Artemisinin inhibits neuronal ferroptosis in Alzheimer's disease models by targeting KEAP1.

Ferroptosis, a form of cell death characterized by lipid peroxidation, is involved in neurodegenerative diseases such as Alzheimer´s disease (AD). Recent studies have shown that a first-line antimalarial drug artemisinin is effective to counteract AD pathology. In this study, we investigated the protective effect of artemisinin against neuronal ferroptosis and the underlying mechanisms. In hippocampal HT22 cells, pretreatment with artemisinin dose-dependently protected against Erastin-induced cell death with an EC50 value of 5.032 µM, comparable to the ferroptosis inhibitor ferrostatin-1 (EC50 = 4.39 µM). We demonstrated that artemisinin (10 µM) significantly increased the nuclear translocation of Nrf2 and upregulated SLC7A11 and GPX4 in HT22 cells. Knockdown of Nrf2, SLC7A11 or GPX4 prevented the protective action of artemisinin, indicating that its anti-ferroptosis effect is mediated by the Nrf2-SLC7A11-GPX4 pathway. Molecular docking and Co-Immunoprecipitation (Co-IP) analysis revealed that artemisinin competitively binds with KEAP1, promoting the dissociation of KEAP1-Nrf2 complex and inhibiting the ubiquitination of Nrf2. Intrahippocampal injection of imidazole-ketone-Erastin (IKE) induced ferroptosis in mice accompanied by cognitive deficits evidenced by lower preference for exploration of new objects and new object locations in the NOR and NOL tests. Artemisinin (5, 10 mg/kg, i.p.) dose-dependently inhibited IKE-induced ferroptosis in hippocampal CA1 region and ameliorated learning and memory impairments. Moreover, we demonstrated that artemisinin reversed Aß1-42-induced ferroptosis, lipid peroxidation and glutathione depletion in HT22 cells, primary hippocampal neurons, and 3×Tg mice via the KEAP1-Nrf2 pathway. Our results demonstrate that artemisinin is a novel neuronal ferroptosis inhibitor that targets KEAP1 to activate the Nrf2-SLC7A11-GPX4 pathway.

Artemisinin pre-treatment fore cisplatin dosage enhances high grade urothelial carcinoma treatment in male albino mice via reverse gene expression modulation of FGFR3, HRAS, P53 and KDM6A.

BACKGROUND: Urinary bladder cancer, is the 10th most common global cancer, diagnosed in over 600,000 people causing 200,000 deaths annually. Artemisinin and its derivatives are safe compounds that have recently been proven to possess potent anti-tumor effects in vivo, through inhibition of cancer cell growth. The aim of this study is to assess the efficiency of artemisinin as a cancer treatment alone and as a pre-treatment fore cisplatin therapy for high grade urothelial carcinoma. METHODS: Sixty male albino mice were divided into six groups, and BBN was used to induce urinary bladder cancer. Blood samples were tested for renal functions and complete blood counts, kidney and urinary bladder tissues were harvested for histopathological examination. Total RNAs from urinary bladder tissues was collected, and gene expression of FGFR3, HRAS, P53, and KDM6A was quantified using qRT-PCR. RESULTS: Compared to the induced cancer group, the results revealed that FGFR3 expression levels were down-regulated in the induced cancer group treated by artemisinin only and the induced cancer group pre-treated with artemisinin prior to cisplatin by ~ 0.86-fold and 0.4-folds, respectively, aligning with HRAS down-regulation by ~ 9.54-fold and 9.05-fold, respectively. Whereas, P53 expression levels were up-regulated by ~ 0.68-fold and 0.84-fold, respectively, in parallel with KDM6A expression, which is up-regulated by ~ 0.95-folds and 5.27-folds, respectively. Also, serum creatinine and urea levels decreased significantly in the induced cancer group treated by artemisinin alone and the induced cancer group pre-treated with artemisinin prior to cisplatin, whereas the induced cancer group treated by cisplatin their levels increased significantly. Moreover, Hb, PLT, RBC, and WBC counts improved in both cancer groups treated by artemisinin alone and pre-treated with artemisinin prior to cisplatin. Histologically, in kidney tissues, artemisinin pre-treatment significantly reduced renal injury caused by cisplatin. While Artemisinin treatment for cancer in bladder tissues reverted invasive urothelial carcinoma to moderate urothelial dysplasia. CONCLUSIONS: This study indicates that artemisinin demonstrated a significant effect in reversal of the multi-step carcinogenesis process of high grade urothelial carcinoma and could enhance the effect of cisplatin therapy using artemisinin pre-treatment.

