Search Results (34)

Background/Objectives: Schistosomiasis, a parasitic disease caused by Schistosoma worms with freshwater snails as intermediate hosts, affects over 250 million people. The current control relies solely on praziquantel, which raises concerns on drug resistance and highlights the need for new therapeutic alternatives. Our bioprospection studies have focused on marine macroalgae as an unexplored source of antischistosomal metabolites with promising results. Guided by WHO recommendations to target both the parasite and its transmission vectors, this study aimed to investigate Ochtodes secundiramea to: (i) isolate active metabolites; (ii) evaluate the isolated compounds against adult worms and oviposition to identify leads for drug development; and (iii) perform an independent screening of their effects against the environmental transmission stages on cercariae and B. glabrata embryos. Methods: A dichloromethane extract of O. secundiramea was submitted to an NMR–biomonitored guided fractionation against Schistosoma mansoni adult worms. Active fractions were further purified through HPLC and characterized by ¹H and ¹³C NMR spectroscopy to identify the isolated compounds. Results: Three halogenated monoterpenes were isolated: ochtodene 1 (4-bromo-1,6,8-trichloro-2,3-ochtodene), ochtodene 2 (2-chloro-1,6,8-tribromo-3,8-ochtodene), and the novel natural product ochtodene 3 [2,6-dibromo-4-(2-chloroethylidene)-1,1dimethylcyclohexane]. Ochtodene 1 was the primary active metabolite against Schistosoma mansoni adult worms, with IC₅₀/96 h values of 47.2 and 46.1 µM for male and female worms respectively, and totally suppressed egg laying with 60 µM, while showing no toxicity toward human fibroblasts. Notably, all metabolites, including the novel ochtodene 3, caused 100% mortality in cercariae and embryos at low concentrations. Conclusions: The discovery of the novel ochtodene 3 and the identification of distinct leads for host treatment and transmission elimination position O. secundiramea as a promising source for integrated schistosomiasis control. Full article

Background: Schistosomiasis remains a major neglected tropical disease, with praziquantel (PZQ) as the only widely used treatment, despite its limitations. Parthenolide (PTL), a sesquiterpene lactone, exhibits potent in vitro antischistosomal activity; however, its poor aqueous solubility, low oral bioavailability, and chemical instability may limit its in vivo efficacy. Objective: This study investigated whether nanoencapsulation in nanostructured lipid carriers (NLC) could enable the in vivo antischistosomal activity of PTL. Methods: PTL was isolated from Tanacetum parthenium and incorporated into NLC using hot emulsification followed by ultrasonication. The resulting formulation (NLC-PTL) was physicochemically characterized, and its in vivo antischistosomal efficacy was evaluated in a murine model of Schistosoma mansoni infection. Results: NLC-PTL exhibited nanoscale size, low polydispersity, high encapsulation efficiency, and sustained drug release. In vivo, free PTL showed no significant effect on worm burden, whereas NLC-PTL achieved a marked reduction (77.9%) in adult worms and significantly decreased egg output compared to controls (p < 0.001). Blank NLC had no antiparasitic effect. Conclusions: Nanoencapsulation was associated with in vivo antischistosomal activity of PTL compared to the free compound. These findings suggest that formulation strategies may influence the in vivo performance of lipophilic natural products in schistosomiasis. Full article

