Investigation of genotoxic effects of paraben in cultured human lymphocytes

In vitro assessment of the antioxidative, toxicological and antimicrobial properties of battery of parabens

The aim of this study was to evaluate antioxidative features using 2,2-diphenyl-1-pycrylhydrazyl free radical (DPPH•) scavenging method, bovine serum albumin (BSA)-binding properties with usage of spectrofluorimetric method, proliferative and cyto/genotoxic status by use of chromosome aberration test, and antimicrobial potential using broth microdilution method, followed by resazurin assay of benzyl-, isopropyl-, isobutyl and phenylparaben in vitro. Our results showed that all parabens had significant antiradical scavenger activity compared to p-hydroxybenzoic acid (PHBA) precursor. Higher mitotic index for benzyl-, isopropyl and isobutylparaben (250 µg/mL) in comparison with control was demonstrated. An increase in the frequency of acentric fragments in lymphocytes treated with benzylparaben and isopropylparaben (125 and 250 µg/mL), and isobutylparaben (250 µg/mL) was observed. Isobutylparaben (250 µg/mL) induced higher number of dicentric chromosomes. An increased number of minute fragments in lymphocytes exposed to benzylparaben (125 and 250 µg/mL) was found. A significant difference in the frequency of chromosome pulverization, between phenylparaben (250 µg/mL) and control, was detected. Benzylparaben (250 µg/mL) and phenylparaben (62.5 µg/mL) caused an increase in the number of apoptotic cells, while isopropylparaben (62.5, 125 and 250 µg/mL) and isobutylparaben (62.5 and 125 µg/mL) induced higher frequency of necrosis. Minimum inhibitory concentration (MIC) of tested parabens ranged 15.62-250 µg/mL for bacteria, and 125-500 µg/mL for the yeast. Minimum microbiocidal concentration ranged 31.25 to 500 µg/mL, and 250 to 1000 µg/mL in bacteria and fungi respectively. The lowest MICs for bacteria were observed for phenyl- (15.62 µg/mL) and isopropylparaben (31.25 µg/mL) against Enterococcus faecalis.

A study on assessing the toxic effects of ethyl paraben on rohu (Labeo rohita) using different biomarkers; hemato-biochemical assays, histology, oxidant and antioxidant activity and genotoxicity

Parabens are being used as preservatives due to their antifungal and antimicrobial effects. They are emerging as aquatic pollutants due to their excessive use in many products. The purpose of this study was to determine the toxic effect of ethyl paraben (C9H10O3) on the hematobiochemical, histological, oxidative, and anti-oxidant enzymatic and non-enzymatic activity; the study also evaluates the potential of ethyl paraben to cause genotoxicity in Rohu Labeo rohita. A number of 15 fish with an average weight of 35.45±1.34g were placed in each group and exposed to ethyl paraben for 21 days. Three different concentrations of ethyl paraben, i.e., T1 (2000μg/L), T2 (4000 μg/L), andT3 (6000 μg/L) on which fish were exposed as compared to the control T0 (0.00 μg/L). Blood was used for hematobiochemical and comet assay. Gills, kidneys, and liver were removed for histological alterations. The results showed a significant rise in all hemato-biochemical parameters such as RBCs, WBCs, PLT count, blood sugar, albumin, globulin, and cholesterol. An increase in aspartate aminotransferase (AST) and alanine transaminase (ALT) levels directed the hepatocytic damage. Histological alterations in the liver, gills and kidneys of fish were found. Ethylparaben induces oxidative stress by suppressing antioxidant enzyme activity such as SOD, GSH, CAT and POD. Based on the comet assay, DNA damage was also observed in blood cells, resulting in genotoxicity. Findings from the present study indicate that ethyl paraben induces hemato-biochemical alterations, tissue damage, oxidative stress, and genotoxicity.

The administration of methyl and butyl parabens interferes with the enzymatic antioxidant system and induces genotoxicity in rat testis: possible relation to male infertility

