Micronucleus tests in mice on 39 food additives and eight miscellaneous chemicals

Medicinal benefits, biological, and nanoencapsulation functions of riboflavin with its toxicity profile: A narrative review

Riboflavin is a precursor of the essential coenzymes flavin mononucleotide and flavin adenine dinucleotide. Both possess antioxidant properties and are involved in oxidation-reduction reactions, which have a significant impact on energy metabolism. Also, the coenzymes participate in metabolism of pyridoxine, niacin, folate, and iron. Humans must obtain riboflavin through their daily diet because of the lack of programmed enzymatic machineries for de novo riboflavin synthesis. Because of its physiological nature and fast elimination from the human body when in excess, riboflavin consumed is unlikely to induce any negative effects or develop toxicity in humans. The use of riboflavin in pharmaceutical and clinical contexts has been previously explored, including for preventing and treating oxidative stress and reperfusion oxidative damage, creating synergistic compounds to mitigate colorectal cancer, modulating blood pressure, improving diabetes mellitus comorbidities, as well as neuroprotective agents and potent photosensitizer in killing bloodborne pathogens. Thus, the goal of this review is to provide a comprehensive understanding of riboflavin's biological applications in medicine, key considerations of riboflavin safety and toxicity, and a brief overview on the nanoencapsulation of riboflavin for various functions including the treatment of a range of diseases, photodynamic therapy, and cellular imaging.

Antimicrobial activity of cinnamaldehyde against multidrug-resistant Klebsiella pneumoniae: an in vitro and in vivo study

The emergence and spread of multidrug-resistant (MDR) Klebsiella pneumoniae strains have increased worldwide, posing a significant health threat by limiting the therapeutic options. This study aimed to investigate the antimicrobial potential of cinnamaldehyde against MDR-K. pneumoniae strains in vitro and in vivo assays. The presence of resistant genes in MDR- K. pneumoniae strains were evaluated by Polymerase Chain Reaction (PCR) and DNA sequencing. Carbapenem-resistant K. pneumoniae strains show the blaKPC-2 gene, while polymyxin-resistant K. pneumoniae presented blaKPC-2 and alterations in the mgrB gene. Cinnamaldehyde exhibited an inhibitory effect against all MDR- K. pneumoniae evaluated. An infected mice model was used to determine the in vivo effects against two K. pneumoniae strains, one carbapenem-resistant and another polymyxin-resistant. After 24 h of cinnamaldehyde treatment, the bacterial load in blood and peritoneal fluids decreased. Cinnamaldehyde showed potential effectiveness as an antibacterial agent by inhibiting the growth of MDR-K. pneumoniae strains.

FEMA GRAS assessment of natural flavor complexes: Allspice, anise, fennel-derived and related flavoring ingredients

The FEMA Expert Panel program to re-evaluate the safety of natural flavor complexes (NFCs) used as flavoring ingredients in food has resulted in the publication of an updated constituent-based procedure as well as publications on the safety evaluation of many botanical-derived NFCs. This publication, ninth in the series and related to the ninth publication, describes the affirmation of the generally recognized as safe (GRAS) status for NFCs with propenylhydroxybenzene and allylalkoxybenzene constituents under their conditions of intended use as flavoring ingredients added to food. The Panel's procedure applies the threshold of toxicological concern (TTC) concept and evaluates relevant data on absorption, metabolism, genotoxic potential and toxicology for the NFCs themselves and their respective constituent congeneric groups. For NFCs containing allylalkoxybenzene constituent(s) with suspected genotoxic potential, the estimated intake of the individual constituent is compared to the TTC for compounds with structural alerts for genotoxicity and if exceeded, a margin of exposure is calculated using BMDL10 values derived from benchmark dose analyses using Bayesian model averaging, as presented in the tenth article of the series. Safety evaluations for NFCs derived from allspice, anise seed, star anise, sweet fennel seed and pimento leaves were conducted and their GRAS status was affirmed for use as flavoring ingredients. The scope of the safety evaluation contained herein does not include added use in dietary supplements or any products other than food.

FEMA GRAS assessment of natural flavor complexes: Asafetida oil, garlic oil and onion oil

The Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) applies its procedure for the safety evaluation of natural flavor complexes (NFCs) to re-evaluate the safety of Asafetida Oil (Ferula assa-foetida L.) FEMA 2108, Garlic Oil (Allium sativum L.) FEMA 2503 and Onion Oil (Allium cepa L.) FEMA 2817 for use as flavoring in food. This safety evaluation is part of a series of evaluations of NFCs for use as flavoring ingredients conducted by the Expert Panel that applies a scientific procedure published in 2005 and updated in 2018. Using a group approach that relies on a complete chemical characterization of the NFC intended for commerce, the constituents of each NFC are organized into well-defined congeneric groups and the estimated intake of each constituent congeneric group is evaluated using the conservative threshold of toxicological concern (TTC) concept. Data on the metabolism, genotoxic potential and toxicology for each constituent congeneric group are reviewed as well as studies on each NFC. Based on the safety evaluation, Asafetida Oil (Ferula assa-foetida L.), Garlic Oil (Allium sativum L.) and Onion Oil (Allium cepa L.) were affirmed as generally recognized as safe (GRASa) under their conditions of intended use as flavor ingredients.

