Pyrrolizidine alkaloid contamination of food in Africa: A review of current trends and implications.

Pyrrolizidine alkaloids (PAs) contamination of foodstuffs has become a topical issue in recent years on account of its potential hepatotoxicity to consumers. This review therefore highlights human exposure to PAs across Africa, focusing on their occurrence, current trends of food contamination, and their associated health implications. A comprehensive search of peer-scientific literature and relevant databases, PubMed, Google Scholar, Science Direct, Web of Science and Scopus, was conducted from 2001 to 2023 focusing mainly on foodstuffs, including grains, herbs, teas, honey, and livestock products. The findings revealed that PA contamination is a prevalent issue in several African countries, with the primary sources of contamination attributed to the consumption of honey and the use of PA plants as herbs in food preparations. Additionally, poor farming practices have been found to influence the presence and levels of PAs in foodstuffs. To mitigate PA contamination in food and safeguarding public health across the continent, several strategies are proposed, including the implementation of stringent regulatory and quality control measures, adoption of Good Agricultural Practices, and public awareness campaigns to educate producers, consumers and beekeepers about the risks associated with PA-contaminated food products.

Foodborne pathogens awareness and food safety knowledge of street-vended food consumers: A case of university students in Ghana.

Food pathogens, such as bacteria, viruses, and parasites are agents present in food or water that can cause foodborne illness. Some of these pathogens have been identified in Ghanaian foods and were responsible for the major foodborne disease outbreaks in Ghana. Thus, the current study assessed the awareness of foodborne pathogens and food safety knowledge of students in Ghana. The study employed non-probability techniques, as well as purposive and convenient techniques, to recruit institutions and students for the study. Out of 803 students, the majority (52.3%) were male, between the ages of 20 and 25 (52.8%), attended Ho Technical University (49.8%), and offered non-science-related courses (45.1%). The majority of the respondents were aware of foodborne pathogens, particularly Staphylococcus aureus (53.4%) and Salmonella typhimurium (53.5%). The mean overall score of foodborne pathogen awareness was 14.36 ± 4.57; the passing rate was 73.6%; tribe, institution, field of study, and level of study all had a significant (p < 0.05) effect on awareness of foodborne pathogens. The mean overall score of food safety knowledge was 12.43 ± 3.27; the passing rate was 77.3%; age, tribe, institution, field of study, and level of study all had a significant (p < 0.05) effect on food safety knowledge. Hence, food safety courses should be extended to all levels of education to increase awareness.

A cross-sectional study on food safety knowledge and practices among food handlers in tertiary and second circle institutions in Ho municipality, Ghana.

In recent years, incidences of food poisoning have been reported in some schools across the country. However, little attention has been paid to the hygiene practices of food vendors in the schools. This study, therefore, investigates the food safety knowledge and practices of food vendors catering for tertiary and second cycle students in the Ho municipality. The piloted and validated questionnaire used to sample 608 respondents revealed that the majority of the respondents sampled were female (76.0%), between the ages of 26 and 40 (51%), married (47.4%), and have tertiary or senior high school certificate (60.7%). They have been in business for not more than 2 years (36.2%) and had neither food safety (62.3%) nor good manufacturing practice (81.9%) training. However, they have sufficient knowledge in food safety regarding purchasing, storage, cooking and reheating, and personal hygiene, but exhibited poor knowledge and practice of food temperature control protocols. Both Kendall's tau-b coefficient correlation and linear regression model revealed a significant positive correlation between food safety knowledge and practices of the vendors. Nevertheless, regular training and monitoring are necessary to enable the vendors to fully implement the food temperature control protocols, which is one of the major causes of food poisoning in the country.

Dietary Polyphenols and Obesity: A Review of Polyphenol Effects on Lipid and Glucose Metabolism, Mitochondrial Homeostasis, and Starch Digestibility and Absorption.

