Sesamol Induces Apoptosis-Like Cell Death in Leishmania donovani

Development of novel dual-target drugs against visceral leishmaniasis and combinational study with miltefosine

The dual-target inhibitors (ZINC000008876351 and ZINC000253403245) were identified by utilizing an advanced computational drug discovery method by targeting two critical enzymes such as FeSODA (Iron superoxide dismutase) and TryR (Trypanothione reductase) within the antioxidant defense system of Leishmania donovani (Ld). In vitro enzyme inhibition kinetics reveals that both the compound's ability to inhibit the function of enzyme LdFeSODA and LdTryR with inhibition constant (Ki) value in the low μM range. Flow cytometry analysis, specifically at IC50 and 2X IC50 doses of both the compounds, the intracellular ROS was significantly increased as compared to the untreated control. The compounds ZINC000253403245 and ZINC000008876351 exhibited strong anti-leishmanial activity in a dose-dependent manner against both the promastigote and amastigote stages of the parasite. The data indicate that these molecules hold promise as potential anti-leishmanial agents for developing new treatments against visceral leishmaniasis, specifically targeting the LdFeSODA and LdTryR enzymes. Additionally, the in vitro MTT assay shows that combining these compounds with miltefosine produces a synergistic effect compared to miltefosine alone. This suggests that the compounds can boost miltefosine's effectiveness by synergistically inhibiting the growth of L. donovani promastigotes. Given the emergence of miltefosine resistance in some Leishmania strains, these findings are particularly significant.

Identification of novel anti-leishmanials targeting glutathione synthetase of the parasite: a drug repurposing approach

Drug repurposing has emerged as an effective strategy against infectious diseases such as visceral leishmaniasis. Here, we evaluated four FDA-approved drugs-valrubicin, ciclesonide, deflazacort, and telithromycin-for their anti-leishmanial activity on Leishmania donovani parasites, especially their ability to target the enzyme glutathione synthetase (LdGS), which enables parasite survival under oxidative stress in host macrophages. Valrubicin and ciclesonide exhibited superior inhibitory effects compared to deflazacort and telithromycin, inhibiting the promastigotes at very low concentrations, with IC50 values of 1.09 ± 0.09 μm and 2.09 ± 0.09 μm, respectively. Subsequent testing on amastigotes revealed the IC50 values of 1.74 ± 0.05 μm and 3.32 ± 0.21 μm for valrubicin and ciclesonide, respectively. Molecular and cellular level analysis further elucidated the mechanisms underlying the anti-leishmanial activity of valrubicin and ciclesonide.

Assessment of the antileishmanial activity of diallyl sulfide combined with meglumine antimoniate on Leishmania major: Molecular docking, in vitro, and animal model

Currently, no safe vaccine against leishmaniasis is available. So far, different control strategies against numerous reservoir hosts and biological vectors have not been environment-friendly and feasible. Hence, employing medicinal components and conventional drugs could be a promising approach to developing novel therapeutic alternatives. This study aimed to explore diallyl sulfide (DAS), a dynamic constituent of garlic, alone and in a mixture with meglumine antimoniate (MAT as standard drug) using in vitro and animal model experiments against Leishmania major stages. The binding affinity of DAS and four major defense elements of the immune system (iNOS, IFN-ɣ, IL-12, and TNF-α) was used to predict the predominant binding mode for molecular docking configurations. Herein, we conducted a broad range of experiments to monitor and assess DAS and MAT potential treatment outcomes. DAS, combined with MAT, displayed no cytotoxicity and employed a powerful anti-leishmanial activity, notably against the clinical stage. The function mechanism involved immunomodulation through the induction of Th1 cytokine phenotypes, triggering a high apoptotic profile, reactive oxygen species (ROS) production, and antioxidant enzymes. This combination significantly decreased cutaneous lesion diameter and parasite load in BALB/c mice. The histopathological findings performed the infiltration of inflammatory cells associated with T-lymphocytes, particularly CD4+ phenotypes, as determined by biochemical markers in alleviating the amastigote stage and improving the pathological changes in L. major infected BALB/c mice. Therefore, DAS and MAT deserve further advanced therapeutic development and should be considered as possible candidates for treating volunteer cases with cutaneous leishmaniasis in designing an upcoming clinical trial.

