Significant variation in the concentration of carcinogenic polycyclic aromatic hydrocarbons in yerba maté samples by brand, batch, and processing method

Development of a novel DGT passive sampler for measuring polycyclic aromatic hydrocarbons in aquatic systems

Polycyclic aromatic hydrocarbons (PAHs) are priority pollutants and need to be measured reliably in waters and other media, to understand their sources, fate, behaviour and to meet regulatory monitoring requirements. Conventional water sampling requires large water volumes, time-consuming pre-concentration and clean-up and is prone to analyte loss or contamination. Here, for the first time, we developed and validated a novel diffusive gradients in thin-films (DGT) passive sampler for PAHs. Based on the well-known DGT principles, the sampler pre-concentrates PAHs with typical deployment times of days/weeks, with minimal sample handling. For the first time, DGT holding devices made of metal and suitable for sampling hydrophobic organic compounds were designed and tested. They minimize sorption and sampling lag times. Following tests on different binding layer resins, a MIP-DGT was preferred - the first time applying MIP for PAHs. It samples PAHs independent of pH (3.9 -8.1), ionic strength (0.01 -0.5 M) and dissolved organic matter < 20 mg L-1, making it suitable for applications across a wide range of environments. Field trials in river water and wastewater demonstrated that DGT is a convenient and reliable tool for monitoring labile PAHs, readily achieving quantitative detection of environmental levels (sub-ng and ng/L range) when coupled with conventional GC-MS or HPLC. ENVIRONMENTAL IMPLICATIONS: PAHs are carcinogenic and genotoxic compounds. They are environmentally ubiquitous and must be monitored in waters and other media. This study successfully developed a new DGT passive sampler for reliable in situ time-integrated measurements of PAHs in waters at the ng/L level. This is the first time to use passive samplers for accurate measurements of hydrophobic organic contaminants in aquatic systems without calibration, a big step forward in monitoring PAHs. The application of this new sampler will enhance our understanding of the sources, fate, behavior and ecotoxicology of PAHs, enabling improved environmental risk assessment and management of these compounds.

Yerba mate (Ilex paraguariensis A. St.-Hil.) for new therapeutic and nutraceutical interventions: A review of patents issued in the last 20 years (2000-2020)

It has been estimated that more than 70% of all drugs approved worldwide between 1981 and 2006 for human health are derived from or structurally similar to natural compounds. The identification of biological matrices containing bioactive compounds with therapeutic and nutraceutical potential is necessary to supply the global market demands. Researches have indicated that the consumption of dry and aqueous extracts of Ilex paraguariensis A. St.-Hil. is safe, providing that plant biomass does not be exposed to smoke over the drying process, avoiding contamination (e.g., ) with polycyclic aromatic hydrocarbon compounds, and can might help avoiding many diseases, with important potential applications in the pharma and nutraceutical industries. A survey was carried out covering the main therapeutic and nutraceutical studies performed on I. paraguariensis extracts and their relationship with the global patents granted in the last 20 years for the products using this specie in their composition. In the PubMed database, by searching for the term "Ilex paraguariensis," an output with 497 scientific publications was found. Each paper was analyzed individually and 26 publications encompassing exclusively therapeutical and nutraceutical approaches of that plant species were selected. For the patent screening regarding Ilex-derived products, the survey considered three patent databases: European Patent Office (EPO) (Espacenet), World Intellectual Property Organization, WIPO), and National Institute of Industrial Property (NIIP-Brazil). The criterion chosen to select the patents in the databases was the inclusion of the terms "Ilex paraguariensis" and "yerba mate" in the title and/or in the abstract, considering the patents issued from 2000 to 2020. Additionally, only patents with therapeutic and nutraceutical potential were considered on the survey. The screening and selection of the documents were performed independently by two researchers and the information cross-checked at the end. This review contributes to show the state of the art over the last 20 years on the knowledge about the therapeutical and nutraceutical usages of the yerba mate, associated to a certain number of issued patents. The patent survey afforded 62 relevant documents covering products based on Ilex paraguariensis biomass. Considering the number of patents issued, most of them are related to the pharmaceutical area (30), followed by food supplements and beverages (17), cosmetics (10) and, finally, nutraceuticals (5). A detailed analysis of the patents issued showed that most are related to pharmaceutical grade products, generally, marketed as oral and injectable compositions for treatments of obesity, insulin resistance, hyperlipemia and diabetes mellitus, arteriosclerosis, neurological diseases, and SARS-Cov-2, for example. In this work, a curious fact is that there are few patents for food, cosmetics, and nutraceuticals products containing yerba mate. Therefore, it seems to be relevant to take into account the potential of that species as source of bioactive compounds for the development of new products not only intended to the pharma sector. In this sense, 26 reports were identified showing possibilities and trendiness in developing new yerba mate based products, such as packaging, biopesticides, antiseptics, and food supply, expanding the possibilities of technological applications of this plant species.

