Risk assessment for pyrrolizidine alkaloids detected in (herbal) teas and plant food supplements

Pyrrolizidine alkaloids (PAs) are plant metabolites present in some botanical preparations, with especially 1,2-unsaturated PAs being of concern because they are genotoxic carcinogens. This study presents an overview of tumour data on PAs and points of departure (PODs) derived from them, corroborating that the BMDL₁₀ for lasiocarpine represents a conservative POD for risk assessment. A risk assessment using this BMDL₁₀ and mean levels of PAs reported in literature for (herbal) teas, indicates that consumption of one cup of tea a day would result in MOE values lower than 10 000 for several types of (herbal) teas, indicating a priority for risk management for these products A refined risk assessment using interim relative potency (REP) factors showed that based on the mean PA levels, 7(54%) of 13 types of (herbal) teas and 1 (14%) of 7 types of plant food supplements (PFS) resulted in MOE values lower than 10 000, indicating a priority for risk management also for these products in particular. This includes both preparations containing PA-producing and non-PA-producing plants. Our study provides insight in the current state-of-the art and limitations in the risk assessment of PA-containing food products, especially (herbal) teas and PFS, indicating that PAs in food presents a field of interest for current and future risk management.     

Characterization and Lifetime Dietary Risk Assessment of Eighteen Pyrrolizidine Alkaloids and Pyrrolizidine Alkaloid N-Oxides in New Zealand Honey

Pyrrolizidine alkaloids (PAs) are a large group of botanical toxins of concern, as they are considered genotoxic carcinogens, with long-term dietary exposure presenting an elevated risk of liver cancer. PAs can contaminate honey through honeybees visiting the flowers of PA-containing plant species. A program of monitoring New Zealand honey has been undertaken over several years to build a comprehensive dataset on the concentration, regional and seasonal distribution, and botanical origin of 18 PAs and PA N-oxides. A bespoke probabilistic exposure model has then been used to assess the averaged lifetime dietary risk to honey consumers, with exposures at each percentile of the model characterized for risk using a margin of exposure from the Joint World Health Organization and United Nations Food and Agriculture Organization Expert Committee on Food Additives (JECFA) Benchmark Dose. Survey findings identify the typical PA types for New Zealand honey as lycopsamine, echimidine, retrorsine and senecionine. Regional and seasonal variation is evident in the types and levels of total PAs, linked to the ranges and flowering times of certain plants. Over a lifetime basis, the average exposure an individual will receive through honey consumption is considered within tolerable levels, although there are uncertainties over high and brand-loyal consumers, and other dietary contributors. An average lifetime risk to the general population from PAs in honey is not expected. However, given the uncertainties in the assessment, risk management approaches to limit or reduce exposures through honey are still of value.     

Risk assessment of botanicals and botanical preparations intended for use in food and food supplements: emerging issues

At present there is a growing interest for use of botanicals and botanical ingredients in medicines, for teas or in foods and in food supplements. In addition, a number of plant-derived food items form an integral part of regular human diets. Currently, there is an increasing awareness among safety experts and regulators of risks associated with the use of botanicals and botanical ingredients in food including food supplements. It is becoming clear that "natural" does not equal "safe" and that, in modern society, adverse health effects can occur as a result of (mis)use. With the growing awareness of these issues efforts to ensure safety of botanicals and botanical ingredients are also increasing. Several guidance documents on safety assessment of botanicals and botanical preparations to be used as ingredients in food and food supplements have been published, although, at present, relevant legislative frameworks and guidances for risk assessment are not established yet. Furthermore, when defining possible guidance documents for risk assessment of botanicals, several issues emerge that need to be developed beyond the present state-of-the-art. The present paper describes some of the issues to be considered and developed to a further extent to improve risk assessment of botanicals and botanical preparations, illustrated by examples based on some allylalkoxybenzenes. It is concluded that, for an improved and more accurate future risk assessment of botanicals, it is necessary to further develop and validate: (i) the use of the margin of exposure (MOE) concept for compounds that are both genotoxic and carcinogenic; (ii) new ways to quantify and incorporate matrix effects into risk assessment strategies; (iii) the use of analytical chemistry approaches, enabling complete chemical characterisation of complex mixtures. Defining new approaches in risk assessment would be in line with the inspiring attitude of the late Professor Robert Kroes, who, for example by supporting the threshold of toxicological concern (TTC) concept, was a pioneer for development and implementation of new paradigms in the field of risk assessment and food safety.     

