Aristolochic acid I: an investigation into the role of food crops contamination, as a potential natural exposure pathway

Unveiling correlations between aristolochic acids and liver cancer: spatiotemporal heterogeneity phenomenon

Aristolochic acids are a class of naturally occurring compounds in Aristolochiaceae that have similar structural skeletons and chemical properties. Exposure to aristolochic acids is a risk factor for severe kidney disease and urinary system cancer. However, the carcinogenicity of aristolochic acids to the liver, which is the main site of aristolochic acid metabolism, is unclear. Although the characteristic fingerprint of aristolochic acid-induced mutations has been detected in the liver and aristolochic acids are known to be hepatotoxic, whether aristolochic acids can directly cause liver cancer is yet to be verified. This review summarizes the findings of long-term carcinogenicity studies of aristolochic acids in experimental animals. We propose that spatiotemporal heterogeneity in the carcinogenicity of these phytochemicals could explain why direct evidence of aristolochic acids causing liver cancer has never been found in adult individuals. We also summarized the reported approaches to mitigate aristolochic acid-induced hepatotoxicity to better address the associated global safety issue and provide directions and recommendations for future investigation.

Target and Suspect Screening for Organic Additives in Six Classifications of Personal Care Products Using Liquid Chromatography-High-Resolution Mass Spectrometry

Personal care products (PCPs) are integral components of daily human existence, including a large number of chemicals intentionally added for functional attributes (e.g., preservatives and fragrances) or unintentionally present, such as plasticizers. This investigation aimed to optimize the methodology for target and suspect screening via liquid chromatography-high-resolution mass spectrometry, focusing on nine prevalent organic additives (comprising bisphenols A, F, and S, methyl, ethyl, propyl, and butylparaben, 5-chloro-2-methyl-4-isothiazolin-3-one, and 4-hydroxybenzoic acid). A total of 50 high-selling PCPs were purchased from the local online market as samples. In detail, PCP samples were classified into body washes, shampoos, hair conditioners, facial cleansers, body lotions, and moisture creams. For calibration, the quality assurance and quality control results demonstrated a coefficient of determination (R2) surpassing 0.999, with detection and quantification limits ranging from 2.5 to 100.0 ng/g. For recovery experiments, replicate recoveries (n = 5) ranged from 61 to 134%. In purchased PCP samples, five of the nine target compounds were detected via a target screening. Methylparaben exhibited the highest concentration (7860 mg/kg) in a facial cleanser, which is known as an endocrine-disrupting chemical. A total of 248 suspects of organic additives were screened in PCPs, leading to a tentative identification of 9. Confirmation (confidence level 1) via reference standards was achieved for three suspects, while six were tentatively identified with a confidence level of 2. This two-step extraction methodology utilizing methyl tert-butyl ether and isopropyl alcohol enabled simultaneous analysis of diverse chemical groups with distinct properties.

Detection and Removal of Aristolochic Acid in Natural Plants, Pharmaceuticals, and Environmental and Biological Samples: A Review

Aristolochic acids (AAs) are a toxic substance present in certain natural plants. Direct human exposure to these plants containing AAs leads to a severe and irreversible condition known as aristolochic acid nephropathy (AAN). Additionally, AAs accumulation in the food chain through environmental mediators can trigger Balkan endemic nephropathy (BEN), an environmental variant of AAN. This paper presents a concise overview of the oncogenic pathways associated with AAs and explores the various routes of environmental exposure to AAs. The detection and removal of AAs in natural plants, drugs, and environmental and biological samples were classified and summarized, and the advantages and disadvantages of the various methods were analyzed. It is hoped that this review can provide effective insights into the detection and removal of AAs in the future.

Efficient separation of aristolochic acid I from Caulis aristolochiae manshuriensis (Guan-mu-tong) with copper mediated magnetic molecularly imprinted polymer

Screening bioactive compounds from natural products is one of the most effective ways for new drug research and development. However, obtaining a single extract component on a large scale and with high purity from a complex matrix is still an arduous and challenging task. Herein, one metal mediated magnetic molecularly imprinted polymer (mMIP) was rationally designed and prepared for specifically capturing Aristolochic acid I (AAI). The preparation was done with copper(II) as binding pivot, (3-aminopropyl) triethoxysilane as functional monomer, and Fe3O4 as core, by a one-step sol-gel method. Under the optimized conditions, the apparent maximum binding amount of copper mediated mMIP (Cu-mMIP) reaches as high as 349.72 mg g-1, the highest among the reported AAI-MIPs. Moreover, the nanoparticles exhibit excellent specificity and selectivity, good reproducibility and stability, high superparamagnetism (60.32 emu g-1), and high imprinting efficiency (an imprinting factor of 7). By simulating an industrial-scale separation, 16.56 mg AAI (purity of 95.11%) is obtained after six cycles with 100 mg nanoparticles from 20 g Caulis aristolochiae manshuriensis (Guan-mu-tong). Notably, this takes only 3 hours and consumes 50 mL of methanol. The study provides a potent tool for the green, fast, and specific extraction of high-purity ingredients from natural plants in the manufacturing industry and conventional analysis in the lab.

