In vitro antimicrobial activity of Annona muricata against Staphylococcus intermedius

Staphylococcus intermedius is part of the normal skin and oral flora of dogs. This bacterium is the predominant coagulase-positive Staphylococcus isolated from canine skin and mucous membranes. Case reports of human infections are rare, but the true incidence is unknown because the pathogen is frequently misidentified as S. aureus. Here, we tested the in vitro activity, of an ethanolic extract of “araticum” Annona muricata L. leaves against S. intermedius strains. Plant material was harvested in UPIS, Lagoa Bonita Farm, Planaltina – DF, Brasil. The leaves were macerated with ethanol for five days and the extracts were concentrated using an evaporator at 50 °C. MICs were determined in 96-well microplates using a tetrazolium salts as an indicator of bacterial growth and corresponded to 5 mg/mL. In addition, antioxidant activity was determined with the ABTS method and polyphenol content was measured with the Folin-Ciocalteau method. The total polyphenols content in A. muricata extract was 192 mg/100 g while the antioxidant activity corresponding to 190 mM/g. These findings suggest an antimicrobial potential for A. muricata leaves. Further research needs to be carried out to identify the active molecules and evaluate the in vivo antibacterial activity as well as sub-acute or chronic toxicities.