Neoplasms of the mammary gland in dogs are a major cause of death in canines due to treatment limitations and the complexity of surgical procedures. Therefore, new alternatives are needed, such as the crude ethanolic extract from the H. martiana leaf, which has antimicrobial, anti-inflammatory and cicatrizant activity. However, little is known about its antitumor effects and primarily on canine tumor cells. The objective of the study was to evaluate the antitumor and cytopathic effect of the crude ethanolic extract of the H. martiana Hayne leaf on dog tumor cells and VERO cells. In this study, we obtained an action of the extract in front of the tumor cells as the concentration of the extract increased. In addition, macroscopic alterations were seen, such as vacuoles formation, nucleus condensation and cell formation. When the MTT test was performed, mitochondrial function decreased as the phytotherapeutic concentration increased (P

It contains several secondary metabolites with biological activity, including usnic acid, which has exhibited a wide range of biological activities. The aim of this study was to evaluate the in vitro antimicrobial activity of the organic extract of C. substellata and purified usnic acid. Initially, Staphylococcus spp., derived from samples of skin and ears of dogs and cats with suspected pyoderma and otitis, were isolated and analyzed. In antimicrobial susceptibility testing against Staphylococcus spp., 77% (105/136) of the isolates were resistant to the antimicrobials tested. In the assessment of biofilm production, 83% (113/136) were classified as producing biofilm. In genetic characterization, 32% (44/136) were positive for blaZ, no isolate (0/136) was positive for the mecA gene, and 2% (3/136) were positive for the icaD gene. The in vitro antimicrobial activity of the organic extract of C. substellata and purified usnic acid against Staphylococcus spp. ranged from 0.25mg/mL to 0.0019mg/mL, inhibiting bacterial growth at low concentrations. The substances were more effective against biofilm-producing bacteria (0.65mg/mL-0.42mg/mL) when compared to non-biofilm producing bacteria (2.52mg/mL-2.71mg/mL). Usnic acid and the organic extract of C. substellata can be effective in the treatment of pyoderma and otitis in dogs and cats caused by Staphylococcus spp.