In the search for new antischistosomal 3-benzylmenadiones (benzylMDs), the screening of a library developed in our laboratory led to the identification of two regioisomeric analogues, the 2′,5′- and 3′,5′-dimethoxy-benzylMD—designated schistodiones A_2′,5′ and A_3′,5′—which were investigated for their activity against the platyhelminth Schistosoma mansoni and various protozoan parasites, bacteria, and fungi. Reported work has shown that benzylMDs act as prodrugs: their bioactivation undergoes a cascade of redox reactions within the parasite, generating multiple drug metabolites, e.g., the main benzoylmenadione (benzoylMD) intermediates, and reactive oxygen species that interfere with key metabolic pathways. Among the secondary metabolites, benzoxanthones have been identified as potential products generated along this oxidative pathway. The aim of the study was to synthetize methoxylated benzoxanthones, as putative metabolites generated from these antischistosomal benzylMDs. During the synthetic work, several difficulties arose, including the absence of starting reagents, the incompatibility of certain reactions with methoxy groups, the possible formation of several isomers, and the easy re-oxidation of sensitive intermediates. To overcome these obstacles, we developed a new retrosynthetic strategy using modified precursors: replacing methoxy groups with O-methylenemethoxy (OMOM) groups that are more stable in basic media, using aldehydes or aromatic esters as precursors, and replacing certain substituents with groups that are easier and less costly to introduce (chlorine or nitro). Selected metabolites (benzoylMDs, benzoxanthones) were then tested in parasite and cellular assays. Furthermore, benzoylMDs were tested as subversive substrates of S. mansoni thioredoxin-glutathione reductase (SmTGR) and selected drug metabolites were investigated in SmTGR modeling experiments. From a One Health perspective, these benzylMD derivatives pose limited environmental risk because their metabolites lack toxicity when encountered externally, as toxicity requires intracellular metabolic activation and localized formation of reactive intermediates in close proximity to their cellular targets inside parasites. Full article

Schistosomiasis remains one of the most significant neglected tropical diseases (NTDs) worldwide, sustained by the complex biology of Schistosoma species and the host’s immunopathological responses to tissue-trapped eggs. Despite decades of reliance on praziquantel (PZQ) as the sole chemotherapeutic option, major limitations persist, including its lack of activity against juvenile worms, incomplete protection against reinfection, and concerns regarding emerging tolerance. These challenges, together with persistent hotspots of transmission and uneven global progress toward disease elimination, underscore the urgent need for alternative or complementary therapies. Plant-derived terpenes have emerged as promising antischistosomal candidates due to their structural diversity, broad-spectrum bioactivity, and favourable safety profiles. Evidence from in vitro and in vivo studies demonstrates that monoterpenes, sesquiterpenes, diterpenes, triterpenes, and triterpenoid saponins exert multimodal effects on Schistosoma, including tegumental disruption, interference with metabolic and redox pathways, inhibition of oviposition, and modulation of host immune and fibrotic responses. Advances in mechanistic studies, supported by omics and computational approaches, further highlight their potential as leads for drug development. Additionally, nano-enabled delivery systems offer strategies to overcome pharmacokinetic limitations and enhance therapeutic performance. This review integrates current knowledge on schistosome biology, treatment challenges, and the growing evidence supporting terpenoids as viable components of a diversified antischistosomal therapeutic arsenal. Full article

Background/Objectives: Schistosomiasis is a neglected tropical disease affecting >200 million people worldwide. Praziquantel is the sole recommended drug against Schistosoma mansoni; however, it lacks activity against juvenile forms and cannot prevent reinfection. Thus, there is an urgent need to identify novel therapeutic targets. Long noncoding RNAs (lncRNAs) are known to regulate various biological processes in S. mansoni, including parasite pairing and fertility; therefore, screening for novel lncRNAs could reveal new potential targets. Methods: We compiled all publicly available RNA-seq data from the Sequence Read Archive (SRA) and performed a hierarchical transcriptome assembly using the multi-sample assembler Ryūtō, combined with version 10 of the S. mansoni genome. We applied HOMER for peak-calling and identification of histone marks and used weighted gene co-expression network analysis (WGCNA) to infer putative functions of lncRNAs in sexual dimorphism. Results: Using a robust pipeline, we identified 10,170 novel lncRNA genes comprising 16,990 novel lncRNA transcripts, including 8783 intergenic, 7918 antisense, and 289 intronic lncRNA transcripts. Most (78.7%) have histone regulatory marks (H3K4me3, H3K27me3, H3K27ac, or H4K20me1) near their transcription start sites, indicating potential expression regulation. Comparing male and female samples, we identified 1991 differentially expressed genes (FDR < 5%, |log₂FC| ≥ 1.5), including 296 known lncRNAs and 339 novel lncRNAs. WGCNA identified hub lncRNAs within co-expression modules, and Gene Ontology enrichment analyses (FDR ≤ 5%) suggest that these lncRNAs are involved in cell differentiation and morphogenesis pathways. Conclusions: We provide a comprehensive catalog of S. mansoni lncRNAs. These findings offer opportunities to discover potential new therapeutic targets, advancing the future development of anti-schistosome therapies. Full article

