Hairless mice as an experimental model of infection with Leishmania amazonensis

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2016-06-29T14:09:11Z No. of bitstreams: 1 Araujo VCP Hairless mice as an....pdf: 1756100 bytes, checksum: 5278f0058e7b1523c51580a101b00ffb (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2016-06-29T16:52:20Z (GMT) No. of bitstreams: 1 Araujo VCP Hairless mice as an....pdf: 1756100 bytes, checksum: 5278f0058e7b1523c51580a101b00ffb (MD5)Made available in DSpace on 2016-06-29T16:52:20Z (GMT). No. of bitstreams: 1 Araujo VCP Hairless mice as an....pdf: 1756100 bytes, checksum: 5278f0058e7b1523c51580a101b00ffb (MD5) Previous issue date: 2015Made available in DSpace on 2016-07-07T11:39:46Z (GMT). No. of bitstreams: 3 Araujo VCP Hairless mice as an....pdf.txt: 40116 bytes, checksum: 8dd1701db3717ea86b09044018100c60 (MD5) Araujo VCP Hairless mice as an....pdf: 1756100 bytes, checksum: 5278f0058e7b1523c51580a101b00ffb (MD5) license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5) Previous issue date: 2015Universidade Federal de Mato Grosso do Sul. Laboratório de Parasitologia Humana. Centro de Ciências Biológicas e da Saúde. Campo Grande, MG, BrasilFundação Gonçalo Moniz, Centro de Pesquisas Gonçalo Moniz. Laborat orio de Imunoparasitologia. Salvador, BA, BrasilUniversidade Federal de Mato Grosso do Sul. Laboratório de Parasitologia Humana. Centro de Ciências Biológicas e da Saúde. Campo Grande, MG, BrasilUniversidade Federal de Mato Grosso do Sul. Laborat ório de Tecnologia Farmacêutica. Centro de Ciências Biológicas e da Saúde. Campo Grande, MG, BrasilUniversidade Federal de Mato Grosso do Sul. Laboratório de Parasitologia Humana. Centro de Ciências Biológicas e da Saúde. Campo Grande, MG, BrasilUniversidade Federal de do Sul. Laboratório de Produtos Naturais e Espectrometria de Massas e LaPNEM. Centro de Ciências Biológicas e da Saúde. Campo Grande, MG, BrasilUniversidade Federal de Mato Grosso do Sul. Laboratório de Parasitologia Humana. Centro de Ciências Biológicas e da Saúde. Campo Grande, MG, BrasilHRS/J Hairless mice have been investigated as an experimental model in cutaneous leishmaniasis induced by Leishmania (Leishmania) amazonensis. The animals were inoculated with 106 promastigotes into the right hind footpad and the course of infection was followed up for 30, 60 and 90 days. BALB/c mice were infected and used as control. Hairless mice were susceptible to L. (L.) amazonensis infection and a progressive increase in number of parasites and footpad thickness was detected over time. Signals of dissemination and visceralization were confirmed by the presence of parasite in the draining lymph node of lesion and spleen, at different times post infection. IL-10 gene expression evaluated by RT-PCR was significantly higher in Hairless mice at 60 days post infection, corroborating the pattern of susceptibility. These results point this inbred strain as a promising susceptible model for the study of experimental infection induced by L. (L.) amazonensis. This model would allow the use of other infectio

In vitro activity of the hydroethanolic extract and biflavonoids isolated from Selaginella sellowii on Leishmania (Leishmania) amazonensis