Artemisitene shows superiority over artemisinin in preventing Schistosoma japonica-induced liver disease.

BACKGROUND: Artemisinin (ART) analogs, such as dihydroartemisinin, arteether, artemether, and artesunate, all featuring an endoperoxide bridge, have demonstrated efficacy against schistosomiasis. Artemisitene (ATT), which contains an additional α, ß-unsaturated carbonyl structure, has shown enhanced biological activities. This study aims to evaluate the anti-schistosomaiasis japonica activity of ATT and compare it with ART. METHODS: We assessed liver inflammation and fibrosis in mice using hematoxylin and eosin staining and Sirius red staining, respectively. RNA sequencing analyzed transcriptomics in female and male Schistosoma japonicum (S. japonicum) adult worms and mice livers, with cytokine profiling and flow cytometry to study immune responses under ART or ATT treatment. RESULTS: ATT exhibits a marked reduction in female S. japonicum adult worms and egg numbers, damaging the adult worms' surface. It also influences the transcription of genes related to cellular anatomical structures. Notably, ATT treatment resulted in significant reductions in liver granuloma size and collagen area, alongside lowering serum levels of glutamic pyruvic and glutamic oxaloacetic transaminase more effectively than ART. Both ART and ATT markedly decreased neutrophil frequency in the liver and elevated eosinophil counts. However, only ATT treatment significantly reduced the M1/M2 and Th1/Th2 indices, indicating a pronounced shift in immune response profiles. ATT-affected host immunity correlated with the extent of liver fibrosis and the count of single males more strongly than ART. CONCLUSION: ATT, as a novel preventive strategy for schistosomiasis japonica in mice, significantly outperforms ART.

A transcription factor of SHI family AaSHI1 activates artemisinin biosynthesis genes in Artemisia annua.

BACKGROUND: Transcription factors (TFs) of plant-specific SHORT INTERNODES (SHI) family play a significant role in regulating development and metabolism in plants. In Artemisia annua, various TFs from different families have been discovered to regulate the accumulation of artemisinin. However, specific members of the SHI family in A. annua (AaSHIs) have not been identified to regulate the biosynthesis of artemisinin. RESULTS: We found five AaSHI genes (AaSHI1 to AaSHI5) in the A. annua genome. The expression levels of AaSHI1, AaSHI2, AaSHI3 and AaSHI4 genes were higher in trichomes and young leaves, also induced by light and decreased when the plants were subjected to dark treatment. The expression pattern of these four AaSHI genes was consistent with the expression pattern of four structural genes of artemisinin biosynthesis and their specific regulatory factors. Dual-luciferase reporter assays, yeast one-hybrid assays, and transient transformation in A. annua provided the evidence that AaSHI1 could directly bind to the promoters of structural genes AaADS and AaCYP71AV1, and positively regulate their expressions. This study has presented candidate genes, with AaSHI1 in particular, that can be considered for the metabolic engineering of artemisinin biosynthesis in A. annua. CONCLUSIONS: Overall, a genome-wide analysis of the AaSHI TF family of A. annua was conducted. Five AaSHIs were identified in A. annua genome. Among the identified AaSHIs, AaSHI1 was found to be localized to the nucleus and activate the expression of structural genes of artemisinin biosynthesis including AaADS and AaCYP71AV1. These results indicated that AaSHI1 had positive roles in modulating artemisinin biosynthesis, providing candidate genes for obtaining high-quality new A. annua germplasms.