Parabens are esters of p-hydroxybenzoic acid, used for decades as a preservative in many products, including agrochemicals, pharmaceuticals, foods and cosmetics. Concerns regarding parabens toxicity include adverse effects on endocrine activity, carcinogenesis, infertility, spermatogenesis, and adipogenesis. The present study aimed to investigate the in vivo administration of methyl and butylparaben at concentrations of 100 and 200 mg/kg body weight, by subcutaneous injection, in variable murinometric measurements, antioxidant systems and genotoxicity. The administration of parabens did not affect the consumption of water and food. However, there was a decrease in the weight of the testes and the seminal vesicle (p < 0.05). The administration of parabens caused an increase in superoxide dismutase for methylparaben (200 mg/kg) and both concentrations of butylparaben (p < 0.05). Catalase showed increased activity in all groups treated with parabens. In contrast, glutathione reductase and glutathione S-transferase suffered a decrease in the groups treated with both parabens. These results show that parabens, especially butyl, can affect the rat testis enzymatic antioxidant system, decreasing the cellular antioxidant capacity, which was confirmed by the decrease in the glutathione reducing power, expressed by the reduced glutathione/oxidized glutathione ratio. Therefore, an increase in lipid peroxidation was observed, which was significant in the case of butyl. Genetic Damage Indicator values show that butylparaben treatments displayed significantly higher values than the control. This study shows for the first time that parabens can induce genotoxicity in the rat male reproductive organ.

Biomonitoring of parabens in wild boars through hair samples analysis

Parabens are compounds widely utilized in the industry as preservative additives to personal care products, cosmetics and food. They pollute the environment and penetrate to the living organisms through the digestive tract, respiratory system and skin. Till now the knowledge about exposure of terrestrial wild mammals to parabens is extremely scarce. Therefore, this study for the first time assessed the concentration levels of five parabens commonly used in industry (methylparaben-MeP, ethylparaben-EtP propylparaben-PrP, benzylparaben -BeP and butylparaben-BuP). Substances have been analyzed in hair samples collected from wild boars using liquid chromatography-mass spectrometry (LC-MS) method. The hair is a matrix, which allows to study long-term exposure of organisms to parabens. During this study MeP was noted in 96.3% of samples with mean 88.3±72.9 pg/mg, PrP in 87.0% of samples with mean 8.5±3.3 pg/mg, BeP in 44.4% of samples with mean 17.2±12.3 pg/mg and EtP in 11.1% of samples with mean 17.2±4.8 pg/mg. In turn BuP was noted only in 3.7% of samples with concentration levels below limit of quantification (2.6 pg/mg). Statistically significant intragender differences in parabens levels have not been noted. Only BeP concentration levels depended on industrialization and density of human population of area, where the animals lived. This study indicates that wild boars are exposed to parabens, especially to MeP and PrP, and analysis of the hair seems to be a useful tool of biomonitoring of parabens in wild mammals.

DNA Damage Estimation after Chronic and Combined Exposure to Endocrine Disruptors: An In Vivo Real-Life Risk Simulation Approach

Exposure to chemical substances has always been a matter of concern for the scientific community. During the last few years, researchers have been focusing on studying the effects resulting from combined exposure to different substances. In this study, we aimed to determine the DNA damage caused after chronic and combined exposure to substances characterized as endocrine disruptors using comet and micronuclei assays, specifically glyphosate (pure and commercial form), bisphenol A, parabens (methyl-, propyl- and butylparaben), triclosan and bis (2-ethylhexyl) phthalate. The highest mean tail intensity was observed in the group exposed to a high-dose (10 × ADI) mixture of substances (Group 3), with a mean value of 11.97 (11.26-13.90), while statistically significant differences were noticed between the groups exposed to low-dose (1 × ADI) (Group 2) and high-dose (10 × ADI) (Group 3) mixtures of substances (p = 0.003), and between Group 3 and both groups exposed to high doses (10 × ADI) of the pure and commercial forms of glyphosate (Groups 4 (p = 0.014) and 5 (p = 0.007)). The micronuclei assay results were moderately correlated with the exposure period. Group 5 was the most impacted exposure group at all sampling times, with mean MN counts ranging between 28.75 ± 1.71 and 60.75 ± 1.71, followed by Group 3 (18.25 ± 1.50-45.75 ± 1.71), showing that commercial forms of glyphosate additives as well as mixtures of endocrine disruptors can enhance MN formation. All exposure groups showed statistically significant differences in micronuclei counts with an increasing time trend.