This study is the first phytochemical investigation of Selaginella sellowii and demonstrates the antileishmanial activity of the hydroethanolic extract from this plant (SSHE), as well as of the biflavonoids amentoflavone and robustaflavone, isolated from this species. The effects of these substances were evaluated on intracellular amastigotes of Leishmania (Leishmania) amazonensis, an aetiological agent of American cutaneous leishmaniasis. SSHE was highly active against intracellular amastigotes [the half maximum inhibitory concentration (IC50) = 20.2 µg/mL]. Fractionation of the extract led to the isolation of the two bioflavonoids with the highest activity: amentoflavone, which was about 200 times more active (IC50 = 0.1 μg/mL) and less cytotoxic than SSHE (IC50 = 2.2 and 3 μg/mL, respectively on NIH/3T3 and J774.A1 cells), with a high selectivity index (SI) (22 and 30), robustaflavone, which was also active against L. amazonensis (IC50 = 2.8 µg/mL), but more cytotoxic, with IC50 = 25.5 µg/mL (SI = 9.1) on NIH/3T3 cells and IC50 = 3.1 µg/mL (SI = 1.1) on J774.A1 cells. The production of nitric oxide (NO) was lower in cells treated with amentoflavone (suggesting that NO does not contribute to the leishmanicidal mechanism in this case), while NO release was higher after treatment with robustaflavone. S. sellowii may be a potential source of biflavonoids that could provide promising compounds for the treatment of cutaneous leishmaniasis

In Vitro antileishmania activity of sesquiterpene-rich essential oils from Nectandra species

Context: New antileishmanias are needed because of toxicity, high cost and resistance problems associated with available drugs. Nectandra (Lauraceae) produces several classes of compounds but its essential oil has not previously been reported to have antileishmania activity. Objective: We evaluated the cytotoxicity and antileishmania activity of essential oils from Nectandra amazonum Nees, N. gardneri Meisn., N. hihua (Ruiz & Pav.) Rohwer and N. megapotamica (Spreng.) Mez. Materials and methods: Nectandra oils were extracted from stem bark/leaves by hydrodistillation and compounds were identified by GC-MS. Oils were tested against Leishmania infantum and L. amazonensis intracellular amastigotes and nitric oxide production was evaluated. Cytotoxicity was achieved on NIH/3T3 and J774.A1 cells for the selectivity index (SI). Results and discussion: Nectandra gardneri was active against L. infantum and L. amazonensis (IC50 =  2.7 ± 1.3/2.1 ± 1.06 μg/mL) and contained 85.4% sesquiterpenes, of which 58.2% was intermediol. Besides low cytotoxicity (SI >11.3), N. gardneri induced a significant increase in NO production by L. infantum-infected macrophages. Nectandra hihua had the best activity on L. infantum amastigotes (IC50 =  0.2 ± 1.1 μg/mL). This oil was 89.0% sesquiterpenes, with 28.1% bicyclogermacrene. The two specimens of N. megapotamica had different activities on amastigotes. The one richer in sesquiterpenes (49.9%) was active against both species (IC50 =  12.5 ± 1.4/21.3 ± 1.2) and had phenylpropanoid E-asarone as the main compound (42.4%). Nectandra amazonum showed moderate activity on both the species (IC50 =  31.9 ± 2.0/22.1 ± 1.3 μg/mL) and low selectivity (0.9 2.6), probably due to the major presence of β-caryophyllene (28.5%). Conclusions: Our data identify compounds that can now be isolated and used for the development of new antileishmanias

In vivo antileishmanial activity and chemical profile of polar extract from Selaginella sellowii

The polar hydroethanolic extract from Selaginella sellowii(SSPHE) has been previously proven active on intracellular amastigotes (in vitro test) and now was tested on hamsters infected with Leishmania (Leishmania) amazonensis (in vivo test). SSPHE suppressed a 100% of the parasite load in the infection site and draining lymph nodes at an intralesional dose of 50 mg/kg/day × 5, which was similar to the results observed in hamsters treated with N-methylglucamine antimonate (Sb) (28 mg/Kg/day × 5). When orally administered, SSPHE (50 mg/kg/day × 20) suppressed 99.2% of the parasite load in infected footpads, while Sb suppressed 98.5%. SSPHE also enhanced the release of nitric oxide through the intralesional route in comparison to Sb. The chemical fingerprint of SSPHE by high-performance liquid chromatography with diode-array detection and tandem mass spectrometry showed the presence of biflavonoids and high molecular weight phenylpropanoid glycosides. These compounds may have a synergistic action in vivo. Histopathological study revealed that the intralesional treatment with SSPHE induced an intense inflammatory infiltrate, composed mainly of mononuclear cells. The present findings reinforce the potential of this natural product as a source of future drug candidates for American cutaneous leishmaniasis