Antimalarial Research Articles

Antiplasmodial Potentials, Phytocompounds and the Possible Toxic Effects of Administration of Ethylacetate Extract of Spondias mombin Linn.

Malaria, caused by Plasmodium parasites, is a global health concern. Natural products, such as plant extracts, are investigated for new antimalarial agents. Spondias mombin, traditionally used for medicinal purposes, was examined for its effects on parasitemia, haematological parameters, antioxidant activities, liver function biomarkers, and serum electrolytes in Plasmodium berghei-infected mice. Mice received varying doses of the ethylacetate extract. Various dosages of the extract and the prescribed medication dramatically slowed the parasite's growth. The extract significantly improved red blood cell (RBC) and platelet counts, particularly at higher doses. Hemoglobin levels were decreased dose-dependently. Antioxidant analysis showed increased superoxide dismutase (SOD), glutathione peroxidase (GPx), and reduced catalase (CAT) activities and malondialdehyde (MDA) levels, indicating robust antioxidant properties. Liver function tests showed mixed effects, with elevated AST, ALP, and TB levels at some doses, yet decreased ALT at the highest dose, suggesting possible hepatoprotective effects. Serum electrolyte levels remained stable. Seventy-eight (78) bioactive components were identified in the extract by GC-MS analysis. The extract demonstrated substantial antimalarial and antioxidant capacities, with minimal liver stress and stable electrolyte levels, suggesting safety as an adjunct therapy for malaria. Further research is needed to ascertain the specific antimalarial bioactive constituents and their mechanisms of action.

Case report: Malaria and hepatitis E coinfection—first experience with such imported entity in Serbia

Acute hepatitis E virus (HEV) and malaria are not rare infections in tropical countries; however, in the European continent, such imported entity has not been reported up to now. Herein, we report a 24-year-old male suffering from malaria and hepatitis E, who was admitted with acute hepatic failure dark colored urine, followed by coagulation and inflammation parameters increase. Blood smear analysis revealed the presence of Plasmodium falciparum, while serological tests revealed anti-HEV IgM antibodies. After the recommended antimalarial drugs and supportive therapy, the patient survived and was discharged disease-free. Conclusions: Following WHO guidelines for the treatment of severe malaria, full recovery in patient was achieved.

Genetic surveillance shows spread of ACT resistance during period of malaria decline in Vietnam (2018-2020)

IntroductionVietnam’s goal to eliminate malaria by 2030 is challenged by the further spread of drug-resistant Plasmodium falciparum malaria to key antimalarials, particularly dihydroartemisinin-piperaquine (DHA-PPQ).MethodsThe custom targeted NGS amplicon sequencing assay, AmpliSeq Pf Vietnam v2, targeting drug resistance, population genetic- and other markers, was applied to detect genetic diversity and resistance profiles in samples from 8 provinces in Vietnam (n = 354), in a period of steep decline of incidence (2018–2020). Variants in 14 putative resistance genes, including P. falciparum Kelch 13 (PfK13) and P. falciparum chloroquine resistance transporter (Pfcrt), were analyzed and within-country parasite diversity was evaluated. Other targets included KEL1-lineage markers and diagnostic markers of Pfhrp2/3.ResultsA concerning level of DHA-PPQ resistance was detected. The C580Y mutation in PfK13 was found in nearly 80% of recent samples, a significant rise from previous data. Vietnam has experienced a significant challenge with the spread of DHA-PPQ resistant malaria parasites, particularly in the provinces of Binh Phuoc and Gia Lai. Resistance spread to high levels in Binh Thuan prior to the country-wide treatment policy change from DHA-PPQ to pyronadine-artesunate (PA). A complex picture of PPQ-resistance dynamics was observed, with an increase of PPQ-resistance associated Pfcrt mutations, indicating an evolutionary response to antimalarial pressure. Additionally, the compensatory mutation C258W in Pfcrt, which increases chloroquine (CQ) resistance while reversing PPQ resistance, is emerging in Gia Lai following the adoption of PA as the first-line treatment. This study found high levels of multidrug resistance, with over 70% of parasites in 6 out of 8 provinces showing significant sulfadoxine-pyrimethamine (SP) resistance and widespread chloroquine-resistant Pfcrt haplotypes. We also report an absence of P. falciparum histidine rich protein 2 and 3 (Pfhrp2/3) gene deletions, ensuring the continued reliability of HRP2/3-based rapid diagnostic tests. P. falciparum populations in Vietnam are becoming more isolated, with clonal populations showing high geographical clustering by province. The central highlands, particularly Gia Lai province, have the highest residual malaria burden but exhibit low diversity and clonal populations, likely due to the pressures from the antimalarial drugs and targeted national malaria control program (NMCP) efforts.DiscussionIn conclusion, examining a broad panel of full-length resistance genes and SNPs provided high-resolution insights into genetic diversity and resistance evolution in Vietnam, offering valuable information to inform local treatment and intervention strategies.

