In an effort to identify novel therapeutic alternatives for the treatment of malaria, the present study evaluated the antimalarial effect of the crude hydroalcoholic extract (HCE) from the leaves of Chenopodium ambrosioides L. For this purpose, the molecular affinity between the total proteins from erythrocytes infected with Plasmodium falciparum and HCE or chloroquine was evaluated by surface plasmon resonance (SPR). Subsequently, the plasmodicidal potential of HCE was assessed in a P. falciparum culture. Using BALB/c mice infected with Plasmodium berghei intraperitoneally (ip.), we evaluated the effects of ip. treatment, for three consecutive days (day 7, 8, and 9 after infection), with chloroquine (45 mg/kg) or HCE (5 mg/kg), considering the survival index and the parasitaemia. The groups were compared to an untreated control group that receives only PBS at the same periods. The results indicated that HCE could bind to the total proteins of infected erythrocytes and could inhibit the parasite growth in vitro (IC = 25.4 g/mL). The in vivo therapeutic treatment with HCE increased the survival and decreased the parasitaemia in the infected animals. Therefore, the HCE treatment exhibited a significant antiplasmodial effect and may be considered as a potential candidate for the development of new antimalarial drugs.

The immunological and the anti-Leishmania amazonensis activity of babassu-loaded poly(lactic-co-glycolic acid) [PLGA] microparticles was evaluated. The anti-Leishmania activity was evaluated against promastigotes or amastigotes forms, in Balb/c macrophages. The size of the microparticles ranged from 3 to 6.4 μm, with a zeta potential of −25 mV and encapsulation efficiency of 48%. The anti-Leishmania activity of the PLGA microparticles loaded with the aqueous extract of babassu mesocarp (MMP) (IC50) was 10-fold higher than that free extract (Meso). MMP exhibited overall bioavailability and was very effective in eliminating intracellular parasites. MMP also reduced ex vivo parasite infectivity probably by the increased production of nitric oxide, hydrogen peroxide, and TNF-α indicating the activation of M1 macrophages. The overexpression of TNF-α did not impair cell viability, suggesting antiapoptotic effects of MMP. In conclusion, babassu-loaded microparticles could be useful for drug targeting in the treatment of leishmaniasis, due to the immunomodulatory effect on macrophage polarization and the increased efficacy as an anti-Leishmania product after the microencapsulation. These findings are of great relevance since the development of new drugs for the treatment of neglected diseases is desirable, mainly if we consider the high morbidity and mortality rates of leishmaniasis worldwide.

During Leishmania infection, host immune response is important to prevent the growth/survival of intracellular amastigotes. In this study, we evaluated in vitro and in vivo whether or not during Leishmania amazonensis infection, pentavalent antimonial treatment/therapy could be more effective under TNF-α inhibition. Both L. amazonensis-infected macrophages (in vitro model) and mice (in vivo model) were treated with a nuclear factor-κB (NF-κB) inhibitor and with Glucantime®, alone and in combined administrations. The in vitro amastigote counts, cytokines and nitrites' production were assessed after 48h incubation with the drugs. Paw lesion sizes and amastigote counts were also evaluated in vivo. Quantification of IL-1β from the infected tissue was performed. In vitro results show that when infected macrophages were incubated with QNZ+Glucantime®, a greater clearance was observed for the amastigotes' growth and this was related to greater nitrite production compared to the group that was only infected. In vivo results show that mice that received the combined treatment had their paw lesion sizes and amastigote nests inside the macrophages greatly diminished, correlating with increased IL-1β levels.

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Objective: To describe the epidemiological profile of patients infected with malaria in Porto Velho and the susceptibility of Plasmodium spp. to different classes of drugs used in current treatment methods. Methods: 708 patients infected with malaria were treated at the Center of Tropical Medicine in Porto Velho, where they answered standard epidemiological questionnaires. Maps were built using place of residence information of 199 infected patients. In chemosensitivity assay, dihydroartemisinin, chloroquine, mefloquine and lumefantrine half maximal inhibitory concentration (IC50) was assessed by schizont maturation assay. Results: A higher prevalence of Plasmodium spp. infection among men, young people, with recurrent events of malaria and residents of urban area can be observed. The most prevalent malaria species was P. vivax followed by P. falciparum. Regarding treatment, it was observed that P. falciparum demonstrated resistance only to chloroquine (CQ) with a median of IC50 (MD of IC50) = 119.8 nM, whereas P. vivax demonstrated sensitivity to all drugs (MD IC50 < 10; 100; 30; and 150 nM for dihydroartemisinin, CQ, mefloquine and lumefantrine, respectively). Conclusion: This study contributes to the understanding of the disease by the city’s public health organs, to Plasmodium chemosensitivity literature and vigilance, and to decision making processes of city officials.