2  = 0.9992-0.9998 for DA, 0.9996-0.9999 for BA), high accuracy (91.53%-111.70% and 96.04%-101.47%), and acceptable precision (1.90%-10.16% and 1.30%-5.48%), in accordance with regulatory validation guidelines. Percutaneous absorption was evaluated using a Franz diffusion cell system with dermatomed dorsal minipig skin. Lotion formulations containing DA (0.12%, 0.24%, and 0.6%) and BA (0.1%, 0.2%, and 0.5%) were topically applied at 10 mg/cm 2 . After 24 h of exposure, concentrations of each compound in the matrices were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The total percutaneous absorption rates of DA were 104.13% ± 5.86%, 91.42% ± 4.05%, and 101.18% ± 7.82% for the 0.12%, 0.24%, and 0.6% formulations, respectively. For BA, the corresponding absorption rates were 74.71% ± 14.78%, 51.54% ± 8.97%, and 79.10% ± 5.65%. [Correction added on 14 April 2026, after first online publication: The first absorption rate in the preceding sentence has been updated in this version.] This indicates that DA and BA were mostly absorbed through the skin within the permitted concentration limits, suggesting that consideration of skin absorption rate is important when evaluating the safety of preservative exposure through the skin.

The Expert Panel for Cosmetic Ingredient Safety (Panel) first published a safety assessment of Sodium Dehydroacetate and Dehydroacetic Acid in 1985. The Panel previously concluded that Sodium Dehydroacetate and Dehydroacetic Acid are safe as used in the present practices of use and concentration, as stated in that report. Upon re-review in 2003, the Panel reaffirmed the original conclusion, as published in 2006. The Panel reviewed updated frequency and concentration of use data again in 2023, in addition to any newly available, relevant safety data. Considering this information, as well as the information provided in the original safety assessment and the prior re-review document, the Panel reaffirmed the 1985 conclusion.

Sodium dehydroacetate (DHA-S), a potent antifungal and antibacterial agent, is widely used in food, feed and cosmetics. However, recent studies have shown that DHA-S could pose a risk for human and animal health. We had previously reported that DHA-S could cause coagulation disorders in rats and chicken. In the present study, we further confirmed that DHA-S induced blood coagulation via VKORC1 and VKORC1L1 in rats, and elucidated the role played by mTOR/ERK signaling. The in vivo studies demonstrated that PT, APTT, and DHA-S content and relative protein expressions in tissues rebounded after drug withdrawal. In BRL-3A cells, 1.0 mM DHA-S increased the expression levels of mTOR, p-mTOR and p-ERK and decreased the levels of VKORC1, VKORC1L1 and Vitamin K. Rapamycin significantly decreased the expression levels of p-mTOR and p-ERK, while FR180204 (p-ERK Inhibition) lead to a decrease in p-ERK level. Rapamycin and FR180202 attenuated the inhibitory effect of DHA-S on VKORC1, VKORC1L1 and vitamin K levels. In addition, DHA-S increased the expression levels of mTOR, p-mTOR and p-ERK in male and female rat livers and prolonged PT and APTT. In summary, this study indicated that DHA-S induced blood coagulation via the modulation of the mTOR/ERK pathway in rats.

From the last decade, research on dehydroacetic acid (DHA) and its derivatives has increased immensely due to its significant role in various fields, including medicine, cosmetics, food industry, and so on. In the medicinal area, DHA plays an essential role in developing novel action-based drugs, which are helpful for treating various diseases. Besides its plethora of biological applications, its chelating ability offers the easiest synthetic route for synthesizing more active metal complexes. DHA derivatives along with their metal complexes show a number of biological activities and also exhibit various interactions with multiple biological targets. This article summarizes recent medicinal applications (2000-onwards) of DHA-based compounds and their analogs, along with their structure-activity relationship (SAR) analysis. Their interactions with different target enzymes are also discussed. This information derived from SAR analysis would be helpful for medicinal chemists working on the development of drugs based on heterocyclic frameworks, particularly those based on the DHA scaffold.

