Topical Treatment of Leishmania tropica Infection Using (-)-α-Bisabolol Ointment in a Hamster Model: Effectiveness and Safety Assessment.

There is currently no reliable treatment for the management of cutaneous leishmaniasis, and intralesional antimonial injections remain the main treatment. The present work aims at evaluating the antileishmanial effectiveness and safety of (-)-α-bisabolol (1) in a novel topical formulation on a cutaneous leishmaniasis model involving Leishmania tropica-infected Syrian hamsters. The topical treatment with 1 reduced lesion thickness to 56% at 2.5%, showing a higher efficacy than the reference control, meglumine antimoniate. Other regimens (ointment at 1% and 5% and oral treatment at 200 mg/kg) reduced the footpad thickness as well. The skin parasite load decreased after the experiment in all treatment groups, particularly in those animals treated with the 2.5% formulation (83.2%). Treatment with (-)-α-bisabolol at different concentrations or through an oral route did not lead to the appearance of toxicity or side effects in healthy hamsters or infected animals. Therefore, topical (-)-α-bisabolol was more effective than meglumine antimoniate in this cutaneous leishmaniasis model without showing toxicity effects on the hamsters. These results are of great interest and might be used for the development of alternatives for the treatment of cutaneous leishmaniasis, either in monotherapy or in combination with other drugs whose skin permeability could be enhanced by this sesquiterpene.

Experimental comparison of pathogenic potential of two sibling species Anisakis simplex s.s. and Anisakis pegreffii in Wistar rat.

OBJECTIVES: There are little data available on the pathology caused by the sibling species Anisakis simplex s.s. and Anisakis pegreffii. The differences shown in their ability to penetrate the muscle of fish may also be manifested in humans. The purpose of this study is to confirm possible differences in pathogenicity between A. simplex s.s. and A. pegreffii using an experimental model which simulates infection in humans. METHODS: Female Wistar rats were infected with 190 Anisakis type I L3 larvae from the Iberian coastline. After the animal was sacrificed, these L3 larvae were then recovered and identified via PCR-RFLP of the ITS1-5.8S-ITS2. A logistic regression analysis was performed searching for association between experimental pathogenic potential and species. RESULTS: The distribution of A. simplex s.s. and A. pegreffii between Atlantic and Mediterranean waters of the Iberian Peninsula showed statistically significant differences (P < 0.001) which were not observed in the hybrid genotypes (P > 0.3). 21.6% showed pathogenic potential, interpreted as the capacity of the larvae to cause lesions, stick to the gastrointestinal wall or penetrate it. The species variable showed association with the pathogenic role of the larva (P = 0.008). Taking A. simplex s.s. as our reference, the OR for A. pegreffii is 0.351 (P = 0.028). CONCLUSIONS: Despite this difference, A. pegreffii is also capable of causing anisakiasis, being responsible for 14.3% of the penetrations of the gastric mucosa found in rats, which justifies both species being considered aetiologic agents of this parasitic disorder.

Activity of Matricaria chamomilla essential oil against anisakiasis.

The increase in diagnosed cases of anisakiasis and the virtual absence of effective treatments have prompted the search for new active compounds against Anisakis L(3) larvae. The biocidal efficacy against different pathogens shown by various essential oils (EO) led us to study the Matricaria chamomilla EO and two of its main components (chamazulene and α-bisabolol) against the L(3) larvae of Anisakis type I. The activity of M. chamomilla EO, chamazulene and α-bisabolol was established by in vitro and in vivo experiments. The EO (125µg/ml) caused the death of all nematodes, which showed cuticle changes and intestinal wall rupture. In the in vivo assays, only 2.2%±1.8 of infected rats treated with M. chamomilla EO showed gastric wall lesions in comparison to 93.3%±3.9 of control. Chamazulene was ineffective, while α-bisabolol showed a high activity to that of the EO in vitro tests but proved less active in vivo. These findings suggest that the larvicidal activity may result from the synergistic action of different compounds of M. chamomilla EO. Neither of the tested products induces irritative damage in the intestinal tissues. In conclusion, M. chamomilla EO is a good candidate for further investigation as a biocidal agent against Anisakis type I.

Actividad de albendazol y los aceites esenciales de menta (Mentha piperita) y manzanilla (Matricaria chamomilla) frente Anisakis tipo I / Activity of albendazole and essential oils of peppermint (Mentha piperita) and chamomile (Matricaria chamomilla) against Anisakis type I

Objetivos: Estudiar la posible actividad sinérgica de los aceites esenciales de Mentha piperita y Matricaria chamomilla frente Anisakis tipo I. Material y métodos: Se ensayó tanto in vitro como in vivo, la actividad larvicida de la mezcla de los aceites esenciales utilizando albendazol como fármaco de referencia y midiéndo su eficacia mediante un modelo estadístico. Resultados: En los ensayos in vitro, a las concentraciones de 250 y 187.5 μg/ml, la mortalidad de las larvas fue del 100% mientras que albendazol no mostró eficacia. In vivo, la mezcla de aceites esenciales fue más eficaz, reduciendo las lesiones en ratas en comparación con las tratadas con albendazol y control. Albendazol no redujo de forma significativa el porcentaje de lesiones producidas por las larvas frente al control. Conclusión: La mezcla de aceite esencial de menta y manzanilla podría ser candidata para su uso en el tratamiento/profilaxis de la anisakiasis humana

Aim: We have studied the possible synergistic activity of the essential oils of Mentha piperita and Matricaria chamomile against Anisakis type I. Materials and methods: the larvicidal activity of the mixture of essential oils was tested in vitro and in vivo, using as a reference the drug Albendazole and effectiveness measured through a statistical model. Results: The in vitro and in vivo experiments both evidenced that the larvicidal activity of essential oils, was higher than the Albendazole activity. In the in vitro assay, at concentrations of 250 and 187.5 μg/ml, the mortality was 100% with the mixture of essential oils while albendazole was ineffective at the concentrations studied. In the in vivo assay, the mixture of essential oils, was significantly more effective in the reduction of numbers of lesions with rats in comparison to albendazole treatments and control. Albendazole did not significantly reduce the percentage of lesions caused by larvae vs. control. Conclusion: Considering the results, we have come to the conclusion that the mixture of peppermint essential oils and chamomile could be used in the treatment/prophylaxis of human Anisakis