Effects of an alternative bleaching method for yerba mate leaves on total phenolic content: evaluation and prediction with soft-computing approaches

BACKGROUND

The effects of an alternative bleaching method on the total phenolic content (TPC) and antioxidant activity (AA) of yerba mate extracts were evaluated. Traditional bleaching ('zapeco') was compared with submerging the leaves in water followed by a hot air oven-drying process. Seven different approaches, i.e. linear model (LM), response surface model (RSM), Mamdani, Larsen, adaptive neuro-fuzzy inference system (ANFIS) with the product (Prod) and the minimum (Min) operators, and ANFIS with automatically membership functions (Auto), were employed to compare the TPC of yerba mate extracts based on drying temperature and AA assays.

RESULTS

The results showed that if leaves were bleached followed by drying at higher temperatures, we obtained higher AA and TPC values. For submerging bleaching treatment, RSM model delivered the best accuracy measures with a mean absolute error (MAE), average absolute percentage error (MAPE), and mean squared error (MSE) of 0.128, 0.006, and 0.028, respectively. The ANFIS Auto model was the best for traditional bleaching treatment, with MAE, MAPE, and MSE of 0.490, 0.013, and 0.612, respectively.

CONCLUSION

The results suggest a second-order linear relation between drying temperature, AA assays to TPC, and a high level of relation complexity of drying temperature, AA assays, and TPC. The evaluated soft-computing approaches have the excellent ability to estimate TPC from bleached leaves. © 2022 Society of Chemical Industry.

Squamous Cell Carcinoma of the Esophagus

Esophageal squamous cell carcinoma (ESCC) is common in the developing world with decreasing incidence in developed countries and carries significant morbidity and mortality. Major risk factors for ESCC development include significant use of alcohol and tobacco. Screening for ESCC can be recommended in high-risk populations living in highly endemic regions. The treatment of ESCC ranges from endoscopic resection therapy or surgery in localized disease to chemoradiotherapy in metastatic disease, and prognosis is directly related to the stage at diagnosis. New immunotherapies and molecular targeted therapies may improve the dismal survival outcomes in patients with metastatic ESCC.

Yerba Mate-A Long but Current History

Bearing in mind the growing interest in Yerba Mate, a comprehensive study has been prepared containing the most important aspects and possibilities of its use. The introduction of the work contains the species characteristics of Yerba Mate, as well as information about the origin and places of cultivation. The next part focuses on the analysis of the composition, pointing to purine alkaloids, polyphenols, saponins, and minerals as groups of active compounds responsible for the clinical activity of Yerba Mate. The review of the results of preclinical and clinical studies indicates activity in relation to the stimulating effect, reducing weight by stimulating lipolysis, cardioprotective, anti-diabetic, and anti-inflammatory effects. The information about the action of Yerba Mate is supplemented by the characteristics of its potential toxicity in terms of PAHs content (in particular benzo[α]pyrene) and preparation as a determinant of increased irritation. The current data on the effects of Yerba Mate and the wide safety margin of its use position this raw material as a valuable component of functional food. The growing frequency of consuming Yerba Mate, conditioned by the availability resulting from the globalization of the market and the information provided about it's the pro-health effects, will position Yerba Mate's popularity among wider population groups.

Indoor wood combustion, carcinogenic exposure and esophageal cancer in southwest Kenya

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) is a risk factor for esophageal squamous cell carcinoma (ESCC) in high-incidence areas of China, Iran and Brazil, but PAH assessments have not been conducted in East Africa, another ESCC hot spot.

OBJECTIVE

To evaluate demographic or lifestyle factors associated with the PAH biomarker concentrations in the study population, and whether PAH metabolite concentrations showed any associations with esophageal precancerous lesions.

METHODS

We recruited a community-based sample of 289 asymptomatic adults from a rural area of Kenya and performed Lugol's chromoendoscopy to detect esophageal squamous dysplasia (ESD); participants completed a questionnaire and provided a spot urine specimen. We analyzed urine for seven hydroxylated metabolites of naphthalene, fluorene, phenanthrene, and pyrene at the U.S. National Center for Environmental Health, and compared creatinine-corrected PAH metabolite concentrations with questionnaire data and the presence of ESD.