New guidelines reduce the risk of hospitalization for adult patients with uncomplicated Plasmodium falciparum malaria: An observational, multicenter, retrospective French study.

OBJECTIVES: We aimed to evaluate the impact of malaria declaration year (before or after 2017) on the frequency of hospitalization in metropolitan France of patients with uncomplicated non-vomiting P.falciparum malaria. PATIENTS AND METHODS: An observational, multicenter, retrospective study was carried out, using the database from the French National Reference Centre for Malaria. Descriptive analysis and multivariate analysis by logistic regression were performed using the multiple imputation by chained equation method to handle missing data. RESULTS: More than 2000 (2184) uncomplicated non-vomiting P.falciparum malaria cases were recorded. Our multivariate analysis showed an association between the year 2018 and reduced risk of hospitalization (OR: 0.89; 95% CI: 0.81-0.97). CONCLUSION: Compared to 2016, during 2018 we observed a trend toward ambulatory care for patients presenting with uncomplicated non-vomiting P.falciparum malaria.

A retrospective analysis of P. falciparum drug resistance markers detects an early (2016/17) high prevalence of the k13 C469Y mutation in asymptomatic infections in Northern Uganda.

The emergence of drug-resistant Plasmodium falciparum parasites in sub-Saharan Africa will substantially challenge malaria control. Here, we evaluated the frequency of common drug resistance markers among adolescents from Northern Uganda with asymptomatic infections. We used an established amplicon deep sequencing strategy to screen dried blood spot samples collected from 2016 to 2017 during a reported malaria epidemic within the districts of Kitgum and Pader in Northern Uganda. We screened single-nucleotide polymorphisms within: kelch13 (Pfk13), dihydropteroate synthase (Pfdhps), multidrug resistance-1 (Pfmdr1), dihydrofolate reductase (Pfdhfr), and apical membrane antigen (Pfama1) genes. Within the study population, the median age was 15 years (14.3-15.0, 95% CI), and 54.9% (78/142) were Plasmodium positive by 18S rRNA qPCR, which were subsequently targeted for sequencing analysis. We observed a high frequency of resistance markers particularly for sulfadoxine-pyrimethamine (SP), with no wild-type-only parasites observed for Pfdhfr (N51I, C59R, and S108N) and Pfdhps (A437G and K540E) mutations. Within Pfmdr1, mixed infections were common for NF/NY (98.5%). While for artemisinin resistance, in kelch13, there was a high frequency of C469Y (34%). Using the pattern for Pfama1, we found a high level of polygenomic infections with all individuals presenting with complexity of infection greater than 2 with a median of 6.9. The high frequency of the quintuple SP drug-resistant parasites and the C469Y artemisinin resistance-associated mutation in asymptomatic individuals suggests an earlier high prevalence than previously reported from symptomatic malaria surveillance studies (in 2016/2017). Our data demonstrate the urgency for routine genomic surveillance programs throughout Africa and the value of deep sequencing.

Exploring sesquiterpene lactone as a dual therapeutic agent for diabetes and oxidative stress: insights into PI3K/AKT modulation.

Diabetic mellitus (DM) is characterized by hyperglycaemia and defective macromolecular metabolism, arising from insulin resistance or lack of insulin production. The present study investigates the potential of artemisinin, a sesquiterpene lactone isolated from Artemisia annua, to exert anti-diabetic and antioxidant effects through modulation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signalling pathway. Our computational analyses demonstrated a high binding affinity of artemisinin with proteins belonging to the PI3K/AKT signalling cascade. α-Amylase and α-glucosidase studies revealed a notable increase in inhibition percentages with artemisinin treatment across concentrations ranging from 10 to 160 µM. A similar significant (p < 0.05) dose-dependent inhibition of free radicals was observed for the in vitro anti-oxidant assays. Further, toxicological profiling of artemisinin in the in vivo zebrafish embryo-larvae model from 4 to 96 h post-fertilization (hpf) did not exhibit any harmful repercussions. In addition, gene expression investigations confirmed artemisinin's potential mechanism in modulating hyperglycaemia and oxidative stress through the regulation of the PI3K/AKT pathway. Overall, our investigation suggests that artemisinin can be used as a therapeutic intervention for diabetes and oxidative stress, opening up opportunities for future investigation in clinical settings. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-024-04050-2.

