Evaluating the Effect of Cinnarizine on Promastigotes and Amastigotes forms of Leishmania major

Cyclizine induces cytotoxicity and apoptosis in macrophages through the extrinsic and intrinsic apoptotic pathways

Cyclizine, an over-the-counter and prescription antihistamine, finds widespread application in the prevention and treatment of motion sickness, encompassing symptoms such as nausea, vomiting, dizziness, along with its effectiveness in managing vertigo. However, the overuse or misuse of cyclizine may lead to hallucinations, confusion, tachycardia, and hypertension. The molecular mechanisms underlying cyclizine-induced cytotoxicity and apoptosis remain unclear. During the 24 h incubation duration, RAW264.7 macrophages were exposed to different concentrations of cyclizine. Cytotoxicity was assessed through the lactate dehydrogenase assay. Flow cytometry employing annexin V-fluorescein isothiocyanate and propidium iodide was utilized to evaluate apoptosis and necrosis. Caspase activity and mitochondrial dysfunction were evaluated through a fluorogenic substrate assay and JC-1 dye, respectively. Flow cytometry employing fluorogenic antibodies was utilized to evaluate the release of cytochrome c and expression of death receptor, including tumor necrosis factor-α receptor and Fas receptor. Western blotting was utilized to evaluate the expression of the Bcl2 and Bad apoptotic regulatory proteins. The findings unveiled from the present study demonstrated that cyclizine exerted a concentration-dependent effect on RAW264.7 macrophages, leading to the induction of cytotoxicity, apoptosis, and necrosis. This compound further activated the intrinsic apoptotic pathway by inducing mitochondrial dysfunction, Bcl2/Bad exchange expression, cytochrome c liberation, and activation of caspases contained caspase 3, 8, and 9. Moreover, the activation of the extrinsic apoptotic pathway was observed as cyclizine induced the upregulation of death receptors and increased caspase activities. Based on our investigations, it can be inferred that cyclizine prompts cytotoxicity and apoptosis in RAW264.7 macrophages in a concentration-dependent manner by triggering both the intrinsic and extrinsic apoptotic pathways.

Hesperidin Targets Leishmania donovani Sterol C-24 Reductase to Fight against Leishmaniasis

Hesperidin, a naturally occurring flavanoid, is present in citrus family of fruits. It was found effective against an array of pathogens including fungi, bacteria, viruses, and protozoa. Here, we evaluated its antileishmanial activity and possible mechanism of action through different in vitro and in silico experiments. It inhibited the growth and proliferation of the parasites significantly with a IC50 value of 1.019 ± 0.116 mM in vitro. It also reduced the growth of intra-macrophagic amastigotes with a IC50 value of 0.2858 ± 0.01398 mM. It induced the reactive oxygen species (ROS) in parasites in a dose-dependent manner. Through 2,7-dichloro dihydro fluorescein diacetate (H₂DCFDA) staining, it was observed that around 96.9% parasites were ROS positive at 2.0 mM concentration of hesperidin. The ROS generated led to the apoptosis of parasites in a dose-dependent manner as observed by annexin/PI staining. Molecular docking with one of the very important and unique drug-targets of Leishmania donovani sterol C-24 reductase resulted in its significant inhibition. Here, we for the first time showed that hesperidin induced the antileishmanial response through the induction of apoptosis and inhibition of sterol C-24 reductase. Our study will be helpful in the development of a cost-effective antileishmanial lead with higher efficacy.