RESULTS

PAH metabolite concentrations among never tobacco users in these rural Kenya residents were 2.4-28.1 times higher than those reported from never tobacco users in Iran, Brazil and the USA. Female sex, cooking indoors, having no post-primary education, and age <50, but not tobacco use, were positively and significantly associated with PAH metabolite concentrations. Almost all participants used wood as cooking fuel. Nine participants had advanced ESD. Adjusted logistic regression showed a significant association between 2-hydroxynaphthalene (OR = 4.19, 95%CI: 1.01-17.47) and advanced ESD. All other PAH metabolites had positive but non-significant associations with advanced ESD.

CONCLUSIONS

Urinary PAH metabolite concentrations among never tobacco users are markedly higher in this group from Kenya than in other populations and are associated with indoor cooking with wood on open, unvented stoves. These metabolite concentrations were also associated with the presence of advanced esophageal dysplasia. Our findings underline the importance of assessing alternative cooking conditions to reduce PAH exposure in this population.

Effects of different drying methods on the chemical, nutritional and colour of yerba mate (Ilex paraguariensis) leaves

This work investigates the effect of different drying processes on chemical, nutritional and leaves colour characteristics for Ilex paraguariensis leaves. These processes were composed of typical drying techniques (roasting + rotary dryer and roasting + conveyor dryer), and cutting-edge techniques (microwave oven [MW], freeze-drying (FD) and oven dryer [OD]). The MW can be an alternative technique, this is because the content of phenolic compounds (77 mg/g), antioxidant capacity (DPPH and ABTS) (∼370 and ∼1040 μM TE/g), methylxanthines and caffeoylquinic acids (2–4 mg/g) were similar, and sometimes higher, to the conventional drying processes. Leaves dried with MW also exhibited satisfactory nutritional analysis for protein (16.4%), dietary fibre (52.3%), ash (6.4%), lipid (6.1%) and moisture (5.7%), implying that yerba mate is a potential source of fibre and protein. Furthermore, the MW preserved leaves green colour (high and low scores of b* and a*, respectively).

Polycyclic aromatic hydrocarbons in yerba mate (Ilex paraguariensis) infusions and probabilistic risk assessment of exposure

The aim of this study was to assess the risk of exposure to polycyclic aromatic hydrocarbons (PAH) from yerba mate infusions in Uruguay using the margin of exposure approach (MOE) and a probabilistic method (Monte Carlo simulation). Servings/day, portion size, weekly frequency of mate consumption and body weight were the factors considered. The amount in infusions of benz[a]pyrene (B[a]P), PAH2 (sum of chrysene and B[a]P), and PAH4 (sum of benz[a]anthracene, chrysene, benz[b]fluoranthene and B[a]P) were used as markers of PAH exposure. Total content of PAH in infusions had large inter-brand variability (48-54 %) with significant differences among brands. PAH content in infusions prepared as habitually consumed was about 40 % of total content. The probability of occurrence of MOE < 10,000 varied according to the infusion preparation and the marker of exposure used, being higher for infusions prepared for total content and when B[a]P was used as marker of exposure. When the average B[a]P amount in infusion as habitually consumed was used in the simulation model, the probability of MOE < 10,000 was 9 %. The main factors contributing to B[a]P MOE variance were B[a]P amount (28.4 %), servings/day (17.3 %), and portion size (9.6 %). Heavy drinkers of yerba mate with high B[a]P content are those at risk to PAH exposure from mate infusions.

Investigating tea temperature and content as risk factors for esophageal cancer in an endemic region of Western Kenya: Validation of a questionnaire and analysis of polycyclic aromatic hydrocarbon content

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is common in certain areas worldwide. One area, western Kenya, has a high risk of ESCC, including many young cases (<30 years old), but has limited prior study of potential risk factors. Thermal injury from hot food and beverages and exposure to polycyclic aromatic hydrocarbons (PAHs) have been proposed as important risk factors for ESCC in other settings. The beverage of choice in western Kenya is milky tea (chai).

METHODS

Healthy individuals >18 years of age who were accompanying relatives to an endoscopy unit were recruited to participate. The preferred initial temperature of chai consumption in these adults was measured by questionnaire and digital thermometer. Comparisons of these results were assessed by kappa statistics. Concentrations of 26 selected PAHs were determined by gas chromatography/mass spectrometry in samples of 11 brands of commercial tea leaves commonly consumed in Kenya.

RESULTS

Kappa values demonstrated moderate agreement between questionnaire responses and measured temperatures. The mean preferred chai temperatures were 72.1 °C overall, 72.6 °C in men (n = 78), and 70.2 °C in women (n = 22; p < 0.05). Chai temperature did not significantly differ by age or ethnic group. The PAH levels in the commercial Kenyan tea leaves were uniformly low (total PAH < 300 ng/g of leaves).