Analysis of US Marketed Artemisinin Supplements for Use in Dogs.

Oral artemisinin has antiparasitic activity and may help improve treatment success rates in dogs infected with Babesia gibsoni. However, these artemisinin products are unapproved and unregulated botanical supplements. They have not been evaluated for safety and efficacy or for strength, purity, or quality compared with a reference standard. Before considering these products for a clinical study, we evaluated the strength of four suppliers of artemisinin capsules using an high-performance liquid chromatography method validated in our laboratory. We found that the four artemisinin-labeled products that were tested had high within product and between product variability in capsule strength compared with the stated capsule strength on the product label. No products met the acceptance criteria of the United States Pharmacopeia and International Council for Harmonisation (ICH) as well as the criteria adapted by the authors. One product had no detectable artemisinin, and the other three products were much higher than the stated label strength. The results of this study reinforce the importance of testing unapproved and unregulated supplements before recommending a supplement for clinical use in dogs.

Enhancement of Anticancer Potential of Artemisinin Derivatives through N-glycosylation.

Cancer cells have significantly higher intracellular free-metal ions levels than normal cells, and it is well known that artemisinin (ART) molecules or its derivatives sensitize cancer cells when its endoperoxide moiety combines with metal ions, resulting in the production of reactive oxygen species, lysosomal degradation of ferritin, or regulation of system Gpx4 leading to apoptosis, ferroptosis or cuproptosis. Artemisinin derivatives (ADs) are reported to interfere more efficiently with metal-regulatory-proteins (MRPs) controlling iron/copper homeostasis by interacting with cytoplasmic unbound metal ions and thereby promoting the association of MRP to mRNA molecules carrying the respective sequences. However, the simple artemisinin analogues are required to be administered in higher doses with repeated administration due to low solubility and smaller plasma half-lives. To overcome these problems, amino ARTs were introduced which are found to be more stable, and later on, a series of ARTs derivatives containing sugar moiety was developed in search of analogues having good water solubility and high pharmacological activity. This review focuses on the preparation of N-glycosylated amino-ART analogues with their application against cancer. The intrinsic capability of glycosylated ART compounds is to give sugar-- containing substrates, which can bind with lectin galectin-8 receptors on the cancer cells making these compounds more specific in targeting cancer. Various AD mechanism of action against cancer is also explored with clinical trials to facilitate the synthesis of newer derivatives. In the future, the latest nano-techniques can be used to create formulations of such compounds to make them more target-specific in cancer.

Polyvinylidene Fluoride-Based Nanowire-Imprinted Membranes with High Flux for Efficient and Selective Separation of Artemisinin/Artemether.

A traditional phase transformation method is commonly used to prepare molecular imprinting membranes for selective separation. However, traditional molecularly imprinted polymers are mostly micron-sized particles, and the imprinting sites in their membrane are easily embedded, leading to a reduced adsorption capacity and decreased selectivity. In this study, an ultra-long nanowire with a diameter of about 15 nm was synthesized for the separation of artemisinin (ART), and its adsorption capacity was as high as 198.29 mg g-1 after imprinting polymerization. Molecular imprinting membranes were prepared, using polyvinylidene fluoride (PVDF), polyethersulfone (PES), and polysulfone (PSF) as the membrane matrix, for comparison. The average membrane pore size of PVDF-MIM was about 480 nm, and PVDF-MIM had the highest adsorption capacity (69 mg g-1) for ART. The optimal flow rate for PVDF-MIM's dynamic adsorption of ART was 7 mL min-1. Under this optimal flow rate, selectivity experiments were carried out to obtain the separation factor of PVDF-MIM (α = 8.37), which was much higher than the corresponding values of PES-MIM and PSF-MIM. In addition, the hydrophobicity and low flux of PES-MIM and PSF-MIM lead to higher non-specific adsorption. The hydrophobicity of PVDF-MIM is lower than that of PES-MIM and PSF-MIM, which greatly reduces the non-specific adsorption of the membrane, thus increasing the selectivity of the membranes. Therefore, the effective density of the imprinting sites in the pores and the membrane structure are the main factors determining the efficient separation of molecularly imprinted membranes.

