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Background: Leishmaniasis is a protozoan disease ranging from simple to mucocutaneous, diffuse, and visceral lesions. Current chemical medicines, including Glucantime, have high toxicity, side effects, and drug resistance. Herbal medicines are unlimited sources for discovering new medications to treat infectious diseases. Objectives: This study aimed to examine the in vitro effect of hydroalcoholic extract of Artemisia absinthium on the growth of Leishmania major in peritoneal macrophages from BALB/c mice. Methods: In this experimental study, the hydroalcoholic extract of A. absinthium was prepared and dissolved in 2% dimethyl sulfoxide (DMSO). Leishmania major (MRHO/IR/75/ER) was cultured in RPMI1640 medium containing 15% fetal bovine serum (FBS). Peritoneal macrophages were extracted from BALB/c mice and were infected with promastigotes at a ratio of 1:10. The extract was added to Leishmania-infected macrophages and promastigotes at different concentrations. After 24, 48, and 72 hours, the effectiveness of A. absinthium on promastigotes was assessed using Trypan blue test and methyl thiazole tetrazolium (MTT) colorimetric assay, and the half maximal inhibitory concentration (IC50) of A. absinthium extract was obtained. Giemsa staining was used to evaluate the effect of A. absinthium extract on amastigotes. Also, inducible nitric oxide synthase (iNOs) level was measured from Leishmania-infected macrophages. The data were analyzed by ANOVA in SPSS software. Results: The hydroalcoholic extract of A. absinthium showed a significant anti-Leishmania activity against promastigotes and amastigotes at various concentrations after 48 and 72 hours. The IC50 values of the alcoholic extract of A. absinthium were obtained at 56 mg/mL and 51 mg/mL concentrations of promastigotes and amastigotes, respectively. The lowest levels of iNOs were seen at 100 and 50 mg/mL concentrations of A. absinthium in treated macrophages. The former was obtained at 60.8 and 58.8 ng/mL after 24 and 48 hours and the latter at 55.5 ng/mL and 50 mg/mL of A. absinthium, respectively, after 72 hours. Conclusions: Findings of the present study showed the anti-parasitic effects of A. absinthium on both promastigotes and amastigotes. Further studies are recommended to be conducted on animal models and the active ingredients of A. absinthium extract to accurately assess the effects of this extract on the growth of L. major.

Purpose: The introduction of novel adjuvants is an important step in attempts to develop a safe and more efficient vaccine. The present study was performed to determine whether the use of a mixed beta-adrenergic receptor antagonist propranolol (PRP) and aluminum (alum), as an adjuvant, have efficacy for Toxoplasma gondii (T. gondii) vaccine to induce protective immunity in a mouse model. Methods: Female BALB/c mice divided into five groups were immunized with excretory-secretory antigens (ESA) vaccine, alum-ESA vaccine, PRP-ESA vaccine, and alum-PRP ESA vaccine, as well as with phosphate buffered saline (PBS), as a negative control group. The immune responses were evaluated by lymphocyte proliferation assay for measuring delayed-type hypersensitivity (DTH) response and by cytokine assay for evaluating IFN-γ and IL-5 levels. The survival rate of mice in all groups was assessed during a three-week monitoring period after an intraperitoneal challenge with T. gondii tachyzoites. Results: The results showed that mice immunized with PRP, as an adjuvant, could secret a higher level of IFN-γ, which was significant in comparison to other groups. However, mice vaccinated with alum-precipitated ESA antigen had ability to produce an elevated level of IL-5 compared to other mouse groups (p≤0.05). Moreover, alum-PRP co-administration together with ESA vaccine resulted in the longer survival of mice. Conclusions: The findings of this study revealed that the combination of alum-PRP adjuvants and ESA vaccine of T. gondii elicits both humoral and cellular immune responses, which are comparable to either alum or PRP alone.

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