Comparative cytotoxicity induced by parabens and their halogenated byproducts in human and fish cell lines

Parabens are a group of para-hydroxybenzoic acid (p-HBA) esters widely used in pharmaceutical industries. Their safety is well documented in mammalian models, but little is known about their toxicity in non-mammal species. In addition, chlorinated and brominated parabens resulting from wastewater treatment have been identified in effluents. In the present study, we explored the cytotoxic effects (EC₅₀) of five parabens: methylparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BuP), and benzylparaben (BeP); the primary metabolite, 4-hydroxybenzoic acid (4-HBA), and three of the wastewater chlorinated/brominated byproducts on fish and human cell lines. In general, higher cytotoxicity was observed with increased paraben chain length. The tested compounds induced toxicity in the order of 4-HBA < MP < EP < PP < BuP < BeP. The halogenated byproducts led to higher toxicity with the addition of second chlorine. The longer chain-parabens (BuP and BeP) caused a concentration-dependent decrease in cell viability in fish cell lines. Intriguingly, the main paraben metabolite, 4-HBA, proved to be more toxic to fish hepatocytes than human hepatocytes by 100-fold. Our study demonstrated that the cytotoxicity of some of these compounds appears to be tissue-dependent. These observations provide valuable information for early cellular responses in human and non-mammalian models upon exposure to paraben congeners.

Genotoxic potential of different nano-silver halides in cultured human lymphocyte cells

Most antibacterial applications in nanotechnology are carried out using silver nanoparticles (AgNPs). However, there is a dearth of information on the biological effects of AgNPs on human blood cells. In this study, the cytotoxic and genotoxic potentials of ionic silver (Ag⁺), AgNP, silver bromide (AgBr), silver chloride (AgCl), and silver iodide (AgI) were evaluated through chromosome aberration (CA) test and cytokinesis-blocked micronucleus (CBMN) test in human cultured lymphocytes in vitro. Furthermore, the potential damages that can cause to DNA were evaluated through alkaline single cell gel electrophoresis (Comet) assay on isolated lymphocytes. The results showed that AgNPs exerted cytotoxic effects by reducing the cytokinesis-block proliferation index and mitotic index at 24 and 48 h. AgNPs also increased micronucleus (MN) formation at both exposure times in the cultured cells. Meanwhile, AgCl had no genotoxic effects on the human lymphocyte cultured cells but had a cytotoxic effect at high doses. AgNP, Ag⁺, AgBr, and AgI caused substantial DNA damage by forming DNA strand breaks. They may also have clastogenic, genotoxic and cytotoxic effects on human lymphocyte cells. Based on the foregoing findings, silver nanomaterials may have genotoxic and cytotoxic potentials on human peripheral lymphocytes in vitro.

A review on advances in removal of endocrine disrupting compounds from aquatic matrices: Future perspectives on utilization of agri-waste based adsorbents

In the recent past, a class of emerging contaminants particularly endocrine disrupting compounds (EDCs) in the aquatic environment have gained a lot of attention. This is due to their toxic behaviour, affecting endocrine activities in humans as well as among aquatic animals. Presently, there are no regulations and discharge limits for EDCs to preclude their negative impact. Furthermore, the conventional treatment processes fail to remove EDCs efficiently. This necessitates the need for more research aimed at development of advanced alternative treatment methods which are economical, efficient, and sustainable. This paper focusses on the occurrence, fate, toxicity, and various treatment processes for removal of EDCs. The treatment processes (physical, chemical, biological and hybrid) have been comprehensively studied highlighting their advantages and disadvantages. Additionally, the use of agri-waste based adsorption technologies has been reviewed. The aim of this review article is to understand the prospect of application of agri-waste based adsorbents for efficient removal of EDCs. Interestingly, research findings have indicated that the use of these low-cost and abundantly available agri-waste based adsorbents can efficiently remove the EDCs. Furthermore, the challenges and future perspectives on the use of agri-waste based adsorbents have been discussed.

Genotoxic effects of gadobutrol and gadoversetamide active substances used in magnetic resonance imaging in human peripheral lymphocytes in vitro

Gadobutrol and gadoversetamide are gadolinium-based contrast agents (GBCAs) widely used during magnetic resonance imaging examination. In this study, the genotoxicity of two GBCAs, gadobutrol and gadoversetamide, was investigated by using different endpoints: chromosome aberration (CAs), sister chromatid exchange (SCEs), and micronucleus (MNi). Human peripheral lymphocytes (PBLs) were treated with five concentrations (7 000, 14 000, 28 000, 56 000, and 112 000 μg/mL) of both agents. While a few concentrations of gadobutrol significantly increased abnormal cell frequency and CA/Cell, nearly all the concentrations of gadoversetamide significantly elevated the same aberrations. Similarly, the effect of gadoversetamide on the formation of SCEs was higher than those of gadobutrol. Only one concentration of gadoversetamide significantly increased MN% but no gadobutrol. The comet assay was applied for the only gadobutrol which induced a significant increase in tail intensity at the highest concentration only. On the other hand, significantly decreased mitotic index (MI) was observed following both substances, again gadoversetamide was slightly higher than those of the gadobutrol. The results revealed that both the contrast agents are likely to induce genotoxic risk in PBLs. However, different concentrations and treatment periods should be examined in vitro and specifically in vivo with different test systems for the safer usage of these contrast agents.

