Exposure to Essential and Toxic Elements via Consumption of Agaricaceae, Amanitaceae, Boletaceae, and Russulaceae Mushrooms from Southern Spain and Northern Morocco

High levels of the health-relevant antioxidant selenoneine identified in the edible mushroom Boletus edulis

BACKGROUND

Selenoneine, the selenium analogue of the sulfur antioxidant ergothioneine, has been ascribed a multitude of beneficial health effects. Natural nutritional sources for this selenium species are, hence, of high interest. So far marine fish is the only significant selenoneine source consumed by larger parts of the population worldwide.

METHODS

As selenoneine and ergothioneine share their biosynthetic pathways and transport mechanisms and the popular edible porcini mushroom Boletus edulis is rich in ergothioneine and selenium, we conducted a preliminary study investigating a composite sample of two specimens of B. edulis for their selenoneine content by HPLC coupled to elemental and molecular mass spectrometry after aqueous extraction.

RESULTS

Selenium speciation analysis by HPLC-ICPMS revealed that ca. 860 µg Se kg-1 wet mass (81 % of the total Se) co-eluted with a selenoneine standard and a minor selenium species with Se-methylselenoneine. The presence of selenoneine was rigorously proven by HPLC-ESI-Orbitrap MS. The selenoneine content of the investigated specimens of B. edulis was higher than that of commonly consumed muscle of marine fish species, like tuna or mackerel.

CONCLUSION

This is the first report of a terrestrial food source containing significant selenoneine levels. Our results suggest that B. edulis might represent a complementary natural supply with this health-relevant selenium species for humans.

Metals Transfer in Mushroom Tricholoma matsutake from Regional High Geochemical Background Areas: Environmental Influences and Human Health Risk

Wild-grown edible mushrooms are important in world diets and are also efficient metal accumulators. Yunnan, Southwest China, is the main producing region, with typically high levels of geochemical metals. The environmental factors, bioaccumulation, distribution and human health risks of metals were examined in paired soil and Tricholoma matsutake (n = 54). T. matsutake grows on acidified soils (pH = 3.95-6.56), and metals show a strong heterogeneity, with Fe, Mn, Zn and Cu in the ranges of 16-201, 0.046-8.58 g kg-1, and 22.6-215, 3.7-155 mg kg-1. High soil Fe content led to great accumulation in T. matsutake (0.24-18.8 g kg-1). However, though the soil Mn content was higher than that of Zn and Cu, their concentrations in T. matsutake were comparable (21.1-487 vs. 38.7-329 and 24.9-217 mg kg-1). This suggested that T. matsutake prefers to accumulate Zn and Cu compared to Mn, and this is supported by the bioaccumulation factors (BAFs = 0.32-17.1 vs. 0.006-1.69). Fe was mainly stored in stipes, while Mn, Zn and Cu were stored in caps, and the translocation factors (TFs) were 0.58 vs. 1.28-1.94. Therefore, stipe Fe showed the highest health risk index (HRI) at 1.28-26.9, followed by cap Cu (1.01-2.33), while 98-100% of the Mn and Zn were risk-free. The higher concentration and greater risk of Fe was attributed to the significant effect of soil Fe content (R = 0.34) and soil pH (R = -0.57). This study suggested that Fe, as an essential mineral, may exert toxic effects via the consumption of T. matsutake from high geochemical background areas.

Mineral composition variation in Boletales mushrooms-indication of soil properties and taxonomic influence

The efficiency of element accumulation depends on numerous factors, where the physico-chemical characteristics of the soil seem to be very important, and the role of taxonomic rank in the accumulation of elements by mushrooms seems to be important. The aim of the study was to compare the mineral composition of 7 species belonging to Leccinum and Suillus genera, collected between 2019 and 2021 from localizations in the west-central part of Poland. The research aimed to indicate the role of selected soil parameters in stimulating/inhibiting the accumulation of elements by selected Boletales mushroom species and to answer the question about the role of species belonging to the genus as an indicator determining the specific mineral composition of fruiting bodies. Soil pH and other soil properties (granulometric composition, organic carbon, degree of organic matter decomposition) may significantly affect mushrooms' mineral composition. Mushroom species belonging to Leccinum genus exhibited the higher amount of essential major and trace elements than species of Suillus genus). It suggests that the affiliation of the studied mushroom species to a specific genus may affect their mineral composition, and the physicochemical properties of the soil may be responsible for the lack of a clear division in the efficiency of element(s) accumulation. Selected species contain high amounts of K, Cu, Fe, and Zn, while others, such as selected Suillus gravellei fruiting bodies, also contain As and Cd. The results described serve as an introduction to a broader scientific discussion and require many further studies to confirm the role of taxonomic ranks and the influence of soil characteristics on the accumulation of elements by fruiting bodies.

