Melaleuca alternifolia anthelmintic activity in gerbils experimentally infected by Haemonchus contortus.

Gastrointestinal parasites are one of the biggest health problems faced in sheep, mainly due to their pathogenicity and resistance to drugs used to control these parasites. Thus, the following study aimed to assess the anthelmintic efficacy of Melaleuca alternifolia against Haemonchus contortus in gerbils (Meriones unguiculatus) experimentally infected. Three treatments were tested: M. alternifolia essential oil, popularly known as tea tree oil (TTO), a solid lipid nanocarrier made with essential oil of Melaleuca (nanoTTO), and terpinen-4-ol (terp-4-ol). In vivo studies were performed by determining the mean worm burden of H. contortus in gerbils TTO (0.75 mL/kg); nanoTTO (0.5 mL/kg) and terp-4-ol (0.5 mL l/kg) were able to reduce 46.36%; 48.64%, and 43.18% worm burden, respectively. H. contortus increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, as demonstrated by liver injury. It was found that the TTO, nanoTTO, and terp-4-ol were not toxic to liver and kidneys since hepatic and renal functions were not affected. Moreover, terp-4-ol was able to prevent increased levels of seric AST and ALT in infected animals, indicating a hepatoprotective effect. Thus, our results indicate that TTO, nanoTTO, and terp-4-ol are safe and efficient against H. contortus infection in gerbils, and possibly the terp-4-ol may be considered the compound present in the Melaleuca alternifolia responsible for parasitic action against H. contortus.

Antimicrobial Susceptibility of Escherichia coli Strains Isolated from Alouatta spp. Feces to Essential Oils.

This study evaluated the in vitro antibacterial activity of essential oils from Lippia graveolens (Mexican oregano), Origanum vulgaris (oregano), Thymus vulgaris (thyme), Rosmarinus officinalis (rosemary), Cymbopogon nardus (citronella), Cymbopogon citratus (lemongrass), and Eucalyptus citriodora (eucalyptus) against Escherichia coli (n = 22) strains isolated from Alouatta spp. feces. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for each isolate using the broth microdilution technique. Essential oils of Mexican oregano (MIC mean = 1818 µg mL(-1); MBC mean = 2618 µg mL(-1)), thyme (MIC mean = 2618 µg mL(-1); MBC mean = 2909 µg mL(-1)), and oregano (MIC mean = 3418 µg mL(-1); MBC mean = 4800 µg mL(-1)) showed the best antibacterial activity, while essential oils of eucalyptus, rosemary, citronella, and lemongrass displayed no antibacterial activity at concentrations greater than or equal to 6400 µg mL(-1). Our results confirm the antimicrobial potential of some essential oils, which deserve further research.

Production, purification and therapeutic potential of egg yolk antibodies for treating Trypanosoma evansi infection.

The use of avian antibodies has aroused interest in biomedical research due to the numerous advantages compared to mammal's antibodies. Our study aimed to produce and purify IgY immunoglobulins in order to use as an alternative therapy against Trypanosoma evansi. Every 14 days, four New Hampshire chickens were immunized with trypomastigotes of T. evansi, totaling five inoculations. Eggs were collected during 70 days and the extraction of IgY was performed by precipitation through the PEG-6000 method. Characterization and purification of IgY anti-T. evansi were carried out by SDS-PAGE and Western blot, where heavy and light chains were detected. The production of IgY was noted during the whole period, and the average production was 2.87 ± 0.14 at the end of this study. Sample's titration allowed the quantification of specific IgY anti-T. evansi, with antibodies produced showing high avidity indexes. The results indicated that T. evansi is able to generate an immune response in poultry, resulting in a production of specific antibodies. In vivo test showed that IgY treatment resulted in increase of prepatent period, longevity and survival of infected animals, when compared with the positive control, demonstrating an initial, but no curative, trypanocidal activity.