Potassium bromate-induced oxidative stress, genotoxicity and cytotoxicity in the blood and liver cells of mice

Potassium bromate (KBrO₃) is an oxidising agent that is extensively used as a food additive, it is also a product of cosmetic and pharmaceutical relevance. The objective of this study was to evaluate the oxidative stress, genotoxicity, and apoptosis induced by KBrO₃ in an experimental animal model. To study the toxic effects and oxidative stress, different doses of KBrO₃ below LD₅₀ (The half maximal lethal dose, 50, 100 and 150 mg/kg body weight) were given intraperitoneally to the mice for multiple time periods (24, 48, and 72 h). The results showed that KBrO₃ significantly induces oxidative damage by increasing the levels of reactive oxygen species (ROS) and lipid peroxidase and depleted the levels of catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH) enzymes in the serum and liver. Moreover, a significant increase of chromosomal aberrations in bone marrow cells and an elevated incidence of micronuclei in the peripheral blood of mice were observed. KBrO₃ induces 3 ´ -OH end double-strand DNA breaks, which was evident in liver sections of the treated mice, and increases the percentage of apoptotic cells, as observed in TUNEL assays and flow cytometry analysis. The present findings indicate that KBrO₃ induces oxidative stress, genotoxicity, and cytotoxicity in a dose- and time-dependent manner in mice.

Amelioration of indole acetic acid-induced cytotoxicity in mice using zinc nanoparticles biosynthesized with Ochradenus arabicus leaf extract

The diversity of natural phytochemicals represents an unlimited source for discovery and development of new drugs. Ochradenus arabicus, (family: Resedaceae) a notable medicinal plant displays a high content of flavonoid glycosides. This study investigates a possible preventative role of zinc nanoparticles biosynthesized by O. arabicus leaf extracts (OAZnO NPs) in limiting genotoxicity and cytotoxicity caused by indole acetic acid (IAA) in laboratory mice. ZnO NPs were synthesized using O. arabicus leaf extracts and characterized with UV–visible spectroscopy, scanning electron microscopy (SEM) and X-Ray diffraction (XRD). The mice were randomly distributed into the following six groups: control, OAZnO NPs treated (10 mg/kg BW), IAA treated (50 mg/kg BW); simultaneous treatment, pre-treatment, and post-treatment. Reactive oxygen species (ROS), DNA damage, chromosome aberration, and apoptosis were analyzed as toxicity endpoints. IAA exposure significantly induced production of ROS, DNA damage, apoptosis, chromosome aberrations, and micronuclei. Pre-, post-, and simultaneous treatment with OAZnO NPs ameliorated the damage caused by IAA exposure. Exposure to OAZnO NPs alone caused no toxicity for any endpoint based on comparison to controls. This study demonstrated that IAA-induced cytotoxic damage in mice could be ameliorated by treatment with OAZnO NPs. These findings require additional verification in mechanistic and in vitro studies.

[Studies on toxicity and inflammatory reactions induced by e-cigarettes : In vitro exposure of human nasal mucosa cells to propylene glycol at the air-liquid interface]

Hintergrund

Die E‑Zigarette erfreut sich in den letzten Jahren zunehmender Beliebtheit. Die Frage nach der Toxizität ist jedoch noch nicht eindeutig geklärt, und es herrscht global Unsicherheit im Umgang mit der E‑Zigarette.

Ziel

Ziel der vorliegenden Arbeit war es, Propylenglykol, ein Hauptbestandteil der Liquide, in Bezug auf mögliche akute Entzündungsreaktionen, zyto- und genotoxische Auswirkungen auf humane Nasenschleimhautzellen zu untersuchen.

Material und Methoden

Die Nasenschleimhautzellen wurden von zehn Probanden im Air-Liquid-Interface kultiviert und anschließend mit unterschiedlichen Konzentrationen des Propylenglykols bedampft. Die Analyse erfolgte mittels Trypanblau-Test, Comet-Assay, Mikrokerntest und IL-6- und IL-8-Sandwich-ELISA.

Ergebnis

Der Trypanblau-Test zeigte keine Reduktion der Vitalität. Im Sandwich-ELISA konnte kein Anstieg der IL-6- und IL-8-Konzentrationen nachgewiesen werden. Im Comet-Assay zeigte das Olive Tail Moment eine Schädigung im Vergleich zur Negativkontrolle in allen untersuchten Konzentrationen. Zudem zeigte sich eine dosisabhängige Schädigung. Im Mikrokerntest konnte ein Unterschied zwischen dem Reinstoff und der Negativkontrolle gefunden werden.

Schlussfolgerung

Es zeigten sich möglicherweise reparable DNS-Schädigungen im Comet-Assay. Im Mikrokerntest konnten diese nur in der Reinstoffkonzentration bestätigt werden. Es sollte ein restriktiver Umgang mit der E‑Zigarette erfolgen, bis insbesondere Langzeitstudien vorliegen. Zudem ist eine eindeutige Deklaration der Inhaltsstoffe der Liquide durch die Hersteller zu fordern, um weitergehende Schädigungspotenziale untersuchen zu können.

The effect of chronic dosing and p53 status on the genotoxicity of pro-oxidant chemicals in vitro

In this study, we have studied the cytotoxicity and genotoxic potency of 3 pro-oxidants; H2O2, menadione and KBrO3 in different dosing scenarios, namely acute (1-day dosing) and chronic (5-days). For this purpose, relative population doubling (RPD%) and mononucleated micronucleus (MN) test were used. TK6 cells and NH32 were employed in in vitro experiments. In the study, the total acute dose was divided into 5 days for each prooxidant chemicals by dose fractionation (1/5th per day) method. Acute dosing was compared to chronic dosing. The oxidative stress caused by the exposure of cells with pro-oxidant chemicals to the cells was determined by an optimized 2',7'-dichlorofluorescein diacetate (DCFHDA) test method. The antioxidant levels of the cell lines were altered with buthionine sulfoxide (BSO) and N-acetyl cysteine (NAC), and the effect of antioxidant capacity on the MN formation in the cells was observed with this method. In the case of H2O2 and menadione, fractional dosing has been observed to result in lower toxicity and lower genotoxicity. But in the case of KBrO3, unlike the other 2 pro-oxidants, higher MN induction was observed with fractionated doses. DCFHDA test clearly demonstrated ROS induction with H2O2 and menadione but not with KBrO3. Unexpectedly, DCFHDA test demonstrated that KBrO3 did not cause an increase ROS levels in both acute and chronic dosing, suggesting an alternative ROS induction mechanism. It was also observed that, treatment with BSO and NAC, caused increasing and decreasing of MN fold change respectively, allowing further ROS specific mechanisms to be explored. Hence, dose fractionation expectedly caused less MN, cytotoxicity and ROS formation with H2O2 and menadione exposure, but not with KBrO3. This implies a unique mechanism of action for KBrO3 induced genotoxicity. Chronic dosing in vitro may be a valuable approach allowing better understanding of how chemicals damage DNA and pose human hazards.

