Antimicrobial Activity In Vitro of Cream from Plant Extracts and Nanosilver, and Clinical Research In Vivo on Veterinary Clinical Cases

Teodora P. Popova, Ignat Ignatov, Toshka E. Petrova, Mila D. Kaleva, Fabio Huether, Stoil D. Karadzhov


The antimicrobial effect of a cream containing extracts of African geranium (Pelargonium sidoides DC.), black elderberry (Sambucus nigra L.), and St. John’s wort (Hypericum perforatum L.) in colloidal nanosilver (AgNPs) at a concentration of 30 ppm, denoted as SILVER STOP® cream (SS® cream), was examined in vitro. The research was performed with Escherichia coli (ATCC and two clinical isolates), Staphylococcus aureus (ATCC and two clinical strains), and Candida albicans (ATCC and two clinical isolates). The agar-gel diffusion method and suspension tests for determination of the time of antimicrobial action of SS® cream were used. SS® cream showed significant antimicrobial activity. The Gram-negative microorganisms tested died in a much shorter time than the Gram-positive ones. In suspension with a density of 104 cells·mL−1, E. coli died for 1 min, the oval fungus C. albicans—after 10 min and S. aureus—after 60 min of exposure to SS® cream. The highest sensitivity was found in E. coli. The curative effect of SILVER STOP® cream was also examined in vivo in dogs with different skin diseases. The results showed successful healing of the diseases and a very good curative effect of the cream.

Keywords:colloidal nanosilver AgNPs; Pelargonium sidoides; Hypericum perforatum; Sambucus nigra; antimicrobial activity; dogs; skin diseases

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