Levels and Health Risk Assessment of Inorganic Arsenic, Methylmercury, and Heavy Metals in Edible Mushrooms Collected from Online Supermarket in China

Chromium (Cr), total arsenic (As), inorganic arsenic (iAs), cadmium (Cd), mercury (Hg), methylmercury (MeHg), and lead (Pb) were analyzed in in Agaricus blazei, Tricholoma matsutake, Pholiota nameko, agrocybe aegirit, Boletus edulis, Auricularia auricula, and Lentinus edodes collected from online supermarket in China from 2015 to 2017. The order of mean concentrations for the five heavy metals in edible mushrooms was As > Cd > Cr > Pb > Hg. No positive correlation was found between total As and iAs, nor between total Hg and MeHg. The contents of iAs were at a low level except for A. blazei samples. The contents of MeHg were at a low level in all test mushroom samples. And Cr, Cd, and Pb pollution were common problems in the test mushroom samples. The comprehensive factor pollution index was between 0.569 (A. auricula) and 3.056 (B. edulis). The THQ values for the five heavy metals from P. nameko, A. auricula, A. aegirit, and L. edodes samples were less than 1. The hazard index (HI) values of A. blazei, T. matsutake, and B. edulis samples for adults and children were greater than 1, indicating significant health hazard to the adults and children consumers. The cancer risk (CR) values for iAs ranged from 3.82 × 10- 6 (T. matsutake) to 8.61 × 10- 5 (A. blazei), indicating no potential carcinogenic risk to the consumers. The order for carcinogenic risk of each edible mushroom species was A. blazei > L. edodes > P. nameko > A. aegirit > A. auricula > B. edulis > T. matsutake.

Phylogenetic analysis, morphological studies, element profiling, and muscarine detection reveal a new toxic Inosperma (Inocybaceae, Agaricales) species from tropical China

Tropical Asian collections of Inosperma are usually poisonous mushrooms that have caused many poisoning incidents. However, the species diversity and the toxic mechanisms of these Inosperma species are still unclear. In this study, we describe the discovery of Inosperma wuzhishanense sp. nov. from Wuzhishan City, Hainan Province, tropical China. The new species was identified based on morphological and multi-locus (ITS, nrLSU, and RPB2) phylogenetic analyses. The new species is characterized by its reddish-brown pileus, fibrillose stipes with finely protruding fibrils, rather crowded lamellae, smooth and ellipsoid basidiospores, and mostly clavate, thin-walled cheilocystidia. The new species is phylogenetically nested in the Old World tropical clade 2 and is sister to the tropical Indian taxa I. akirnum. Detailed descriptions, color photos of the new species, and comparisons with its closely related species are provided. Additionally, the muscarine content of the new species was analyzed by ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS). The muscarine contents ranged from 4,359.79 ± 83.87 mg/kg to 7,114.03 ± 76.55 mg/kg, 2,748.37 ± 106.85 mg/kg to 4,491.35 ± 467.21 mg/kg, and 2,301.36 ± 83.52 mg/kg to 2,775.90 ± 205.624 mg/kg in the stipe, pileus, and lamellae, respectively. The elemental composition and concentration were determined using inductively coupled plasma-mass spectrometry (ICP-MS). A total of 24 elements were detected. Among the heavy metals detected, arsenic showed the highest level of toxicity with a concentration of 36.76 ± 0.43 mg/kg.

