Risk assessment of plant food supplements and other herbal products containing aristolochic acids using the margin of exposure (MOE) approach

Trends in the incidence of urothelial carcinoma in Taiwan after the ban on aristolochic acid-containing Chinese herbal preparations, 2001-2018: a national population-based cohort study

PURPOSE

Urothelial carcinoma (UC) of the bladder (BUC) and the upper urinary tract (UTUC) are the two most common UCs. The incidence of UTUC in Taiwan is the highest worldwide. Aristolochic acid (AA) was identified as the main cause of UTUC in Taiwan. To explore trends in the incidence of UC in Taiwan after the ban on Chinese herbal preparations containing AA in 2003.

METHODS

We used data from the Taiwanese National Health Insurance Research Database-linked Taiwanese National Cancer Registry for 2001-2018. UC was defined in accordance with the International Classification of Disease for Oncology. The age-standardized incidence was calculated on the basis of the World Health Organization standard population. Trends in the incidence were calculated as the annual percent change (APC) by using the Joinpoint regression program.

RESULTS

Over the investigated period, the incidence of UC decreased at an average annual percent change (AAPC) of - 1.19% (95% CI - 1.47 ~ - 0.91, P < 0.001). However, the incidence in UTUC significantly increased, with the AAPC being 1.47% (95% CI 1.03 ~ 1.90, P < 0.001). In contrast, the incidence of BUC significantly decreased, with the overall AAPC being - 1.92% (95% CI - 2.3 ~ - 1.54, P < 0. 001). From 2001 to 2018, the overall incidence of UCs and BUC decreased in Taiwan, but the incidence of UTUC significantly increased.

CONCLUSION

We suggest to apply the same review standards of new drug development process to herbal preparations and incorporate them into the adverse drug reaction or poison surveillance system. Most importantly, raise public awareness of the potential toxicity of phytotherapy.

Food-Borne Chemical Carcinogens and the Evidence for Human Cancer Risk

Commonly consumed foods and beverages can contain chemicals with reported carcinogenic activity in rodent models. Moreover, exposures to some of these substances have been associated with increased cancer risks in humans. Food-borne carcinogens span a range of chemical classes and can arise from natural or anthropogenic sources, as well as form endogenously. Important considerations include the mechanism(s) of action (MoA), their relevance to human biology, and the level of exposure in diet. The MoAs of carcinogens have been classified as either DNA-reactive (genotoxic), involving covalent reaction with nuclear DNA, or epigenetic, involving molecular and cellular effects other than DNA reactivity. Carcinogens are generally present in food at low levels, resulting in low daily intakes, although there are some exceptions. Carcinogens of the DNA-reactive type produce effects at lower dosages than epigenetic carcinogens. Several food-related DNA-reactive carcinogens, including aflatoxins, aristolochic acid, benzene, benzo[a]pyrene and ethylene oxide, are recognized by the International Agency for Research on Cancer (IARC) as causes of human cancer. Of the epigenetic type, the only carcinogen considered to be associated with increased cancer in humans, although not from low-level food exposure, is dioxin (TCDD). Thus, DNA-reactive carcinogens in food represent a much greater risk than epigenetic carcinogens.

Safety assessment of natural products in Malaysia: current practices, challenges, and new strategies

The belief that natural products are inherently safe is a primary reason for consumers to choose traditional medicines and herbal supplements for health maintenance and disease prevention. Unfortunately, some natural products on the market have been found to contain toxic compounds, such as heavy metals and microbes, as well as banned ingredients such as aristolochic acids. It shows that the existing regulatory system is inadequate and highlights the importance of thorough safety evaluations. In Malaysia, the National Pharmaceutical Regulatory Agency is responsible for the regulatory control of medicinal products and cosmetics, including natural products. For registration purpose, the safety of natural products is primarily determined through the review of documents, including monographs, research articles and scientific reports. One of the main factors hampering safety evaluations of natural products is the lack of toxicological data from animal studies. However, international regulatory agencies such as the European Food Safety Authority and the United States Food and Drug Administration are beginning to accept data obtained using alternative strategies such as non-animal predictive toxicological tools. Our paper discusses the use of state-of-the-art techniques, including chemometrics, in silico modelling and omics technologies and their applications to the safety assessments of natural products.

The Human Health Risk Assessment of Heavy Metals Impurities (Cd and Pb) in Herbal Medicinal Products as Menthae piperitae tinctura (Mentha × piperita L., folium) Available in Pharmacies from Poland

Appropriate human health risk assessment (HHRA) is desire in modern regulatory toxicology, especially for elemental impurity studies. The aim of this article is the comprehensive HHRA of two heavy metals impurities—Cd and Pb in herbal medicinal products (HMP) as Menthae piperitae tinctura (Mentha × piperita L., folium) available in Polish pharmacies. These phytopharmaceuticals registered in EU are very common and usually applied OTC products by adults and also children/adolescents. For this purpose, we applied double regulatory approach, including: (1) requirements of ICH Q3D R1 guideline about elemental impurities and (2) additionally margin of exposure (MoE)-based concept to cover also specific population groups. Raw results shows that Cd and Pb were present in all analyzed HMP with Mentha × piperita L., folium (PTM1–PTM10) available in Polish pharmacies. In all samples, Cd impurities (in the range: 0.305–0.506 µg/L) were greatly lower than Pb impurities (in the range: 1.122–4.4921 µg/L). The HHRA of Cd and Pb impurities considering ICH Q3D R1 guideline-based approach made it possible to conclude that all results were below the permissible limit set by FAO/WHO for medicinal herbs and plants in different countries (300 µg/kg for Cd and 10,000 µg/kg for Pb). Additionally, the estimated daily intake of investigated elemental impurities compared to the PDE value confirm all samples safety. The second approach, an MoE-based strategy, indicated that the obtained values of MoE for Cd and Pb in daily dose for each samples were above 10,000; hence, exposure to these elemental impurities would not cause a health risk for all investigated population groups (children, adolescents, and adults). To the best our knowledge, this article is the first study about heavy metals impurities level in final HMPs as Menthae piperitae tinctura (Mentha × piperita L., folium) available in Polish pharmacies.