Consumer and farmer safety evaluation of application of botanical pesticides in black pepper crop protection

This study presents a consumer and farmer safety evaluation on the use of four botanical pesticides in pepper berry crop protection. The pesticides evaluated include preparations from clove, tuba root, sweet flag and pyrethrum. Their safety evaluation was based on their active ingredients being eugenol, rotenone, β-asarone and pyrethrins, respectively.Botanical pesticides from Acorus calamus are of possible concern because of the genotoxic and carcinogenic ingredient β-asarone although estimated margins of exposure (MOE) for consumers indicate a low priority for risk management.For the other three botanical pesticides the margin of safety (MOS) between established acute reference doses and/or acceptable daily intake values and intake estimates for the consumer, resulting from their use as a botanical pesticide are not of safety concern, with the exception for levels of rotenone upon use of tuba root extracts on stored berries. Used levels of clove and pyrethrum as botanical pesticides in pepper berry crop production is not of safety concern for consumers or farmers, whereas for use of tuba root and sweet flag some risk factors were defined requiring further evaluation and/or risk management. It seems prudent to look for alternatives for use of sweet flag extracts containing β-asarone.     

Determination and risk assessment of naturally occurring genotoxic and carcinogenic alkenylbenzenes in nutmeg‐based plant food supplements

A risk assessment of nutmeg‐based plant food supplements (PFS) containing different alkenylbenzenes was performed based on the alkenylbenzene levels quantified in a series of PFS collected via the online market. The estimated daily intake (EDI) of the alkenylbenzenes amounted to 0.3 to 312 μg kg⁻¹ body weight (bw) for individual alkenylbenzenes, to 1.5 to 631 μg kg⁻¹ bw when adding up the alkenylbenzene levels assuming equal potency, and to 0.4 to 295 μg kg⁻¹ bw when expressed in safrole equivalents using toxic equivalency factors (TEFs). The margin of exposure approach (MOE) was used to evaluate the potential risks. Independent of the method used for the intake estimate, the MOE values obtained were generally lower than 10000 indicating a priority for risk management. When taking into account that PFS may be used for shorter periods of time and using Haber's rule to correct for shorter than lifetime exposure it was shown that limiting exposure to only 1 or 2 weeks would result in MOE values that would be, with the presently determined levels of alkenylbenzenes and proposed uses of the PFS, of low priority for risk management (MOE > 10000). It is concluded that the results of the present paper reveal that nutmeg‐based PFS consumption following recommendations for daily intake especially for longer periods of time raise a concern. Copyright © 2017 John Wiley & Sons, Ltd.     

A critique of prevailing approaches to nutrient risk analysis pertaining to food supplements with specific reference to the European Union

In the European Union (EU), interest in risk analysis as applied to micronutrients is being stimulated by the increasing availability and marketing of food (dietary) supplements, functional and fortified foods. There is also strong inter-governmental interest in harmonising methods regionally and globally. Various models are being evaluated in the EU for the purposes of developing Community-wide, mandatory maximum (and minimum) permitted levels, as required by EC Directive 2002/46/EC and Regulation (EC) No 1925/2006 on food supplements and fortified foods, respectively. This paper provides a scientific critique of models currently proposed in the EU and demonstrates weaknesses in both the risk assessment methods used to determine upper tolerable levels (ULs) as well as the risk management approaches being considered for the determination of maximum levels, particularly as applied to food supplements. Methods for ameliorating existing models are proposed here, including a proposal for using decision science as the underlying methodology in nutrient risk analysis. Risk management approaches based on more plausible scientific methods would avoid unnecessarily restrictive policy-based levels that would adversely impact consumer choice, while contributing to a ‘better regulation’ approach. Scientifically robust and rational methods of nutrient risk analysis are consistent with disease risk reduction, health management and consumer protection strategies.     