Obesity is a major global public health concern, limiting socio-economic development and human productivity. As studies focus on finding sustainable solutions to this challenge, polyphenols have shown promising results and have become a research focus. This is mainly because of associated lower risks of side effects with their use, compared to synthetic pharmaceuticals. In this study, the anti-obesity potentials of dietary polyphenols have been reviewed. Using a narrative approach, the biological activities of polyphenols and their influence on energy metabolism and mechanisms are discussed. Specifically, their roles in insulin-dependent glucose uptake, insulin sensitivity, lipid metabolism and storage in adipocytes, starch digestibility, and regulation of mitophagy and mitogenesis in muscle cells and adipocytes, were considered. After considering the major findings of many related studies, it was confirmed that polyphenols can prevent and ameliorate obesity by fighting insulin resistance (IR) induced by pro-inflammatory cytokines, scavenging reactive oxygen species (ROS) and limiting their effects, and by regulating the expression and/or activity of key enzymes along relevant pathways. More human studies are needed to reveal more about the anti-obesity effects of dietary polyphenols and their effective doses in humans.

High-performance counter-current chromatography purification and off-line mass spectrometry monitoring and identification of pyrrolizidine alkaloid markers of tropical Ghanaian honey.

The nutritional and medicinal properties of honey have been well-documented. However, honey has occasionally been contaminated with hepatotoxic pyrrolizidine alkaloids as a result of bees foraging on the flowers of pyrrolizidine alkaloid plants. This study establishes a simple and rapid method to determine the marker pyrrolizidine alkaloids in honey using high-performance counter-current chromatography and an off-line electrospray ionization-tandem mass spectrometry, in order to identify the botanical sources responsible for the contamination. The honey sample was initially liquid-liquid extracted (sulfuric acid/hexane, 2:3, v/v) to enrich the pyrrolizidine alkaloids and subsequently purified by a semi-preparative high-performance counter-current chromatography using a solvent system, hexane/butanol/1% aqueous ammonia, 1:1:2, v/v, based on partition coefficient measurements of the target alkaloids. The recovered fractions were profiled by injecting them sequentially into an off-line electrospray ionization-tandem mass spectrometry device to monitor the preparative molecular weight based on elution and extrusion modes. The monitored lycopsamine-type pyrrolizidine alkaloids and their N-oxides (m/z 300, 316; lycopsamine, intermedine, rinderine, and echinatine) were used as the phytochemical markers to identify plants like Chromolaena odorata, Ageratum spp., or Heliotropium spp. to be responsible for the pyrrolizidine alkaloid contamination. Identification of these pyrrolizidine alkaloid plants could guide beekeepers in locating their beehives in order to minimize their potential liver damaging effects.

Uptake and accumulation of pyrrolizidine alkaloids in the tissues of maize (Zea mays L.) plants from the soil of a 4-year-old Chromolaena odorata dominated fallow farmland.

In an attempt to maximize yields of food crops, smallholder farmers have, over the years, increasingly employed agricultural practices such as slash-and-burn and slash-and-mulch on Chromolaena odorata dominated fallow farmlands. However, owing to recently introduced "Horizontal Natural Product Transfer" concept, concerns have been raised over how these common agricultural practices could potentially lead to toxic pyrrolizidine alkaloids (PAs), from decaying or burnt C. odorata residues, taken up by food crops and subsequently accumulate in the food chain. A field experiment was therefore conducted to analyze the PA contents in the tissues of maize (Zea mays L.) plants grown on slash-and-burn and slash-and-mulch plots, previously dominated with Chromolaena odorata, using liquid chromatography mass spectroscopy (LC-ESI-MS/MS). The results revealed, in general, trace amounts of PAs in the maize tissues (i.e. roots, leaves and grains) at maturity while significantly higher levels were detected in the surface soils sampled before sowing (for both plots), 45 days after sowing (slash-and-burn plot) and 90 days after sowing (slash-and-mulch plot). These findings demonstrate, for the first time, the leaching out of PAs from C. odorata residues (e.g. mulch and ash particles) and taken up by maize tissues. In spite of its air polluting and farmland degrading effects, slash-and-burn agricultural practices could lead, in the long term, to relatively lower accumulation of PAs in maize cultivated on PA-plant dominated fallow farmlands, hence smallholder farmers are encouraged to frequently employ this farming system.