Preface to the Special Issue 'Heavy Metals in Mushrooms'

Population growth, intensive industrialization and urbanization have led to environmental pollution, especially soil and water pollution [...].

Nutritional value, elemental bioaccumulation and antioxidant activity of fruiting bodies and mycelial cultures of an unrecorded wild Lactarius hatsudake from Nanyue mountainous region in China

An unrecorded wild mushroom Lactarius hatsudake from Nanyue mountainous region in China was identified. Subsequently, comparative investigation on the nutritional value, elemental bioaccumulation, and antioxidant activity was performed in the fruiting body (FB) and mycelium (MY) samples of this species. It revealed that the contents of moisture (87.66 ± 0.16 g/100 g fw) and ash (6.97 ± 0.16 g/100 g dw) were significantly higher in FB, and the total carbohydrate, fat, and protein concentrations of FB were similar to those in MY. Among nutritionally important elements, FB possessed higher concentrations of potassium (37808.61 ± 1237.38 mg/kg dw), iron (470.69 ± 85.54 mg/kg dw), and zinc (136.13 ± 5.16 mg/kg dw), whereas MY was a better source of magnesium (1481.76 ± 18.03 mg/kg dw), calcium (2203.87 ± 69.61 mg/kg dw), and sodium (277.44 ± 22.93 mg/kg dw). According to the health risk estimation, FB might pose an aluminum-related health problem when a prolonged period of exposure, while MY was risk-free for consumers. The results of antioxidant capacity (1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays) in FB and MY were within the range of 104.19 ± 5.70 mg ascorbic acid equivalents (AAE)/g to 169.50 ± 4.94 mg AAE/g, and half maximal effective concentration EC50 values ranged from 0.23 ± 0.01 mg/mL to 0.62 ± 0.05 mg/mL. The aqueous extracts of MY demonstrated a strong ABTS radical scavenging capacity with the highest AAE value.

A Coding Basis and Three-in-One Integrated Data Visualization Method 'Ana' for the Rapid Analysis of Multidimensional Omics Dataset

With innovations and advancements in analytical instruments and computer technology, omics studies based on statistical analysis, such as phytochemical omics, oilomics/lipidomics, proteomics, metabolomics, and glycomics, are increasingly popular in the areas of food chemistry and nutrition science. However, a remaining hurdle is the labor-intensive data process because learning coding skills and software operations are usually time-consuming for researchers without coding backgrounds. A MATLAB® coding basis and three-in-one integrated method, 'Ana', was created for data visualizations and statistical analysis in this work. The program loaded and analyzed an omics dataset from an Excel® file with 7 samples * 22 compounds as an example, and output six figures for three types of data visualization, including a 3D heatmap, heatmap hierarchical clustering analysis, and principal component analysis (PCA), in 18 s on a personal computer (PC) with a Windows 10 system and in 20 s on a Mac with a MacOS Monterey system. The code is rapid and efficient to print out high-quality figures up to 150 or 300 dpi. The output figures provide enough contrast to differentiate the omics dataset by both color code and bar size adjustments per their higher or lower values, allowing the figures to be qualified for publication and presentation purposes. It provides a rapid analysis method that would liberate researchers from labor-intensive and time-consuming manual or coding basis data analysis. A coding example with proper code annotations and completed user guidance is provided for undergraduate and postgraduate students to learn coding basis statistical data analysis and to help them utilize such techniques for their future research.

Risk Assessment of Heavy Metals Occurrence in Two Wild Edible Oyster Mushrooms (Pleurotus spp.) Collected from Rajaji National Park