Disulfiram (DSF) is a well-established inhibitor of aldehyde dehydrogenases (ALDHs) and an FDA-approved drug for chronic alcoholism. DSF has gained attention as a versatile scaffold for drug repurposing. Its metabolite, diethyldithiocarbamate (DDTC), mediates multiple biological effects via metal chelation and covalent modification of key cysteine residues. Beyond its established anticancer properties, DSF modulates cancer stem cells, reactive oxygen species, proteasome function, and drug-resistance pathways. It also shows promise in metabolic disorders, including type 2 diabetes and obesity, by targeting enzymes such as fructose-1,6-bisphosphatase and α-glucosidase, and influences energy expenditure and autophagy. DSF exhibits antimicrobial and antiparasitic activity, enhances antibiotic efficacy against multidrug-resistant bacteria, and demonstrates antischistosomal and anti-Trichomonas effects, while also providing radioprotective benefits. The clinical translation of DSF is limited by poor solubility, rapid metabolism, and off-target effects; consequently, the development of DSF analogs has become a major focus. Structural optimization has yielded derivatives with improved selectivity, stability, solubility, and target specificity, enabling precise modulation of key enzymes while reducing adverse effects. A key structure-based strategy involves introducing bulkier substituents to exploit differences in ALDH active-site architecture and achieve target selectivity. This concept is exemplified by compounds (1) and (2), in which bulky substituents confer selective inhibition of ALDH1A1 while sparing ALDH2. This review provides a comprehensive overview of DSF analogs, their molecular mechanisms, and therapeutic potential, highlighting their promise as multifunctional agents for cancer, metabolic disorders, infectious diseases, and radioprotection. Full article

Background/Objectives: Recent reports have demonstrated the antiparasitic activity of 1,4-dihydropyridine (1,4-DHPs). This study aimed to assess the in vitro antischistosomal activity of 24 1,4-DHPs against Schistosoma mansoni adult worms. Methods: Sixteen hexahydroquinolines (1–16) and eight Hantzsch esters (17–24) previously obtained through a multicomponent Hantzsch reaction were tested in vitro against Schistosoma mansoni adult worms. In silico studies with the most active compounds were also carried out. Results: Among the tested compounds, the Hantzsch esters 20 (diethyl 4-(4-bromophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate) and 21 (diethyl 4-(3-fluorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate) provided the lowest IC₅₀ (15.2 and 13.1 µM, respectively) and the highest selectivity for this parasite (SI = 2.31 and >4.59, respectively). Conclusions: Docking studies revealed that compound 21 has a high affinity for the S. mansoni target (PDB ID: 6UY4). Furthermore, ADMET predictions indicated that compound 21 meets the drug-likeness criteria without violating any Lipinski, Veber, or Egan’s rules. Full article

Schistosomiasis is a neglected tropical disease that affects over 240 million people worldwide. Currently, praziquantel is the only drug recommended by the World Health Organization for treatment. However, cases of drug resistance have been reported, which indicates an urgent need for new therapeutics. In this context, natural compounds represent valuable sources of pharmacological substances. Plant-derived natural products have been greatly explored for their potential antischistosomal activity, while animal-derived compounds have received little attention. Recent advances in the biotechnology field allow the wide exploration of animal-derived compounds in drug discovery, which may represent a cost-effective option to find bioactive molecules also against Schistosoma mansoni and other parasites. This review highlights the research into animal-derived products and compounds that have already been tested against schistosomes. Phenotypic effects on schistosomes have been observed upon incubation with some of these substances, which may, therefore, represent possible candidates to be used in the development of new drugs. Overall, these studies advance the discovery of antischistosomal compounds by exploring a yet understudied natural resource. The present review also discusses the challenges of testing animal-derived products and provides examples of the experimental in vitro testing of different selected animal natural products against S. mansoni. Full article