Electrospray mass-spectrometry guided target isolation of neolignans from Nectandra leucantha (Lauraceae) by high performance- and spiral-coil countercurrent chromatography.

Nectandra leucantha (Lauraceae) is a tree indigenous to the tropical Atlantic forests of Brazil, one of the most biodiverse flora hotspots worldwide. This plant species contains high concentrations of neolignan and dehydrodieugenol derivatives that express significant in-vitro activities against various parasite strains. These activities are however responsible for severe tropical human infections, such as Leishmaniasis (Leishmania spp.) and Chagas disease (Trypanosoma cruzi), which have been classified by the World Health Organization (WHO) as Neglected Tropical Diseases (NTDs). In order to optimize the isolation process for these target metabolites, n-hexane extract of the leaves was separated by means of semi-preparative high performance countercurrent chromatography (HPCCC) and scale-up spiral-coil countercurrent chromatography (sp-CCC) systems. Several biphasic solvent mixtures were evaluated for their partitioning effects on neolignans, resulting in the selection of an optimized system n-hexane - ethylacetate - methanol - water (7:3:7:3, v/v/v/v). The chromatographic experiments on the HPCCC and sp-CCC were run in the head-to-tail mode with 500 mg and 16 g injections, respectively. For specific and multiple metabolite detection, the recovered CCC-fractions were off-line injected, in the sequence of recovery, to an electrospray mass-spectrometry (ESI-MS/MS) device. A projection of the single ion traces of the target compounds, in the positive ionization mode at a scan range of m/z 100-1500, located chromatographic areas where the co-elution effects occurred and pure target metabolites were present. Five major target neolignans were specifically detected, which enabled the accurate pooling of CCC-fractions for an optimum recovery of the metabolites. The direct comparison of the performance characteristics of the two CCC-devices, with very different mechanical designs was achieved by the conversion of the time axis into a partition ratio (KD) separation scale. As a result, the compound specific KD-elution values of the target neolignan were determined in high precision, while the comparison of the calculated separation factor (α) and resolution factor (RS) values revealed a superior separation performance for the HPCCC system. Also, the reproducibility of detected metabolites in the two CCC experiments was confirmed by small variations (ΔKD ±0.1). Neolignan target compounds with anti-parasite activities were successfully isolated in the 100 mg to 4 g range in a single lab-scale countercurrent chromatographic process step.

Incidence of Pyrrolizidine Alkaloids in Herbal Medicines from German Retail Markets: Risk Assessments and Implications to Consumers.

The occurrence of potentially toxic pyrrolizidine alkaloids (PAs) in herbal medicines (HMs) is currently intensely being discussed in Europe. Pyrrolizidine alkaloids, particularly the 1,2-unsaturated PAs, are undesired compounds in HMs due to their potential hepatotoxic and carcinogenic properties. In this study, 98 widely patronized HMs from six popular German retail supermarkets/drugstores, as well as from pharmacies, were analyzed by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry for the presence of PAs. The results showed that about 63% of the HMs were PA positive, whereas the average PA concentration of the samples was 201 µg/kg, the highest concentration of PAs (3270 µg/kg) was attributed to a product that was purchased from the pharmacy and contained Hypericum perforatum L. (St. John's Wort) as an active ingredient. In addition, H. perforatum-containing products were frequently contaminated with PAs from Echium spp., while both Cynara cardunculus L. products and fixed-combination products of Gentiana lutea L., Rumex acetosa L., Verbena officinalis L., Sambucus nigra L., and Primula veris L. products were commonly contaminated with PAs of Senecio spp. The study showed that H. perforatum, C. cardunculus, Urtica dioica L., and fixed-combination products were frequently contaminated with PA levels above the recommended values of both the German and European Medicines Agencies. Copyright © 2017 John Wiley & Sons, Ltd.

Pyrrolizidine alkaloids in floral honeys of tropical Ghana: a health risk assessment.