Botanical ingredients in cosmeceuticals

During the last 10 to 15 years, complementary and alternative medicine (CAM) has become increasingly popular in the US. Within this realm of health care, oral and topical herbal supplements have become some of the most frequently used alternative therapies. Most herbal supplements are based on, or include, several botanical ingredients with long histories of traditional or folk medicine usage. Among the numerous botanical ingredients available on the market today, several are believed to confer dermatologic benefits. This article will focus on a select group of botanical compounds, many of which have long traditions in Asian medicine, with potential or exhibited dermatologic applications, including curcumin, Ginkgo biloba, ginseng, silymarin, soy, and tea tree oil. Other botanical agents, such as arnica, bromelain, chamomile, pomegranate, caffeine, green tea, licorice, and resveratrol, are also briefly considered. Some of these ingredients have been incorporated into topical formulations.     

Criteria for risk assessment of botanical food supplements

The increasing use of botanical food supplements has raised concerns among scientific and regulatory communities. Occasional cases of intoxication have occurred from misuse, misidentification of the botanical species or contamination with extraneous plants. Consequently, risk assessment of botanical products requires adequate specification of identity and composition. Sources vary from staple food plants to herbals used in folk medicine; the supplement may comprise the whole plant, extracts thereof or purified components. This variability poses problems in adopting a generic approach to their risk assessment. The nature and extent of toxicological testing required will depend on: nature of the supplement, prior knowledge of human consumption, likely exposure and nutritional impact, and intended beneficial effects. Generally, for herbs or complex extracts, it is not possible to make a risk assessment on the basis of a single active component as more than one may be of toxicological significance and matrix effects may affect bioavailability. Nevertheless, studies on single components may be useful in elucidating potential interactions. Botanical supplements are intended to produce physiological effects, so there is a need to distinguish a No Observed Effect Level from a No Observed 'Adverse' Effect Level and the margin of exposure between that producing the desired effect and the upper safe level may be smaller than that adopted for food additives and contaminants. Human studies of efficacy and possible side effects may help in determining the acceptable margin of exposure. A decision tree will be presented to assist in determining the extent of data requirements based on the nature of the product.     

Safety of botanical ingredients in personal care products/cosmetics

The key issue of the safety assessment of botanical ingredients in personal care products (PCP) is the phytochemical characterisation of the plant source, data on contamination, adulteration and hazardous residues. The comparative approach used in the safety assessment of GM-plants may be applied to novel botanical PCP ingredients. Comparator(s) are the parent plant or varieties of the same species. Chemical grouping includes definition of chemical groups suitable for a read-across approach; it allows the estimation of toxicological endpoints on the basis of data from related substances (congeneric groups) with physical/chemical properties producing similar toxicities. The Threshold of Toxicological Concern (TTC) and Dermal Sensitisation Threshold (DST) are tools for the assessment of trace substances or minor ingredients. The evaluation of skin penetration of substances present in human food is unnecessary, whereas mixtures may be assessed on the basis of physical/chemical properties of individual substances. Adverse dermal effects of botanicals include irritation, sensitisation, phototoxicity and immediate-type allergy. The experience from dietary supplements or herbal medicines showed that being natural is not equivalent to being safe. Pragmatic approaches for quality and safety standards of botanical ingredients are needed; consumer safety should be the first objective of conventional and botanical PCP ingredients.     

Application of the threshold of toxicological concern approach for the safety evaluation of calendula flower (Calendula officinalis) petals and extracts used in cosmetic and personal care products

Calendula flower (Calendula officinalis) (CF) has been used in herbal medicine because of its anti-inflammatory activity. CF and C. officinalis extracts (CFE) are used as skin conditioning agents in cosmetics. Although data on dermal irritation and sensitization of CF and CFE’s are available, the risk of subchronic systemic toxicity following dermal application has not been evaluated. The threshold of toxicological concern (TTC) is a pragmatic, risk assessment based approach that has gained regulatory acceptance for food and has been recently adapted to address cosmetic ingredient safety. The purpose of this paper is to determine if the safe use of CF and CFE can be established based upon the TTC class for each of its known constituents. For each constituent, the concentration in the plant, the molecular weight, and the estimated skin penetration potential were used to calculate a maximal daily systemic exposure which was then compared to its corresponding TTC class value. Since the composition of plant extracts are variable, back calculation was used to determine the maximum acceptable concentration of a given constituent in an extract of CF. This paper demonstrates the utility and practical application of the TTC concept when used as a tool in the safety evaluation of botanical extracts.     