Fabrication of a Simple and Efficient HPLC Reduction Column for Online Conversion of Aristolochic Acids to Aristolactams Prior to Sensitive Fluorescence Detection

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.

Aristolochic acid I exposure triggers ovarian dysfunction by activating NLRP3 inflammasome and affecting mitochondrial homeostasis

Aristolochic acids are widely distributed in the plants of Aristolochiaceae family and Asarum species. Aristolochic acid I (AAI) is the most frequent compound of aristolochic acids, which can accumulate in the soil, and then contaminates crops and water and enters the human body. Research has shown that AAI affects the reproductive system. However, the mechanism of AAI's effects on the ovaries at the tissue level still needs to be clarified. In this research, we found AAI exposure reduced the body and ovarian growth in mice, decreased the ovarian coefficient, prevented follicular development, and increased atretic follicles. Further experiments showed that AAI upregulated nuclear factor-κB and tumor necrosis factor-α expression, activated the NOD-like receptor protein 3 inflammasome, and led to ovarian inflammation and fibrosis. AAI also affected mitochondrial complex function and the balance between mitochondrial fusion and division. Metabolomic results also showed ovarian inflammation and mitochondrial dysfunction due to AAI exposure. These disruptions reduced the oocyte developmental potential by forming abnormal microtubule organizing centers and expressing abnormal BubR1 to destroy spindle assembly. In summary, AAI exposure triggers ovarian inflammation and fibrosis, affecting the oocyte developmental potential.

Uptake, Translocation, and Fate of Carcinogenic Aristolochic Acid in Typical Vegetables in Soil-Plant Systems

When Aristolochia plants wilt and decay, aristolochic acids (AAs) are released into the soil, causing soil contamination. It has been demonstrated that aristolochic acid can be accumulated and enriched in crops through plant uptake. However, there is a lack of systematic studies on the migration and accumulation of AAs in a realistic simulated soil environment. In this study, Aristolochia herbal extracts were mixed with soil for growing three typical vegetables: lettuce, celery, and tomato. The contents of AAs in the above-mentioned plants were determined by an established highly sensitive LC-MS/MS method to study the migration and accumulation of AAs. We found that AAs in the soil can be transferred and accumulated in plants. AAs first entered the roots, which were more likely to accumulate AAs, and partially entered the above-ground parts. This further confirms that AAs can enter the food chain through plants and can have serious effects on human health. It was also shown that plants with vigorous growth and a large size absorbed AAs from the soil at a faster rate. The more AAs present in the soil, the more they accumulated in the plant.

Aristolochic acid I exposure decreases oocyte quality

Oocyte quality is a determinant of a successful pregnancy. The final step of oocyte development is oocyte maturation, which is susceptible to environmental exposures. Aristolochic acids (AAs), widely existing in Aristolochia and Asarum plants that have been used in traditional medicine, can result in a smaller ovary and fewer superovulated oocytes after in vivo exposure to mice. However, whether AAs affect oocyte maturation and the underlying mechanism(s) are unclear. In this study, we focused on the effect of Aristolochic acid I (AAI), a major compound of AAs, on the maturation of in vitro cultured mouse oocytes. We showed that AAI exposure significantly decreased oocyte quality, including elevated aneuploidy, accompanied by aberrant chiasma patterns and spindle organization, and decreased first polar body extrusion and fertilization capability. Moreover, embryo development potential was also dramatically decreased. Further analyses revealed that AAI exposure significantly decreased mitochondrial membrane potential and ATP synthesis and increased the level of reactive oxygen species (ROS), implying impaired mitochondrial function. Insufficient ATP supply can cause aberrant spindle assembly and excessive ROS can cause premature loss of sister chromatid cohesion and thus alterations in chiasma patterns. Both aberrant spindles and changed chiasma patterns can contribute to chromosome misalignment and thus aneuploidy. Therefore, AAI exposure decreases oocyte quality probably via impairing mitochondrial function.