CONCLUSIONS

Study participants drink chai at higher temperatures than previously reported in other high-risk ESCC regions. Chai is not, however, a source of significant PAH exposure. Very hot chai consumption should be further evaluated as a risk factor for ESCC in Kenya with the proposed questionnaire.

Polycyclic aromatic hydrocarbons as a potential source of carcinogenicity of mate

Drinking mate, an infusion of the herb ilex paraguariensis, is very common in several South American countries, and has been associated with an increased risk of esophageal cancer. This increased risk may be attributed to drinking mate very hot, or to mate's potentially carcinogenic contaminants, such as polycyclic aromatic hydrocarbons (PAHs). Mate leaves are often dried via smoking, and therefore commercial samples may have high amounts of PAHs. We found 10 original articles that had measured PAHs in commercial dry samples, and nearly all found very high mass fractions. Most studies found benzo[a]pyrene mass fractions to be over 25 ng/g, and some found levels up to 600 ng/g. However, carcinogenic PAHs are often hydrophobic, and may not readily transfer into infusions. Seven articles studied transfer rates, and these rates varied from 1 to 50%, depending on the methods employed. Further careful studies of transfer rates in situations that mimic real life drinking of mate are recommended. Also, further studies of biological indicators of PAH exposure, particularly in randomized experiments, and analyzing DNA from tumor samples of mate drinkers are recommended.

Comparative oesophageal cancer risk assessment of hot beverage consumption (coffee, mate and tea): the margin of exposure of PAH vs very hot temperatures

Background

Consumption of very hot (> 65 °C) beverages is probably associated with increased risk of oesophageal cancer. First associations were reported for yerba mate and it was initially believed that high content of polycyclic aromatic hydrocarbons (PAH) might explain the risk. Later research on other beverage groups such as tea and coffee, which are also consumed very hot, found associations with increased risk of oesophageal cancer as well. The risk may therefore not be inherent in any compound contained in mate, but due to temperature. The aim of this study was to quantitatively assess the risk of PAH in comparison with the risk of the temperature effect using the margin of exposure (MOE) methodology.

Methods

The human dietary benzo[a]pyrene (BaP) and PAH4 (sum of benzo[a]pyrene, benzo[a]anthracene, chrysene, and benzo[b]fluoranthene) exposure through consumption of coffee, mate, and tea was estimated. The oesophageal cancer risk assessment for both PAH and temperature was conducted using the MOE approach.

Results

Considering differences in the transfer of the PAH from the leaves of mate and tea or from the ground coffee to the infusion, and considering the different preparation methods, exposures may vary considerably. The average individual exposure in μg/kg bw/day arising from consumption of 1 cup (0.2 L) of infusion was highest for mate (2.85E-04 BaP and 7.22E-04 PAH4). The average per capita exposure in μg/kg bw/day was as follows: coffee (4.21E-04 BaP, 4.15E-03 PAH4), mate (4.26E-03 BaP, 2.45E-02 PAH4), and tea (8.03E-04 BaP, 4.98E-03 PAH4). For all individual and population-based exposure scenarios, the average MOE for BaP and PAH4 was > 100,000 independent of beverage type. MOE values in this magnitude are considered as a very low risk. On the contrary, the MOE for the temperature effect was estimated as < 1 for very hot drinking temperatures, corroborating epidemiological observations about a probable oesophageal cancer risk caused by this behaviour.

Conclusions

The temperature effect but not PAH exposure may pose an oesophageal cancer risk. Consumer education on risks associated with consumption of ‘very hot’ beverages and policy measures to threshold serving temperatures should be discussed.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4060-z) contains supplementary material, which is available to authorized users.

Urinary Concentrations of Polycyclic Aromatic Hydrocarbon Metabolites in Maté Drinkers in Rio Grande do Sul, Brazil