A three-stage-integrative approach for the identification of potential hepatotoxic compounds from botanical products

With the increasing use of herbal medicines and dietary supplements, intensive concerns about their potential toxicities have been raised. Screening and identifying the toxic compounds from these botanical products composed by hundreds of components have become a critical but challenging problem. In this study, 3 methods, including fraction separation, an in-house-developed fluorescein diacetate-based automatic microscopy screening (FAMS) platform, and liquid chromatography-mass spectrometry-based compounds identification were integrated within the Three-Stage-Integrative (TSI) approach for the identification of potential hepatotoxicants from botanical products. The sensitivity and linear range of FAMS assay was validated and compared with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay by previously reported hepatotoxic compounds. The success of TSI approach was further demonstrated by its application to Fructus aristolochiae. Aristolochic acid IVa and aristolodione were tentatively identified to be potential hepatotoxicants in this plant. These applications suggested that our TSI approach provides an effective tool for identifying potential toxic compounds from botanical products.     

A rationale for determining, testing, and controlling specific impurities in pharmaceuticals that possess potential for genotoxicity

The synthesis of pharmaceutical products frequently involves the use of reactive reagents and the formation of intermediates and by-products. Low levels of some of these may be present in the final drug substance and drug product as impurities. Such chemically reactive impurities may have at the same time the potential for unwanted toxicities including genotoxicity and carcinogenicity and hence can have an impact on product risk assessment. This paper outlines a procedure for testing, classification, qualification, toxicological risk assessment, and control of impurities possessing genotoxic potential in pharmaceutical products. Referencing accepted principles of cancer risk assessment, this document proposes a staged threshold of toxicological concern (TTC) approach for the intake of genotoxic impurities over various periods of exposure. This staged TTC is based on knowledge about tumorigenic potency of a wide range of genotoxic carcinogens and can be used for genotoxic compounds, for which cancer data are limited or not available. The delineated acceptable daily intake values of between approximately 1.5 microg/day for approximately lifetime intake and approximately 120 microg/day for < or = 1 month are virtually safe doses. Based on sound scientific reasoning, these virtually safe intake values do not pose an unacceptable risk to either human volunteers or patients at any stage of clinical development and marketing of a pharmaceutical product. The intake levels are estimated to give an excess cancer risk of 1 in 100,000 to 1 in a million over a lifetime, and are extremely conservative given the current lifetime cancer risk in the population of over 1 in 4 (http://seer.cancer.gov/statfacts/html.all.html). The proposals in this document apply to all clinical routes of administration and to compounds at all stages of clinical development. It is important to note that certain types of products, such as those for life-threatening indications for which there are no safer alternatives, allow for special considerations using adaptations of the principles outlined in this paper.     

Pharmacovigilance on sexual enhancing herbal supplements

The use of herbal medicines continues to expand rapidly across world and many people show positive interest to use herbal products for their health. The safety of herbal supplements has become a globally major concern in national and international health authorities due to increasing adverse events and adulterations.It is difficult to analyze herbal products that cause adverse events due to lack of sufficient information and expertise. Inadequate regulatory measures, weak quality control system and uncontrolled distribution channels are some of reasons that enhance the informal pharmaceutical market. In recent years, the unfulfilled desire for sex has been a subject that has aroused increasing public interest with respect to improve sexual functions. The use of herbal medicines substantially increased due to escalated prevalence and impact of sexual problems worldwide and estimates predicting the incidence to raise over 320 million by year 2025. The various reasons to use herbal supplements in men may be due to experiencing changes in erectile dysfunction (ED) due to certain medical conditions such as diabetes and hypertension and bodily changes as a normal part of life and aging.There is a lack of adequate evidence, no impetus to evaluate and absence of any regulatory obligations to undertake rigorous testing for safety and efficacy of herbal supplements before they sold over-the-counter (OTC). Pharmacovigilance on herbal supplements is still not well established. Sexual enhancing herbals are on demand in men health but informal adulteration is growing issue of concern. Recently, increase in use of herbal supplements for erectile dysfunction has laid a path for many illegal compositions. This paper explores facts and evidences that were observed in different countries attempting to demonstrate the importance of strengthening regulatory system to strengthen the application of pharmacovigilance principles on sexual enhancing supplements. We hereby explore the problem of sexual herbal supplements from pharmacovigilance perspectives.We provide insights into the various concerns and call for collaboration to resolve the problem. We highly recommend to include herbal medicines in national pharmacovigilance systems and to establish comprehensive national pharmacovigilance program to raise the awareness about herbal medicines particularly those used in enhancing sexual desire.     