Exploring the potential antimalarial properties, safety profile, and phytochemical composition of Mesua ferrea Linn.

The increased resistance of Plasmodium falciparum to artemisinin and its partner drugs poses a serious challenge to global malaria control and elimination programs. This study aimed to investigate the therapeutic potential of Mesua ferrea Linn., a medicinal plant, as a source for novel antimalarial compounds. In this study, we conducted in vitro assays to evaluate the antimalarial activity and cytotoxicity of crude extracts derived from M. ferrea L. leaves and branches. Subsequently, the most promising extracts were subjected to assessments of their antimalarial efficacy and acute oral toxicity tests in mouse models. Furthermore, selected crude extracts underwent gas chromatography-mass spectrometry (GC-MS) analysis to identify their phytochemical compositions. Our findings revealed that the ethanolic extract of M. ferrea L. branches (EMFB) exhibited high antimalarial activity, with an IC50 value of 4.54 μg/mL, closely followed by the ethanolic extract of M. ferrea L. leaves (EMFL), with an IC50 value of 6.76 μg/mL. Conversely, the aqueous extracts of M. ferrea L. branches (AMFB) and leaves (AMFL) exhibited weak and inactive activity, respectively. The selected extracts, EMFB and EMFL, demonstrated significant dose-dependent parasitemia suppression, reaching a maximum of 62.61% and 54.48% at 600 mg/kg body weight, respectively. Furthermore, the acute oral toxicity test indicated no observable toxicity at a dosage of 2,000 mg/kg body weight for both extracts. GC-MS analysis revealed abundant compounds in the EMFB, such as oleamide, cis-β-farnesene, alloaromadendrene, physcion, palmitic acid, 5-hydroxymethylfurfural, and 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-, while the EMFL contained friedelin, friedelinol, betulin, β-caryophyllene, oleamide, and 5-hydroxymethylfurfural. Notably, both extracts shared several phytochemical compounds, including 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-, 5-hydroxymethylfurfural, α-copaene, cyperene, β-caryophyllene, alloaromadendrene, palmitic acid, ethyl palmitate, and oleamide. Additionally, further study is needed to isolate and characterize these bioactive compounds from M. ferrea L. leaves and branches for their potential utilization as scaffolds in the development of novel antimalarial drugs.

Quassinoids from Eurycoma longifolia as Potential Dihydrofolate Reductase Inhibitors: A Computational Study.