Artemisinin and Its Derivatives as Potential Anticancer Agents.

Artemisinin is a natural sesquiterpene lactone obtained from the traditional Chinese medicinal herb Artemisia annua L. (qinghao). Artemisinin and its derivatives share an unusual endoperoxide bridge and are extensively used for malaria treatment worldwide. In addition to antimalarial activities, artemisinin and its derivatives have been reported to exhibit promising anticancer effects in recent decades. In this review, we focused on the research progress of artemisinin and its derivatives with potential anticancer activities. The pharmacological effects, potential mechanisms, and clinical trials in cancer therapy of artemisinin and its derivatives were discussed. This review may facilitate the future exploration of artemisinin and its derivatives as effective anticancer agents.

In vitro assessment of the anti-adenoviral activity of artemisinin and its derivatives.

Adenoviral infections, particularly in children, remain a significant public health issue with no approved targeted treatments. Artemisinin and its derivatives, well-known for their use in malaria treatment, have shown antiviral activities in recent studies. However, their efficacy against human adenovirus (HAdV) remains unexplored. This study aimed to assess the activity of artemisinin and its derivatives against HAdV infection in vitro using cell lines and primary cells. Our data revealed that artemisinin exhibited dose-dependent anti-HAdV activity with no apparent cytotoxicity over a wide concentration range. Mechanistically, artemisinin did not affect viral attachment or entry into target cells, nor the viral genome entry into cell nucleus. Instead, it inhibited HAdV through suppression of viral DNA replication. Comparative analysis with its derivatives, artesunate and artemisone, showed distinct cytotoxicity and anti-adenoviral profiles, with artemisone showing superior efficacy and lower toxicity. Further validation using a primary airway epithelial cell model confirmed the anti-adenoviral activity of both artemisinin and artemisone against different virus strains. Together, our findings suggest that artemisinin and its derivatives may be promising candidates for anti-HAdV treatment.

AaMYC3 bridges the regulation of glandular trichome density and artemisinin biosynthesis in Artemisia annua.

Artemisinin, the well-known natural product for treating malaria, is biosynthesised and stored in the glandular-secreting trichomes (GSTs) of Artemisia annua. While numerous efforts have clarified artemisinin metabolism and regulation, the molecular association between artemisinin biosynthesis and GST development remains elusive. Here, we identified AaMYC3, a bHLH transcription factor of A. annua, induced by jasmonic acid (JA), which simultaneously regulates GST density and artemisinin biosynthesis. Overexpressing AaMYC3 led to a substantial increase in GST density and artemisinin accumulation. Conversely, in the RNAi-AaMYC3 lines, both GST density and artemisinin content were markedly reduced. Through RNA-seq and analyses conducted both in vivo and in vitro, AaMYC3 not only directly activates AaHD1 transcription, initiating GST development, but also up-regulates the expression of artemisinin biosynthetic genes, including CYP71AV1 and ALDH1, thereby promoting artemisinin production. Furthermore, AaMYC3 acts as a co-activator, interacting with AabHLH1 and AabHLH113, to trigger the transcription of two crucial enzymes in the artemisinin biosynthesis pathway, ADS and DBR2, ultimately boosting yield. Our findings highlight a critical connection between GST initiation and artemisinin biosynthesis in A. annua, providing a new target for molecular design breeding of traditional Chinese medicine.

Receipt of antimalarials among children aged 6-59 months in Nigeria from 2010 to 2021.

