RESUMO
Cutaneous leishmaniasis exhibits a wide spectrum of clinical manifestations; however, only a limited number of drugs are available and include Glucantime® and amphotericin B, which induce unacceptable side effects in patients, limiting their use. Thus, there is an urgent demand to develop a treatment for leishmaniasis. Recently, it was demonstrated that 8-hydroxyquinoline (8-HQ) showed significant leishmanicidal effects in vitro and in vivo. Based on that, this work aimed to develop a topical formulation containing 8-HQ and assess its activity in experimental cutaneous leishmaniasis. 8-HQ was formulated using a Beeler base at 1 and 2% and showed an emulsion size with a D50 of 25 and 51.3 µm, respectively, with a shear-thinning rheological behaviour. The creams were able to permeate artificial Strat-M membranes and excised porcine skin without causing any morphological changes in the porcine skin or murine skin tested. In BALB/c mice infected with L. (L.) amazonensis, topical treatment with creams containing 1 or 2% of 8-HQ was found to reduce the parasite burden and lesion size compared to infected controls with comparable efficacy to Glucantime® (50 mg/kg) administered at the site of the cutaneous lesion. In the histological section of the skin from infected controls, a diffuse inflammatory infiltrate with many heavily infected macrophages that were associated with areas of necrosis was observed. On the other hand, animals treated with both creams showed only moderate inflammatory infiltrate, characterised by few infected macrophages, while tissue necrosis was not observed. These histological characteristics in topically treated animals were associated with an increase in the amount of IFN-γ and a reduction in IL-4 levels. The topical use of 8-HQ was active in decreasing tissue parasitism and should therefore be considered an interesting alternative directed to the treatment of leishmaniasis, considering that this type of treatment is non-invasive, painless, and, importantly, does not require hospitalisation, improving patient compliance by allowing the treatment to be conducted.
RESUMO
Several species of the genus Ocotea are used in traditional medicine due to their anti-inflammatory and analgesic properties. In this work we sought to investigate the effects of biseugenol, the main component of the hexane extract from the leaves of Ocotea cymbarum (Lauraceae), during a chronic inflammatory process induced by polyester-polyurethane sponge in mice. In addition to the inflammatory component, sponge discs also allowed us to evaluate parameters associated with the formation of new blood vessels and the deposition and organization of the extracellular matrix, processes that are related to the chronification of the inflammatory response. Daily treatment with biseugenol (0.1, 1 or 10 µg in 10 µl of 0.5% DMSO) inhibited the synthesis of inflammatory cytokines (TNF-α, CXCL-1 and CCL2) and the neutrophil and macrophage infiltrate into to the implants, indirectly evaluated by the activity of myeloperoxidase and N-acetyl-ß-D-glycosaminidase enzymes, respectively. In implants treated with biseugenol, we observed a reduction in angiogenesis, assessed through histological quantification of mean number of blood vessels, the levels of the pro-angiogenic cytokines FGF and VEGF and the activity of metalloproteinases. Except for VEGF levels, all mentioned parameters showed significant reductions after treatment with biseugenol. Finally, the administration of the compound also reduced TGF-ß1 levels, collagen synthesis and deposition, in addition to modifying the organization of the newly formed matrix, presenting a potential anti-fibrotic effect. Therefore, our results demonstrate the potential therapeutic use of biseugenol for the treatment of a series of pathological conditions, where parameters associated with inflammation, angiogenesis and fibrogenesis are deregulated.