Quassinoids are degraded triterpene compounds that can be obtained from various species of the Simaroubaceae plant family, including Eurycoma longifolia. Quassinoids are the major compounds in E. longifolia, and they are known to have various medicinal potentials, such as anticancer and antimalarial properties. Dihydrofolate reductase (DHFR) was reported to be one of the important targets for certain anticancer and antimalarial drugs. Twelve quassinoids from E. longifolia were identified to have anticancer effects based on their IC50 values. This study aimed to evaluate the interactions of these twelve quassinoids with DHFR via Autodock 4.2 software and Biovia Discovery Studio Visualiser. Twelve quassinoids from E. longifolia and their interactions with DHFR were evaluated via Autodock 4.2 software and Biovia Discovery Studio Visualiser. Their drug-likeness and pharmacokinetic properties were also assessed using the ADMETlab 2.0 program. The molecular docking results showed that eleven quassinoids showed better docking scores than methotrexate, in which the binding energy (BE) of these quassinoids ranged from - 7.87 to -9.58 kcal/mol. Their inhibition constant (Ki) ranged from 0.095 to 1.71 μM. At the same time, the BE and Ki values for methotrexate were -7.80 kcal/mol and 1.64 μM, respectively. From the analysis, 6-dehydrolongilactone and eurycomalide B are among the twelve compounds that showed great potential as hit-to-lead compounds based on the docking score on DHFR, drug-likeness, and ADMET properties. These results suggest a great potential to pursue validation studies via in vitro and in vivo models.

Importance of tailored non-clinical safety testing of novel antimalarial drugs: Industry best-practice

Malaria is an acute, debilitating parasitic illness. There were 249 million cases of malaria in 2022, resulting in 608,000 deaths globally, 76% of which were children ≤5 years. The unique nature of this disease (recurrences leading to re-treatments and numerous organ systems affected), specific clinical treatment regimens, poor compliance, and diversity of affected populations (predominantly pediatrics, women of childbearing potential, pregnant and lactating women), often makes standard testing approaches inadequate, and tailor-made safety assessments are more appropriate.We provide best practice recommendations based on company experience for the non-clinical safety assessment of antimalarial drugs, with a focus on small molecules since they represent the majority of drug candidates for this illness. We focus on specific testing considerations for repeat dose toxicity studies, including combination toxicity assessments, since new drug treatment regimens typically foresee short treatment durations to improve compliance (i.e., 1 day) with combinations of compounds to improve efficacy and limit potential resistance. Due to the target population, the timing of reproductive, developmental, and juvenile toxicity studies may be earlier than general testing roadmaps for other small molecule drugs.In conclusion, key recommendations presented should enable a more effective and efficient development path whilst protecting clinical trial participants and patients.

The Role of JAK Inhibitors in the Treatment of Cutaneous Lupus Erythematosus: A Review.

Cutaneous lupus erythematosus (CLE), a manifestation of the chronic autoimmune disease lupus erythematosus (LE), showcases diverse clinical, immunologic, and histologic attributes. CLE can be further categorized into subtypes -- acute (ACLE), subacute (SCLE), or chronic (CCLE) -- with each class characterized by distinct features, including the degree of cutaneous involvement, lesion duration, and associated laboratory findings. While conventional treatments, including photoprotective strategies, topical corticosteroids, and antimalarial agents, have proven effective for some, recent immunomodulatory therapies offer alternative avenues. Janus kinase (JAK) inhibitors, in particular, have gained attention due to their demonstrated efficacy in the management of various autoimmune disorders. Dysregulation of the JAK/signal transducer and activator of transcription (STAT) signaling pathway has been implicated in the pathogenesis of CLE, further underscoring the promise of JAK inhibitors as an adjunctive therapy alongside systemic immunosuppression. This systematic review aims to discuss the diagnosis and categorization of CLE and its subtypes, elucidate the intricacies of intracellular signaling within the JAK/STAT pathway, and discuss the current applications of JAK inhibitors in the treatment of autoimmune disease. Supported by cases, randomized control trials, basic science articles, and other reviews in the literature, this review provides evidence for the use of the JAK/STAT pathway as a therapeutic target. Nevertheless, the role of JAK inhibitors and their therapeutic properties warrant further scrutiny through rigorous investigation and comprehensive randomized control trials to ascertain safety and efficacy. J Drugs Dermatol. 2024;23(12):1100-1107. doi:10.36849/JDD.8045.