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.

Phytochemical Analysis and Toxicity Study of Aristolochia paucinervis Rhizomes Decoction Used in Moroccan Alternative Medicine: Histopathological and Biochemical Profiles

Ethnopharmacological Relevance

Aristolochia paucinervis (A. paucinervis) (Aristolochiaceae) is a plant frequently used in Moroccan alternative medicine. The aim of the current study is to investigate the phytochemical composition of rhizomes decoction of A. paucinervis (RDA) and to evaluate its acute and subacute toxicity following the OECD guidelines.

Materials and Methods

The qualitative phytochemical analysis of A. paucinervis was performed using standard qualitative phytochemical procedures. The acute toxicity of rhizomes decoction of the studied plant was evaluated in mice at single doses of 1, 2, and 4 g/kg of body weight for 14 days. In subacute toxicity study, the decoction was orally administered to mice at three different doses (0.5, 1, and 1.5 g/kg/day) for 28 days. Histopathological and biochemical parameters were investigated.

Results

The preliminary phytochemical screening showed the presence of flavonoids, saponins, alkaloids, and polyphenols and the absence of anthraquinones, sterols, and terpenes. There was no mortality and no significant changes occurred in animals treated with 1 and 2 g/kg in the acute toxicity model. The signs of toxicity and morbidity were remarkable with the highest tested dose (4g/kg). LD₅₀ (dose required to kill 50% of the test population) was determined as 4 g/kg. Repeated oral administration of 1 and 1.5 g/kg/day of RDA for 28 days induced significant disturbance of serum parameters (AST, ALT, LDH, urea, creatinine). Kidney and liver extracted from mice fed with 1 and 1.5 g/kg/day showed significant histopathological injuries as tubular necrosis, inflammatory infiltrate, tubular degeneration, necrosis, and hepatic cholestasis. Meanwhile, neither histopathological nor biochemical alterations were observed in mice treated with 0.5 g/kg/day of body weight in comparison to the control group.

Conclusion

RDA showed toxicity in mice at a dose of 1 g/kg/day under subacute toxicity conditions. RDA is safe at a single dose inferior to 4 g/kg of body weight. The plant extract prepared by decoction showed more poisonous effect than the extract prepared by maceration at room temperature.

Systematic Overview of Aristolochic Acids: Nephrotoxicity, Carcinogenicity, and Underlying Mechanisms

Aristolochic acids (AAs) are a group of toxins commonly present in the plants of genus Aristolochia and Asarum, which are spread all over the world. Since the 1990s, AA-induced nephropathy (AAN) and upper tract urothelial carcinoma (UTUC) have been reported in many countries. The underlying mechanisms of AAN and AA-induced UTUC have been extensively investigated. AA-derived DNA adducts are recognized as specific biomarkers of AA exposure, and a mutational signature predominantly characterized by A→T transversions has been detected in AA-induced UTUC tumor tissues. In addition, various enzymes and organic anion transporters are involved in AA-induced adverse reactions. The progressive lesions and mutational events initiated by AAs are irreversible, and no effective therapeutic regimen for AAN and AA-induced UTUC has been established until now. Because of several warnings on the toxic effects of AAs by the US Food and Drug Administration and the regulatory authorities of some other countries, the sale and use of AA-containing products have been banned or restricted in most countries. However, AA-related adverse events still occur, especially in the Asian and Balkan regions. Therefore, the use of AA-containing herbal remedies and the consumption of food contaminated by AAs still carry high risk. More strict precautions should be taken to protect the public from AA exposure.

Sequence-Specific Detection of Aristolochia DNA - A Simple Test for Contamination of Herbal Products

Herbal medicines are used globally for their health benefits as an alternative therapy method to modern medicines. The market for herbal products has increased rapidly over the last few decades, but this has in turn increased the opportunities for malpractices such as contamination or substitution of products with alternative plant species. In the 1990s, a series of severe renal disease cases were reported in Belgium associated with weight loss treatment, in which the active species Stephania tetrandra was found to be substituted with Aristolochia fangchi. A. fangchi contains toxic aristolochic acids, which have been linked to kidney failure, as well as cancers of the urinary tract. Because of these known toxicities, herbal medicines containing these compounds, or potentially contaminated by these plants, have been restricted or banned in some countries, but they are still available via the internet and in alternate formulations. In this study, a DNA based method based on quantitative real-time PCR (qPCR) was tested to detect and distinguish Aristolochia subg. Siphisia (Duch.) O.C.Schmidt species from a range of medicinal plants that could potentially be contaminated with Aristolochia material. Specific primers were designed to confirm that Aristolochia subg. Siphisia can be detected, even in small amounts, if it is present in the products, fulfilling the aim of offering a simple, cheaper and faster solution than the chemical methods. A synthetic gBlock template containing the primer sequences was used as a reference standard to calibrate the qPCR assay and to estimate the copy number of a target gene per sample. Generic primers covering the conserved 5.8S rRNA coding region were used as internal control to verify DNA quality and also as a reference gene for relative quantitation. To cope with potentially degraded DNA, all qPCR primer sets were designed to generate PCR products of under 100 bp allowing detection and quantification of A. fangchi gBlock even when mixed with S. tetrandra gBlock in different ratios. All proportions of Aristolochia, from 100 to 2%, were detected. Using standards, associating the copy number to each start quantity, the detection limit was calculated and set to about 50 copies.