Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) related to Coumarin

Developmental exposure to environmentally relevant doses of phthalates alters the neural control of male and female reproduction in mice

The present study aims to analyze the effects of developmental exposure to phthalates at environmentally relevant doses on the neural control of male and female reproduction. For this purpose, C57Bl/6J mice were exposed to di-(2-ethylexyl) phthalate (DEHP) alone (5 or 50 μg/kg/d), or DEHP (5 μg/kg/d) in a phthalate mixture. Exposure through diet started 6 weeks before the first mating and lasted until weaning of litters from the second gestation (multiparous dams). Analyses of offspring born from multiparous dams exposed to DEHP alone or in a phthalate mixture showed that females experienced a delayed pubertal onset, and as adults they had prolonged estrous cyclicity and reduced Kiss1 expression in the preoptic area and mediobasal hypothalamus. Male littermates showed a reduced anogenital distance and delayed pubertal onset compared with controls. However, in adulthood the weight of androgen-sensitive organs and hypothalamic Kiss1 expression were unaffected, suggesting normal functioning of the male gonadotropic axis. Developmental exposure to DEHP alone or in a phthalate mixture reduced the ability of intact males and ovariectomized and hormonally primed females to attract a sexual partner and to express copulatory behaviors. In addition, females were unable to discriminate between male and female stimuli in the olfactory preference test. Social interaction was also impaired in females, while locomotor activity and anxiety-like behavior in both sexes were unaffected by the treatment. The sexual deficiencies were associated with reduced expression of the androgen receptor in the preoptic area and progesterone receptor in the mediobasal hypothalamus, the key regions involved in male and female sexual behavior, respectively. Thus, the neural structures controlling reproduction are vulnerable to developmental exposure to phthalates at environmentally relevant doses in male and female mice. Adult females had an impaired gonadotropic axis and showed more affected behaviors than adult males.

Nuclear Magnetic Resonance Fingerprints and Mini DNA Markers for the Authentication of Cinnamon Species Ingredients Used in Food and Natural Health Products

Cinnamomum verum (syn C. zeylanicum) is considered 'true' cinnamon. However, it is reported that less expensive sources of cinnamon from C. cassia (syn C. aromaticum), C. loureiroi, and C. burmannii (toxic coumarin) may be used in the place of C. verum. We lack the quality assurance tools that are required to differentiate C. verum from other cinnamon species when verifying that the correct species is sourced from ingredient suppliers. The current research on cinnamon species authentication using DNA tools is limited to a few species and the use of high-quality DNA extracted from raw leaf materials. The cinnamon bark traded in the supply chain contains much less DNA and poorer-quality DNA than leaves. Our research advances DNA methods to authenticate cinnamon, as we utilized full-length chloroplast genomes via a genome skimming approach for C. burmannii and C. cassia to facilitate the design of optimal mini DNA markers. Furthermore, we developed and validated the use of NMR fingerprints for several commercial cinnamon species, including the quantification of 16 molecules. NMR fingerprints provided additional data that were useful for quality assessment in cinnamon extract powders and product consistency. Both the new mini DNA markers and NMR fingerprints were tested on commercial cinnamon products.

Application of urea-based magnetic covalent organic framework as sorbent for the determination of coumarin and its derivatives in food samples combined with liquid chromatography-mass spectrometry

A magnetic solid-phase extraction (MSPE) protocol using novel Urea-based magnetic covalent organic framework coupled with liquid chromatography-mass spectrometry was developed for the detection of coumarins in food samples (soft drink, biscuit and sesame paste). This adsorbent was synthesized through atom economic polymerization of tetrakis(4-aminophenyl) methane and 1,4-phenylene diisocyanate, which was successfully verified by a series of techniques. Major parameters influencing MSPE efficiency were optimized. This protocol had some advantages, such as organic-reagent-saving (2.0 mL), easy operating, short extraction time, and high repeatability (8 times). The established method exhibited superior linearity (R2 ≥ 0.999) and the limits of detection ranging from 1.0 to 5.0 µg/kg. The recoveries of coumarin and its derivatives ranged from 73.8% to 113.5% and both intra- and inter-day precision were less than 15%. These data indicate the protocol is a highly promising alternative for coumarin extraction and enrichment.