Cell Death in Leishmania donovani promastigotes in response to Mammalian Aurora Kinase B Inhibitor- Hesperadin

Deciphering how hesperadin, a repurposed mammalian aurora kinase B inhibitor, affects the cellular pathways in Leishmania donovani might be beneficial. This investigation sought to assess the physiological effects of hesperadin on promastigotes of L. donovani, by altering the duration of treatment following exposure to hesperadin. Groups pre-treated with inhibitors such as EGTA, NAC, and z-VAD-fmk before hesperadin exposure were also included. Morphological changes by microscopy, ATP and ROS changes by luminometry; DNA degradation using agarose gel electrophoresis and metacaspase levels through RT-PCR were assessed. Flow cytometry was used to study mitochondrial depolarization using JC-1 and MitoTracker Red; mitochondrial-superoxide accumulation using MitoSOX; plasma membrane modifications using Annexin-V and propidium iodide, and lastly, caspase activation using ApoStat. Significant alterations in promastigote morphology were noted. Caspase activity and mitochondrial-superoxide rose early after exposure whereas mitochondrial membrane potential demonstrated uncharacteristic variations, with significant functional disturbances such as leakage of superoxide radicals after prolonged treatments. ATP depletion and ROS accumulation demonstrated inverse patterns, genomic DNA showed fragmentation and plasma membrane showed Annexin-V binding, soon followed by propidium iodide uptake. Multilobed macronuclei and micronuclei accumulated in hesperadin exposed cells before they disintegrated into necrotic debris. The pathologic alterations were unlike the intrinsic or extrinsic pathways of classical apoptosis and suggest a caspase-mediated cell death most akin to mitotic-catastrophe. Most likely, a G2/M transition block caused accumulation of death signals, disorganized spindles and mechanical stresses, causing changes in morphology, organellar functions and ultimately promastigote death. Thus, death was a consequence of mitotic-arrest followed by ablation of kinetoplast functions, often implicated in L. donovani killing.

Buparvaquone Induces Ultrastructural and Physiological Alterations Leading to Mitochondrial Dysfunction and Caspase-Independent Apoptotic Cell Death in Leishmania donovani

Leishmaniasis is a neglected tropical disease (endemic in 99 countries) caused by parasitic protozoa of the genus Leishmania. As treatment options are limited, there is an unmet need for new drugs. The hydroxynaphthoquinone class of compounds demonstrates broad-spectrum activity against protozoan parasites. Buparvaquone (BPQ), a member of this class, is the only drug licensed for the treatment of theileriosis. BPQ has shown promising antileishmanial activity but its mode of action is largely unknown. The aim of this study was to evaluate the ultrastructural and physiological effects of BPQ for elucidating the mechanisms underlying the in vitro antiproliferative activity in Leishmania donovani. Transmission and scanning electron microscopy analyses of BPQ-treated parasites revealed ultrastructural effects characteristic of apoptosis-like cell death, which include alterations in the nucleus, mitochondrion, kinetoplast, flagella, and the flagellar pocket. Using flow cytometry, laser scanning confocal microscopy, and fluorometry, we found that BPQ induced caspase-independent apoptosis-like cell death by losing plasma membrane phospholipid asymmetry and cell cycle arrest at sub-G0/G1 phase. Depolarization of the mitochondrial membrane leads to the generation of oxidative stress and impaired ATP synthesis followed by disruption of intracellular calcium homeostasis. Collectively, these findings provide valuable mechanistic insights and demonstrate BPQ's potential for development as an antileishmanial agent.

Sesamol as a potent anticancer compound: from chemistry to cellular interactions

Sesamol (SM), a well-known component isolated from sesame seeds (Sesamum indicum), used in traditional medicines in treating numerous ailments. However, numerous molecular investigations revealed the various mechanisms behind its activity, emphasizing its antiproliferative, anti-inflammatory, and apoptosis-inducing properties, preventing cancer cell spread to distant organs. In several cells derived from various malignant tissues, SM-regulated signal transduction pathways and cellular targets have been identified. This review paper comprehensively describes the anticancer properties of SM and SM-viable anticancer drugs. Additionally, the interactions of this natural substance with standard anticancer drugs are examined, and the benefits of using nanotechnology in SM applications are explored. This makes SM a prime example of how ethnopharmacological knowledge can be applied to the development of contemporary drugs.

Casiopeina III-ia: A Copper Compound with Potential Use for Treatment of Infections Caused by Leishmania mexicana

INTRODUCTION

Casiopeina III-ia (CasIII-ia) is a mixed chelate copper (II) compound capable of interacting with free radicals generated in the respiratory chain through redox reactions, producing toxic reactive oxygen species (ROS) that compromise the viability of cancer cells, bacteria and protozoa. Due to its remarkable effect on protozoa, this study evaluated the effect of CasIII-ia on Leishmania mexicana amastigotes and its potential use as a treatment for cutaneous leishmaniasis in the murine model.