Background: Consumption of maté, an infusion of the herb Ilex paraguariensis (yerba maté), is associated with increased risk of esophageal squamous cell carcinoma (ESCC), but the carcinogenic mechanism is unclear. Commercial brands of yerba maté contain high levels of carcinogenic polycyclic aromatic hydrocarbons (PAHs), which are acquired during the traditional drying process. The purpose of this study was to characterize exposure to PAHs in maté drinkers over a wide range of maté consumption.Methods: We recruited 244 adults who answered a questionnaire and collected a fasting spot urine specimen. We quantified urinary concentrations of seven PAH metabolites and assessed associations between self-reported recent maté consumption and urinary PAH metabolites by multivariate regression.Results: Recent maté consumption showed a significant dose-response association with 6 of 7 PAH metabolites in unadjusted models (P_trend < 0.05). After adjustment for creatinine and potential confounders, concentrations of 2-naphthol, 1-hydroxyphenanthrene, and the sum of 2- and 3-hydroxyphenanthrene remained significantly associated with recent maté intake. The sum of the urinary concentrations of the phenanthrene metabolites was similar or higher among maté drinkers who did not smoke than among smokers who did not drink matéConclusions: Urinary concentrations of PAH metabolites were significantly associated with self-reported amounts of recent maté intake, and drinking maté increased urinary concentrations of some PAH metabolites as much as smoking cigarettes.Impact: Drinking maté is a source of exposure to potentially carcinogenic PAHs, consistent with the hypothesis that the PAH content of maté may contribute to the increased risk of ESCC in maté drinkers. Cancer Epidemiol Biomarkers Prev; 27(3); 331-7. ©2017 AACR.

Optimisation of extraction methods and quantification of benzo[a]pyrene and benz[a]anthracene in yerba maté tea by isotope dilution mass spectrometry

A gas chromatography-isotope dilution mass spectrometry (GC-IDMS) technique was developed for the quantification of two heavy polyaromatic hydrocarbons (PAHs), benz[a]anthracene and benzo[a]pyrene, in yerba maté tea (maté). The optimisation of two extraction methods, namely liquid-liquid extraction and accelerated solvent extraction, was carried out. Both optimised methods were validated using a certified reference material of fine dust and the results were within the expanded uncertainties at 95% confidence level. Recoveries of 99.2-106.7% with RSD of measurements of 1.1-2.3% were achieved for benz[a]anthracene. Recoveries of 95.7-101.9% with RSD of measurements of 0.4-1.4% were achieved for benzo[a]pyrene. The validated methods were applied for the extraction of benz[a]anthracene and benzo[a]pyrene in maté powder from NIST. A metrological approach was undertaken to ensure the traceability of measurement results. The uncertainties associated with the results were rigorously evaluated and also reported herein. Graphical abstract Quantification of benz[a]anthracene and benzo[a]pyrene using IDMS.

International cancer seminars: a focus on esophageal squamous cell carcinoma

The International Agency for Research on Cancer (IARC) and the US National Cancer Institute (NCI) have initiated a series of cancer-focused seminars [Scelo G, Hofmann JN, Banks RE et al. International cancer seminars: a focus on kidney cancer. Ann Oncol 2016; 27(8): 1382-1385]. In this, the second seminar, IARC and NCI convened a workshop in order to examine the state of the current science on esophageal squamous cell carcinoma etiology, genetics, early detection, treatment, and palliation, was reviewed to identify the most critical open research questions. The results of these discussions were summarized by formulating a series of 'difficult questions', which should inform and prioritize future research efforts.

Mate Intake and Risk of Breast Cancer in Uruguay: a Case- Control Study

Regarding 'mate' intake (infusion of Ilex paraguariensis herb, a staple beverage in temperate South American regions), most epidemiologic studies showed positive associations with risk of some cancers, (e.g. upper aerodigestive tract), but evidence on breast cancer (BC) risk is limited to a previous multi-site study, which reported a non significant odds ratio [OR]=0.85, 95% confidence interval [95% CI] 0.67-1.09, p for trend=0.31) for the highest quartile of intake. The present study was conducted in order to further assess associations of 'mate' intake with BC risk. We combined two databases of women belonging to public and private healthcare hospitals. The sample included 572 BC incident cases and 889 controls interviewed with a specific questionnaire featured by socio-demographic, reproductive and lifestyle variables, and a food frequency questionnaire of 64 items, also analyzing 'mate' intake (consumer status, daily intake, age at start, age at quit, duration of habit, intensity of intake). ORs and their 95%CI were calculated through unconditional logistic regression, adjusting for relevant potential confounders. The highest quartile of 'mate' intake was inversely associated with BC risk (OR=0.40, 95%CI 0.26-0.57, p for trend <0.001). Stratified analyses also displayed strong significant inverse associations for 'mate' in frequent tea drinkers (OR=0.22), high energy intake (OR=0.23), high body mass index (OR=0.29) and in postmenopausal women (OR=0.36), among other results. As conclusions, we found evidence of a significant inverse association for 'mate' intake and BC risk.

Diet and esophageal disease

The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on macronutrients, dietary patterns, and risk of adenocarcinoma in Barrett's esophagus; micronutrients, trace elements, and risk of Barrett's esophagus and esophageal adenocarcinoma; the role of mate consumption in the development of squamous cell carcinoma; the relationship between energy excess and development of esophageal adenocarcinoma; and the nutritional management of the esophageal cancer patient.