Toxicity and sublethal effects of methylparaben on zebrafish (Danio rerio) larvae and adults

Among the parabens, methylparaben (MeP) is the most commonly found in personal care products. Due to the continuous use of MeP and low removal efficiency by wastewater treatment plants (WWTPs), it reaches aquatic environments, where it is incorporated by organisms inhabiting these waters. The present study aimed to evaluate the effects of MeP on the zebrafish Danio rerio larvae and adults through toxicity tests and physiological and biochemical biomarkers in order to assess possible harmful effects of MeP. For biomarker measurements, fish were exposed to the environmental concentration of 30 μg/L of MeP and the non-effect concentration (NOEC) estimated for larvae (60 mg/L) and adult (50 mg/L) in toxicity tests. The median lethal concentration (LC₅₀) of MeP was 105.09 mg/L for adults and 211.12 mg/L for larvae. These values unexpectedly indicated that adults were more sensitive to MeP compared to larvae. In adult fish, exposure to 50 mg/L MeP induced a significant decrease in phase 1 biotransformation (ethoxyresorufin O-deethylase activity) and an increase in lipoperoxidation (LPO) in gills, as well as an increase in frequency of micronuclei in erythrocytes of these fish. Biomarkers results were integrated (integrated biomarker response [IBR] index), and it observed lower IBR scores in tissues of fish exposed to MeP, suggesting a suppression of biological responses. In addition, LPO contributed mostly to the IBR score estimated for gills of fish exposed to 50 mg/L MeP. Based on LPO quantity, sublethal exposure of MeP (30 μg/L and 60 mg/L) did not cause toxicity to larvae. Hence, we investigated whether the difference in sensitivity between adults and larvae could be associated with the antimicrobial action of MeP that could affect the intestinal microbiota of adults. We only found an increase in the number of carbon sources consumed by them without effects on diversity and abundance. This outcome can be considered an adaptation to environmental stress, but not a negative effect. However, the LPO and genotoxicity caused by MeP to zebrafish adults call direct attention to the importance of regulating the presence of this compound in the environment and improve cleaning processes adopted by WWTP.

Controversy around parabens: Alternative strategies for preservative use in cosmetics and personal care products

Parabens usage as preservatives in cosmetics and personal care products have been debated among scientists and consumers. Parabens are easy to production, effective and cheap, but its safety status remains controversial. Other popular cosmetics preservatives are formaldehyde, triclosan, methylisothiazolinone, methylchloroisothiazolinone, phenoxyethanol, benzyl alcohol and sodium benzoate. Although their high antimicrobial effectiveness, they also exhibit some adverse health effects. Lately, scientists have shown that natural substances such as essential oils and plant extracts present antimicrobial potential. However, their use in cosmetic is a challenge. The present review article is a comprehensive summary of the available methods to prevent microbial contamination of cosmetics and personal care products, which can allow reducing the use of parabens in these products.

Exposure to ethylparaben and propylparaben interfere with embryo implantation by compromising endometrial decidualization in early pregnant mice

Ethylparaben (EtP) and propylparaben (PrP) are common preservatives and well-known endocrine-disrupting chemicals. Studies have demonstrated that they can reduce female fertility, but the underlying mechanism, especially that on embryo implantation, is still poorly understood. Endometrial decidualization is a critical event for embryo implantation. In this study, we aimed to explore the effects of EtP/PrP on endometrial decidualization. Pregnant mice were dosed daily by oral gavage with EtP at 0, 400, 800 and 1600 mg/kg or with PrP at 0, 625, 1250 and 2500 mg/kg from Day 1 of pregnancy until sacrifice. The results showed that the rate of pregnant mice with impaired embryo implantation, whose number of implantation sites was less than 7, was significantly increased after exposure to 1600 mg/kg EtP or 2500 mg/kg PrP. Further study found that the expression of endometrial decidualization markers HOXA10, MMP9 and PR was significantly downregulated in 1600 mg/kg EtP group and 2500 mg/kg PrP group. Notably, serum oestrogen and progesterone levels were significantly increased, whereas the expression of uterine oestrogen receptor and progesterone receptor was decreased following 1600 mg/kg EtP or 2500 mg/kg PrP exposure. In the breeding test, fewer offspring were found after females were exposed to 1600 mg/kg EtP or 2500 mg/kg PrP in early pregnancy. This demonstrated that exposure to EtP/PrP interfered with embryo implantation by compromising endometrial decidualization in early-stage pregnant mice. Disorders of reproductive hormones and hormone receptor signals could be responsible for impaired decidualization. This study broadened the understanding on the biological safety of EtP and PrP.