METHODS

We analyzed the leishmanicidal effect of CasIII-ia on L. mexicana amastigotes and on their survival in bone marrow-derived macrophages. Furthermore, we evaluated the production of ROS in treated parasites and the efficacy of CasIII-ia in the treatment of mice infected with L. mexicana.

RESULTS

Our results show that CasIII-ia reduces parasite viability in a dose-dependent manner that correlates with increased ROS production. A decrease in the size of footpad lesions and in parasite loads was observed in infected mice treated with the intraperitoneal administration of CasIII-ia.

CONCLUSIONS

We propose CasIII-ia as a potential drug for the treatment of cutaneous leishmaniasis.

Antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, on Leishmania (Leishmania) amazonensis

BACKGROUND

Leishmaniasis, a neglected disease caused by the parasite Leishmania, is treated with drugs associated with high toxicity and limited efficacy, in addition to constant reports of the emergence of resistant parasites. In this context, snake serums emerge as good candidates since they are natural sources with the potential to yield novel drugs.

OBJECTIVES

We aimed to show the antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, against Leishmania (Leishmania) amazonensis.

METHODS

Promastigotes forms were exposed to γCdcPLI, and we assessed the parasite viability and cell cycle, as well as invasion and proliferation assays.

FINDINGS

Despite the low cytotoxicity effect on macrophages, our data indicate that γCdcPLI has a direct effect on parasites promoting an arrest in the G1 phase and reduction in the G2/M phase at the highest dose tested. Moreover, this PLA2 inhibitor reduced the parasite infectivity when promastigotes were pre-treated. Also, we demonstrated that the γCdcPLI treatment modulated the host cell environment impairing early and late steps of the parasitism.

MAIN CONCLUSIONS

γCdcPLI is an interesting tool for the discovery of new essential targets on the parasite, as well as an alternative compound to improve the effectiveness of the leishmaniasis treatment.

Therapeutic importance of Kigelia africana subsp. africana: an alternative medicine

AIM

To summarise a detailed up-to-date review of the traditional uses, phytoconstituents, and pharmacological activities of various parts of Kigelia africana.

MATERIALS AND METHODS

Google Scholar, PubMed, PubChem, Elsevier, King Draw, indianbiodiversity.org.

RESULT

The phytochemical analysis of Kigelia africana subsp. africana has revealed the presence of approximately 145 compounds extracted from different parts of the plant. These bioactive extracts of the plant possess anti-inflammatory, antioxidant, antimicrobial, antidiabetic, antineoplastic, and anti-urolithic activities. Due to its anti-inflammatory, antioxidant, and immune-booster properties, Kigelia can prove to be an essential source of drugs for treating various disorders.

CONCLUSION

Knowledge of the phytoconstituents, non-medicinal and medicinal traditional uses, pharmacological activities, and products obtained from Kigelia is described in this review with the hope that the updated findings will promote research on its biological pathways.

Prosopis juliflora (Sw.) DC.induces apoptotic-like programmed cell death in Leishmania donovani via over production of oxidative stress, mitochondrial dysfunction and ATP depletion

Background

Leishmaniasis is endemic in more than 60 countries with a large number of mortality cases. The current chemotherapy approaches employed for managing the leishmaniasis is associated with severe side effects. Therefore there is a need to develop effective, safe, and cost affordable antileishmanial drug candidates.

Purpose of the study

This study was designed to evaluate the in vitro antileishmanial activity of a Prosopis juliflora leaves extract (PJLME) towards the Leishmania donovani parasites.

Material and methods

PJLME was evaluated for its cytotoxicity against the L. donovani parasites and the mouse macrophage cells. Further, various in vitro experiments like ROS assay, mitochondrial membrane potential assay, annexin v assay, cell cycle assay, and caspase 3/7 assay were performed to understand the mechanism of cell death. Phytochemical profiling of P. juliflorawas performed by utilizing HPTLC and GC-MS analysis.