Coumarin-Induced Hepatotoxicity: A Narrative Review

Coumarin is an effective treatment for primary lymphoedema, as well as lymphoedema related to breast cancer radiotherapy or surgery. However, its clinical use is limited in several countries due to the possible occurrence of hepatotoxicity, mainly in the form of mild to moderate transaminase elevation. It is worth noting that only a few cases of severe hepatotoxicity have been described in the literature, with no reported cases of liver failure. Data available on coumarin absorption, distribution, metabolism, and excretion have been reviewed, focusing on hepatotoxicity studies carried out in vitro and in vivo. Finally, safety and tolerability data from clinical trials have been thoroughly discussed. Based on these data, coumarin-induced hepatotoxicity is restricted to a small subset of patients, probably due to the activation in these individuals of alternative metabolic pathways involving specific CYP450s isoforms. The aim of this work is to stimulate research to clearly identify patients at risk of developing hepatotoxicity following coumarin treatment. Early identification of this subset of patients could open the possibility of more safely exploiting the therapeutical properties of coumarin, allowing patients suffering from lymphoedema to benefit from the anti-oedematous activity of the treatment.

The effect of a natural polyphenol supplement on iron absorption in adults with hereditary hemochromatosis

Objectives

We developed a natural polyphenol supplement that strongly chelates iron in vitro and assessed its effect on non-heme iron absorption in patients with hereditary hemochromatosis (HH).

Methods

We performed in vitro iron digestion experiments to determine iron precipitation by 12 polyphenol-rich dietary sources, and formulated a polyphenol supplement (PPS) containing black tea powder, cocoa powder and grape juice extract. In a multi-center, single-blind, placebo-controlled cross-over study, we assessed the effect of the PPS on iron absorption from an extrinsically labelled test meal and test drink in patients (n = 14) with HH homozygous for the p.C282Y variant in the HFE gene. We measured fractional iron absorption (FIA) as stable iron isotope incorporation into erythrocytes.

Results

Black tea powder, cocoa powder and grape juice extract most effectively precipitated iron in vitro. A PPS mixture of these three extracts precipitated ~ 80% of iron when 2 g was added to a 500 g iron solution containing 20 µg Fe/g. In the iron absorption study, the PPS reduced FIA by ~ 40%: FIA from the meal consumed with the PPS was lower (3.01% (1.60, 5.64)) than with placebo (5.21% (3.92, 6.92)) (p = 0.026)), and FIA from the test drink with the PPS was lower (10.3% (7.29 14.6)) than with placebo (16.9% (12.8 22.2)) (p = 0.002).

Conclusion

Our results indicate that when taken with meals, this natural PPS can decrease dietary iron absorption, and might thereby reduce body iron accumulation and the frequency of phlebotomy in patients with HH.

Trial registry: clinicaltrials.gov (registration date: 9.6.2019, NCT03990181).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02829-8.

Safety Profile of Nutraceuticals Rich in Coumarins: An Update

Coumarins are a family of benzopyrones largely distributed in the natural kingdom, being present in the seeds, fruits, flowers, or roots of various plant species. Natural coumarin compounds are found in significant concentrations in some herbs or spices used as nutraceuticals, but they are also present in cosmetics or household products, due to their pleasant odor. Therefore, an accidental exposure to high doses of coumarins, could lead to the development of harmful effects in some patients. This review summarizes the latest published data from preclinical and clinical studies with natural coumarins, focused on the investigation of general and specific toxicity, with the aim of a better understanding of the safety profile of these valuable compounds. Regulatory aspects concerning the use of natural coumarins in several world regions are also reviewed.

Two Biotechnological Approaches to the Preparative Synthesis of Natural Dihydrocoumarin

In this work, we describe two different biotechnological processes that provide the natural flavour dihydrocoumarin in preparative scale. Both the presented approaches are based on the enzyme-mediated reduction of natural coumarin. The first one is a whole-cell process exploiting the reductive activity of the yeast Kluyveromyces marxianus, a Generally Recognized As Safe (GRAS) microorganism that possesses high resistance to the substrate toxicity. Differently, the second is based on the reduction of natural coumarin by nicotinamide adenine dinucleotide phosphate (NADPH) and using the Old Yellow Enzyme reductase OYE2 as catalyst. NADPH is used in catalytic amount since the co-factor regeneration is warranted employing an enzymatic system based on glucose oxidation, in turn catalysed by a further enzyme, namely glucose dehydrogenase (GDH). Both processes compare favourably over the previously reported industrial method as they work with higher coumarin concentration (up to 3 g/L for the enzymatic process) yet allowing the complete conversion of the substrate. Furthermore, the two approaches have significant differences. The microbial reduction is experimentally simple but the isolated dihydrocoumarin yield does not exceed 60%. On the contrary, the enzymatic approach requires the use of two specially prepared recombinant enzymes, however, it is more efficient, affording the product in 90% of isolated yield.

