Abstract
Introduction: Tobacco and other similar/related products represent a substantial proportion of recreationally-used substances in Malawi. Ngirimbo is a smokeless substance taken orally to reduce tobacco smoking. This study aimed to determine the toxicological characteristics of Ngirimbo in terms of pesticide residues, microbial, trace and heavy metal contaminants, herbal compounds, and nicotine, moisture, and pH levels. Methods: Samples were analysed using atomic absorption spectrophotometry, titration, X-ray fluorescence spectroscopy, UV-visible Spectrophotometer, gas chromatography-mass spectrometry, pH and gravimetric analysis, ISO4833, ISO21527, ISO16654, and ISO6579. Results: From a total of 12 samples, 5 samples contained nicotine ranging from 0.08–0.84%, while the remaining 7 samples showed no trace of nicotine. Sample pH ranged from 6.68 to 8.32, and moisture content from 12.87–47.11%. Samples had no detectable contamination with chlorine or pesticide residue. Heavy metals tested: Cadmium, Nickel, Lead, and Copper were found to be below the detection limit of 0.01mg/kg. On the other hand, X-ray fluorescence spectroscopy analysis revealed the presence of Nickel, Bromine, Rubidium, Strontium, Zirconium, Molybdenum, Rhodium, Cadmium, Chromium, and Tellurium. Samples had good levels of Calcium, Iron, Potassium, Sodium, and Zinc ranging from 23mg/kg to 57,800mg/kg. Samples contained phytocompounds and herbal material of medicinal relevance. In terms of the microbiological content, Escherichia coli and Salmonella were absent, while Moulds and Yeast were present at a level of <1cfu/g, with the total plate count varying across all samples between 1,400cfu/g and 640,000cfu/g. Conclusion: These findings demonstrate that the current state of Ngirimbo available in Malawi is toxic and a hazard to human health. Implications: Prolonged use of Ngirimbo may lead to users developing mouth cancers or thermal burns to the oral mucosal membrane. Further, Ngirimbo consumers are at risk of developing dental caries, known to harbour microorganisms and development of infectious diseases. The control and regulation of Ngirimbo is highly recommended to maximise its capacity for use as a treatment/medication for tobacco replacement while minimising the negative impact on public health. Further work needs to be done to quantify the contents of Ngirimbo, and develop tolerance limits so that it may be used as a nicotine and tobacco replacement product.