This study aimed at assessing the concentration of six heavy metals (Cd, Cr, Cu, Fe, Mn, and Zn) in two wild edible oyster mushrooms (Pleurotus ostreatus and Pleurotus djamor) collected from Rajaji National Park in Haridwar, India. For this purpose, mushroom samples were collected from selected locations (forest, residential, tourist, industrial areas, and transportation activities) from June 2021 to July 2022 and subsequently analyzed for selected heavy metals using atomic absorption spectroscopy (AAS). Results showed that both Pleurotus spp. had significantly varying (p < 0.05) concentrations of heavy metals. However, P. ostreatus showed relatively higher concentration levels of these metals compared to P. djamor. The mean concentrations (mg/kg dry weight) of the Cd, Cr, Cu, Fe, Mn, and Zn in P. ostreatus and P. djamor were 0.10 and 0.08, 0.87 and 0.64, 16.19 and 14.77, 28.49 and 27.15, 9.93 and 8.73, and 18.15 and 15.76, respectively. As indicated by the multivariate analysis tools i.e., principal component analysis (PCA) and hierarchical cluster analysis (HCA), the locations near the residential, industrial, and transportation activities had higher concentration levels of heavy metals. Moreover, the health risk studies using the target hazard quotient (THQ < 1) showed no significant health risk as the consumption of both Pleurotus spp., except for at one location, had high-traffic activities. The findings of this study provide vital information about the occurrence of potentially toxic heavy metals in wild edible Pleurotus spp. in Rajaji National Park in Haridwar, India representing a safeguard for mushroom consumers.

Structural Features and Immunomodulatory Effects of Water-Extractable Polysaccharides from Macrolepiota procera (Scop.) Singer

Macrolepiota procera (MP) is an edible mushroom used in the treatment of diabetes, hypertension and inflammation. However, the structure and biological effects of its polysaccharides (PSs) are unclear. This study investigates the structural features of a PS complex from MP (MP-PSC), its immunomodulatory activities and effects on probiotic and pathogenic bacteria. MP-PSC was obtained by boiling water, and PSs were characterized by 2D NMR spectroscopy. The immunomodulatory effects on blood and derived neutrophils, other leukocytes, and murine macrophages were studied by flow cytometry, chemiluminescence, spectrophotometry, and ELISA. The total carbohydrate content of MP-PSC was 74.2%, with glycogen occupying 36.7%, followed by β-D-glucan, α-L-fuco-2-(1,6)-D-galactan, and β-D-glucomannan. MP-PSC (200 μg/mL) increased the number of CD14+ monocyte cells in the blood, after ex vivo incubation for 24 h. It dose-dependently (50-200 μg/mL) activated the spontaneous oxidative burst of whole blood phagocytes, NO, and interleukin 6 productions in RAW264.7 cells. MP-PSC exhibited a low antioxidant activity and failed to suppress the oxidative burst and NO generation, induced by inflammatory agents. It (2.0%, w/v) stimulated probiotic co-cultures and hindered the growth and biofilm development of Escherichia coli, Streptococcus mutans and Salmonella enterica. MP PSs can be included in synbiotics to test their immunostimulating effects on compromised immune systems and gut health.

Occurrence and Health Risk Assessment of Cadmium Accumulation in Three Tricholoma Mushroom Species Collected from Wild Habitats of Central and Coastal Croatia

This study deals with the biomonitoring of cadmium (Cd) heavy metal in the three selected Tricholoma mushroom species collected from wild habitats of central and coastal Croatia. For this, mushroom (T. columbetta: n = 38, T. portentosum: n = 35, and T. terreum: n = 34) and surface soil samples were collected from nine forest localities of Croatia and analyzed for Cd concentration using inductively coupled plasma−optical emission spectrometry (ICP−OES) through the acid digestion method. The findings revealed that Cd was present in Tricholoma spp. and surface soil. However, the maximum mean Cd concentration (mg/kg dry weight) was recorded in T. portentosum (cap: 0.98; stipe: 0.72), followed by T. columbetta (cap: 0.96; stipe: 0.73) and T. terreum (cap: 0.81; stipe: 0.63). The bioconcentration factor (BCF) value (>1) revealed that the selected Tricholoma spp. had the potential for Cd accumulation. Moreover, the principal component (PC) and hierarchical cluster (HC) analyses were used to derive the interactions and similarities between Cd levels Tricholoma spp. and sampling localities. The multivariate analysis suggested that central sampling localities had higher Cd levels as compared to coastal localities. However, the daily intake of metals (DIM < 0.426) and health risk index (HRI < 1) showed that there was no potential health risk associated with the consumption of selected Tricholoma spp. The findings of this study are helpful to understand the Cd accumulation behavior of wild edible Tricholoma spp. collected from Croatia.