Synergistic effects of Cinnamomum cassia L. essential oil in combination with polymyxin B against carbapenemase-producing Klebsiella pneumoniae and Serratia marcescens

Multidrug resistance prompts the search for new sources of antibiotics with new targets at bacteria cell. To investigate the antibacterial activity of Cinnamomum cassia L. essential oil (CCeo) alone and in combination with antibiotics against carbapenemase-producing Klebsiella pneumoniae and Serratia marcescens. The antimicrobial susceptibility of the strains was determined by Vitek^® 2 and confirmed by MALDI-TOF/TOF. The antibacterial activity of CCeo and its synergism with antibiotics was determined using agar disk diffusion, broth microdilution, time-kill, and checkboard methods. The integrity of the bacterial cell membrane in S. marcescens was monitored by protein leakage assay. CCeo exhibited inhibitory effects with MIC = 281.25 μg.mL^-1. The association between CCeo and polymyxin B showed a decrease in terms of viable cell counts on survival curves over time after a 4 hour-treatment with a FIC index value of 0.006. Protein leakage was observed with increasing concentrations for CCeo and CCeo + polymyxin B treatments. CCeo showed antibacterial activity against the studied strains. When associated with polymyxin B, a synergistic effect was able to inhibit bacterial growth rapidly and consistently, making it a potential candidate for the development of an alternative treatment and drug delivery system for carbapenemase-producing strains.

RIFM fragrance ingredient safety assessment, p-isopropylbenzyl alcohol, CAS Registry Number 536-60-7

The existing information supports the use of this material as described in this safety assessment. p-Isopropylbenzyl alcohol was evaluated for genotoxicity, repeated dose toxicity, developmental and reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from the read-across analog benzyl alcohol (CAS # 100-51-6) show that p-isopropylbenzyl alcohol is not expected to be genotoxic. Data from the read-across analog benzyl alcohol (CAS # 100-51-6) provide a calculated MOE >100 for the repeated dose, developmental, and local respiratory toxicity endpoints. The reproductive toxicity endpoint was evaluated using the TTC for a Cramer Class I material, and the exposure is below the TTC (0.03 mg/kg/day). Data from read-across analog benzyl alcohol (CAS # 100-51-6) provided p-isopropylbenzyl alcohol a NESIL of 5900 μg/cm² for the skin sensitization endpoint. The phototoxicity and photoallergenicity endpoints were evaluated based on UV spectra; p-isopropylbenzyl alcohol is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; p-isopropylbenzyl alcohol was found not to be a PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC) are <1.

Re-evaluation of l(+)-tartaric acid (E 334), sodium tartrates (E 335), potassium tartrates (E 336), potassium sodium tartrate (E 337) and calcium tartrate (E 354) as food additives

The EFSA Panel on Food Additives and Flavourings (FAF) provides a scientific opinion on tartaric acid-tartrates (E 334-337, 354) when used as food additives. The Scientific Committee for Food (SCF) in 1990 established an acceptable daily intake (ADI) of 30 mg/kg body weight (bw) per day, for l(+)-tartaric acid and its potassium and sodium salts. The metabolism of l(+)-tartaric acid and its potassium sodium salt was shown to be species dependent, with a greater absorption in rats than in humans. No toxic effects, including nephrotoxicity, were observed in toxicological studies in which the l(+)-form was tested. There was no indication for a genotoxic potential of tartaric acid and its sodium and potassium salts. In a chronic study in rats, no indication for carcinogenicity of monosodium l(+)-tartrate was reported at the highest dose tested (3,100 mg/kg bw per day). The available studies for maternal or developmental toxicity did not report any relevant effects; no studies for reproductive toxicity were available; however, no effects on reproductive organs were observed in the chronic toxicity study. The Panel concluded that the data on systemic availability were robust enough to derive a chemical-specific uncertainty factor instead of the usual default uncertainty factor of 100. A total uncertainty factor of 10 was derived by applying a total interspecies uncertainty factor of 1 instead of 10, based on data showing lower internal exposure in humans compared to rats. The Panel established a group ADI for l(+)-tartaric acid-tartrates (E 334-337 and E 354) of 240 mg/kg bw per day, expressed as tartaric acid, by applying the total uncertainty factor of 10 to the reference point of 3,100 mg sodium tartrate/kg bw per day, approximately to 2,440 mg tartaric acid/kg bw per day. The exposure estimates for the different population groups for the refined non-brand-loyal exposure scenario did not exceed the group ADI of 240 mg/kg bw per day, expressed as tartaric acid. Some recommendations were made by the Panel.

Micronucleus Assay: The State of Art, and Future Directions

During almost 40 years of use, the micronucleus assay (MN) has become one of the most popular methods to assess genotoxicity of different chemical and physical factors, including ionizing radiation-induced DNA damage. In this minireview, we focus on the position of MN among the other genotoxicity tests, its usefulness in different applications and visibility by international organizations, such as International Atomic Energy Agency, Organization for Economic Co-operation and Development and International Organization for Standardization. In addition, the mechanism of micronuclei formation is discussed. Finally, foreseen directions of the MN development are pointed, such as automation, buccal cells MN and chromothripsis phenomenon.

