BACKGROUND Severe bacterial infections initiate inadequate inflammation that leads to disseminated intravascular coagulation and death. OBJECTIVES To evaluate the influence of bacterial infection on blood viscosity and red blood cells (RBCs) morphology, and the ability of Calotropis procera proteins (CpLP) to prevent the patho-hemorheology in infected animals. METHODS Rheology of blood, atomic force microscopy measurements on specific blood elements and blood count were performed to examine changes in blood viscosity, RBCs morphology, platelets activation, and RBCs indices. FINDINGS Infected mice hold their blood rheological behaviour as compared to that of the control group. However, they presented hyperactivated platelets, RBCs at different stages of eryptosis, and variation on RBCs indices. CpLP administration in healthy animals altered blood behaviour from pseudoplastic to Bingham-like fluid. Such effect disappeared over time and by inhibiting its proteases. No alterations were observed in RBCs morphology or platelets. Treatment of infected animals with CpLP prevented the changes in RBCs indices and morphology. MAIN CONCLUSIONS The inflammatory process triggered by bacterial infection induced pathological changes in RBCs and platelets activation. Treatment of infected animals with CpLP prevented the emergence of RBCs abnormal morphology and this may have implications in the protective effect of CpLP, avoiding animal death.

The essential oils from leaves, stems and fruits of Piper divaricatum were analyzed by GC-MS. The tissues showed high safrole content: leaves (98%), fruits (87%) and stems (83%), with yields of 2.0, 4.8 and 1.7%, respectively. This is a new alternative source of safrole, a compound widely used as a flavoring agent and insecticide. The leaf's oil showed antibacterial activity against gram-negative bacteria while safrole was active against Salmonella Typhimurium and Pseudomonas aeruginosa. In addition, the study of circadian rhythm of the safrole concentration in the essential oils of leaves showed a negligible variation of 92 to 98%.

No presente estudo, 32 extratos hexânicos e etanólicos de Protium bahianum, P. heptaphyllum, Croton sellowii, C. rhamnifolius, C. jacobinensis, C. micans e Muntingia calabura, foram avaliados para atividade antibacteriana, pelo método de difusão em disco. Ensaios de citoxicidade foram realizados com o modelo do microcrustáceo Artemia salina Leach para determinar a concentração letal para 50% dos indivíduos (CL50 µg/mL). A presença de atividade antibacteriana foi observada com os extratos hexânicos das flores de M. calabura contra B. subtilis, e extratos etanólicos das folhas contra S. aureus and B. subtilis na concentração de 1 mg/mL. Dentre os 32 extratos, 19 apresentaram toxicidade baixa ou ausente (CL50 > 250 µg/mL), 6 mostraram toxicidade moderada (CL50 entre 80 µg/mL e 250 µg/mL) e 7 foram muito tóxicos (CL50 < 80 µg/mL).

In the present study, 32 hexane and ethanol extracts of Protium bahianum, P. heptaphyllum, Croton sellowii, C. rhamnifolius, C. jacobinensis, C. micans and Muntingia calabura were screened for antibacterial activity by the disc-diffusion method. Cytotoxicity assays using the brine shrimp Artemia salina Leach as a model were performed to determine lethal doses for 50% of individuals (LC50 µg/mL). Antibacterial activity was found in flowers hexane extracts of M. calabura against B. subtilis, and leaves ethanol extracts against S. aureus and B. subtilis at concentration of 1mg/mL. Among 32 extracts, 19 showed low or no toxicity (LC50 > 250 µg/mL), 6 showed moderate toxicity (LC50 between 80 µg/mL and 250µg/mL), and 7 were highly toxic (LC50 < 80 µg/mL).