Interferometry as a tool for evaluating effects of antimicrobial doses on Mycobacterium bovis growth.

Interferometry was used together with the conventional microplate resazurin assay to evaluate the antimycobacterial properties of essential oil (EO) from fruits of Pterodon emarginatus and also of rifampicin against Mycobacterium bovis. The aim of this work is not only to investigate the potential antimycobacterial activity of this EO, but also to test the interferometric method in comparison with the conventional one. The Minimum Inhibitory Concentration (MIC) values of EO (625 µg/mL) and rifampicin (4 ng/mL) were firstly identified with the microplate method. These values were used as parameters in Drug Susceptibility Tests (DST) with interferometry. The interferometry confirmed the MIC value of EO identified with microplate and revealed a bacteriostatic behavior for this concentration. At 2500 µg/mL interferometry revealed bactericidal activity of the EO. Mycobacterial growth was detected with interferometry at 4 ng/mL of rifampicin and even at higher concentrations. One important difference is that the interferometric method preserves the sample, so that after weeks of quantitative observation, the sample can be used to evaluate the bactericidal activity of the tested drug.

[Malaricide activity of the quercetin in Gallus gallus L., 1758 immunocompromised infected by Plasmodium (Bennettinia) juxtanucleare Versiani and Gomes, 1941]. / Atividade malaricida da quercetina em Gallus gallus L., 1758 imunossuprimidos infectados por Plasmodium (Bennettinia) juxtanuclear Versiani e Gomes, 1941.

The aim of this study was comparatively to evaluate the malaricide activity of the quercetin to the action of the chloroquine in Gallus gallus experimentally infected for Plasmodium juxtanucleare and immunocompromised. Thirty- four hens had been used, previously infected for P. juxtanucleare and immunocompromised by the administration of 26 mg/kg of metilprednisolon 40mg/ml in the pectoral muscle. These had been divided in three groups: 1- control, 2- treated with chloroquine and 3- with quercetin. The administration of substances occurred way gavagem to four consecutive days. The malaricide action of the drugs was evaluated in agreement the parasitemia for P. juxtanucleare in blood smears, during 30 days after the infection. The groups that had received treatment with chloroquine and quercetin had presented significant reduction (p < 0,01 in both) of the parasitaemia comparative to the group control, it suggesting that the drugs had acted as malaricide in the infection for P. juxtanucleare.

Essential oil from leaves of Lantana camara: a potential source of medicine against leishmaniasis

Leishmaniasis is an infection of viscera or tegument caused by protozoa Leishmania sp. The extensive period required for the treatment, which involves the use of toxic medicines, leads patients to drop treatment increasing the development of resistant forms of Leishmania sp. Lantana camara L., Verbenaceae, is a tropical plant native from America. Folk uses have been described for treatment of tumors, tetanus, rheumatism and malaria. This study evaluates the leishmanicidal activity of the essential oil of leaves from L. camara on promastigote forms of Leishmania chagasi and L. amazonensis and its toxic effects on Artemia salina (brine shrimp test), macrophage cultures and BALB/c mice. The chemical composition was evaluated using the gas chromatography coupled with mass spectrometer (GC-MS). Thirty substances, mostly mono and sesquiterpenes were identified. The most representative constituents were: germacrene D (24.90%), farnesene derivatives (22%) and (E)-cariophylene (14.31%). Bioassays revealed a significant leishmanicidal activity of essential oil against L. amazonensis (IC50 0.25 µg/ mL) and a potential toxic effect on Brine shrimp (LC50 10 µg/mL) and macrophage assays (CC50 4 µg/mL), while there was no toxic manifestation on mice. The data show the relevant potential of L. camara as a source of medicine for leishmaniasis treatment.