The controversies of parabens - an overview nowadays

Effects of paraben toxicity, i.e., endocrine-disruption properties, are in the focus of researchers for decades, but still - they are a hot subject of debate. Parabens are aliphatic esters of p-hydroxybenzoic acid, which are widely used as antimicrobial agents for the preservation of cosmetics, pharmaceuticals and foods. Mostly used parabens are methyl-, ethyl-, propyl- and butylparaben. Although the toxicity of parabens is reported in animals and in in vitro studies, it cannot be taken for granted when discussing hazards for human health due to an unrealistic exposure -safety profile. Many studies have demonstrated that parabens are non-teratogenic, non-mutagenic, non-carcinogenic and the real evidence for their toxicity in humans has not been established. For now, methyl-, ethyl- and propylparaben are considered safe for use in cosmetics and pharmaceuticals within the recommended range of doses. Regarding alternatives for parabens, a variety of approaches have been proposed, but every substitute would need to be tested rigorously for toxicity and safety.

In vitro genotoxicity assessment of monopotassium glutamate and magnesium diglutamate

Food additives are approved chemicals used for various purposes in foods; to provide nutritional safety, increase flavor, extend shelf life, reduce nutrient losses etc. In this study, the in vitro genotoxic effects of flavor enhancers, Monopotassium glutamate (MPG) and Magnesium diglutamate (MDG) were investigated in human peripheral blood lymphocytes by using chromosome aberrations (CAs), sister chromatid exchanges (SCEs), cytokinesis-block micronucleus cytome (CBMN-Cyt), and comet assays. Four concentrations of MPG (125, 250, 500, and 1000 μg/mL) and MDG (93.75, 187.5, 375, and 750 μg/mL) were used. Both food additives significantly reduced mitotic index and increased the frequency of CAs at high concentrations. MPG and MDG (except 93.75 μg/mL) significantly increased SCEs/Cell in concentration-dependent manner. In the CBMN-Cyt test, both MPG and MDG increased the formation of micronucleus, nuclear buds, and nucleoplasmic bridges compared to control in a concentration-dependent manner. However, these increases were statistically significant at higher concentrations. MPG (at 500 and 1000 μg/mL) and MDG (except 93.75 μg/mL) significantly increased DNA damages observed by comet assay. It is concluded from these results that MPG and MDG have clastogenic, mutagenic, aneugenic, and cytotoxic effects, particularly at high concentrations in human lymphocytes in vitro.

In vitro genotoxic and cytotoxic effects of some paraben esters on human peripheral lymphocytes

Parabens (PBs) are p-hydroxybenzoic acid ester compounds commonly employed as antimicrobial preservatives, mainly in food, cosmetic, and pharmaceutical products. The aim of the present study was to investigate the genotoxic and cytotoxic effects of some paraben esters (butyl paraben, propyl paraben, isobutyl paraben, and isopropyl paraben) on human peripheral lymphocytes, using in vitro sister chromatid exchange (SCE), chromosome aberration (CA), and cytokinesis-block micronucleus (CBMN) tests. Lymphocyte cultures were treated with four concentrations of PBs (100, 50, 25 and 10 µg/mL) for 24 and 48 h. Paraben esters significantly induced MN formations as compared to solvent control. Furthermore, butyl paraben and propyl paraben increased MN formations a concentration-dependent manner at 24 and 48 h. PBs increased the CA at 24 and 48 h. However, this increase was not meaningful for butyl paraben and isopropyl paraben at 48 h when compared with solvent control. Butyl, isobutyl, and isopropyl paraben significantly increased the SCE at 24 and 48 h. However, propyl paraben did not induce SCE meaningfully in both treatment periods. A significant decrease in the cytokinesis-block proliferation index and mitotic index was observed in cells exposed to all concentrations of PBs at 24 and 48 h. However, proliferation index was not affected at all concentrations of PBs after 24 h treatment, although it was decreased at the highest concentration of PBs at 48 h. It is concluded that all of the paraben esters used in this study have highly genotoxic and cytotoxic effects on human lymphocytes cells in vitro.