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We synthesized and characterized curcumin-coated gold nanoparticles (Cur@AuNPs) and investigated their stability, cytotoxicity, leishmanicidal activity in in vitro and in in vivo experiments. Cur@AuNPs synthesized through a simple one-pot green chemistry technique. The in vitro leishmanicidal activity of curcumin-coated gold nanoparticles against extracellular promastigotes and intracellular amastigotes of protozoan parasite Leishmania major (L. major) was determined by applying the tetrazolium reduction colorimetric quantitative MTT technique. For in vivo assessment, the footpad lesion size and parasite burden in two infection site organs including lymph nodes and footpads of susceptible BALB/c mice infected with L. major were measured. Mice immune responses in all study groups were quantified by measuring the levels of gamma interferon (IFN-γ) and interleukin-4 (IL-4). Viability of Leishmania promastigotes significantly diminished with the inhibition in promastigotes growth (IC 50 ) of 64.79 μg/mL and 29.89 μg/mL for 24 h and 48 h, respectively. In vitro nanoparticles treatment efficiently cleared the L. major amastigotes explanted in macrophages but had no harmful toxicity on the mice cells. In the in vivo condition, in the treated infected BALB/c mice the CL lesion size, Leishmania parasite burden, and IL-4 were decreased, while IFN-γ was significantly increased. The results suggest that Cur@AuNP was an effective compound against Leishmania parasite in vitro and in vivo, efficiently induced T-helper 1 (Th1) responses and augmented host cellular immune responses, and ending in a reduced Leishmania parasite burden. Therefore, it may be identified as a novel potential therapeutic approach for the local therapy of zoonotic CL treatment with high cure rates., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Cutaneous leishmaniasis (CL) is a Neglected Tropical Disease (NTD) that causes high morbidity in the tropics and sub-tropics. Despite the remarkable advancements in the treatment of CL, the available therapeutics are far from ideal and also cause serious adverse side effects. Negative air ions (NAIs) generators are widely available for domestic and industrial uses. Several studies have reported on positive effects of NAIs therapy on human health as a non-pharmaceutical treatment for respiratory disease, allergy, or stress-related health conditions, including infectious diseases. To our knowledge, no studies have examined the effectiveness of the NAIs therapy against Leishmania parasites. The aims of this study were to investigate the effect of NAIs therapy on Leishmania major (L. major) the causative agent of CL in in vitro and in a murine model., Methodology/principal Findings: In vitro anti-leishmanial effects of NAIs therapy were measured by parasitological methods. NAIs therapy was assessed in vivo in L. major infected BALB/c mice by measuring the footpad (FP) lesion size and parasite load using metric caliper tool and qPCR, respectively. Immune responses in treated and non-treated mice were assessed by measuring the levels of IFN-γ, IL-4, NO and arginase activity. In vitro NAIs therapy significantly decreased the viability of Leishmania promastigotes and of amastigotes cultured in macrophages, but did not affect the host cells. NAIs therapy of L. major infected BALB/c mice resulted in reduced FP lesion size, diminished parasite burden, and importantly decreased induction of IL-4 and arginase activity in the presence of NAIs. In contrast IFN-γ and NO levels were significantly enhanced. NAIs therapy significantly diminished the progression of disease compared to the control group, but was less effective than amphotericin B treatment., Conclusions: Our study shows that NAIs treatment was effective in vitro and in Leishmania-infected mice, elicited a T-helper 1 (Th1) response and increased efficient cellular immunity, resulting in a diminished parasite load. Therefore, NAIs therapy can be considered as a useful and safe tool that can contribute to clearing L. major infections without inducing toxicity in host cells. The applications and mechanisms of NAIs therapy warrant further investigation especially in humans suffering from CL., Competing Interests: The authors have declared that no competing interests exist.

Background: Leishmaniasis is a vector-borne disease that is endemic in the tropical and sub-tropical areas of the world. Low efficacy and high cytotoxicity of the current treatment regimens for leishmaniasis is one of the most important health problems. In this experimental study, anti-leishmanial effects of different concentrations of resveratrol and resveratrol nano-emulsion (RNE) were assessed., Methods: RNE was prepared using the probe ultra-sonication method. The cytotoxicity was evaluated using the MTT technique on the L929 cell line. The anti-leishmanial activities on promastigotes of leishmania were assessed using vital staining and infected BALB/c mice were used to assess the in vivo anti-leishmanial effects., Results: In vitro and in vivo assays revealed that all concentrations of resveratrol and RNE had valuable inhibitory effects against Leishmania major in comparison to the control group (P < 0.05). The half maximal inhibitory concentration (IC 50 ) values were calculated as 16.23 and 35.71 µg/mL for resveratrol and RNE, respectively. Resveratrol and RNE showed no cytotoxicity against the L929 cell line., Conclusions: According to the potent in vitro and in vivo anti-leishmanial activity of RNE at low concentration against L. major, we suggest that it could be a promising anti-leishmanial therapeutic against L. major in the future., (© 2022. The Author(s).)