Comparative analysis of the severity and progression of cutaneous leishmaniasis caused by Leishmania tropica in untreated and glucantime-treated patients

Millions of people worldwide are affected by cutaneous leishmaniasis (CL), a disease that has a significant impact on morbidity and mortality. Understanding the immune responses responsible for tissue damage or the process of lesion healing plays a pivotal role in shaping optimal treatment strategies. In this study, we investigated immunological phenotypes for three groups: glucantime treated (n = 30) and untreated (n = 30) CL patients infected with Leishmania tropica (L. tropica), and healthy controls (n = 20). T-lymphocytes (CD4+ and CD8+), and B lymphocytes (CD14+ and CD19+) were isolated using antibody-conjugated microbeads and magnetic field isolation to achieve high purity. A higher significant difference was observed between T-lymphocytes (CD4+ and CD8+), and B-lymphocytes (CD14+ and CD19+) cells in CL-infected groups before and after treatment (p < 0.0001). When compared, there was also a significant difference among T-lymphocytes (CD4+ and CD8+), B lymphocytes (CD14+ and CD19+) p < 0.0001, p < 0.0005, and p < 0.0007, respectively between CL-infected individuals (before and after treatment) to controls. Our findings suggest that an increased proportion of these cells seen in treated patients may mediate healing, while it is also possible that they may contribute to tissue injury. Understanding the immune system and lesion size of CL can help develop immunotherapies and comprehend the evolution of this parasitic disease.

Natural compounds from plants controlling leishmanial growth via DNA damage and inhibiting trypanothione reductase and trypanothione synthetase: an in vitro and in silico approach

In the present study, four different natural compounds including quercetin, gallic acid, rutin, and lupeol were studied for their anti-leishmanial potentials with anticipated mechanism of action through in vitro and in silico approaches. Results showed that rutin was exceedingly active (IC₅₀; 91.2 µg/ml) against the promastigote form of Leishmania tropica compared to quercetin (IC₅₀; 182.3 µg/ml), gallic acid (IC₅₀; 198.00 µg/ml) and lupeol (IC₅₀; 200.77 µg/ml). Similarly, rutin was highly active against the amastigote form as well, followed by quercetin, gallic acid and lupeol with IC₅₀ values of 101.3 µg/ml, 137.4 µg/ml, 277.2 µg/ml, and 298.9 µg/ml, respectively. These compounds were found to be nontoxic to human blood erythrocytes even at the highest concentration (1000 µg/ml) tested. Rutin and lupeol showed promising DNA degradation/fragmentation activity against the DNA of treated promastigotes which increased with the increase in concentration of the compounds. The in silico investigation revealed that these ligands have high affinity with the important catalytic residues of trypanothione reductase (Try-R) where, rutin showed the lowest docking score (i.e., - 6.191) followed by lupeol (- 5.799), gallic acid and quercetin. In case of ligands' interaction with trypanothione synthetase (Try-S), rutin again showed highest interaction with docking score of - 6.601 followed by quercetin (- 4.996), lupeol and gallic acid. The ADMET prediction of these compounds showed that all the parameters were within the acceptable range as defined for human use while molecular dynamics simulation supported the good interaction of quercetin and rutin against both enzymes. These findings suggest that the studied compounds may control leishmanial growth via DNA damage and inhibiting Try-R and Try-S, the two unique but critical enzymes for leishmania growth.

Biosynthesis of anti-leishmanial natural products in callus cultures of Artemisia scoparia

Clinically, available synthetic chemotherapeutics in the treatment for leishmaniasis are associated with serious complications, such as toxicity and emergence of resistance. Natural products from plants can provide better remedies against the Leishmania parasite and can possibly minimize the associated side effects. In this study, various extracts of the callus cultures of Artimisia scoparia established in response to different plant growth regulators (PGRs) were evaluated for their anti-leishmanial effects against Leishmania tropica promastigotes, followed by an investigation of the possible mechanism of action through reactive apoptosis assay using fluorescent microscopy. Amongst the different callus extracts, higher anti-leishmanial activity (IC₅₀:19.13 µg/mL) was observed in the callus raised in-vitro in the presence of 6-Benzylaminopurine (BA) plus 2,4-Dichlorophenoxyacetic Acid (2,4-D) at the concentration of 1.5 mg/L, each. Further, the results of apoptosis assay showed a large number of early-stage apoptotic (EA) and late-stage apoptotic (LA) cells in the Leishmania under the effect of callus extract grown in-vitro at BA plus 2,4-D. For the determination of the potent natural products in the callus extracts responsible for the anti-leishmanial activity, extracts were subjected to Gas chromatography-mass spectrometry (GC-MS) for the metabolite analysis. Nonetheless, higher levels of the metabolites, such as nerolidol (22%), pelletierine (18%), aspidin (15%) and ascaridole (11%) were detected in the callus grown in vitro at BA plus 2,4-D (1.5 mg/L, each). This protocol determines a novel method of production of anti-leishmanial natural products through callus cultures of A. scoparia, a medicinal plant.