Microbial Quality and Antimicrobial Potential of some Herbal Remedies Marketed in Owerri-West Nigeria

Abstract

Background Herbal remedies are complex mixtures of plant extracts and natural products. Their adoption for therapeutic purposes dates back to ancient times. Despite the acceptance of these herbal remedies, there is still concern about their purity and safety. The objective was to determine the quality of the herbal remedies by their microbial load and organisms present in the samples. The study also determined the therapeutic potential of selected pathogenic organisms from clinical sources. Materials and Methods Microbial enumeration and identification of bacteria and fungi from 20 common herbal remedies were performed using standard microbiological protocols. Further identification was done using molecular typing. Antibiotic susceptibility tests, minimum inhibitory and bactericidal concentration of the remedies was also determined on Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Staphylococcus aureus were done using agar well diffusion method. Results Bacteria counts in the remedies varied from 1.0x104 – 1.4x105 while fungi counts ranged from 2.0x103 – 1.6x105. S. aureus, P. aeruginosa, E. coli and Bacillus spp were the bacterial species isolated from the remedies. Bacillus was the highest in the occurrence of (53%), while the least was E. coli (7%). Seven species of fungi namely Penicillium citrinum (MN960659) 21.1%, Pichia cecembensis (MN960658) 21.1%, Aspergillus niger 26.3% (MN960657), Saccharomyces spp (5.3%), Mucor spp (5.3 %), Fusarium spp (7. 3%) and Rhizopus spp (13.2 %), were identified. The inhibitory activity of herbal remedies on pathogenic organisms ranged from 8mm -18mm. Minimum inhibitory concentration (MIC) ranged from 62.5 – 125mg/ml while Minimum bactericidal concentration (MBC) ranged from 125mg/ml – 250mg/ml. The lowest activity was seen with Candida albicans and S. aureus while the highest activity was seen with P. aeruginosa, while Salmonella typhi was resistant. Conclusions Producers of herbal remedies should observe standard protocols and regulatory agencies should monitor and enforce microbial quality of products continually.