“Novel chemo-enzymatic synthesis, structural elucidation and first antiprotozoal activity profiling of the atropoisomeric dimers of trans-8-Hydroxycalamenene”

Leishmaniasis and malaria are two debilitating protozoan diseases affecting millions globally, particularly in tropical and subtropical regions. Current therapeutic options face significant challenges due to emerging drug-resistant strains, necessitating the discovery of novel antiprotozoal agents. This study explores, for the first time, the antiprotozoal potential of calamenenes and their dimers, naturally occurring sesquiterpenes found in essential oils, through a novel chemo-enzymatic synthesis approach. Using the laccase from Trametes versicolor, atropoisomeric dimers of (−)- and (+)-8-trans-hydroxycalamenene were synthesized from commercially available (−)- and (+)-menthol. Structural elucidation was achieved via 2D-NMR spectroscopy, electronic circular dichroism, and DFT calculations. In vitro profiling against Leishmania spp and drug-resistant Plasmodium falciparum revealed that calamenene dimers exhibited significantly higher antiprotozoal activity compared to their monomeric counterparts, highlighting the potential of dimeric terpenoids as promising antiprotozoal agents. This work lays the foundation for developing novel antimalarial drugs based on calamenene scaffolds, encouraging further interactome studies to optimize their pharmacological properties.

Antimalarial Effects of Nano Chloroquine Loaded Curcumin In vivo.

Malaria is still the deadliest parasitic disease caused by Plasmodium spp. Due to drug resistance and their unpleasant side effects, of conventional researchers are enormously seeking to achieve antimalarial drugs with more curative effective, less toxic and cost-affordable drugs using more advanced technology such as nanodrugs. The present study aimed to examine the antimalarial effects of a novel synthesized nonochloroquine-loaded curcumin relying on dendrimer G2 in susceptible mice. Antimalarial activity and toxicity of the nanocomposite were examined on BALB/C mice with microscopy, checking RBCs morphology and related enzymatic activity rate. The maximum inhibitory effect of the nanocomposite was seen at 10 mg/kg, killing 98% of P. berghei compared to sole chloroquine, whereas ED50 was reported at 5.5 mg/kg. The safety of the synthesized nanocomposite was confirmed with biochemical tests with no detrimental effects on mice. The sustainability and longevity of the nanodrug increased significantly with the NDC-CQ assay compared to the control groups. The study showed that nonochloroquine-loaded curcumin had a promising inhibitory effect on P. berghei growth in infected mice compared to standard drugs. However, further studies and clinical trials with large samples are recommended to study different aspects of using nanodrug.

Hepatoprotective and neuroprotective effects of quinacrine against bile duct ligation-induced hepatic encephalopathy in rats: Role of bone morphogenetic proteins signaling

AimsThis study aimed to assess the potential protective effect of quinacrine, an FDA approved antimalarial drug with reported anti-inflammatory effects, on hepatic encephalopathy (HE) in a bile duct ligation (BDL) experimental model and to investigate the mechanisms responsible for this effect, namely those associated with the liver-brain axis, particularly, bone morphogenetic protein 2 (BMP2) signaling. Materials and methodsFive groups of rats were selected at random: sham, BDL, (BDL+ quinacrine 5), (BDL+ quinacrine 10), and (quinacrine 10 + sham). Daily Intraperitoneal (I.P.) administration of quinacrine was initiated on the surgery day and continued for 28 days. Key findingsResults showed that rats that underwent BDL exhibited marked elevation of serum liver enzymes, ammonia, total bilirubin, together with oxidative stress, inflammation, dysregulated farnesoid x receptor (FXR), dysregulated BMP2 signaling and escalated fibrotic markers indicating hepatotoxicity, cholestasis and fibrosis. Besides, neurotoxicity was detected as manifested by cognitive deficits and dysregulation of hippocampal FXR, BMP2 signaling, WNT3A signaling, brain derived neurotrophic factor (BDNF), phospholipase A2 (PLA2) and glial fibrillary acidic protein (GFAP). In contrast, co-treatment with quinacrine mitigated BDL-induced hepatotoxicity, cholestasis, fibrosis, and neurotoxicity. Notably, quinacrine improved learning and memory and restored FXR, BMP2 signaling in the liver and hippocampus. In addition, quinacrine restored hippocampal WNT3A signaling, BDNF, whereas it downregulated expression of hippocampal PLA2 and GFAP. SignificanceThese findings demonstrated implication of BMP2 signaling in the molecular process of BDL-induced HE and proposed that quinacrine has potential hepatoprotective and neuroprotective properties against HE.