Long-term exposure to solar radiation can lead to skin damage such as photoageing, and photocarcinogenesis. This can be prevented by topically applying α-tocopherol phosphate (α-TP). The major challenge is that a significant amount of α-TP needs to reach viable skin layers for effective photoprotection. This study aims to develop candidate formulations of α-TP (gel-like, solution, lotion, and gel), and investigate formulation characteristics' effect on membrane diffusion and human skin permeation. All the formulations developed in the study had an appealing appearance and no signs of separation. All formulations had low viscosity and high spreadability except the gel. The flux of α-TP through the polyethersulfone membrane was the highest for lotion (6.63 ± 0.86 mg/cm 2 /h), followed by control gel-like (6.14 ± 1.76 mg/cm 2 /h), solution (4.65 ± 0.86 mg/cm 2 /h), and gel (1.02 ± 0.22 mg/cm 2 /h). The flux of α-TP through the human skin membrane was numerically higher for lotion compared to the gel-like (328.6 vs.175.2 µg/cm 2 /h). The lotion delivered 3-fold and 5-fold higher α-TP in viable skin layers at 3 h and 24 h, respectively, compared to that of the gel-like. The low skin membrane penetration rate and deposition of α-TP in viable skin layers were observed for the solution and gel. Our study demonstrated that dermal penetration of α-TP was influenced by characteristics of formulation such as formulation type, pH, and viscosity. The α-TP in the lotion scavenged higher DPPH free radicals compared to that of gel-like (almost 73% vs. 46%). The IC 50 of α-TP in lotion was significantly lower than that of gel-like (397.2 vs. 626.0 µg/mL). The preservative challenge test specifications were fulfilled by Geogard 221 and suggested that the combination of benzyl alcohol and Dehydroacetic Acid effectively preserved 2% α-TP lotion. This result confirms the suitability of the α-TP cosmeceutical lotion formulation employed in the present work for effective photoprotection.

Sodium dehydroacetate (Na-DHA) is widely used as an antibacterial and preservative additive in food and cosmetics. Previously, we reported that repeated oral administration of Na-DHA induces coagulation disorders, and inhibited liver vitamin K epoxide reductase complex subunit 1 (VKORC1) and VKORC1-like protein 1 (VKORC1L1) in rats. However, the effects of Na-DHA on coagulation factors in rat hepatocytes and the mechanism of VKORC1 and VKORC1L1 signaling in that process are unclear. Here, we constructed stable Vkorc1 and Vkorc1l1 overexpressing cell lines using lentiviruses and transfected small interfering RNAs into buffalo rat liver BRL3A cells for Vkorc1 and Vkorc1l1 overexpression and silencing, respectively. After treatment with 5 mmol/L Na-DHA for 24 h, VKORC1 and VKORC1L1 expression levels were detected by real-time PCR and western blotting. Vitamin K (VK) and factor IX (FIX) contents were detected using enzyme linked immunosorbent assays. We observed that Na-DHA inhibited VKORC1 and VKORC1L1 expression levels and reduced VK and FIX levels in rat hepatocytes. Overexpression or silencing of Vkorc1 and Vkorc1l1 increased or decreased, respectively, the production and secretion of VK and FIX in rat hepatocytes, and alleviated or aggravated the inhibitory effects of Na-DHA on VKORC1 and VKORC1L1 expression levels. Taken together, the results indicated that both VKORC1 and VKORC1L1 signaling play regulatory roles in the effects of Na-DHA on coagulation factors in rat hepatocytes.