Potassium bromate: Effects on bread components, health, environment and method of analysis: A review

Potassium bromate, is an oxidizing agent and one of the best and cheapest dough improvers in the baking industry. Due to its positive effects it plays a major role in the bread-making industry. Potassium bromate has significant effect on food biomolecules, such as starch and protein, as it affects the extent of gelatinization, viscosity, swelling characteristics as well as gluten proteins; it removes the sulfhydryl group and leads to the formation of disulfide linkages and thus improves the bread properties. However, there are many reports elucidating its negative impact on human health. It is deemed as a potential human carcinogen by IARC and classified under class 2B. Due to this, countries across world have either partially or completely banned it. Numerous techniques have evolved to determine the concentration of potassium bromate in bread. This review explains in detail, the effects of potassium bromate on biomolecules, human health, environment and various methods of analysis.

Binding mechanism of maltol with catalase investigated by spectroscopy, molecular docking, and enzyme activity assay

Maltol is a flavor additive that is widely used in the daily diet of humans, and its biosafety attention is concomitantly increasing. Catalase (CAT) is an antioxidant enzyme to maintain homeostasis in the tissue's environment of human body and protect cells from oxidative damages. The adverse effects of maltol to CAT activity within mouse hepatocytes as well as the structural and functional changes of CAT on molecular level were investigated by multiple spectroscopy techniques, enzyme activity experiments, and molecular docking. Results suggested that when the maltol concentrations reached to 8 × 10^-5 mol L^-1 , the viability of hepatocytes decreased to 93%, and CAT activity was stimulated by maltol to 111% than the control group after exposure for 24 hours. Changes in CAT activity on molecular level were consistent with those on cellular level. The fluorescence quenching of CAT by maltol was static with the forming of maltol-CAT complex. Moreover, ultraviolet-visible (UV-visible) absorption, synchronous fluorescence, and circular dichroism (CD) spectra reflected that the presence of maltol caused conformational change of CAT and made the CAT molecule skeleton loose and increased α-helix of CAT. Maltol mainly bound with CAT through hydrogen bond, and binding site that is near the heme ring in the enzyme activity center did not interact with its main amino acid residues. This study explores the combination between maltol and CAT, providing references for evaluating health damages caused by maltol.

FEMA GRAS assessment of natural flavor complexes: Mint, buchu, dill and caraway derived flavoring ingredients

In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavor ingredients. NFC flavor materials include a variety of essential oils and botanical extracts. The re-evaluation of NFCs is conducted based on a constituent-based procedure outlined in 2005 and updated in 2018 that evaluates the safety of NFCs for their intended use as flavor ingredients. This procedure is applied in the re-evaluation of the generally recognized as safe (GRAS) status of NFCs with constituent profiles that are dominated by alicyclic ketones such as menthone and carvone, secondary alcohols such as menthol and carveol, and related compounds. The FEMA Expert Panel affirmed the GRAS status of Peppermint Oil (FEMA 2848), Spearmint Oil (FEMA 3032), Spearmint Extract (FEMA 3031), Cornmint Oil (FEMA 4219), Erospicata Oil (FEMA 4777), Curly Mint Oil (FEMA 4778), Pennyroyal Oil (FEMA 2839), Buchu Leaves Oil (FEMA 2169), Caraway Oil (FEMA 2238) and Dill Oil (FEMA 2383) and determined FEMA GRAS status for Buchu Leaves Extract (FEMA 4923), Peppermint Oil, Terpeneless (FEMA 4924) and Spearmint Oil, Terpeneless (FEMA 4925).

Re-evaluation of benzyl alcohol (E 1519) as food additive

The Panel on Food Additives and Flavourings (FAF) provided a scientific opinion re-evaluating the safety of benzyl alcohol (E 1519) when used as a food additive. The Panel considered that adequate exposure and toxicity data were available. Benzyl alcohol (E 1519) is authorised as a food additive in the EU in accordance with Annex III to Regulation (EC) No 1333/2008. The Panel considered benzyl alcohol of low acute toxicity with no concern with respect to genotoxicity and carcinogenicity and established an acceptable daily intake (ADI) of 4 mg/kg body weight (bw) per day based on a no observable adverse effect level (NOAEL) of 400 mg/kg bw per day from the carcinogenicity study in rats. The mean and high exposure estimates in the refined exposure scenarios were maximally 0.27 and 0.81 mg/kg bw per day in toddlers, respectively. The exposure estimates to benzyl alcohol (E 1519) were below the ADI of 4 mg/kg bw per day in all population groups. The Panel noted that also the exposure in the regulatory maximum level exposure assessment scenario is below the ADI in all population groups. The Panel concluded that the exposure to benzyl alcohol (E 1519) does not raise a safety concern at the reported uses and use levels.

In vivo genotoxicity testing strategies: Report from the 7th International workshop on genotoxicity testing (IWGT)

The working group reached complete or majority agreement on many issues. Results from TGR and in vivo comet assays for 91 chemicals showed they have similar ability to detect in vivo genotoxicity per se with bacterial mutagens and Ames-positive carcinogens. TGR and comet assay results were not significantly different when compared with IARC Group 1, 2 A, and unclassified carcinogens. There were significantly more comet assay positive responses for Group 2B chemicals, and for IARC classified and unclassified carcinogens combined, which may be expected since mutation is a sub-set of genotoxicity. A liver comet assay combined with the bone marrow/blood micronucleus (MNviv) test would detect in vivo genotoxins that do not exhibit tissue-specific or site-of-contact effects, and is appropriate for routine in vivo genotoxicity testing. Generally for orally administered substances, a comet assay at only one site-of-contact GI tract tissue (stomach or duodenum/jejunum) is required. In MNviv tests, evidence of target tissue exposure can be obtained in a number of different ways, as recommended by ICH S2(R1) and EFSA (Hardy et al., 2017). Except for special cases the i.p. route is inappropriate for in vivo testing; for risk evaluations more weight should be given to data from a physiologically relevant administration route. The liver MN test is sufficiently validated for the development of an OECD guideline. However, the impact of dosing animals >6 weeks of age needs to be evaluated. The GI tract MN test shows promise but needs more validation for an OECD guideline. The Pig-a assay detects systemically available mutagens and is a valuable follow-up to in vitro positive results. A new freeze-thaw protocol provides more flexibility. Mutant reticulocyte and erythrocyte frequencies should both be determined. Preliminary data are available for the Pig-a assay in male rat germ cells which require validation including germ cell DNA mutation origin.