Infant total diet study in France: Exposure to substances migrating from food contact materials

A total diet study (TDS) was conducted in France to assess the health risks related to the chemicals in food of non-breastfed children under three years of age (Infant TDS). For the first time, substances coming from food contact materials, such as bisphenol A (BPA), bisphenol A diglycidyl ether (BADGE) and its derivatives, some phthalates, and some ink photoinitiators, were targeted because of growing interest in these substances. Food samples were collected to be representative of the whole diet of non-breastfed children aged 1-36 months, and prepared as consumed prior to analysis. Dietary exposure was assessed for 705 representative children under three years of age. Generally, the substances from food contact materials were detected in few samples: 38% for BPA, 0% for BADGE and its derivatives, 0-35% for phthalates, 1.9% for benzophenone, and 0% for the other ink photoinitiators. Regarding exposure levels, the situation was deemed tolerable for BADGE and its hydrolysis products, di-isodecyl phthalate, dibutyl phthalate, butyl benzyl phthalate, bis(2-ethylhexyl) phthalate, and di-isononyl phthalate, benzophenone, and 4-methylbenzophenone. Only for BPA, the exposure levels of some children exceeded the lowest toxicological value established by the French Agency for Food, Environmental and Occupational Health & Safety at 0.083 µg.kg bw^-1.d^-1. The temporary tolerable daily intake of the European Food Safety Authority (EFSA), set at 4 µg.kg bw^-1.d^-1, was never exceeded. However, actual exposure to BPA was probably overestimated, as well as the associated risk, because the foods were sampled prior to the recent regulations banning BPA in food packaging. This study is the first worldwide to provide an estimate of infant food contamination levels and exposures of children under 3 years of age, based on a TDS approach. It therefore provides key data on the exposure of this particularly sensitive population to substances released from food contact materials, and presents useful data for studies evaluating exposure to mixtures or aggregated exposure.

Profiling of Primary Metabolites and Volatile Determinants in Mahlab Cherry (Prunus mahaleb L.) Seeds in the Context of Its Different Varieties and Roasting as Analyzed Using Chemometric Tools

Mahlab cherry (Prunus mahaleb L.) is a plant native to the Mediterranean basin and Eastern Europe, with several health benefits and culinary uses. We explored the compositional heterogeneity in the aroma profile and nutrients of three P. mahaleb seeds in the context of its cultivar type, i.e., white and red, and in response to roasting. A holistic untargeted metabolomics approach was employed for the first time using solid-phase microextraction (SPME-GC-MS) profiles of seed volatiles and primary metabolites coupled with chemometrics. Around 65 peaks belonging to sugars, fatty acids, esters and organic acids were identified by GC-MS. White mahlab from Egypt is rich in fatty acids, e.g., oleic and α-linolenic acids. Some acyl esters, e.g., glycerylmonostearate and n-butylcaprylate, characterized mahlab cultivars from various origins. A total of 135 volatiles were identified, with organic acids and aldehydes the most abundant. Aldehydes were the most discriminatory in seed origin and in accounting for its distinct aroma. Several roasting indices were identified, viz. 1-octanol, γ-caprolactone and isomintlactone. A direct relationship between furans and fatty acids was rationalized by cyclic transformation of the latter into furan derivatives. This study provides the first chemical evidence supporting the nutritional and flavor determinants of mahlab seeds, suggesting novel uses as a functional food.

Titanium Dioxide Presents a Different Profile in Dextran Sodium Sulphate-Induced Experimental Colitis in Mice Lacking the IBD Risk Gene Ptpn2 in Myeloid Cells

Environmental and genetic factors have been demonstrated to contribute to the development of inflammatory bowel disease (IBD). Recent studies suggested that the food additive; titanium dioxide (TiO2) might play a causative role in the disease. Therefore, in the present study we aimed to explore the interaction between the food additive TiO2 and the well-characterized IBD risk gene protein tyrosine phosphatase non-receptor type 2 (Ptpn2) and their role in the development of intestinal inflammation. Dextran sodium sulphate (DSS)-induced acute colitis was performed in mice lacking the expression of Ptpn2 in myeloid cells (Ptpn2LysMCre) or their wild type littermates (Ptpn2fl/fl) and exposed to the microparticle TiO2. The impact of Ptpn2 on TiO2 signalling pathways and TiO2-induced IL-1β and IL-10 levels were studied using bone marrow-derived macrophages (BMDMs). Ptpn2LysMCre exposed to TiO2 exhibited more severe intestinal inflammation than their wild type counterparts. This effect was likely due to the impact of TiO2 on the differentiation of intestinal macrophages, suppressing the number of anti-inflammatory macrophages in Ptpn2 deficient mice. Moreover, we also found that TiO2 was able to induce the secretion of IL-1β via mitogen-activated proteins kinases (MAPKs) and to repress the expression of IL-10 in bone marrow-derived macrophages via MAPK-independent pathways. This is the first evidence of the cooperation between the genetic risk factor Ptpn2 and the environmental factor TiO2 in the regulation of intestinal inflammation. The results presented here suggest that the ingestion of certain industrial compounds should be taken into account, especially in individuals with increased genetic risk.

