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@#We aimed at determination of acaricidal, larvacidal, and repellent activities of green synthesized silver nanoparticles (SNP) against Hyalomma dromedarii as one of the most common ticks in camels. SNP were green synthesized by reducing Lupinus albus extract through the precipitation technique. The acaricidal, larvicidal, and repellent activity of SNP against H. dromedarii was studied through the adult immersion test (AIT), the larval packet test (LPT), the vertical movement behavior of tick’s larvae method, anti-acetylcholinesterase (AChE) activity, and oxidative enzyme activity. The green synthesized SNP displayed a spherical form with a size ranging from 25–90 nm; whereas the most distribution of particles size was reported at 50-65 nm. SNP dose-dependently (p<0.001) increased the mortality rate of H. dromedarii adult; whereas at 16 and 32 µg/mL completely killed the adult females. Treatment of exposure of H. dromedarii adult to SNP markedly (p<0.001) declined the mean number, weight, and hatchability of eggs. Treatment of H. dromedarii larvae with SNP reduced the viability rate of larvae with the LC50 and LC90 values of 3.1 and 6.9 µg/mL, respectively. Exposure of H. dromedarii larvae to SNP, especially at ½ LC50 and LC50, markedly (p<0.001) increased the oxidative stress and declined the level of antioxidant enzymes in H. dromedarii larvae; whereas, markedly suppressed the AChE activity of the larvae stage of H. dromedarii in comparison to the control group. These results showed that SNP green synthesized by L. albus extract had promising acaricidal, larvicidal and repellent activity against H. dromedarii adults and larvae as a dose-dependent response. SNP also considrably decreased the level of acetylcholinesterase and antioxidant activity and also provokes oxidative stress in H. dromedarii larvae. However, more investigation must be designed to clear the accurate mechanisms and the efficacy of SNP in practical use.
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@#This study aimed to consider the in vitro and in vivo effects of the Stachys lavandulifolia methanolic extract (SLME) (2.5, 5, 10, 25, 50, 100 µg/mL) against Leishmania major infection. The in vitro antileishmanial effects of SLME was studies on promastigote and amastigote forms of L. major. The effect of SLME on the nitric oxide (NO) and apoptosis, secretion of Th1/2 cytokines, and infectivity rate in macrophages cells were also studies. The cytotoxicity of SLME on human (THP-1) and murine (J774-A1 cell) macrophage cells was investigated through the measuring the 50% cytotoxic concentrations (CC50). Moreover, the in vivo effects of SLME for healing the cutaneous leishmaniasis (CL) lesions in infected BALB/c mice studied by assessing the lesions size and the parasite load during four weeks of treatment. The calculated 50% inhibitory concentration (IC50) valuesfor SLME and meglumine antimoniate (MA) against the promastigote stage were 23.4 and 71.1 µg/mL, respectively. For amastigote stage, the IC50 values for SLME and MA were 39.3 µg/mL and 44.3 µg/mL, respectively. Followed by 28 days’ topically therapy with SLME at doses of 50 and 100 mg/kg/day, the CL lesions size as well as parasite load were significantly (p<0.001) reduced; such that the recovery percentage of the infected mice was 80% and 97% after treatment with SLME at the dose of 50 and 100 mg/kg, respectively. SLME also markedly induced the NO production and apoptosis; whereas decreased infection rate in macrophage cells. After incubation of infected macrophages with SLME, the level interferon gamma was meaningfully (p<0.001) elevated as a dose-dependent response; in contrast, release of interleukin 10 (IL-10) and IL-4 markedly (p<0.001) decreased. The CC50 value for SLME against THP-1 and J774-A1 cell was 996.4 µg/mL and 741.3 µg/mL, respectively. The calculated selectivity index of >10 for SLME and MA confirmed their specificity to amastigotes and the low toxicity for macrophages. Our results showed the potent effects of SLME in eliminating and controlling Leishmania parasites in both in vitro and in vivo assays. Based on the current experimental study, SLME can be suggested as an alternative medicine for the isolation and production of a new agent for treating CL caused by L. major. Although, we found some cellular mechanisms of SLME against Leishmania parasites, but, additional surveys are necessary to specify the accurate mechanisms of action, toxicity, and its efficacy mainly in human subjects.