Malignant transformation of mouse M2-fibroblasts by glycerol chlorohydrines contained in protein hydrolysates and commercial food

Glycerol chlorohydrines, such as 3-chloro-1,2-propanediol and 1,3-dichloro-2-propanol, are present in commercial protein hydrolysates used for human nutrition. These compounds are genotoxic and 1,3-dichloro-2-propanol induced tumors in rats. Now it is reported that both compounds are active at inducing malignant transformation of mouse fibroblasts. Therefore, the carcinogenic risk to humans by exposure to these compounds contained in food is of concern. The investigation of the in vivo carcinogenic potential of 3-chloro-1,2-propanediol is urgently required to further evaluate the carcinogenic risk to exposed consumers.     

Printed paper and board food contact materials as a potential source of food contamination

Food contact materials (FCM) are estimated to be the largest source of food contamination. Apart from plastics, the most commonly used FCM are made of printed paper and board. Unlike their plastic counterparts, these are not covered by a specific European regulation. Several contamination issues have raised concerns towards potential adverse health effects caused by exposure to substances migrating from printed paper and board FCM. In the current study, an inventory combining the substances which may be used in printed paper and board FCM, was created. More than 6000 unique compounds were identified, the majority (77%) considered non-evaluated in terms of potential toxicity. Based on a preliminary study of their physicochemical properties, it is estimated that most of the non-evaluated single substances have the potential to migrate into the food and become bioavailable after oral intake. Almost all are included in the FACET tool, indicating that their use in primary food packaging has been confirmed by industry. Importantly, 19 substances are also present in one of the lists with substances of concern compiled by the European Chemicals Agency (ECHA). To ensure consumer safety, the actual use of these substances in printed paper and board FCM should be investigated urgently.     

Screening botanical extracts for quinoid metabolites.

Botanical dietary supplements represent a significant share of the growing market for alternative medicine in the USA, where current regulations do not require assessment of their safety. To help ensure the safety of such products, an in vitro assay using pulsed ultrafiltration and LC-MS-MS has been developed to screen botanical extracts for the formation of electrophilic and potentially toxic quinoid species upon bioactivation by hepatic cytochromes P450. Rat liver microsomes were trapped in a flow-through chamber by an ultrafiltration membrane, and samples containing botanical extracts, GSH and NADP(H), were flow-injected into the chamber. Botanical compounds that were metabolized to reactive intermediates formed stable GSH adducts mimicking a common in vivo detoxification pathway. If present in the ultrafiltrate, GSH conjugates were detected using LC-MS-MS with precursor ion scanning followed by additional characterization using product ion scanning and comparison to standard compounds. As expected, no GSH adducts of reactive metabolites were found in extracts of Trifolium pratense L. (red clover), which are under investigation as botanical dietary supplements for the management of menopause. However, extracts of Sassafras albidum (Nutt.) Nees (sassafras), Symphytum officinale L. (comfrey), and Rosmarinus officinalis L. (rosemary), all of which are known to contain compounds that are either carcinogenic or toxic to mammals, produced GSH adducts during this screening assay. Several compounds that formed GSH conjugates including novel metabolites of rosmarinic acid were identified using database searching and additional LC-MS-MS studies. This assay should be useful as a preliminary toxicity screen during the development of botanical dietary supplements. A positive test suggests that additional toxicological studies are warranted before human consumption of a botanical product.     

