Occurrence of Aflatoxins and Fumonisins Contamination in Herbal Medicinal Products Sold in Nairobi, Kenya

Abstract

Aflatoxins and fumonisins are referred to as Mycotoxins. They are secondary metabolites of some moulds which are highly toxic, mutagenic or teratogenic compounds. These substances are not formed by all mould species but are characteristic of their producers. The aim of this study was to determine the occurrence of Aflatoxin and Fumonisins contamination in herbal medicinal products sold in Nairobi Kenya. The study was undertaken in Nairobi, the capital and largest city in Kenya. Nairobi has several herbal clinics, especially in densely populated areas. This study employed an exploratory as well as laboratory-based experimental design to sample 138 herbal medicinal products. The sample were in different preparations, which included liquids, powders, capsules, creams/lotions, and syrups. Screening of the presence of aflatoxins and fumonisins were done using Envirologix Quick Tox^TM Kit following the manufacturer’s instructions. Fumonisins and aflatoxins concentration in parts per billion (ppb) was analyzed statistically using Pearson Chi square test at 95% confidence interval. Contaminations were presented in form of frequencies and percentages. Aflatoxins were detected in 74(53.6%) samples while fumonisins were detected in 75(54.3%). Four (11.8%) samples from herbal clinics and 3(4.1%) from street vendors in form of powders and liquids had aflatoxins levels above 4.0ppb. Nine (26.5%) samples from herbal clinics, 10(13.5%) from streets vendors/hawkers and two (10.5%) from the supermarkets in form of powders and liquids had fumonisins levels above 4.0ppb. There was no significant association (c² test; p>0.05) between detection of fungi from an herbal product and the occurrence of mycotoxins. Aspergillus flavus and A. parasiticus isolated in this study were associated with occurrence of aflatoxins while the Fusarium isolated were responsible for the presence of fumonisins among the herbal products. We conclude that herbal products investigated were contaminated with fumonisins and aflatoxins in varying degrees. Some were contaminated beyond the accepted limits. There were many genera of molds isolated in this study, which are associated with mycotoxins production, but the current study only focused on aflatoxins and fumonisins and therefore other mycotoxins should be investigated so as to ensure overall fungi toxins safety among the herbal products.

Key words: aflatoxin, fumonisins, contamination, herbal medicinal products, Aspergillus, Fusarium, Nairobi.