The safety assessment of cosmetic products is based on the safety of the ingredients, which requires information on chemical structures, toxicological profiles, and exposure data. Approximately 6% of the population is sensitized to cosmetic ingredients, especially preservatives and fragrances. In this context, the aim of this study was to perform a hazard assessment and risk characterization of benzalkonium chloride (BAC), benzyl alcohol (BA), caprylyl glycol (CG), ethylhexylglycerin (EG), chlorphenesin (CP), dehydroacetic acid (DHA), sodium dehydroacetate (SDH), iodopropynyl butylcarbamate (IPBC), methylchloroisothiazolinone and methylisothiazolinone (MCI/MIT), methylisothiazolinone (MIT), phenoxyethanol (PE), potassium sorbate (PS), and sodium benzoate (SB). Considering the integrated approaches to testing and assessment (IATA) and weight of evidence (WoE) as a decision tree, based on published safety reports. The hazard assessment was composed of a toxicological matrix correlating the toxicity level, defined as low (L), moderate (M), or high (H) and local or systemic exposure, considering the endpoints of skin sensitization, skin irritation, eye irritation, phototoxicity, acute oral toxicity, carcinogenicity, mutagenicity/genotoxicity, and endocrine activity. In a risk assessment approach, most preservatives had a margin of safety (MoS) above 100, except for DHA, SDH, and EG, considering the worst-case scenario (100% dermal absorption). However, isolated data do not set up a safety assessment. It is necessary to carry out a rational risk characterization considering hazard and exposure assessment to estimate the level of risk of an adverse health outcome, based on the concentration in a product, frequency of use, type of product, route of exposure, body surface location, and target population.

The environmental effects of additives have attracted increasing attention. Sodium dehydroacetate (DHA-S), as an approved preservative, is widely added in processed foods, cosmetics and personal care products. However, DHA-S has been recently reported to induce hemorrhage and coagulation aberration in rats. Yet little is known about the ecotoxicological effect and underlying mechanisms of DHA-S. Here, we utilized the advantage of zebrafish model to evaluate such effects. DHA-S induced cerebral hemorrhage, mandibular dysplasia and pericardial edema in zebrafish after 24 h exposure (48-72 hpf) at 50 mg/L. We also observed the defective heart looping and apoptosis in DHA-S-treated zebrafish through o-dianisidine and acridine orange staining. Meanwhile, DHA-S induced the deficiency of Ca 2+ and vitamin D3 in zebrafish. We further demonstrated that DHA-S stimulated Ca 2+ influx resulting in Ca 2+ -dependent mitochondrial damage in cardiomyocytes. Additionally, DHA-S inhibited glucose uptake and repressed the biosynthesis of amino acids. Finally, we identified that sodium bicarbonate could rescue zebrafish from DHA-S induced cardiovascular toxicity. Altogether, our results suggest that DHA-S is a potential risk for cardiovascular system.

Environmental exposure to sodium dehydroacetate (DHA-S) is inevitable as DHA-S is a high-volume preservative widely used in cosmetics, processed foods and personal care products. DHA-S is absorbed rapidly when administered orally or on the skin and generally considered to be safe and well tolerated. However, DHA-S has recently been reported to induce weight loss and allergic contact dermatitis, yet little is known about how DHA-S affect the related biological processes. Here, we characterize the biological effects of DHA-S on zebrafish model by directly waterborne exposure. Zebrafish is susceptible to DHA-S exposure at early developmental stage. DHA-S decreased the hatch rate and locomotor persistence of zebrafish, and eventually induced lethality during the continuous exposure at relatively low concentrations of commonly addition. Acute DHA-S exposure decreased respiration capacity in larval zebrafish, promoted the expression of HIF-1α (hypoxia-inducible factor-1α) and caused rapid adult zebrafish death in 30 h. We further demonstrated that DHA-S inhibited the activity of succinate dehydrogenase (SDH) inducing respiratory chain interruption, energy deficiency and organic acids accumulation. These results suggest that the approved DHA-S may pose serious environmental/ecological pressures on the aquatic animal's migration.