Genotoxicity of yellow shammah (smokeless tobacco) in murine bone marrow cells in vivo

Shammah is a traditional form of smokeless tobacco (ST) that is manufactured and used locally by people of Middle East with highest usage in Saudi Arabia, Yemen and Sudan. In Saudi Arabia, shammah comes in three variants: white, brown and yellow. In the present study, we investigated the genotoxicity of yellow shammah (YS) on bone marrow (BM) cells in vivo using mice. Bone marrow (BM) chromosomal aberration (CA) and micronucleus (MN) assay were performed and hepatic markers of oxidative stress were determined. Swiss albino mice were divided into five groups (n = 6) including negative control (NC) and positive control (PC) groups. The three treated groups included YS-100, 200 and 300 mg/kg, doses freshly prepared in 0.5% carboxymethyl cellulose (CMC) and administered orally once a day for 2 weeks. PC animals were administered cyclophosphamide (CP) at a dose of 40 mg/kg body weight, 24 h before termination. Two weeks continuous treatment of YS induced a dose dependent and significant increase in aberrant metaphases (AM), CA per cell and depression in mitotic activity. In micronucleus assay, YS treatment increased the percentage of micronucleated polychromatic erythrocytes (MNPCE) frequency and showed statistically significant reduction in polychromatic erythrocyte/normochromatic erythrocyte ratio at all doses, as compared to NC. YS also markedly inhibited the activities of superoxide dismutase, reduced glutathione and increased malondialdehyde content. CP was used as clastogen (positive control) and yielded the expected positive results. Therefore, it may be concluded that YS has genotoxic and cytotoxic effects for BM cells of mice in vivo.

Spectroscopic characterization, calorimetric study and molecular docking to evaluate the bioconjugation of maltol with hemoglobin

Maltol, a food additive, is extensively used in our daily life. To date, its biological safety is still debated. In this article, binding interaction of maltol with bovine hemoglobin (BHb), an important functional protein, was studied by molecular docking research and spectroscopic and calorimetric measurements. We found that maltol could cause structural changes of BHb. By interacting with Glu 101 (1.27 Å) and Lys 104 (2.49 Å) residues, maltol changed the cavity structure and induced a microenvironment change around tryptophan (Trp) residue. Thermodynamic parameters obtained from isothermal titration calorimetry (ITC) measurement showed that hydrophobic forces were the main forces existing in this system. The association constant of K (8.0 ± 3.4 × 10⁴  M^-1 ) shows the mild ligand-protein binding for maltol with BHb. The α-helix amount in BHb increased (59.6-62.6%) with different concentrations of maltol and the intrinsic fluorescence intensity was quenched by maltol, indicating the conformation changes and denaturation of BHb. This work presents the interactions of maltol with BHb at the molecular level and obtains evidence that maltol induces adverse effects to proteins in vitro.

Summarized data of genotoxicity tests for designated food additives in Japan

The Ministry of Health, Labour and Welfare has carried out genotoxicity tests for food additives used in Japan in cooperation with the Japan Food Additives Association since 1979. Hayashi et al. summarized these data and published a list of 337 designated additives (Shitei-tenkabutsu in Japanese) with genotoxicity test data in 2000. Thereafter, 29 items were eliminated, and 146 items were newly added. Currently, 454 designated additives are allowed to be used as food additives in Japan. This report, based on the Hayashi report, covers the addition of newly derived genotoxicity test data. Routinely, the bacterial reverse mutation test (Ames test), mammalian cell chromosomal aberration test, and in vivo rodent bone marrow micronucleus test have been used for the evaluation of genotoxicity of food additives. In addition to the data from these tests being updated in this report, it newly includes results of transgenic rodent somatic and germ cell gene mutation assays (TGR assays), incorporated in the Organisation for Economic Co-operation and Development (OECD) test guidelines after 2000. We re-evaluated the genotoxicity of 13 designated food additives considering their TGR data.

Scientific Opinion on Flavouring Group Evaluation 208 Revision 3 (FGE.208Rev3): consideration of genotoxicity data on alicyclic aldehydes with α,β-unsaturation in ring/side-chain and precursors from chemical subgroup 2.2 of FGE.19

The EFSA Panel on Food Additives and Flavourings was requested to evaluate the genotoxic potential of flavouring substances from subgroup 2.2 of FGE.19 in the Flavouring Group Evaluation 208 Revision 3 (FGE.208Rev3). In FGE.208Rev1, the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) evaluated genotoxicity studies on the representative substance p-mentha-1,8-dien-7-al [FL-no: 05.117], which was found to be genotoxic in vivo. The Panel concluded that there was a potential safety concern for the nine substances in this FGE that were all represented by [FL-no: 05.177]. Consequently, substance [FL-no: 05.117], as well as four substances ([FL-no: 05.121, 09.272, 09.899 and 09.900]), no longer supported by industry were deleted from the Union List. In FGE.208Rev2, the Panel assessed genotoxicity studies submitted on five flavouring substances [FL-no: 02.060, 02.091, 05.106, 09.278 and 09.302] and concluded that the concern for genotoxicity could be ruled out for these substances, except from myrtenal [FL-no: 05.106] for which the available data were considered equivocal. Thus, industry provided additional genotoxicity studies (a bacterial reverse mutation assay and a combined in vivo bone marrow erythrocytes micronucleus test and Comet assay in liver and duodenum) for this substance which were evaluated in the present opinion, FGE.208Rev3. Based on these new data, the Panel concluded that the concern for genotoxicity could be ruled out for myrtenal [FL-no: 05.106]. Subsequently, this substance can be evaluated through the Procedure.