In the present study, the hexane extract from branches of Drimys brasiliensis (Winteraceae) displayed potent activity against Schistosoma mansoni parasites (100% mortality of the worms at 200 μg/mL). Bioactivity-guided fractionation afforded, in addition to the previously reported bioactive sesquiterpene 3,6-epidioxy-bisabola-1,10-diene, two chemically related drimane sesquiterpenes—polygodial (1) and 9-deoxymuzigadial (2). The anti-S. mansoni effects for compounds 1 and 2 were determined in vitro, with compound 1 demonstrating significant potency (EC₅₀ value of 10 μM for both male and female worms), while 2 was inactive. Cytotoxicity assays against Vero cells revealed no toxicity for either compound (CC₅₀ > 200 μM). Additionally, an in silico analysis was conducted using the SwissADME platform for 1, revealing that this natural sesquiterpene exhibited adherence to several ADME parameters and no PAINS violations. Finally, in vivo studies with S. mansoni-infected mice treated with compound 1 demonstrated a 44.0% reduction in worm burden, accompanied by decreases in egg production of 71.8% in feces and 69.5% in intestines. These findings highlight the potential of polygodial (1) as a promising prototype for schistosomiasis treatment. Full article

Schistosomiasis, a neglected tropical disease impacting over 250 million individuals globally, remains a major public health challenge due to its prevalence and significant impact on affected communities. Praziquantel, the sole available treatment, highlights the urgency of the need for novel anthelmintic agents to achieve the World Health Organization (WHO) goal of schistosomiasis elimination. Previous studies reported the promising antiparasitic activity of different terpenoids against Schistosoma mansoni Sambon (Diplostomida: Schistosomatidae). In the present work, the hexane extract from branches of Drimys brasiliensis afforded a diastereomeric mixture of endoperoxide sesquiterpenes, including 3,6-epidioxy-bisabola-1,10-diene (EDBD). This compound was evaluated in vitro and in vivo against S. mansoni. EDBD exhibited a significant reduction in S. mansoni viability in vitro, with an effective concentration (EC₅₀) value of 4.1 µM. Additionally, EDBD demonstrated no toxicity to mammalian cells. In silico analysis predicted good drug-likeness properties, adhering to pharmaceutical industry standards, including favorable ADME profiles. Furthermore, oral treatment of S. mansoni-infected mice with EDBD (400 mg/kg) resulted in a remarkable egg burden reduction (98% and 99% in tissues and feces, respectively) surpassing praziquantel’s efficacy. These findings suggest the promising potential of EDBD as a lead molecule for developing a novel schistosomiasis treatment. Full article

The burden of human schistosomiasis, a known but neglected tropical disease in Sub-Saharan Africa, has been worrisome in recent years. It is becoming increasingly difficult to tackle schistosomiasis with praziquantel, a drug known to be effective against all Schistosoma species, due to reports of reduced efficacy and resistance. Therefore, this study seeks to investigate the antischistosomal potential of phytochemicals from Azadirachta indica against proteins that have been implicated as druggable targets for the treatment of schistosomiasis using computational techniques. In this study, sixty-three (63) previously isolated and characterized phytochemicals from A. indica were identified from the literature and retrieved from the PubChem database. In silico screening was conducted to assess the inhibitory potential of these phytochemicals against three receptors (Schistosoma mansoni Thioredoxin glutathione reductase, dihydroorotate dehydrogenase, and Arginase) that may serve as therapeutic targets for schistosomiasis treatment. Molecular docking, ADMET prediction, ligand interaction, MMGBSA, and molecular dynamics simulation of the hit compounds were conducted using the Schrodinger molecular drug discovery suite. The results show that Andrographolide possesses a satisfactory pharmacokinetic profile, does not violate the Lipinski rule of five, binds with favourable affinity with the receptors, and interacts with key amino acids at the active site. Importantly, its interaction with dihydroorotate dehydrogenase, an enzyme responsible for the catalysis of the de novo pyrimidine nucleotide biosynthetic pathway rate-limiting step, shows a glide score and MMGBSA of −10.19 and −45.75 Kcal/mol, respectively. In addition, the MD simulation shows its stability at the active site of the receptor. Overall, this study revealed that Andrographolide from Azadirachta indica could serve as a potential lead compound for the development of an anti-schistosomal drug. Full article

