Antimicrobial activity of Persicaria pensylvanica extract against Staphylococcus aureus
Abdi, R. D., and O. Kerro Dego.  2019.  European Journal of Integrative Medicine, Volume 29, August 2019.

Introduction: Staphylococcus aureus causes contagious mastitis in dairy cows with annual economic losses of 2 billion dollars in the United States alone. S. aureus mastitis remains important and difficult to eliminate using antimicrobial therapy due to its ability to form a biofilm, becomes a small colony variant or acquires antimicrobial resistance (AMR). Antimicrobial resistant S. aureus strains including methicillin-resistant S. aureus (MRSA) have emerged and increasingly are isolated from animal and animal products. Thus, developing an alternative therapeutic approach is critically needed. Natural botanical products have received greater attention as alternatives to antibiotics since they contain a diverse array of antimicrobial compounds. Methods: In this study, we evaluated the antimicrobial activity of the extracts from herbal plant Persicaria pensylvanica’s flower, leaf, stem, and root. This plant is also known by a common name Pennsylvania smartweed. The antimicrobial effect of the extracts was tested using minimum inhibitory concentration (MIC) and minimum bacteriocidal concentration (MBC) methods in comparison with tetracycline, a commercial antibiotic. Results: We found that extract from P. pensylvanica kills bovine mammary glands pathogenic S. aureus strain Newbould 305. The minimum inhibitory concentration (MIC) breakpoints for extracts from the flower, leaf, stem, and root were 62.5 ėg/ml, 31.25 ėg/ml, 7.8 ėg/ml and<46.9 ėg/ml, respectively. The minimum bactericidal concentration (MBC) of plant extracts on S. aureus grown on blood agar was 2 ėg/ml for tetracycline, 31.25 ėg/ml for leaf and stem, 125 ėg/ml for flower, and 187.5 ėg/ml for root extracts. Conclusion: The crude extracts from different body parts of P. pensylvanica have a bacteriocidal effect against S. aureus. Purified active antimicrobial phytochemical compound/s from P. pensylvanica may serve as an alternative natural product to treat staphylococcal infections in human and animals.