Persistence of Epigenomic Effects After Recovery From Repeated Treatment With Two Nephrocarcinogens

The discovery of the epigenetic regulation of transcription has provided a new source of mechanistic understanding to long lasting effects of chemicals. However, this information is still seldom exploited in a toxicological context and studies of chemical effect after washout remain rare. Here we studied the effects of two nephrocarcinogens on the human proximal tubule cell line RPTEC/TERT1 using high-content mRNA microarrays coupled with miRNA, histone acetylation (HA) and DNA methylation (DM) arrays and metabolomics during a 5-day repeat-dose exposure and 3 days after washout. The mycotoxin ochratoxin A (OTA) was chosen as a model compound for its known impact on HA and DM. The foremost effect observed was the modulation of thousands of mRNAs and histones by OTA during and after exposure. In comparison, the oxidant potassium bromate (KBrO₃) had a milder impact on gene expression and epigenetics. However, there was no strong correlation between epigenetic modifications and mRNA changes with OTA while with KBrO₃ the gene expression data correlated better with HA for both up- and down-regulated genes. Even when focusing on the genes with persistent epigenetic modifications after washout, only half were coupled to matching changes in gene expression induced by OTA, suggesting that while OTA causes a major effect on the two epigenetic mechanisms studied, these alone cannot explain its impact on gene expression. Mechanistic analysis confirmed the known activation of Nrf2 and p53 by KBrO₃, while OTA inhibited most of the same genes, and genes involved in the unfolded protein response. A few miRNAs could be linked to these effects of OTA, albeit without clear contribution of epigenetics to the modulation of the pathways at large. Metabolomics revealed disturbances in amino acid balance, energy catabolism, nucleotide metabolism and polyamine metabolism with both chemicals. In conclusion, the large impact of OTA on transcription was confirmed at the mRNA level but also with two high-content epigenomic methodologies. Transcriptomic data confirmed the previously reported activation (by KBrO₃) and inhibition (by OTA) of protective pathways. However, the integration of omic datasets suggested that HA and DM were not driving forces in the gene expression changes induced by either chemical.

Mechanisms of oxidative stress-induced in vivo mutagenicity by potassium bromate and nitrofurantoin

Oxidative stress is well known as a key factor of chemical carcinogenesis. However, the actual role of oxidative stress in carcinogenesis, such as oxidative stress-related in vivo mutagenicity, remains unclear. It has been reported that 8-hydroxydeoxyguanosine (8-OHdG), an oxidized DNA lesion, might contribute to chemical carcinogenesis. Potassium bromate (KBrO3) and nitrofurantoin (NFT) are known as renal carcinogens in rats. Our previous studies showed an increase in mutant frequencies accompanied by an increased level of 8-OHdG in the kidneys of rodents following KBrO3 or NFT exposure. Furthermore, KBrO3 and NFT induced different types of gene mutations. Thus, in the present study, we performed reporter gene mutation assays and 8-OHdG measurements following KBrO3 or NFT exposure using Nrf2-proficient and Nrf2-deficient mice to clarify the relationship between KBrO3- or NFT-induced oxidative stress and subsequent genotoxicity. Administration of 1,500 ppm of KBrO3 in drinking water resulted in an increase in deletion mutations accompanied by an increase in 8-OHdG level, and administration of 2,500 ppm of NFT in diet induced an increase in guanine base substitution mutations without elevation of the 8-OHdG level in Nrf2-deficient mice. These results demonstrated that the formation of 8-OHdG, which resulted from the oxidizing potential of KBrO3, was directly involved in the increase in deletion mutations, although factors related to oxidative stress other than 8-OHdG might be crucial for NFT-induced guanine base substitution mutations. The present study provides new insight into oxidative stress-related in vivo mutagenicity.

Re-evaluation of propane-1,2-diol (E 1520) as a food additive

The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of propane-1,2-diol (E 1520) when used as a food additive. In 1996, the Scientific Committee on Food (SCF) established an acceptable daily intake (ADI) of 25 mg/kg body weight (bw) per day for propane-1,2-diol. Propane-1,2-diol is readily absorbed from the gastrointestinal and is expected to be widely distributed to organs and tissues. The major route of metabolism is oxidation to lactic acid and pyruvic acid. At high concentrations, free propane-1,2-diol is excreted in the urine. No treatment-related effects were observed in subchronic toxicity studies. The available data did not raise concern with respect to genotoxicity. Haematological changes suggestive of an increased red blood cell destruction with a compensatory increased rate of haematopoiesis were observed at the highest dose level (5,000 mg/kg bw per day) in a 2-year study in dogs. No adverse effects were reported in a 2-year chronic study in rats with propane-1,2-diol (up to 2,500 mg/kg bw per day). The SCF used this study to derive the ADI. No adverse effects were observed in the available reproductive and developmental toxicity studies. Propane-1,2-diol (E 1520) is authorised according to Annex III in some food additives, food flavourings, enzymes and nutrients and it is then carried over to the final food. Dietary exposure to E 1520 was assessed based on the use levels and analytical data. The Panel considered that for the food categories for which information was available, the exposure was likely to be overestimated. Considering the toxicity database, the Panel concluded that there was no reason to revise the current ADI of 25 mg/kg bw per day. The Panel also concluded that the mean and the high exposure levels (P95) of the brand-loyal refined exposure scenario did not exceed the ADI in any of the population groups from the use of propane-1,2-diol (E 1520) at the reported use levels and analytical results.