Antimalarial Drug Artemotil Promotes Induction of Type 1 Regulatory T Cells.

Artemisinin and its derivatives, used as front-line anti-malarial drugs, exhibit anti-inflammatory properties. They were found to suppress the generation and function of Th1 and Th17 cells while promoting the generation of Foxp3 + regulatory T cells (Tregs). However, the specific role of Artemotil (β-arteether) in modulating the generation and functions of CD4 + T cells, particularly Type 1 regulatory T cells (Tr1), remains to be explored. Tr1 cells are one of the key cell types that are essential for regulating inflammatory response through IL-10. In this study, we report that Artemotil selectively promotes generation of Tr1 cells induced by IL-27 by upregulating signature genes of Tr1 cells, such as c-Maf, AhR, prdm1, IRF-1, and Batf, while inhibiting the Th1, Th2, and Th17 cells generation. We found that co-administration of Artemotil with anti-CD3 antibody increases the induction of IL-10 and frequency of Tr1 cells while suppressing Th1 and Th17 cells in vivo. Artemotil suppresses T-cell-induced enteropathy and alleviates the signs of colitis associated with the increased frequencies of Tr1 cells. Taken together, our data suggest that Artemotil provides protection in T-cell-mediated colitis by increasing the expansion of Tr1 cells and inhibiting the generation of Th1 and Th17 cells.

Auto QSAR-based active learning docking for hit identification of potential inhibitors of Plasmodium falciparum Hsp90 as antimalarial agents.

Malaria which is mainly caused by Plasmodium falciparum parasite remains a devastating public health concern, necessitating the need to develop new antimalarial agents. P. falciparum heat shock protein 90 (Hsp90), is indispensable for parasite survival and a promising drug target. Inhibitors targeting the ATP-binding pocket of the N-terminal domain have anti-Plasmodium effects. We proposed a de novo active learning (AL) driven method in tandem with docking to predict inhibitors with unique scaffolds and preferential selectivity towards PfHsp90. Reference compounds, predicted to bind PfHsp90 at the ATP-binding pocket and possessing anti-Plasmodium activities, were used to generate 10,000 unique derivatives and to build the Auto-quantitative structures activity relationships (QSAR) models. Glide docking was performed to predict the docking scores of the derivatives and > 15,000 compounds obtained from the ChEMBL database. Re-iterative training and testing of the models was performed until the optimum Kennel-based Partial Least Square (KPLS) regression model with a regression coefficient R2 = 0.75 for the training set and squared correlation prediction Q2 = 0.62 for the test set reached convergence. Rescoring using induced fit docking and molecular dynamics simulations enabled us to prioritize 15 ATP/ADP-like design ideas for purchase. The compounds exerted moderate activity towards P. falciparum NF54 strain with IC50 values of ≤ 6μM and displayed moderate to weak affinity towards PfHsp90 (KD range: 13.5-19.9μM) comparable to the reported affinity of ADP. The most potent compound was FTN-T5 (PfN54 IC50:1.44μM; HepG2/CHO cells SI≥ 29) which bound to PfHsp90 with moderate affinity (KD:7.7μM), providing a starting point for optimization efforts. Our work demonstrates the great utility of AL for the rapid identification of novel molecules for drug discovery (i.e., hit identification). The potency of FTN-T5 will be critical for designing species-selective inhibitors towards developing more efficient agents against malaria.

