Aflatoxin exposure in Southwestern Uganda and the ameliorative effects of selected medicinal plants on induced aflatoxicosis in wistar rats

Abstract

Introduction: Over 5.5 billion people, worldwide are chronically exposed to aflatoxins. This contributes to 40% of the African disease burden. Aflatoxins are mycotoxins produced by Aspergillus flavus and A. parasiticus, A. nomius, and A. tamarii, which are fungal species. Aflatoxin B1 (AFB1) is the most prevalent and carcinogenic among them. Since prevention of their production is not practical, we ingest them making toxicity control the easiest option. Consumption of high phenolic medicinal plant ameliorates the toxicological effects of aflatoxins. Objectives: The goal of the study was to assess dietary aflatoxin exposure in selected foodstuffs in Southwestern Uganda and the ameliorative effects of selected medicinal plants on aflatoxicosis in wistar rats. Specifically, the study set out to: (i) determine the aflatoxin susceptible food consumption frequency, prevalence and levels of aflatoxins in household foodstuffs in Southwestern Uganda; (ii) determine the phenolic, and flavonoid contents and antioxidant capacity of different selected medicinal plants (iii) assess the ameliorative effects of the selected medicinal plants on aflatoxin induced changes in liver, kidney and immune functions. Methods: Flours of Arachis hypogaea (groundnuts), Zea mays (maize), Eleusine coracana (millet), and Sorghum bicolor (sorghum), the most commonly aflatoxin contaminated foods, were systematically sampled, following a consumption frequency questionnaire. Samples were analysed for aflatoxin content using competitive ELISA. Ocimum gratissimum, Allium sativum, Cymbopogon citratus, Zingiber officinale, and primary grades and green tea, Camellia sinensis, were analysed for phenolics and flavonoids, following Folin-ciocalteu and Aluminium chloride methods respectively. Their antioxidant capacity was determined following DPPH and FRAP methods. Ninety-six male wistar rats were grouped into 16 groups of 6 and treated for 30 days as follows; 1. Control, 2. Olive oil. 3. AFB1 Low-dose (100µg/kg), 10. AFB1 High-dose (300µg/kgAFB1). 4-9. AFB1 Low-dose + 2% extracts, 11-16. AFB1 High-dose + 2% extract. Liver and kidney functions, histopathology, and immune function indicators were evaluated using standard methods. Results: The highest aflatoxin prevalence, levels and consumption frequency were observed in maize and groundnuts (Tables 4.1.2 and 4.1.1, respectively). Indoor dried/processed medicinal plants yielded higher total phenolic content (TPC) than fresh ones. In addition, 40 minutes extracts of medicinal plants yielded higher TPC. Green tea yielded the highest DPPH (93.82%) and FRAP (39.04µg AAE/mL), and tea harvested from Buganda (4,371 µgQE/g) the highest total flavonoid content (TFC). Green and black tea, C. sinensis, O. gratissimum, and C. citratus reduced the damaging effects of aflatoxin toxicity in liver functions, histopathology and blood and immunity parameters. Conclusion: Groundnut and maize were the main foods through which aflatoxin exposure occurs. For maximum TPC, it is better to use processed medicinal plants and longer extraction periods. Green and black tea, C. sinensis, O. gratissimum, and C. citratus have ameliorative effects in aflatoxicosis. Community awareness in aflatoxin contamination avenues and health effects, and encouragement to regularly consume high phenolic medicinal plants is urgently needed.