Hypersensitivity of mouse embryonic fibroblast cells defective for DNA polymerases η, ι and κ to various genotoxic compounds: Its potential for application in chemical genotoxic screening

Genotoxic agents cause modifications of genomic DNA, such as alkylation, oxidation, bulky adduct formation, and strand breaks, which potentially induce mutations and changes to the structure or number of genes. Majority of point mutations are generated during error-prone bypass of modified nucleotides (translesion DNA synthesis, TLS); however, when TLS fails, replication forks stalled at lesions eventually result in more lethal effects, formation of double-stranded breaks (DSBs). Here we compared sensitivities to various compounds among mouse embryonic fibroblasts derived from wild-type and knock-out mice lacking one of the three Y-family TLS DNA polymerases (Polη, Polι, and Polκ) or all of them (TKO). The compounds tested in this study include genotoxins such as methyl methanesulfonate (MMS) and nongenotoxins such as ammonium chloride. We found that TKO cells exhibited the highest sensitivities to most of the tested genotoxins, but not to the non-genotoxins. In order to quantitatively evaluate the hypersensitivity of TKO cells to different chemicals, we calculated ratios of half-maximal inhibitory concentration for WT and TKO cells. The ratios for 9 out of 10 genotoxins ranged from 2.29 to 5.73, while those for 5 nongenotoxins ranged from 0.81 to 1.63. Additionally, the two markers for DNA damage, ubiquitylated proliferating cell nuclear antigen and γ-H2AX after MMS treatment, were accumulated in TKO cells more greatly than in WT cells. Furthermore, following MMS treatment, TKO cells exhibited increased frequency of sister chromatid exchange compared with WT cells. These results indicated that the hypersensitivity of TKO cells to genotoxins resulted from replication fork stalling and subsequent DNA double-strand breaks, thus demonstrating that TKO cells should be useful for evaluating chemical genotoxicity.

Re-evaluation of potassium nitrite (E 249) and sodium nitrite (E 250) as food additives

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provided a scientific opinion re-evaluating the safety of potassium nitrite (E 249) and sodium nitrite (E 250) when used as food additives. The ADIs established by the SCF (1997) and by JECFA (2002) for nitrite were 0-0.06 and 0-0.07 mg/kg bw per day, respectively. The available information did not indicate in vivo genotoxic potential for sodium and potassium nitrite. Overall, an ADI for nitrite per se could be derived from the available repeated dose toxicity studies in animals, also considering the negative carcinogenicity results. The Panel concluded that an increased methaemoglobin level, observed in human and animals, was a relevant effect for the derivation of the ADI. The Panel, using a BMD approach, derived an ADI of 0.07 mg nitrite ion/kg bw per day. The exposure to nitrite resulting from its use as food additive did not exceed this ADI for the general population, except for a slight exceedance in children at the highest percentile. The Panel assessed the endogenous formation of nitrosamines from nitrites based on the theoretical calculation of the NDMA produced upon ingestion of nitrites at the ADI and estimated a MoE > 10,000. The Panel estimated the MoE to exogenous nitrosamines in meat products to be < 10,000 in all age groups at high level exposure. Based on the results of a systematic review, it was not possible to clearly discern nitrosamines produced from the nitrite added at the authorised levels, from those found in the food matrix without addition of external nitrite. In epidemiological studies there was some evidence to link (i) dietary nitrite and gastric cancers and (ii) the combination of nitrite plus nitrate from processed meat and colorectal cancers. There was evidence to link preformed NDMA and colorectal cancers.

Japan Flavour and Fragrance Materials Association's (JFFMA) safety assessment of food-flavouring substances uniquely used in Japan that belong to the class of aliphatic primary alcohols, aldehydes, carboxylic acids, acetals and esters containing additional oxygenated functional groups

We performed a safety evaluation using the procedure devised by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) of the following four flavouring substances that belong to the class of 'aliphatic primary alcohols, aldehydes, carboxylic acids, acetals, and esters containing additional oxygenated functional groups' and are uniquely used in Japan: butyl butyrylacetate, ethyl 2-hydroxy-4-methylpentanoate, 3-hydroxyhexanoic acid and methyl hydroxyacetate. Although no genotoxicity study data were found in the published literature, none of the four substances had chemical structural alerts predicting genotoxicity. All four substances were categorised as class I by using Cramer's classification. The estimated daily intake of each of the four substances was determined to be 0.007-2.9 μg/person/day by using the maximised survey-derived intake method and based on the annual production data in Japan in 2001, 2005 and 2010, and was determined to be 0.250-600.0 μg/person/day by using the single-portion exposure technique and based on average-use levels in standard portion sizes of flavoured foods. Both of these estimated daily intake ranges were below the threshold of toxicological concern for class I substances, which is 1800 μg/person/day. Although no information from in vitro and in vivo toxicity studies for the four substances was available, these substances were judged to raise no safety concerns at the current levels of intake.

Scientific Opinion on Flavouring Group Evaluation 208 Revision 2 (FGE.208Rev2): Consideration of genotoxicity data on alicyclic aldehydes with α,β-unsaturation in ring/side-chain and precursors from chemical subgroup 2.2 of FGE.19