Synthesis and In Vitro Antimalarial Activity of Amino Chalcone Derivative Compounds by Inhibition of Heme Polymerization

This study investigated the potential of chalcone derivatives as antimalarial agents. The structures of the chalcone derivatives were designed by including amino substituents on acetophenone and methoxy variants on benzaldehyde. As a result, three amino chalcone derivatives (1-3) were synthesized. The synthesis was conducted by performing the Claisen-Schmidt condensation reaction with 40% NaOH as the base catalyst, resulting in a yield ranging from 66% to 83%. In addition, the structures of the compounds were determined by FTIR, MS, and 1H-NMR spectroscopy techniques, confirming that the compounds possess structures that align with the desired molecular structure. The antimalarial activity test was conducted by inhibiting the process of heme polymerization into hemozoin (β-hematin) in a controlled laboratory setting. This process is one of the key targets of antimalarial medication therapy. Among the compounds, compound 2 exhibited superior antimalarial activity, with an IC50 value of 118.15 μg/mL, in comparison to the positive control hydroxychloroquine sulphate (IC50 value of 184.98 μg/mL). The inhibitory action of heme polymerization in the synthesis of hemozoin was influenced by the location and quantity of methoxy groups in the chalcone molecule, as observed in this work.

Rapid and supersensitive allele detection of Plasmodium falciparum chloroquine resistance via a Pyrococcus furiosus argonaute-triggered dual-signal biosensing platform

BackgroundMalaria remains a serious public health problem worldwide, particularly in Africa. Resistance to antimalarial drugs is an essential issue for malaria control and elimination. Currently, polymerase chain reaction (PCR) combined with Sanger sequencing is regarded as the gold standard for mutation detection. However, this method fails to meet the requirements of point-of-care testing (POCT) because of its time-consuming, expensive instruments and professional dependence. To support this strategy, we developed a novel diagnostic platform that combines recombinase polymerase amplification (RPA) with the Pyrococcus furiosus argonaute (PfAgo) protein and was designed to detect gene mutations related to antimalarial drug resistance. The Pfcrt haplotypes CVMNK and CVIET of chloroquine resistance (CQR) were used as examples and were assessed in this study.MethodsBy meticulously designing strategies, RPA primers, guide DNAs, and probes were screened, the reaction was optimized, and the resulting parameters were employed to ascertain the genotype of Pfcrt. The recombinant plasmids pUC57/Pfcrt-CVIET and pUC57/Pfcrt-CVMNK were constructed and diluted for sensitivity detection. The pUC57/Pfcrt-CVIET plasmid mixture was added to the pUC57/Pfcrt-CVMNK plasmid mixture in different additions to configure several specific proportions of mixed plasmid mixtures. The RPA-PfAgo platform was used, and the mixed plasmid was detected simultaneously via nest-PCR (nPCR) and Sanger sequencing. The platform was then evaluated on 85 clinical samples and compared with Sanger sequencing.ResultsThe entire process achieves the key mutation Pfcrt-CVMNK/CVIET genotype identification of CQR within 90 min. The platform achieved 1.8 × 104 copies/μL sensitivity and could detect as little as 3% CVIET in mixed plasmids, which is a higher sensitivity than that of Sanger sequencing (5%). Notably, the platform shows 100% concordance with the gold standard method when 85 clinical samples are tested. The sensitivity and specificity were 100% for the 85 clinical samples.ConclusionsThis study established an RPA-PfAgo platform for genotyping the key mutation Pfcrt-CVMNK/CVIET of CQR. This method can rapidly produce reliable results and avoid the disadvantages of nPCR with sequencing. This approach has the characteristics of a short operation time, low device dependence, and a good match to the POCT strategy, suggesting that the platform can be easily applied locally or on site.Graphical abstract

Co-encapsulation of antimalarial drug and SPIO in glucose-conjugated polymeric micelles against parasite-infected erythrocytes