There is a vast amount of information about the nutritional and medicinal properties of honey as a result of its numerous benefits. However, honeys have been found to be contaminated with hepatotoxic and carcinogenic pyrrolizidine alkaloids (PAs) on account of bees foraging on PA-containing plants. This study deals with the analysis of PAs in tropical honeys emanating from different agro-ecological zones of Ghana in order to assess its potential health risk. PAs of 48 honey samples were analysed using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The results show that a total of 85% of the honeys from various agro-ecological zones were PA positive including all honeys from supermarkets. The highest concentration of PAs was 2639 µg kg-1, while the average PA concentration of the samples was 283 µg kg-1. The study also found Chromolaena odorata pollens in majority of the honeys, thus indicating the plant as major source of PA contamination of honeys in the tropical regions.

Toxic pyrrolizidine alkaloids in herbal medicines commonly used in Ghana.

ETHNOPHARMACOLOGICAL RELEVANCE: Herbal medicines have been used for centuries for the management and treatment of various ailments due to the belief that they pose only little or no health risk and side effects, and also, in part, due to their availability, affordability and/or self-supply. However, the increasing information over the recent years on the occurrence of pyrrolizidine alkaloids (PAs) in honey, herbal food and tea products has raised concerns about the safety of herbal medicines with respect to contamination. To this day, little is known on the occurrence of toxic PAs in herbal medicines, especially in tropical West Africa. The aim of this study was therefore to determine the PA content of 70 well-known and widely patronized plant-derived medicinal preparations, which are commercialized in Ghana and some West African countries, in order to ascertain their potential health risk. MATERIALS AND METHODS: PAs of the herbal medicinal products, sourced from specialized drugstores and mostly regulatory approved, were analyzed for their PA content by a HPLC-ESI-MS/MS sum parameter method. RESULTS: The results show that a total of 60% of the analyzed herbal products were PA positive, indicating an average PA-concentration of 25.0µg/kg. The maximum PA level (1290.0µg/kg) was attributed to a regulatory-approved herbal medicine not known, according to the list of declared ingredients, to contain PA-plant parts. Interestingly, higher PA content (average, 30.2µg/kg) was detected in regulatory-approved herbal medicines, in contrast to lower amount (average, 8.0µg/kg) detected in non-regulatory-approved products. CONCLUSION: The findings of this study clearly demonstrate that herbal medicines containing PA plants as ingredients, as well as some of those containing plant species not known to produce PAs, are likely to contain hepatotoxic PA at levels higher than the daily dose in food and herbal medicinal products proposed by the European Medicines Agency (i.e. 0.35µg PA per day for 50kg adult and 0.14µg PA per day for 20kg children). Hence, regulatory authorities are advised to carry out more rigorous quality control tests with respect to PAs so as to minimize the exposure of the consumers to these toxic compounds.

Survey of pyrrolizidine alkaloids in seven varieties of Lappula squarrosa: An alternative source of heart-healthy vegetable oil.

INTRODUCTION: Growing demand for heart-healthy omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is putting stress on wild fish stocks. There is now a compelling need for new and novel sources of non-traditional seed oils containing high stearidonic acid (SDA), a precursor of EPA and DHA, to reduce this demand. The seed oil of Lappula squarrosa is one of the richest sources of SDA, however, the plant has been found to contain toxic pyrrolizidine alkaloids (PAs). OBJECTIVE: In this study, the PA concentrations of seven varieties (A-G) of Lappula squarrosa were analysed to determine the most suitable varieties for commercial seed oil production. METHODS: Whilst the clean-up procedure for the PAs in the roots, flowers and leaves was on diatomaceous earth columns and finally analysed with GC-EI-MS, that of the seeds was through SCX-SPE and a more sensitive HPLC-ESI-MS/MS sum parameter method was used in the analysis. RESULTS: Altogether six PAs (supinine, amabiline, intermedine, lycopsamine and 3'-acetylintermedine) including one unknown retronecine-type PA were identified with variety C recording the lowest total PA concentration (4.64 mg seneciphylline equivalents (SE)/g dry weight (d.w.)). Besides, the total PA concentrations in the seeds of Lappula squarrosa varieties ranged between 2.88 µg PA/g and 10.36 µg PA/g d.w. CONCLUSION: Based solely on overall PA concentrations and PA distribution, variety D (5.95 mg SE/g d.w.) was found to be a potential candidate for commercial seed oil cultivation.