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) was requested to evaluate the genotoxic potential of flavouring substances from subgroup 2.2 of FGE.19 in the Flavouring Group Evaluation 208 Revision 2 (FGE.208Rev2). In FGE.208Rev1, the CEF Panel evaluated genotoxicity studies on p-mentha-1,8-dien-7-al [FL-no: 05.117], the representative substance for FGE.19 subgroup 2.2. The Comet assay performed in liver showed a positive result, and therefore, the Panel concluded that p-mentha-1,8-dien-7-al [FL-no: 05.117] is genotoxic in vivo and that, accordingly, there is a safety concern for its use as flavouring substance. Since p-mentha-1,8-dien-7-al [FL-no: 05.117] is representative for the nine remaining substances of subgroup 2.2 (p-mentha-1,8-dien-7-ol [FL-no: 02.060], myrtenol [FL-no: 02.091], myrtenal [FL-no: 05.106], 2,6,6-trimethyl-1-cyclohexen-1-carboxaldehyde [FL-no: 05.121], myrtenyl formate [FL-no: 09.272], p-mentha-1,8-dien-7-yl acetate [FL-no: 09.278], myrtenyl acetate [FL-no: 09.302], myrtenyl-2-methylbutyrate [FL-no: 09.899] and myrtenyl-3-methylbutyrate [FL-no: 09.900]), the Panel concluded in the previous revision of FGE.208 (FGE.208Rev1) that there is a potential safety concern for these substances. Subsequently, the industry has submitted genotoxicity studies on five substances of FGE.19 subgroup 2.2: p-mentha-1,8-dien-7-ol [FL-no: 02.060], myrtenol [FL-no: 02.091], myrtenal [FL-no: 05.106], p-mentha-1,8-dien-7-yl acetate [FL-no: 09.278] and myrtenyl acetate [FL-no: 09.302], which are evaluated in the present revision of FGE.208 (FGE.208Rev2). The Panel concluded that the concern for genotoxicity could be ruled out for p-mentha-1,8-dien-7-ol [FL-no: 02.060], myrtenol [FL-no: 02.091], p-mentha-1,8-dien-7-yl acetate [FL-no: 09.278] and myrtenyl acetate [FL-no: 09.302], which will be evaluated through the Procedure. Genotoxicity data on myrtenal [FL-no: 05.106] were considered equivocal, therefore, it cannot be evaluated through the Procedure, presently. p-Mentha-1,8-dien-7-al [FL-no: 05.117] and four substances not supported by industry (2,6,6-trimethyl-1-cyclohexen-1-carboxaldehyde [FL-no: 05.121], myrtenyl formate [FL-no: 09.272], myrtenyl-2-methylbutyrate [FL-no: 09.899] and myrtenyl-3-methylbutyrate [FL-no: 09.900]) have been deleted from the Union List.

Final Report on the Safety Assessment of Propylene Glycol and Polypropylene Glycols

Propylene Glycol is an aliphatic alcohol manufactured as a reaction product of propylene oxide and water. Polypropylene Glycol is a polymer formed by adding propylene oxide to dipropylene glycol. Propylene Glycol is reportedly used as a skin-conditioning agent-humectant, solvent, viscosity-decreasing agent, and humectant in thousands of cosmetic formulations. Polypropylene Glycols of various polymer lengths are reportedly used as miscellaneous skin-conditioning agents in far fewer formulations. Acute, subchronic, and short-term animal studies suggested little toxicity beyond slight growth and body weight decreases. Little ocular or skin irritation was observed in animal studies, and no sensitization was seen. Small increases in fetal malformations were seen in mice injected subcutaneously with Propylene Glycol, but a continuous breeding reproduction study in mice showed no reproductive toxicity following oral administration. A wide range of mutagenesis assays were negative, and studies in mice and rats showed no evidence of carcinogenesis. Clinical data showed skin irritation and sensitization reactions in Propylene Glycol in normal subjects at concentrations as low as 10% under occlusive conditions and dermatitis patients at concentrations as low as 2%. A careful evaluation of skin irritation and sensitization data as a function of disease state of the individual, occlusion, and concentration was done. On the basis of that analysis, it is concluded that Propylene Glycol and Polypropylene Glycol are safe for use in cosmetic products at concentrations up to 50%.

Genotoxicity assessment of the flavouring agent, perillaldehyde

Perillaldehyde, a natural monocyclic terpenoid found most abundantly in the herb perilla, has a long history of use as a flavouring ingredient to add spiciness and citrus taste to foods. Previously, it was judged to be safe by several international expert panels. To confirm the safety of flavourings placed on the European Union list of flavourings, perillaldehyde was selected by the European Food Safety Authority as a representative of a subgroup of alicyclic aldehyde flavouring substances to be evaluated for genotoxic potential. Perillaldehyde was tested in a bacterial reverse mutation assay, an in vitro micronucleus assay in human lymphocytes, an HPRT assay in mouse lymphoma cells, and a micronucleus/comet assay in Han Wistar rats. In contrast to previously published results, perillaldehyde induced mutation in Salmonella typhimurium strain TA98 in the absence of metabolic activation. The comet assay was negative for duodenum and weakly positive for liver but only at a hepatotoxic dose of perillaldehyde. All other genotoxicity assays were negative. These data do not provide an indication of any genotoxic potential for perillaldehyde, and they provide the primary basis for recent scientific opinions regarding perillaldehyde genotoxicity announced by several international organizations responsible for safety assessment of food additives and flavourings.

A Quantitative Toxicogenomics Assay for High-throughput and Mechanistic Genotoxicity Assessment and Screening of Environmental Pollutants

The ecological and health concern of mutagenicity and carcinogenicity potentially associated with an overwhelmingly large and ever-increasing number of chemicals demands for cost-effective and feasible method for genotoxicity screening and risk assessment. This study proposed a genotoxicity assay using GFP-tagged yeast reporter strains, covering 38 selected protein biomarkers indicative of all the seven known DNA damage repair pathways. The assay was applied to assess four model genotoxic chemicals, eight environmental pollutants and four negative controls across six concentrations. Quantitative molecular genotoxicity end points were derived based on dose response modeling of a newly developed integrated molecular effect quantifier, Protein Effect Level Index (PELI). The molecular genotoxicity end points were consistent with multiple conventional in vitro genotoxicity assays, as well as with in vivo carcinogenicity assay results. Further more, the proposed genotoxicity end point PELI values quantitatively correlated with both comet assay in human cell and carcinogenicity potency assay in mice, providing promising evidence for linking the molecular disturbance measurements to adverse outcomes at a biological relevant level. In addition, the high-resolution DNA damaging repair pathway alternated protein expression profiles allowed for chemical clustering and classification. This toxicogenomics-based assay presents a promising alternative for fast, efficient and mechanistic genotoxicity screening and assessment of drugs, foods, and environmental contaminants.