Malaria, a life-threatening infectious disease transmitted through bites of Anopheles mosquitoes, remains a major global health challenge. The erythrocytic stage of malaria, where the parasite undergoes multiplication within red blood cells, is crucial for disease progression. Targeting this stage is essential for effective treatment and eradication of the parasite. However, the emergence of drug resistance highlights the need for innovative therapeutic approaches. Furthermore, accurate detection and tracking of parasites are imperative for confirming complete parasite eradication. Enhancing drug efficacy and specifically targeting molecular entities are key strategies to address this challenge. To combat the disease, a drug delivery system was developed to encapsulate the drug along with contrast agents. This system was conjugated with glucose to target both new permeable pathways (NPPs) and the Plasmodium falciparum hexose transporter (PfHT). In this study, glucose-conjugated polymeric micelles containing superparamagnetic ironoxide (SPIO) nanoparticles and quinine were synthesized and characterized. These micelles demonstrated hemocompatibility and exhibited superior drug release profiles under acidic conditions mimicking the parasite's environment. In vitro studies on infected red blood cells (RBCs) revealed targeted micelles enhanced antimalarial activity compared to non-targeted micelles and free drug. Additionally, targeted micelles exhibited the highest fluorescence signal intensity and MRI contrast enhancement. Based on these results, glucose/quinine/SPIO micelles hold significant promise for tracking and treatment functions in malaria, offering precise detection and targeted drug delivery to eradicate the parasite effectively.

Genotyping and Characterizing Plasmodium falciparum to Reveal Genetic Diversity and Multiplicity of Infection by Merozoite Surface Proteins 1 and 2 (msp-1 and msp-2) and Glutamate-Rich Protein (glurp) Genes.

Resistance to current antimalarial drugs is steadily increasing, and new drugs are required. Drug efficacy trials remain the gold standard to assess the effectiveness of a given drug. The World Health Organization (WHO)'s recommendation for the optimal duration of follow-up for assessing antimalarial efficacy is a minimum of 28 days. However, assessing antimalarial drug efficacy in highly endemic regions can be challenging due to the potential risks of acquiring a new infection in the follow-up period, and thus, it may underestimate the efficacy of the given drugs. A new treatment should be introduced if treatment failure rates exceed 10%. Overestimation occurs as a result of retaining a drug with a clinical efficacy of less than 90% with increases in morbidity and mortality, while underestimation may occur due to a misclassification of new infections as treatment failures with tremendous clinical and economic implications. Therefore, molecular genotyping is necessary to distinguish true new infections from treatment failures to ensure accuracy in determining antimalarial efficacy. There are three genetic markers that are commonly used in antimalarial efficiency trials to discriminate between treatment failures and new infections. These include merozoite surface protein 1 (msp-1), merozoite surface protein 2 (msp-2), and glutamate-rich protein (glurp). The genotyping of P. falciparum by nested polymerase chain reaction (n-PCR) targeting these markers is discussed with the inherent limitations and uncertainties associated with the PCR technique and limitations enforced by the parasite's biology itself.

Production of the antimalarial drug precursor amorphadiene by microbial terpene synthase-like from the moss Sanionia uncinata

Main conclusionThe microbial terpene synthase-like of the moss Sanionia uncinata displays the convergent evolution of a rare plant metabolite amorpha-4,11-diene synthesis.Despite increasing demand for the exploration of biological resources, the diversity of natural compounds synthesized by organisms inhabiting various climates remains largely unexplored. This study focuses on the moss Sanionia uncinata, known as a predominant species within the polar climates of the Antarctic Peninsula, to systematically explore its metabolic profile both in-field and in controlled environments. We here report a diverse array of moss-derived terpene volatiles, including the identification of amorpha-4,11-diene, a rare sesquiterpene compound that is a precursor for antimalarial drugs. Phylogenetic reconstruction and functional validation in planta and in vitro identified a moss terpene synthase, S. uncinata microbial terpene synthase-like 2 (SuMTPSL2), which is associated with amorpha-4,11-diene production. We demonstrate that expressing SuMTPSL2 in various heterologous systems is sufficient to produce amorpha-4,11-diene. These results highlight the metabolic diversity in Antarctica, but also provide insights into the convergent evolution leading to the synthesis of a rare plant metabolite.

