Microbial and Heavy Metal Contents of Selected Herbal Medicines Sold in Enugu State, Nigeria

Abstract

This study investigates the microbial and heavy metal contents of selected herbal medicines sold in Enugu State, Nigeria. Specifically, the study evaluated the presence of bacterial, parasitic, and fungal loads and heavy metals (mercury, lead, zinc, and iron) in herbal medicine samples. Ten branded samples were purchased from Ogige and Ogbete main markets and labelled A to J. These medicines were indicated for the treatment of malaria, typhoid fever, ulcers, sexually transmitted infections, worm infestations, and general blood cleansers. Laboratory analysis, using standard methods, was employed to determine the microbial and heavy metal contents of the samples. Culturing and microscopy methods were used for microbial analysis while heavy metal analysis was done using atomic absorption spectrophotometry. The analyses were carried out in duplicates using percentages, means, and standard deviations. The results showed that 60% of the samples exceeded safety limits for microbial contamination, while all
samples had excessive iron levels. Sample (A) contained mercury (0.161mg/100ml) above the safe standards established by the FAO/WHO. Seven samples (A, B, C, D, E, G, and I) were found to contain coliform bacteria and sample A contained Escherichia coli, Proteus mirabilis, and Bacillus polymyxa above safety limits. No sample was found with fungal and parasitic load above safety limits. The study concludes that herbal medicines may not be assured of safety in terms of bacterial, and heavy metal (iron and mercury) contents. The findings underline the health risks associated with unregulated locally prepared herbal medicines.