Scopoletin increases glucose uptake through activation of PI3K and AMPK signaling pathway and improves insulin sensitivity in 3T3-L1 cells

Coumarins have been shown to reduce blood glucose levels and improve insulin sensitivity in other studies. The purpose of this study was to investigate the effects of scopoletin, which is a type of coumarin family, on glucose uptake in 3T3-L1 cells to test the hypothesis that scopoletin exerts an antidiabetic function on adipocytes. Scopoletin significantly increased glucose uptake, which was associated with increased expression of the plasma membrane glucose transporter type 4 (PM-GLUT4) in 3T3-L1 adipocytes. This increase in PM-GLUT4 expression was promoted by phosphorylation of protein kinase B, activation of phosphatidylinositol-3-kinase (PI3K), and enhanced intracellular glucose uptake. Scopoletin also promoted phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and enhanced PM-GLUT4 expression. Scopoletin-induced glucose uptake in 3T3-L1 adipocytes was inhibited by treatment with the PI3K inhibitor wortmannin and the AMPK inhibitor compound C. These results suggest that scopoletin has an antidiabetic effect by stimulating GLUT4 translocation to the PM through activation of the PI3K and AMPK pathways in 3T3-L1 adipocytes, thereby upregulating glucose uptake.

Biocatalytic Synthesis of Natural Dihydrocoumarin by Microbial Reduction of Coumarin

Dihydrocoumarin is a natural product of great relevance for the flavour industry. In this work, we describe a study on the biotransformation of the toxic compound coumarin into natural dihydrocoumarin, recognized as safe for food aromatization. To this end, we screened a variety of yeasts and filamentous fungi, isolated from different sources, in order to evaluate their ability to reduce selectively the conjugated double bond of coumarin. Moreover, since coumarin induces cytotoxicity and therefore inhibits cell growth as well as the cell metabolic activity, we tested out different substrate concentrations. All strains were able to convert the substrate, although showing very different conversion rates and different sensitivity to the coumarin concentration. In particular, the yeasts Torulaspora delbrueckii, Kluyveromyces marxianus and the fungus Penicillium camemberti displayed the higher activity and selectivity in the substrate transformation. Among the latter strains, Kluyveromyces marxianus presented the best resistance to substrate toxicity, allowing the biotransformation process even with coumarin concentration up to 1.8 g/L.

Bioprofiling of Cosmetics with Focus on Streamlined Coumarin Analysis

Facing the widespread use of cosmetic products in daily use and recognizing the very limited information obtained by target analysis, a method suited for comprehensive characterization of cosmetics was aimed at. The biological activity of ingredients of 20 cosmetics taken from 16 different product groups and their coumarin contents were investigated via chromatography linked to bioassays (direct bioautography) and mass spectrometry. It allows for screening a large number of cosmetic products within a short time to generate a more valid database on their coumarin content and their contribution to the overall exposure. Bioactivity profiling of cosmetics with regard to bioactive ingredients opens new avenues for a comprehensive characterization of important substances in products of daily use, helpful for the legally required safety and risk assessment of cosmetic products, especially for multiple product usage. As for coumarin, a ubiquitary fragrance compound of allergenic potential, which is under recurrent discussion due to its hepatoxic properties, it is necessary to be able to estimate the regular intake via cosmetics for a valid risk assessment. This newly developed bioprofiling method allowed a selective determination of coumarin down to 1.3 mg kg^-1, even for very matrix-rich cosmetics despite minimalism in sample preparation. The declaration limits according to European Cosmetics Regulation were completely covered. Mean coumarin contents of 20 cosmetic products reached up to 2218 mg kg^-1. The repeatabilities (%RSD, n = 3) were between 1.1 and 2.9%, and the mean recoveries (n = 5) were between 96 and 102% for the different cosmetic matrices.

Blank problems in trace analysis of diethylhexyl and dibutyl phthalate: Investigation of the sources, tips and tricks

The analysis of phthalates, particularly that of di(2-ethylhexyl)phthalate (DEHP) and dibutyl phthalate (DBP), is notorious for blank problems. Methods and tools are listed to identify the sources and reduce the system contamination to below 1 pg DEHP and DBP or below 1 ng mL(-1) of sample solution. Once direct contact with phthalate-containing plastic articles is ruled out, the air is the major source, primarily via absorption to the surfaces of laboratory glass ware. A main improvement was achieved by cleaning solvents with aluminium oxide permanently left in the reservoirs. The data enables to estimate the contamination to be expected and to design methods keeping blanks below a critical threshold.