Malaria and schistosomiasis are two of the neglected tropical diseases that persistently wreak havoc worldwide. Although many antimalarial drugs such as chloroquine are readily available, the emergence of drug resistance necessitates the development of new therapies to combat this disease. Conversely, Praziquantel (PZQ) remains the sole effective drug against schistosomiasis, but its extensive use raises concerns about the potential for drug resistance to develop. In this project, the concept of molecular hybridization was used as a strategy to design the synthesis of new molecular hybrids with potential antimalarial and antischistosomal activity. A total of seventeen molecular hybrids and two PZQ analogues were prepared by coupling 6-alkylpraziquanamines with cinnamic acids and cyclohexane carboxylic acid, respectively. The synthesised compounds were evaluated for their antimalarial and antischistosomal activity; while all of the above compounds were inactive against Plasmodium falciparum (IC₅₀ > 6 µM), many were active against schistosomiasis with four particular compounds exhibiting up to 100% activity against newly transformed schistosomula and adult worms at 50 µM. Compared to PZQ, the reference drug, the activity of which is 91.7% at 1 µM, one particular molecular hybrid, compound 32, which bears a para-isopropyl group on the cinnamic acid moiety, exhibited a notable activity at 10 µM (78.2% activity). This compound has emerged as the front runner candidate that might, after further optimization, hold promise as a potential lead compound in the fight against schistosomiasis. Full article

A synthesis of bridged 1,2,4-trioxolanes (bridged ozonides) from 1,5-diketones and hydrogen peroxide catalyzed by SnCl₄ was developed. It was shown that the ratio of target ozonides can be affected by the application of SnCl₄ as a catalyst and varying the solvent. A wide range of bridged 1,2,4-trioxolanes (ozonides) was obtained in yields from 50 to 84%. The ozonide cycle was moderately resistant to the reduction of the ester group near the peroxide cycle to alcohol with LiAlH₄. The bridged ozonides were evaluated for their antischistosomal activity. These ozonides exhibited a very high activity against newly transformed schistosomula and adult Schistosoma mansoni. Full article

Schistosomiasis, caused by parasites of the genus Schistosoma, is a neglected disease with high global prevalence, affecting more than 240 million people in several countries. Praziquantel (PZQ) is the only drug currently available for the treatment. S. mansoni NTPDases (known as SmNTPDases, ATP diphosphohydrolases or ecto-apyrases) are potential drug targets for the discovery of new antischistosomal drugs. In this study, we screen NTPDases inhibitors from Centella erecta (Apiaceae) using an ultrafiltration combined UHPLC-QTOF-MS method and potato apyrase, identifying asiaticoside as one of the apyrase-binding compounds. After isolation of asiaticoside from C. erecta extract, we assessed its in vivo antischistosomal activities against Schistosoma mansoni worms and its in vitro enzymatic apyrase inhibition. Also, molecular docking analysis of asiaticoside against potato apyrase, S. mansoni NTPDases 1 and 2 were performed. Asiaticoside showed a significant in vitro apyrase inhibition and molecular docking studies corroborate with its possible actions in potato apyrase and S. mansoni NTPDases. In mice harboring a patent S. mansoni infection, a single oral dose of asiaticoside (400 mg/kg. p.o.) showed significantly in vivo antischistosomal efficacy, markedly decreasing the total worm load and egg burden, giving support for further exploration of apyrase inhibitors as antischistosomal agents. Full article

Schistosomiasis is a neglected tropical disease affecting more than 200 million people worldwide. Chemotherapy relies on one single drug, praziquantel, which is safe but ineffective at killing larval stages of this parasite. Furthermore, concerns have been expressed about the rise in resistance against this drug. In the absence of an antischistosomal vaccine, it is, therefore, necessary to develop new drugs against the different species of schistosomes. Protein kinases are important molecules involved in key cellular processes such as signaling, growth, and differentiation. The kinome of schistosomes has been studied and the suitability of schistosomal protein kinases as targets demonstrated by RNA interference studies. Although protein kinase inhibitors are mostly used in cancer therapy, e.g., for the treatment of chronic myeloid leukemia or melanoma, they are now being increasingly explored for the treatment of non-oncological conditions, including schistosomiasis. Here, we discuss the various approaches including screening of natural and synthetic compounds, de novo drug development, and drug repurposing in the context of the search for protein kinase inhibitors against schistosomiasis. We discuss the status quo of the development of kinase inhibitors against schistosomal serine/threonine kinases such as polo-like kinases (PLKs) and mitogen-activated protein kinases (MAP kinases), as well as protein tyrosine kinases (PTKs). Full article