Imidazolium salts as an alternative for anti-Leishmania drugs: Oxidative and immunomodulatory activities

Multiple mechanisms of action of a triazole-derived salt against Leishmania amazonensis: Apoptosis-like death and autophagy

Current chemotherapy for leishmaniasis faces significant limitations due to high toxicity, prolonged treatment regimens, and increasing parasite resistance, highlighting the urgent need for innovative treatment strategies. This study aimed to evaluate the in vitro activity of 1,2,3-triazole derivatives against promastigotes and amastigotes of Leishmania amazonensis, as well as their cytotoxicity in murine macrophages. Additionally, we investigated the mechanism of parasite death through different biochemical and cellular indicators of cell death parameters. Our results underscored the importance of the salt form, as the neutral form showed no inhibition of parasite growth. In contrast, the triazole-derived salt demonstrated promising selective index (SI = 34.28) and antileishmanial activity (IC50 = 0.13 μM and IC50 = 2.06 μM against promastigote and amastigote forms, respectively), proving more active than miltefosine, the standard drug. Regarding the mode of action of the triazole-derived salt, this compound induced significant mitochondrial alterations in the parasite, characterized by an increase in mitochondrial membrane potential (ΔΨm), elevated levels of total and mitochondrial Reactive Oxygen Species (ROS), and lipid body accumulation in the cytoplasm. Treatment with triazole-derived salt also produced several ultrastructural, biochemical, and cellular changes in the promastigote forms, such as the occurrence of apoptosis-like death, including cell shrinkage and reduction in length, as well as exposure of phosphatidylserine in the outer leaflet of the plasma membrane and marked cell cycle interruption, in addition to DNA fragmentation. Despite MDC positive and the presence of membrane-bound vacuoles resembling autophagosomal structures observed by TEM analysis, autophagy is not a predominant process, with severe mitochondrial damage emerging as the primary event leading to parasite death. These findings demonstrate the promising antileishmanial potential of the triazole-derived salt, with its effect on multiple targets in parasite cells. Moreover, the association of the active compound with miltefosine showed an additive effect in treating L. amazonensis-infected macrophages. Altogether, these results highlight the therapeutic potential of the evaluated salt and support further studies to assess its in vivo efficacy in a murine model of cutaneous leishmaniasis.

Anti-Leishmania effect of icetexanes from Salvia procurrens

BACKGROUND AND PURPOSE

Leishmaniasis is a globally prevalent vector-borne disease caused by parasites of the genus Leishmania. The available chemotherapeutic drugs present problems related to efficacy, emergence of parasite resistance, toxicity and high cost, justifying the search for new drugs. Several classes of compounds have demonstrated activity against Leishmania, including icetexane-type diterpenes, previously isolated from Salvia and other Lamiaceae genera. Thus, in this study, compounds of Salvia procurrens were investigated for their leishmanicidal and immunomodulatory activities.

METHODS

The exudate of S. procurrens was obtained by rapidly dipping the aerial parts in dichloromethane. The compounds were isolated by column and centrifugal planar chromatography over silica gel. The effects on L. amazonensis growth, survival, membrane integrity, reactive oxygen species (ROS) generation, mitochondrial membrane potential and cytotoxicity of the compounds towards human erythrocytes, peripheral blood mononuclear cells and macrophages were evaluated. The effects on intracellular amastigote forms, nitric oxide (NO) and TNF-α production were also investigated.

RESULTS

The exudate from the leaves afforded the novel icetexane 7-hydroxyfruticulin A (1) as well as the known demethylisofruticulin A (2), fruticulin A (3) and demethylfruticulin A (4). The compounds (1-4) were tested against promastigotes of L. amazonensis and showed an effective inhibition of the parasite survival (IC50 = 4.08-16.26 μM). In addition, they also induced mitochondrial ROS production, plasma membrane permeability and mitochondrial dysfunction in treated parasites, and presented low cytotoxicity against macrophages. Furthermore, all diterpenes tested reduced the number of parasites inside macrophages, by mechanisms involving TNF-α, NO and ROS.

CONCLUSION

The results suggest the potential of 7-hydroxyfruticulin A (1) as well as the known demethylisofruticulin A (2),fruticulin A (3) and demethylfruticulin A (4) as candidates for use in further studies on the design of anti-leishmanial drugs.

