Aristolochic acids (AAs) have been known as potent nephrotoxins since the use of AA-containing herbal medicines was linked with a series of sporadic renal fibrotic nephropathy cases, and yet an ...estimated 100 million people worldwide are still at risk today because of continued use of similar medicines. However, a similar nephropathic condition is endemic in the rural Balkan regions (e.g., Serbian farming villages) and AAs were again found to be the causative agents. In the case of this Balkan endemic nephropathy, AAs were found to have originated from a widespread local weed Aristolochia clematitis L. In this study, we tested the hypothesis that AAs released from decomposition of A. clematitis were also being leached into groundwater, thus polluting the drinking water of local residents. We initiated the study by developing a dispersive solid-phase extraction-based sample preparation method for water samples suspected of AA contamination. The validated method was then coupled with a liquid chromatography-tandem mass spectrometric method to measure AAs in groundwater samples collected from Serbia. Our study revealed for the first time that groundwater in Serbia is extensively contaminated with AA-I, at ng/L levels. Results also showed that AAs are long-lived water contaminants, with no observable concentration changes over a 2-month period of sample storage.
•Nephrotoxic aristolochic acids (AA) contaminated food and soil of Balkans.•Chronic exposure to AA via AA-tainted food resulted in renal fibrosis and cancer.•A new LC–MS/MS method was developed for ...analysis of AAs in food and soil samples.•Zn/H+ treatment dramatically increase analytical sensitivity of AA in LC–MS/MS.•The method detects for the first time AA in supermarket flour samples in Balkan area.
Prolonged dietary exposure to AA-contaminated food crops cultivated in contaminated farmland was shown to be one of the main culprits of Balkan endemic nephropathy. Ultra-sensitive methods for the detection of AA at trace levels are important for surveillance purposes. We report the development of a novel liquid chromatography-tandem mass spectrometry (LC–MS/MS) method for AA-detection. One striking feature of the method is that the Zn/H+-induced nitroreduction convert AA into their respective aristolactams, which dramatically enhances their analytical sensitivity. The method was applied to quantitate AA in food grains and soil samples collected from farming villages of Serbia, and flour samples purchased from supermarkets. To the best of our knowledge, this is the first report of detecting AA in food ingredients available in supermarkets, which is alarming because it reveals AA poses insidious threats not only to residents of rural farming villages, but also to people residing in urban areas.
Prolonged exposure to aristolochic acids (AAs) through AA-containing herbal medicine or AA-contaminated food is associated with the development of aristolochic acid nephropathy (AAN) and Balkan ...endemic nephropathy (BEN), both public health risks to which the World Health Organization is calling for global action to remove exposure sources. The AA exposure-induced DNA damage is believed to be related to both the nephrotoxicity and carcinogenicity of AA observed in patients suffering from BEN. While the chemical toxicology of AA is well-studied, we investigated in this study the understated effect of different nutrients, food additives, or health supplements on DNA adduct formation by aristolochic acid I (AA-I). By culturing human embryonic kidney cells in an AAI-containing medium enriched with different nutrients, results showed that cells cultured in fatty acid-, acetic acid-, and amino acid-enriched media produced ALI-dA adducts at significantly higher frequencies than that cultured in the normal medium. ALI-dA adduct formation was most sensitive to amino acids, indicating that amino acid- or protein-rich diets might lead to a higher risk of mutation and even cancer. On the other hand, cells cultured in media supplemented with sodium bicarbonate, GSH, and NAC reduced ALI-dA adduct formation rates, which sheds light on their potential use as risk-mitigating strategies for people at risk of AA exposure. It is anticipated that the results of this study will help to better understand the effect of dietary habits on cancer and BEN development.
Tens of thousands of people in southern Europe suffer from Balkan endemic nephropathy (BEN), and four times as many are at risk. Incidental ingestion of aristolochic acids (AAs), stemming from the ...ubiquitousAristolochia clematitis(birthwort) weed in the region, leads to DNA adduct-induced toxicity in kidney cells, the primary cause of BEN. Numerous cofactors, including toxic organics and metals, have been investigated, but all have shown small contributions to the overall BEN relative to non-BEN village distribution gradients. Here, we reveal that combustion-derived pollutants from wood and coal burning in Serbia also contaminate arable soil and test as plausible causative factors of BEN. Using a GC–MS screening method, biomass-burning-derived furfural and coal-burning-derived medium-chain alkanes were detected in soil samples from BEN endemic areas levels at up to 63-times and 14-times higher, respectively, than in nonendemic areas. Significantly higher amounts were also detected in colocated wheat grains. Coexposure studies with cultured kidney cells showed that these pollutants enhance DNA adduct formation by AA, – the cause of AA nephrotoxicity and carcinogenicity. With the coincidence of birthwort-derived AAs and the widespread practice of biomass and coal burning for household cooking and heating purposes and agricultural burning in rural low-lying flood-affected areas in the Balkans, these results implicate combustion-derived pollutants in promoting the development of BEN.
Aristolochic acid released from decaying Aristolochia clematitis weed is contaminating soil and food crops in Eastern Europe and is one of the major causes to Balkan endemic nephropathy. Measures ...should be taken to prevent people from being exposed to these highly potent phytotoxins. Research needs to develop remediation methods.