A PCR-lateral flow immunochromatographic assay (PCR-LFA) for detecting Aristolochia species, the plants responsible for aristolochic acid nephropathy

Aristolochic acids (AAs), which are strong carcinogens, have caused dietary supplements with Aristolochia plants to be discontinued worldwide. Therefore, the development of a method to identify these herbs is critical for customer safety. To support the regulation of Aristolochia-free products, a PCR coupled with lateral flow immunochromatographic assay (PCR-LFA) that is specific to the nucleotide signature in plastid rbcL gene region of Aristolochia species was developed to detect Aristolochia plants and related herbal products. Triplex primers (A397F, C357F and R502) were designed based on specific nucleotides observed exclusively in the rbcL sequences of Aristolochia. Positive results for Aristolochia occur when the three pink lines are clearly developed on the developed lateral flow strip and can be seen by the naked eye. In this study, the lateral flow strip has sensitivity for detecting amplicons amplified from genomic DNA at the concentrations as low as 0.01 ng. Various kinds of samples, including purchased crude drugs and polyherbal samples, have been investigated, and the results showed that Aristolochia crude drugs and Aristolochia-containing products are still present in dispensaries. In conclusion, with the goal of protecting consumers from the health risks associated with Aristolochia contamination, PCR-LFA was developed and demonstrated to be efficient for detecting plants belonging to Aristolochia in various kinds of samples.

Aristolochic acid I as an emerging biogenic contaminant involved in chronic kidney diseases: A comprehensive review on exposure pathways, environmental health issues and future challenges

Described in the 1950s, Balkan Endemic Nephropathy (BEN) has been recognized as a chronic kidney disease (CKD) with clinical peculiarities and multiple etiological factors. Environmental contaminants - aromatic compounds, mycotoxins and phytotoxins like aristolochic acids (AAs) - polluting food and drinking water sources, were incriminated in BEN, due to their nephrotoxic and carcinogenic properties. The implication of AAs in BEN etiology is currently a highly debated topic due to the fact that they are found within the Aristolochiaceae plants family, used around the globe as traditional medicine and they were also incriminated in Aristolochic Acid Nephropathy (AAN). Exposure pathways have been investigated, but it is unclear to what extent AAs are acting alone or in synergy with other cofactors (environmental, genetics) in triggering kidney damage. Experimental studies strengthen the hypothesis that AAI, the most studied compound in the AAs class, is a significant environmental contaminant and a most important causative factor of BEN. The aim of this review is to compile information about the natural exposure pathways to AAI, via traditional medicinal plants, soil, crop plants, water, food, air. Data that either supports or contradicts the AAI theory concerning BEN etiology was consolidated and available solutions to reduce human exposure were discussed. Because AAI is a phytotoxin with physicochemical properties that allow its transportation in environmental matrices from different types of areas (endemic, nonendemic), and induce CKDs (BEN, AAN) and urinary cancers through bioaccumulation, this review aims to shed a new light on this compound as a biogenic emerging pollutant.

Aristolochic acid: What urologists should know

To the Editor, Aristolochic acid is one of major causes for upper tract urothelial carcinoma, especially in younger population. While it is mentioned as a cause in guidelines, little is actually known about the toxin by urologists. We are aiming in our letter to provide some direct and clear information to ourselves that would help us to know more about that toxin and how it can adversely affect our patients [...].

Aristolochic Acid I-Induced Hepatotoxicity in Tianfu Broilers Is Associated with Oxidative-Stress-Mediated Apoptosis and Mitochondrial Damage

Simple Summary

Aristolochic acid (AA) is a component of traditional Chinese herbs and commonly used in the farm poultry industry in China for anti-infection, anti-viral and anti-bacterial treatment. However, long-term and over-exposure of these drugs has been proven to be associated with serious hepatotoxicity, but the mechanism of AA-I-induced hepatotoxicity remains unknown. Therefore, in this study, a subchronic toxicity test was conducted to evaluate the mechanism of AA-I-induced hepatotoxicity in Tianfu broilers. Subchronic exposure to high doses of AA-I in broilers can cause serious hepatotoxicity by breaking the redox balance to form oxidative stress, along with promoting oxidative-stress-mediated apoptosis and mitochondrial damage. In conclusion, AA-I has been found to damage broilers’ livers in high doses. This study provides suggestions for the clinical application of traditional Chinese medicine containing AA-I in the poultry industry.

Abstract

Aristolochic acid (AA) is a component of traditional Chinese herbs and commonly used for farm animals in China. Over-exposure of AA has been proven to be associated with hepatotoxicity; however, the mechanism of action of AA-I-induced hepatotoxicity remains unknown. In the current study, a subchronic toxicity test was conducted to evaluate the mechanism of AA-induced hepatotoxicity in Tianfu broilers. According to the results, AA-I-induced hepatotoxicity in Tianfu broilers was evidenced by the elevation of liver weight, levels of serum glutamic oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT). Furthermore, hepatocyte swelling, vesicular degeneration and steatosis were observed. Additionally, AA-I elevated the production of reactive oxygen species (ROS) and induced oxidative stress, which further led to excessive apoptosis, characterized by mitochondrial depolarization, upregulation of Bax, and down-regulation of Bcl-2 expression. In conclusion, the mechanism of AA-I-induced hepatotoxicity was associated with oxidative-stress-mediated apoptosis and mitochondrial damage.