Results

PJLME demonstrated antileishmanial activity at a remarkably lower concentration of IC50 6.5 μg/mL. Of note, interestingly PJLME IC50 concentration has not demonstrated cytotoxicity against the mouse macrophage cell line. Performed experiments confirmed ROS inducing potential of PJLME which adversely affected the mitochondrial membrane potential and caused loss of mitochondrial membrane potential and thereby ATP levels. PJLME also arrested the cell cycle and induced apoptotic-like cell death in PJLME treated L. donovani promastigotes.

Conclusion

The results clearly established the significance of Prosopis juliflora as an effective and safe natural resource for managing visceral leishmaniasis. The findings can be used as a baseline reference for developing novel leads/formulations for effective management of visceral leishmaniasis.

Leishmania donovani 6-phosphogluconolactonase: Crucial for growth and host infection?

The hexose monophosphate shunt is a crucial pathway in a variety of microorganisms owing to its vital metabolic products and intermediates such as NADPH, ribose 5-phosphate etc. The enzyme 6-phosphogluconolactonase catalyses the second step of this pathway, converting 6-phosphogluconolactone to 6-phosphogluconic acid. This enzyme has been known to have a significant involvement in growth, pathogenesis and sensitivity to oxidative stress in bacterial and protozoal pathogens. However, the functional role of kinetoplastid Leishmania donovani 6-phospohogluconolactonase (Ld6PGL) remains unexplored. L. donovani is the second largest parasitic killer and causative organism of life threatening visceral leishmaniasis. To understand its possible functional role in the parasite, the alleles of Ld6PGL were sequentially knocked-out followed by gene complementation. The Ld6PGL mutant cell lines showed decrease in transcriptional and translational expression as well as in the enzyme activity. In case of Ld6PGL null mutants, approximately 2-fold reduction was observed in growth. The null mutants also showed ∼38% decrease in infectivity, which recovered to ∼15% on complementation. Scanning electron microscopy showed a marked decrease in flagellar length in the knockout parasites. When treated with the standard drug miltefosine, the mutant strains had no significant change in the drug sensitivity. However, the Ld6PGL mutants were more susceptible to oxidative stress. Our findings suggest that 6PGL is required for parasite growth and infection but it is not essential.

Holanamine, a Steroidal Alkaloid from the Bark of Holarrhena pubescens Wall. ex G. Don Inhibits the Growth of Leishmania donovani by Targeting DNA Topoisomerase 1B

Leishmaniasis is a group of neglected tropical diseases (NTDs) caused by about 20 species of obligate intracellular protozoan parasites of the genus Leishmania, which occurs in cutaneous, mucocutaneous, and visceral forms. Many researchers have sought to utilize natural products for novel and effective treatments to combat many infectious diseases, including leishmaniasis. Holarrhena pubescens Wall. ex G. Don (Apocynaceae) bark is a rich source of bioactive steroidal alkaloids. The total alkaloidal extract (IC₅₀ 6.12 ± 0.117 μg/mL), and the isolated alkaloid, holanamine, showed significant antileishmanial activity (IC₅₀ 2.66 ± 0.112 μM against AG83 and 3.80 ± 0.126 μM against BHU-575) against the Leishmania donovani parasite, better than miltefosine (IC₅₀ 19.61 ± 0.093 μM against AG83 and 23.20 ± 0.094 μM against BHU-575). Holanamine inhibited the L. donovani topoisomerase 1B (LdToP1B) in a non-competitive manner (IC₅₀ 2.81 ± 0.105 μM), indicating that it interacts with the free enzyme and enzyme-DNA complex without inhibiting human topoisomerase. Hydrogen bonding and hydrophobic interactions of holanamine with the N-terminal and hinge region of the large subunit of LTop1B is responsible for its potent antileishmanial activity, as shown by docking studies. Treatment with holanamine causes apoptotic-like cell death by generating cellular and mitochondrial reactive oxygen species, disrupting the mitochondrial membrane potential and inducing ultrastructural alterations in the promastigotes. Holanamine effectively clears intracellular amastigotes but minimally affects host macrophages with no significant cytotoxicity in HEK 293 and L929 cell lines. Thus, our studies show that holanamine can further be used to develop effective antileishmanial agents against evolving drug-resistant parasites.

