Leishmania braziliensis is the species responsible for the majority of cases of human cutaneous leishmaniasis in Brazil. In the present study, L. braziliensis isolates from two different geographic areas in Brazil were studied by RAPD, using arbitrary primers. We also evaluated other biological features of these two isolates. We compared (a) the clinical features they initiate or not once delivered subcutaneously as stationary-phase promastigotes in the footpad of BALB/c mice; (b) the parasite load in both the footpad and the draining lymph node; (c) the cytokines present in the supernatant of cultures of the cell suspensions from the draining lymph nodes; and (d) the cell types present at the site of parasite delivery. The results show that the L. braziliensis strain from Ceará (H3227) is genotypically different from the L. braziliensis strain from Bahia (BA788). H3227-parasitized mice developed detectable lesions, whereas BA788-parasitized mice did not. Fifteen days post parasite inoculation there was an increase in the numbers of macrophages and lymphocytes in the footpads, whatever the parasite inoculum. Parasite load at the inoculation site--namely the footpad--did not differ significantly; in draining lymph nodes, however, it increased over the period under study. Early after parasite inoculation, the cells recovered from the draining lymph nodes of BA788-parasitized mice produced higher levels of IFN-gamma, a feature coupled to a higher number of NK cells. Later, after the parasite inoculation, there was an increased content of IL-12p70 and IL-10 in the supernatant of cells recovered from the lymph nodes of H3227-parasitized mice. This comparative analysis points out that L. braziliensis isolates differing in their genomic profiles do establish different parasitic processes in BALB/c mice.
In conclusion, the absorption in the UVA range, coupled with ROS scavenging potential, proved the positive effect of rutin applied to anti-UVB formulations, making this bioactive compound a promising candidate for photoprotection improvement.
The excessive exposure to ultraviolet (UV) radiation is the main cause of skin cancer, the most commonly diagnosed cancer in the world. In this context, the development of innovative and more effective sunscreens, with bioactive compounds like caffeine, displaying antioxidant and anticancer potential, is required. This research work assessed
in vitro
and
in vivo
the efficacy and safety of topical sunscreen formulations containing caffeine as an adjuvant of the UV filters. Sunscreens were prepared with 2.5% w/w caffeine or in the absence of this compound. In order to evaluate the safety of these formulations,
stratum corneum
hydration, skin barrier and colorimetry were assessed
in vivo
in healthy subjects before and after skin treatment with the samples. The efficacy of the sunscreens was assessed
in vitro
, using PMMA plates and a spectrophotometer equipped with an integrating sphere; and
in vivo
by the determination of the sun protection factor (SPF). None of the formulations caused erythema or impaired the skin barrier function. The
in vitro
functional characterization showed higher SPF values for the caffeine formulation. The
in vivo
studies also confirmed the higher SPF value of the formulation combining caffeine with the filters, compared to the caffeine-free sample. This improvement contributed to an increase of, approximately, 25% in the
in vivo
anti-UVB protection. In conclusion, caffeine was well tolerated by the skin and increased the photoprotective activity, being a new alternative adjuvant in sunscreens formulation.
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