Sodium dehydroacetate (Na-DHA), an antibiotic agent that combats growth of bacteria, fungi, and yeast, is used as a preservative in animal feed, food, and cosmetics. We previously reported that Na-DHA induces coagulation anomalies in Wistar rats, but the anticoagulant mechanism of Na-DHA remains to be established. Here we report that Na-DHA prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT) in male and female Wistar rats. In addition, Na-DHA decreased vitamin K (VK) levels and increased the levels of protein induced by vitamin K absence/antagonist-II (PIVKA-II) in rat serum. Moreover, we found that treatment with VK not only reversed Na-DHA-decreased serum VK and -increased PIVKA-II levels, but also attenuated Na-DHA-prolonged PT and APTT, suggesting that Na-DHA-decreased serum VK level contributes to the anticoagulation due to Na-DHA. Further we found that Na-DHA inhibited vitamin K epoxide reductase complex subunit 1 (VKORC1), a key enzyme in VK recycling, in the liver tissue of Wistar rats, as evidenced by reduced mRNA and protein levels of VKORC1 following Na-DHA treatment. Taken together, our data indicate that Na-DHA inhibits liver VKORC1, resulting in a decrease of serum VK levels, leading to abnormal coagulation in rats.

A method was developed for the simultaneous determination of benzoic acid and its esters, parabens, phenoxyisopropanol, chlorphenesin, dehydroacetic acid, 2,6-di- tert -butyl-4-methylphenol, methylchloroisothiazolone, methylisothiazolone and other preservatives in cosmetics by gas chromatography-tandem mass spectrometry (GC-MS/MS). The samples were extracted ultrasonically with a 0.1 mg/mL L(+)-ascorbic acid menthol solution after being spiked with a mixture solution of 2-octanol, phenol and heptachlor as internal standards and anhydrous sodium sulfate as a dehydrating reagent. Finally, the extract was centrifuged, filtered, and then analyzed by GC-MS/MS. The analytes were separated using an HP-5MS capillary column (30 m×0.25 mm×0.25 μm) with a temperature-programming program. The inlet, transfer line and ion source temperatures were set to 260, 250 and 230℃, respectively. Helium (99.999%) was used as the carrier gas at a flow rate of 1 mL/min. The final extract (1 μL) was injected in split mode (10:1). Analysis was performed in the multiple reaction monitoring (MRM) mode. Three types of cosmetics, as well as water, milk and cream as samples were selected to verify the accuracy of the method at four levels. The average spiked recoveries ranged from 82.3% to 119.4% with relative standard deviations ( n =6) of less than 14.3%. The limits of detection were lower than 0.99 μg/kg for all the preservatives. The method is sensitive, and reliable for the simultaneous determination of the 25 preservatives in cosmetics. Nonetheless, complementary methods need to be developed for the determination of some other preservatives that cannot be detected by GC-MS/MS.

Preservatives are widely used in cosmetic and personal care products to prevent microbial contamination and prolong products' shelf lives. However, concerns about human exposure to these chemicals are increasing due to their confirmed and/or potential negative effects on human health. In this study, we developed a nontarget and suspect screening strategy to identify 5 emerging preservatives and their metabolites in human urine using ultra-high performance liquid chromatography coupled with a high-resolution mass spectrometer (UHPLC-Q-Orbitrap HRMS). A workflow was established for metabolites identification by integrating m/z values of the parent preservatives with specific metabolic reactions. A total of 117 preservatives and relevant metabolites were tentatively identified in the urine samples collected from a general population of Guangzhou, China. p-hydroxyacetophenone (p-HAP) was the only detected parent preservative. Thirty metabolites with confidence levels (CLs) of 2 and 3 included 19 of p-HAP, 5 of dehydroacetic acid (DHA), 5 of caprylhydroxamic acid (CHA) and 1 of methylisothiazolinone (MIT). Sulfation, amino acid conjugation, and composite reactions were predominant metabolic pathways of the preservatives in human urine. This study presented a robust approach for screening and identifying emerging preservatives and relevant metabolites in human urine for comprehensive investigation of exposure and metabolism of preservative chemicals in human bodies.