Balkan endemic nephropathy (BEN) is a slowly progressive interstitial fibrotic disease affecting numerous people living along the Danube River in the Balkan Peninsula, of which aristolochic acids ...(AAs) produced naturally in Aristolochia plants are key etiological agents. However, the exposure biology of the disease remains poorly understood. Initially, the high incidence of BEN in the Balkan Peninsula was thought to occur through ingestion of bread prepared from flour made with wheat grains comingled with the seeds of Aristolochia clematitis L., an AA-containing weed that grows abundantly in the wheat fields of the affected areas. In this study, by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, we show for the first time that vegetables, in particular root vegetables of endemic areas, are extensively contaminated with AAs taken up through root absorption from the AA-tainted soil. Furthermore, we found a pH dependence of the n-octanol/water partition coefficient (K ow) of AAs, which resulted in a dramatically higher hydrophobicity-driven plant uptake efficiency of AAs into food crops in endemic areas, characterized by higher acidity levels, compared to non-endemic areas. We believe the results of this study have significantly unraveled the mystery surrounding the uneven distribution of BEN incidence.
While to date investigations provided convincing evidence on the role of aristolochic acids (AAs) in the etiology of Balkan endemic nephropathy (BEN) and upper urothelial cancer (UUC), the exposure ...pathways by which AAs enter human bodies to cause BEN and UUC remain obscure. The goal of this study is to test the hypothesis that environmental pollution by AAs and root uptake of AAs in the polluted soil may be one of the pathways by which AAs enter the human food chain. The hypothesis driving this study was that the decay of Aristolochia clematitis L., a AA-containing herbaceous plant that is found growing widespread in the endemic regions, could release free AAs to the soil, which could be taken up by food crops growing nearby, thereby transferring this potent human nephrotoxin and carcinogen into their edible parts. Using the highly sensitive and selective high-performance liquid chromatography coupled with fluorescence detection method, we identified and quantitated in this study for the first time AAs in corn, wheat grain, and soil samples collected from the endemic village Kutles in Serbia. Our results provide the first direct evidence that food crops and soil in the Balkans are contaminated with AAs. It is possible that the presence of AAs in edible parts of crops originating from the AA-contaminated soil could be one of the major pathways by which humans become exposed to AAs.
Aristolochic acids (AAs) are nephrotoxic and carcinogenic nitrophenanthrene carboxylic acids produced naturally by plants from the Aristolochia and Asarum genera, which have been used extensively as ...herbal medicines. In addition to consuming AA-containing herbal medicinal products, there is emerging evidence that humans are also exposed to AA through the environment. In 2022, the World Health Organization (WHO) called for global action to remove AA exposure sources and to implement preventative measures against the development of AA-associated cancers. Herein, we report the development of a simple and efficient iron powder-packed reduction column that allows online post-column conversion of the nonfluorescing AA to its corresponding strongly fluorescing aristolactam (AL), facilitating the sensitive and selective detection of AA in herbal medicinal products, food grain, arable soil, or groundwater samples by high-performance liquid chromatography with fluorescence detection. Moreover, AL, a group of naturally occurring derivatives of AA that have demonstrated toxicity to cultured bacteria, human cells, and rats, is monitored and quantified simultaneously with AA in one single run without sacrificing sensitivity. In comparison with existing analytical methods for AA measurement, the newly developed method is not only inexpensive and less laborious, but it also offers improved sensitivity. We believe this novel method will find wide application in identifying the presence of AA in food, herbal medicines, and environmental samples, thus assisting in the identification and removal of AA exposure sources.
Exposure to aristolochic acids (AAs) from Aristolochia plants is one of the major global causes of nephropathy, including Balkan endemic nephropathy (BEN); renal failure; and urothelial cancer. The ...high incidence of BEN on the Balkan Peninsula is assumed to result from consumption of Aristolochia clematitis L. seeds coharvested with crops. Here, we show that AAs are long-lived soil contaminants that enter wheat and maize plants by root uptake with strong pH dependence. Soil and crops from Serbian farms in areas endemic for A. clematitis were found to be extensively contaminated with AAs, with contamination strongly correlated with local incidence of BEN. The persistence of AAs as soil contaminants suggests that weed control for A. clematitis plants is needed to reduce the incidence of BEN and aristolochic acid nephropathy, systematic surveys of soil and crop AA levels would identify high-risk regions, and it is imperative to research soil-remediation methods.
Balkan endemic nephropathy (BEN) is a chronic tubulointerstitial nephropathy affecting residents of rural farming areas in many Balkan countries. Although it is generally believed that BEN is an ...environmental disease caused by multiple geochemical factors with much attention on aristolochic acids (AAs), its etiology remains controversial. In this study, we tested the hypothesis that environmental contamination and subsequent food contamination by polycyclic aromatic hydrocarbons (PAHs) and phthalate esters are AA toxicity factors and important to BEN development. We identified significantly higher concentrations of phenanthrene, anthracene, diethyl phthalate (DEP), dibutyl phthalate (DBP), and benzyl butyl phthalate (BBP) in both maize and wheat grain samples collected from endemic villages than from nonendemic villages. Other PAHs and phthalate esters were also detected at higher concentrations in the soil samples from endemic villages. Subsequent genotoxicity testing of cultured human kidney cells showed an alarming phenomenon that phenanthrene, DEP, BBP, and DBP can interact synergistically with AAs to form elevated levels of AA-DNA adducts, which are associated with both the nephrotoxicity and carcinogenicity of AAs, further increasing their disease risks. This study provides direct evidence that prolonged coexposure to these environmental contaminants via dietary intake may lead to greater toxicity and accelerated development of BEN.
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