In vitro Screening of Herbal Extracts and Antibiotics against Bacteria Isolated from Fish Products at Retail Outlets

Aims: Many studies have been conducted on the antibacterial activity of medicinal plants against human pathogens. However, a little has been done on fish pathogens. The aim of this research work was to isolate bacterial pathogens from spoiled fish leading to human diseases and compare the efficacies of selected antibiotics and medicinal herbal extracts against these infectious pathogens.
Study Design: An experimental study.
Place and Duration of Study: Biotechnology Lab, Department of Zoology, University of AJ&K, Muzaffarabad, Pakistan, between Feb 2011 and August 2012.
Methodology: Bacterial pathogens Enterobacter amnigenus, Serratia odorifera, Salmonella Typhimurium and Shigella flexneri were isolated from spoiled fishes. Various extracts of seed and stem parts of medicinal plants including Cinnnamomum zylanicum, Cuminum cyminum, Syzygium aromaticum, Curcuma long Linn, Trachyspermum ammi and Momordica charantia (both seeds and green parts of Bitter gourd) against common fish associated bacterial pathogens by filter disc diffusion method.
Results: The highest zone of inhibition was observed by Ciprofloxacin against S. Typhimurium (61 mm), whereas 55 mm by Gentamicin and 51 mm by Streptomycin against S. flexneri. However, Penicillin G, Ampicillin, and Amoxicillin had no effect on S. flexneri and E. amnigenus. The extracts of green part of M. charantia showed better results as compared to the seed extracts. Phytochemical screening of medicinal plants indicated that individual compounds viz., thyme from ajwain, ar-turmerone from turmeric, eugenol, taninns and flavonoids from clove have antimicrobial activities.
Conclusion: Current study supports the traditional use of medicinal plants as antibacterial agents.