Accelerating Antimalarial Drug Discovery with a New High-Throughput Screen for Fast-Killing Compounds.

The urgent need for rapidly acting compounds in the development of antimalarial drugs underscores the significance of such compounds in overcoming resistance issues and improving patient adherence to antimalarial treatments. The present study introduces a high-throughput screening (HTS) approach using 1536-well plates, employing Plasmodium falciparum lactate dehydrogenase (PfLDH) combined with nitroreductase (NTR) and fluorescent probes to evaluate inhibition of the growth of the asexual blood stage of malaria parasites. This method was adapted to efficiently assess the speed of action profiling (SAP) in a 384-well plate format, streamlining the traditionally time-consuming screening process. By successfully screening numerous compounds, this approach identified fast-killing hits early in the screening process, addressing challenges associated with artemisinin-based combination therapies. The high-throughput SAP method is expected to be of value in continuously monitoring fast-killing properties during structure-activity relationship studies, expediting the identification and development of novel, rapidly acting antimalarial drugs within phenotypic drug discovery campaigns.

Severe Malaria in Angola: The Clinical Profile and Disease Outcome Among Adults from a Low-Endemic Area.

Severe malaria poses a significant public health concern in Angola, particularly among adults. This study assessed the clinical manifestations and outcomes of severe Plasmodium falciparum malaria in adult patients admitted to Hospital Central Dr. António Agostinho Neto of Lubango (HCL), Angola. The study retrospectively reviewed medical records of patients over 14 years old admitted with severe malaria during the first quarter of 2021 and 2022, coinciding with the peak transmission season. The World Health Organization (WHO) criteria were used to clarify the disease severity. The cohort included 640 patients-167 in 2021 and 473 in 2022-distributed across the following departments: the Intensive Care Unit (ICU; n = 81), Medicine (MED; n = 458) and Infectiology (INF; n = 101). The median age was 26 years and 59.4% were males. Renal impairment was the most frequent severe manifestation, affecting 37.4% of cases. The mortality rate across the study period was 7%, showing a notable decrease from 10.2% in 2021 to 5.9% in 2022. The higher mortality rate in 2021 may reflect the impact of the COVID-19 pandemic, which limited hospital access and delayed care, resulting in more critical cases being admitted at a later stage. In 2022, with reduced COVID-19 pressures, earlier access to treatment may have improved outcomes, contributing to the lower mortality rate. This study emphasizes the need to assess the clinical burden of severe malaria in low-endemic regions, where shifting patterns may signal emerging threats such as antimalarial drug resistance. Further research is essential to optimize control strategies and strengthen surveillance systems, reducing morbidity and mortality.

Highly multiplexed design of an allosteric transcription factor to sense new ligands

Allosteric transcription factors (aTF) regulate gene expression through conformational changes induced by small molecule binding. Although widely used as biosensors, aTFs have proven challenging to design for detecting new molecules because mutation of ligand-binding residues often disrupts allostery. Here, we develop Sensor-seq, a high-throughput platform to design and identify aTF biosensors that bind to non-native ligands. We screen a library of 17,737 variants of the aTF TtgR, a regulator of a multidrug exporter, against six non-native ligands of diverse chemical structures – four derivatives of the cancer therapeutic tamoxifen, the antimalarial drug quinine, and the opiate analog naltrexone – as well as two native flavonoid ligands, naringenin and phloretin. Sensor-seq identifies biosensors for each of these ligands with high dynamic range and diverse specificity profiles. The structure of a naltrexone-bound design shows shape-complementary methionine-aromatic interactions driving ligand specificity. To demonstrate practical utility, we develop cell-free detection systems for naltrexone and quinine. Sensor-seq enables rapid and scalable design of new biosensors, overcoming constraints of natural biosensors.