Safety assessment of chromium by exposure from cosmetic products

Low level impurities often reside in cosmetic products. The aim of the present study was to estimate the human exposure to chromium from cosmetic products purchased at a local market in South Korea, and to assess the risk on public health. Hexavalent chromium is an impurity substance that contaminates cosmetic products during manufacture. The potential for chromium to induce and elicit allergic contact dermatitis, as well as the degree of chromium exposure from cosmetic products, were assessed. Chromium exposure was estimated using the chromium concentrations found in cosmetic samples taken from the local market along with the expected user pattern data that was taken from the literature. Of the cosmetics we tested and available for purchase on the Korean market, seven had chromium contents above the detection limit of 0.1 ppm (0.1 μg/mL), ranging from 0.2 to 3.15 ppm. In risk assessment, scientifically defensible dose-response relationships must be established for the end points of concern. In the case of chromium contaminated cosmetic products, this includes conducting dose-response assessments for allergic contact dermatitis following dermal exposure. This dose-response information can then be integrated with site-specific exposure assessments to regulate consumer safety by use of these products. We found that dermal exposure to chromium concentrations ranging from 0.0002 to 0.003 μg/cm² does not appear to cause concern for eliciting allergic contact dermatitis.     

Authentication of medicinal plants using molecular biology techniques to compliment conventional methods

Medicinal plants have become extremely popular in the United States as botanical supplements, herbal medicines and sources of lead compounds for pharmaceutical development. It is estimated that in 1997 Americans used or consumed 5.1 billion US dollars worth of herbal medicines. For the protection of consumers, authentication of medicinal plants is a critical issue. Ideally, authentication should occur from the harvesting of the plant material to the final product. Unfortunately there is no single or superior method to assure 100 percent authentication during the entire process, but the goal can be achieved through the application of a variety of different methodologies. The whole process starts with good voucher specimens that act as reference material and to prove chain of custody. Macroscopic and microscopic examinations can be used as rapid and inexpensive identification techniques. Chemical analysis is by far the best method for the detection of contaminants and can be an excellent method for plant identification. Each of these methodologies has limitations and more analytical methods are needed to assist in the authentication process. Molecular biology offers an assortment of techniques that can be very useful for authentication of medicinal plants. This review covers various aspects of authentication methods, with special emphasis on molecular biology techniques.     

Safety concerns of herbal products and traditional Chinese herbal medicines: dehydropyrrolizidine alkaloids and aristolochic acid

In many countries, including the United States, herbal supplements, tisanes and vegetable products, including traditional Chinese medicines, are largely unregulated and their content is not registered, monitored or verified. Consequently, potent plant toxins including dehydropyrrolizidine alkaloids and other potential carcinogens can contaminate these products. As herbal and food supplement producers are left to their own means to determine the safety and purity of their products prior to marketing, disturbingly often good marketing practices currently in place are ignored and content is largely undocumented. Historical examples of poisoning and health issues relating to plant material containing dehydopyrrolizidine alkaloids and aristolochic acids were used as examples to demonstrate the risk and potential toxicity of herbal products, food supplements, or traditional medicines. More work is needed to educate consumers of the potential risk and require the industry to be more responsible to verify the content and insure the safety of their products. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.     

Genotoxicity of pyrrolizidine alkaloids

Pyrrolizidine alkaloids (PAs) are common constituents of many plant species around the world. PA‐containing plants are probably the most common poisonous plants affecting livestock and wildlife. They can inflict harm to humans through contaminated food sources, herbal medicines and dietary supplements. Half of the identified PAs are genotoxic and many of them are tumorigenic. The mutagenicity of PAs has been extensively studied in different biological systems. Upon metabolic activation, PAs produce DNA adducts, DNA cross‐linking, DNA breaks, sister chromatid exchange, micronuclei, chromosomal aberrations, gene mutations and chromosome mutations in vivo and in vitro. PAs induced mutations in the cII gene of rat liver and in the p53 and K‐ras genes of mouse liver tumors. It has been suggested that all PAs produce a set of (±)‐6,7‐dihydro‐7‐hydroxy‐1‐hydroxymethyl‐5H‐pyrrolizine‐derived DNA adducts and similar types of gene mutations. The signature types of mutations are G : C → T : A transversion and tandem base substitutions. Overall, PAs are mutagenic in vivo and in vitro and their mutagenicity appears to be responsible for the carcinogenesis of PAs. Published in 2010 by John Wiley & Sons, Ltd.