Antiprotozoal potential of Vismia species (Hypericaceae), medicinal plants used to fight cutaneous leishmaniasis

ETHNOPHARMACOLOGICAL RELEVANCE

Species of Vismia (Hypericaceae), known in Brazil as "lacre", are commonly used in traditional Amazonian medicine for the treatment of skin lesions, including those caused by Leishmania infection.

AIM OF THE STUDY

Hexane extracts from the leaves of Vismia cayennensis, V. gracilis, V. sandwithii and V. guianensis, as well as from the fruits of the latter, in addition to the anthraquinones vismiaquinone, physcion and chrysophanol isolated from these species were explored for their anti-promastigote and anti-amastigote activity on Leishmania amazonensis.

MATERIALS AND METHODS

Extracts were prepared by static maceration with n-hexane. The compounds, isolated by chromatographic techniques, were identified by spectroscopic methods (1H and 13C NMR). Promastigotes of L.amazonensis were incubated with hexane extracts (1-50 μg/mL) or anthraquinones (1-50 μM) and the parasite survival analyzed. The action of compounds on reactive oxygen species (ROS) production, mitochondrial membrane potential, and membrane integrity of promastigotes were evaluated by flow cytometer, and the cytotoxicity on mammalian cells using MTT assay. Furthermore, the activity of compounds against amastigotes and nitric oxide production were also investigated.

RESULTS

Vismiaquinone and physcion were obtained from the leaves of V. guianensis. Physcion, as well as chrysophanol, were isolated from V. sandwithii. Vismia cayennensis and V. gracilis also showed vismiaquinone, compound detected in lower quantity in the fruits of V. guianensis. All extracts were active against the parasite, corroborating the popular use. The greatest activity against promastigotes was achieved with V. guianensis extract (IC50 4.3 μg/mL), precisely the most used Vismia species for treating cutaneous leishmaniasis. Vismiaquinone and physcion exhibited relevant activity with IC50 12.6 and 2.6 μM, respectively. Moreover, all extracts and anthraquinones tested induced ROS production, mitochondrial dysfunction, membrane disruption and were able to kill intracellular amastigote forms, being worthy of further in vivo studies as potential antileishmanial drugs.

CONCLUSIONS

The overall data achieved in the current investigation scientifically validate the traditional use of Vismia species, mainly V. guianensis, as an anti-Leishmania agent. Furthermore, the promising results presented here indicate species of Vismia as potentially useful resources of Brazilian flora for the discovery of therapeutic solutions for neglected diseases.

Wortmannin Inhibits Cell Growth and Induces Apoptosis in Colorectal Cancer Cells by Suppressing the PI3K/AKT Pathway

BACKGROUND

Colorectal cancer (CRC) remains a significant contributor to mortality, often exacerbated by metastasis and chemoresistance. Novel therapeutic strategies are imperative to enhance current treatments. The dysregulation of the PI3K/Akt signaling pathway is implicated in CRC progression. This study investigates the therapeutic potential of Wortmannin, combined with 5-fluorouracil (5-FU), to target the PI3K/Akt pathway in CRC.

METHODS

Anti-migratory and antiproliferative effects were assessed through wound healing and MTT assays. Apoptosis and cell cycle alterations were evaluated using Annexin V/Propidium Iodide Apoptosis Assay. Wortmannin's impact on the oxidant/antioxidant equilibrium was examined via ROS, SOD, CAT, MDA, and T-SH levels. Downstream target genes of the PI3K/AKT pathway were analyzed at mRNA and protein levels using RTPCR and western blot, respectively.

RESULTS

Wortmannin demonstrated a significant inhibitory effect on cell proliferation, modulating survivin, cyclinD1, PI3K, and p-Akt. The PI3K inhibitor attenuated migratory activity, inducing E-cadherin expression. Combined Wortmannin with 5-FU induced apoptosis, increasing cells in sub-G1 via elevated ROS levels.

CONCLUSION

This study underscores Wortmannin's potential in inhibiting CRC cell growth and migration through PI3K/Akt pathway modulation. It also highlights its candidacy for further investigation as a promising therapeutic option in colorectal cancer treatment.