Mycological Quality of Powdered Herbal Medicinal Preparations Packaged for Human Consumption in North Western Nigeria

Abstract

The increase in the consumption of natural drugs have made their use a public health problem due to its poor quality, presence of  fungal contamination and the risk of the presence of mycotoxins. This investigation was designed to throw light on the mycological and aflatoxigenic status of powdered herbal medicinal products marketed in North Western Nigeria. A total of four hundred and thirty two(432) powdered herbal medicinal preparations consisting of twelve(12) each from six(6) localities in each of the six(6) states’ metropolis of the North Western Nigeria were obtained. These samples were subjected to various analyses. The parameters measured were grouped as follows: level of fungal contaminations of fungi; frequency of distribution of  fungi and  mycoflora type present in the herbal preparations. Results indicated that all the four hundred and thirty two herbal medicinal preparations assessed did not comply with the maximum acceptable limit of 2x10² cfu/g for fungal load. The study showed that samples from Kaduna and Kebbi  had  a significantly  higher  mean fungal count (1.09x10⁵cfu/g and 1.05x10⁵cfu/g respectively) that were not significantly different (p?0.05), hence suggesting higher contamination with fungi. The least was observed in Zamfara state with the lowest mean value of fungal load. The statistical analysis showed that fungal load in Katsina, Sokoto, Kano and  Zamfara  states were  not the same but not significantly different (p?0.05). This suggested low level of contamination with fungi when compared with samples from Kaduna and Kebbi state. In terms of fungal distribution in  herbal medicinal preparations, this study indicated that  fungi of the genus Aspergillus spp and Penicillus spp were the most frequently isolated and were found to be higher in frequency of occurrence. Out of one thousand and ninety five (1095)  total frequency of occurrence of fungi in the herbal medicinal preparations, the total frequency of occurrence of Aspergillus spp in this study is seven hundred and seventy five(70.77%), Penicillium spp (n=190;17.35%); Fusarium spp (n=86;7.85%)  and Rhizopus spp (n=44;4.02%). In this finding it could be suggested that Aspergillus spp and Penicillium spp are the major contaminant of herbal drugs. In all the samples screened from the six states, higher level of contamination with Aspergillus spp were found. Among  the Aspergillus spp observed,  A. flavus, A. paraceticus, A. niger were the most frequently occurred fungi in the herbal medicinal samples suggesting that these type of fungi are the major contaminant of the herbal medicinal products in all the six states of the North West of Nigeria. The highest frequency of occurrence of fungi observed in samples from Kaduna 151(69.59%), Kano139 (72.02%),sokoto135 (73.37%), Kebbi127 (66.49%), Kastina112 (70.89%) and Zamfara111 (68.52%)  may be as a result of poor harvesting, processing and storage practice of the handler of the herbal products. The  means of  frequency of occurrence of fungal isolates in herbal preparations from the North Western Nigeria also showed that incidence of  Aspergillus flavus, Aspergillus paraceticus, Aspergillus niger and Penicillium spp were not significantly  different at p<0.05 but significantly higher than Aspergillus ochraceus and Aspergillus versicolor. The result obtained also indicates that Fusarium spp and Rhizopus spp were significantly the lowest. This result suggests that the samples of herbal medicines obtained in the North Western Nigeria is heavily contaminated with the fungal species of Aspergillus spp and Penicillium spp.

Keywords:  herbal medicines, fungal contamination, North Western Nigeria