Integrated network pharmacology and experimental analysis unveil multi-targeted effect of 18α- glycyrrhetinic acid against non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is one of the most malignant types of cancer with soaring incidence rates worldwide, attributed to its heterogeneity and complex etiology. Evidently, alternative anti-cancer therapies comprising traditional medicines and natural products have gained attention for their ability to act as chemopreventive agents with minimal toxicities, either alone or in combination. Accumulating studies have substantiated the inevitability of network pharmacology studies for effectively mapping molecular targets of natural products against multifaceted diseases, including cancer. The 18α-Glycyrrhetinic acid (18α-GA), a triterpenoid found in licorice plants, has shown promising medicinal properties, although, its mechanism of action against NSCLC yet remains elusive. The present study was conducted to explore the anti- NSCLC potential of 18α-GA, employing integrative network pharmacology, molecular docking, and experimental research. Initially, network analysis revealed 181 common targets of 18α-GA in NSCLC as shown in the “compound-target- disease” network employing Cytoscape 3.8.2. Further analyses identified EGFR, AKT1, PI3KR1, MAPK1, IGF1, and SRC as the most crucial hub targets of 18α-GA against NSCLC. Moreover, molecular docking simulations and functional enrichment analyses indicated the involvement of multiple signaling pathways in suppressing NSCLC. Subsequent in-vitro studies verified the antiproliferative effect of 18α-GA on two NSCLC cancer cell lines, H1299 and A549. Mechanistically, 18α-GA arrested cell cycle at the G1 phase, induced apoptosis, decreased migratory potential, and protein expression levels of EGFR-PI3K/AKT, as examined by flow cytometry, morphological assessment, RT-PCR, and western blot. In conclusion, this study delineates the therapeutic potential and underlying mechanism(s) of 18α-GA as a putative novel drug against NSCLC. However, further studies are warranted to elucidate the complete molecular mechanism(s) using animal models of NSCLC.

Direct In Vitro Comparison of the Anti-Leishmanial Activity of Different Olive Oil Total Polyphenolic Fractions and Assessment of Their Combined Effects with Miltefosine

The bioactive compounds present in the edible products of the olive tree have been extensively studied and their favorable effects on various disease risk factors have been demonstrated. The aim of this study was to perform a comparative analysis of the anti-leishmanial effects of total phenolic fractions (TPFs) derived from extra virgin olive oil with different phenolic contents and diverse quantitative patterns. Moreover, the present study investigated their association with miltefosine, a standard anti-leishmanial drug, against both extracellular promastigotes and intracellular amastigotes of a viscerotropic and a dermotropic Leishmania strain. The chemical compositions of TPFs were determined by high performance liquid chromatography with diode array detection (HPLC-DAD). Analysis of parasite growth kinetics, reactive oxygen species production and apoptotic events were determined by microscopy and flow cytometry. Our results revealed that the presence of oleacein (OLEA) and oleocanthal (OLEO) secoiridoids enhances the anti-leishmanial effect of TPF. The association between TPFs and miltefosine was suggested as being additive in Leishmania infantum and Leishmania major promastigotes, and as antagonistic in intracellular amastigotes, as was evaluated with the modified isobologram method. The obtained data verified that TPFs are bioactive dietary extracts with a strong anti-leishmanial activity and highlighted that fractions that are richer in OLEA and OLEO phenolic compounds possess stronger inhibitory effects against parasites. This study may contribute to improving the therapeutic approaches against leishmaniasis.

Chrysin and Capsaicin Induces Premature Senescence and Apoptosis via Mitochondrial dysfunction and p53 elevation in Cervical Cancer cells

Current studies are focusing on the anti-cancerous properties of natural bioactive compounds, primarily those included in the human diet. These compounds have the potential to alter the redox balance that can hinder cancer cell's growth. In cancer cells, an abnormal rate of ROS production is balanced with higher antioxidant activities, which if not maintained, results in cancer cells being prone to cell death due to oxidative stress. Here, we have analyzed the effects of Chrysin and Capsaicin on the HeLa cells viability and cellular redox signaling. Both these compounds stimulate cellular and mitochondrial ROS overproduction that perturbs the cellular redox state and results in mitochondrial membrane potential loss. Apart from this, these compounds induce cell cycle arrest and induce premature senescence, along with the overexpression of p21, p53, and p16 protein at lower concentration treatment of Chrysin or Capsaicin. Moreover, at higher concentration treatment with these compounds, pro-apoptotic activity was observed with the high level of Bax and cleaved caspase-3 along with suppression of the Bcl-2 protein levels. In-Silico analysis with STITCH v5 also confirms the direct interaction of Chrysin and Capsaicin with target protein p53. This suggests that Chrysin and Capsaicin trigger an increase in mitochondrial ROS, and p53 interaction leading to premature senescence and apoptosis in concentration dependent manner and have therapeutic potential for cancer treatment.