Janice Luehring Giongo

Antimicrobial activity of Amazonian oils against Paenibacillus species

The Gram-positive, spore-forming bacterium Paenibacillus larvae is the primary bacterial pathogen of honeybee brood and the causative agent of American foulbrood disease (AFB). One of the feasible alternative treatments being used for their control of this disease is essential oils. In this study in vitro antimicrobial activity of Andiroba and Copaíba essential oils against Paenibacillus species, including P. larvae was evaluated. Minimal inhibitory concentration (MIC) in Mueller-Hinton broth by the microdilution method was assessed. Andiroba registered MIC values of 1.56-25%, while the MICs values obtained for Copaíba oil were of 1.56-12.5%. In order to determine the time-response effect of essential oils on P. larvae, this microorganism was exposed to the oils for up to 48 h. After 24 h treatment with Andiroba oil and after 48 h treatment with Copaíba oil no viable cells of P. larvae ATCC 9545 were observed. The possible toxic effect of essential oils were assessed by the spraying application method of the same concentrations of MICs. Bee mortality was evident only in treatment with Andiroba oil and the Copaíba oil shows no toxic effects after 10 days of observation. Taking together ours results showed for the first time that these oils presented a high activity against Paenibacillus species showing that Copaíba oil may be a candidate for the treatment or prevention of AFB.

Trypanocidal activity of the essential oils in their conventional and nanoemulsion forms: in vitro tests.

The aim of this study was to investigate the susceptibility in vitro of Trypanosoma evansi to the essential oils of andiroba (Carapa guaianensis) and aroeira (Schinus molle), in their conventional and nanostructured forms. For that, pure oils at concentrations of 0.5%, 1.0% and 2.0% were used. A negative control (untreated) and a positive control (diminazene aceturate 0.5%) were used as comparative parameters. Later, the same tests were performed, using nanoemulsions oils at concentrations of 0.5% and 1.0%. The tests were carried out in triplicates and the numbers of parasites were quantified on 1, 3 and 6 h from onset of the study. A dose-dependent reduction in the number of parasites to the forms of two oils tested was observed after 1 h. The concentration of parasites was significantly reduced at low concentrations after 3 h, as well as at 6 h no alive parasites were observed for the essential oils tested. Ours findings indicate, for the first time, that oils of andiroba and aroeira (in their conventional and nanoemulsion forms) have high activity against T. evansi in vitro, leading to the suggestion that these oils may be applied as an alternative treatment for this disease.

Synthesis, antimicrobial activity and cytotoxic investigation of novel trifluoromethylated tetrazolo[1,5-a]pyrimidines

A series of novel trifluoromethylated tetrazolo[1,5-a]pyrimidines were easily prepared via a highly regioselective cyclocondensation reaction between β-alkoxyvinyl trifluoromethyl ketones [CF3C(O)CH=C(R)OMe] (in which R = Ph, 4-F–C6H4, 4-Cl–C6H4, 4-Br–C6H4, 4-I–C6H4, 4-CH3–C6H4, 4-OCH3–C6H4, Thien-2-yl, 4-Ph–C6H4, Me) and 5-aminotetrazole, using conventional heating in an oil bath or microwave irradiation. The results showed that when ionic liquid was used as the reaction medium, the reaction time drastically decreased and the yield improved. Additionally, all the newly synthesized compounds were evaluated to determine their antimicrobial activity. Two of the compounds tested were the most promising because they displayed activity against the Gram-positive and Gram-negative bacteria used in the tests, and they were moderately active against the yeast Candida albicans. And finally, the cytotoxicity of lymphocytes of the two compounds was evaluated by using MTT assay. Results showed at active concentration such compounds would be safe.

Listeria monocytogenes impairs enzymes of the phosphotransfer network and alters antioxidant/oxidant status in cattle brain structures

Several evidences have suggested the involvement of enzymes belonging to the phosphotransfer network, formed by creatine kinase (CK), pyruvate kinase (PK) and adenylate kinase (AK), as well the oxidative stress on the pathogenesis of infectious diseases associated with the central nervous system (CNS). Thus, the aim of this study was to evaluate whether listeriosis alters the brain energy metabolism and/or causes oxidative stress in different brain structures of cattle experimentally infected by Listeria monocytogenes. The cytosolic CK activity was inhibited in the cerebral cortex, cerebellum, brainstem and hippocampus of infected animals compared to uninfected animals, while the mitochondrial CK activity was increased. The PK activity was inhibited in all brain structures of infected animals, while the AK activity was unchanged. Na+, K+-ATPase activity decreased in the cerebral cortex, cerebellum and hippocampus of animals infected by L. monocytogenes. Regarding the oxidative strees variables, the cerebellum and brainstem of infected animals showed increased thiobarbituric acid reactive substances, while the catalase activity was inhibited. Glutathione S-transferarase was inhibited in the cerebral cortex and brainstem of infected animals, and it was increased in the cerebellum. L. monocytogenes was quantified in the liver (n = 5/5) and cerebral cortex (n = 4/5) of the infected cattle. Based on these evidences, the nucleocytoplasmic communication between CK isoenzymes was insufficient to avoid an impairment of cerebral bioenergetics. Moreover, the inhibition on brain PK activity caused an impairment in the communication between sites of ATP generation and ATP utilization. The lipid peroxidation and alteration on antioxidant status observed in some brain structures were also involved during the disease. In summary, these alterations contribute to disease pathogenesis linked to CNS during cattle listeriosis.

Polysaccharide-based film loaded with vitamin C and propolis: A promising device to accelerate diabetic wound healing

ABSTRACT Wound healing can be a painful and time‐consuming process in patients with diabetes mellitus. In light of this, the use of wound healing devices could help to accelerate this process. Here, cellulose‐based films loaded with vitamin C (VitC) and/or propolis (Prop), two natural compounds with attractive properties were engineered. The starting materials and the cellulose‐based films were characterized in detail. As assessed, vitamin C can be released from the Cel‐PVA/VitC and Cel‐PVA/VitC/Prop films in a controlled manner. In vitro antibacterial activity studies showed a reduction of bacteria counts (Escherichia coli and Staphylococcus aureus) after Cel‐PVA/VitC, Cel‐PVA/Prop, and Cel‐PVA/VitC/Prop treatments. Moreover, we examined the antibacterial and wound healing properties of the cellulose‐based films in a streptozotocin (STZ)‐induced diabetic animal model. Diabetic mice exhibited impaired wound healing while the Cel‐PVA/VitC/Prop treatment increased the wound closure. A marked reduction in bacterial counts present in the wound environment of diabetic mice was observed after Cel‐PVA/VitC, Cel‐PVA/Prop and Cel‐PVA/VitC/Prop treatment. Histological analysis demonstrated that the non‐treated diabetic mice group did not exhibit adequate wound healing while the treated group with Cel‐PVA/VitC and Cel‐PVA/VitC/Prop films presented good cicatricial response. Furthermore, these novel eco‐friendly films may represent a new therapeutic approach to accelerate diabetic wound healing.