BACKGROUND: Nigeria has the highest malaria burden globally, and anti-malarials have been commonly used to treat malaria without parasitological confirmation. In 2012, Nigeria implemented rapid diagnostic tests (RDTs) to reduce the use of anti-malarials for those without malaria and to increase the use of artemisinin-based combination therapy (ACT) for malaria treatment. This study examined changes in anti-malarial receipt among children aged 6-59 months during a 12-year period of increasing RDT availability. METHODS: A cross-sectional analysis was conducted using the Nigeria Malaria Indicator Survey (NMIS) data from 2010 (before RDT implementation in 2012), 2015, and 2021. The analysis assessed trends in prevalence of malaria by survey RDT result, and fever and anti-malarial/ACT receipt in the 2 weeks prior to the survey. A multivariable logistic regression was used to account for the complex survey design and to examine factors associated with anti-malarial receipt, stratified by survey RDT result, a proxy for recent/current malaria infection. RESULTS: In a nationally-representative, weighted sample of 22,802 children aged 6-59 months, fever prevalence remained stable over time, while confirmed malaria prevalence decreased from 51.2% in 2010 to 44.3% in 2015 and 38.5% in 2021 (trend test p < 0.0001). Anti-malarial use among these children decreased from 19% in 2010 to 10% in 2021 (trend test p < 0.0001), accompanied by an increase in ACT use (2% in 2010 to 8% in 2021; trend test p < 0.0001). Overall, among children who had experienced fever, 30.6% of survey RDT-positive and 36.1% of survey RDT-negative children had received anti-malarials. The proportion of anti-malarials obtained from the private sector increased from 61.8% in 2010 to 80.1% in 2021 for RDT-positive children; most of the anti-malarials received in 2021 were artemisinin-based combinations. Factors associated with anti-malarial receipt for both RDT-positive and RDT-negative children included geographic region, greater household wealth, higher maternal education, and older children. CONCLUSION: From 2010 to 2021 in Nigeria, both malaria prevalence and anti-malarial treatments among children aged 6-59 months decreased, as RDT availability increased. Among children who had fever in the prior 2 weeks, anti-malarial receipt was similar between children with either positive or negative survey RDT results, indicative of persistent challenges in reducing inappropriate anti-malarials uptake.

Artemisinin ameliorates thyroid function and complications in adult male hypothyroid rats via upregulation of the L1 cell adhesion molecule.

BACKGROUND: Hypothyroidism, a common worldwide syndrome caused by insufficient thyroid hormone secretion, affects number of people at different ages. Artemisinin (ART), a well-known effective agent in the treatment of malaria, also has anti-oxidative stress functions in various diseases. The L1 cell adhesion molecule exerts multiple protective roles in diseased systems. The aim of the present study was to evaluate the role of ART in adult male hypothyroid rats and the underlying mechanisms. METHODS: The propylthiouracil (PTU) rat model was treated with or without 5 mg/kg ART and with or without L1 short-interfering RNA (siRNA), followed by the experiments to determine the effect of ART on thyroid function, depression and anxiety, cognition impairments, liver, kidney and heart functions, and oxidative stress. RESULTS: In the current study, it was shown that ART can ameliorate thyroid function, mitigate depression and anxiety symptoms, attenuate cognition impairments, improve liver, kidney and heart functions, and inhibit oxidative stress; however, the effects exerted by ART could not be observed when L1 was silenced by L1 siRNA. CONCLUSION: These results indicated that ART can upregulate the L1 cell adhesion molecule to ameliorate thyroid function and the complications in adult male hypothyroid rats, laying the foundation for ART to be a novel strategy for the treatment of hypothyroidism.

From Traditional Use to Modern Evidence: The Medicinal Chemistry of Antimalarials from Genus Artemisia.

While the use of plants in traditional medicine dates back to 1500 B.C., modern advancements led to the development of innovative therapeutic techniques. On the other hand, in the field of anti-infective agents, lack of efficacy and the onset of resistance stimulate the search for novel agents. Genus Artemisia is one of the most diverse among perennial plants with a variety of species, properties, and chemical components. The genus is known for its therapeutic values and, in particular, for its role in the origin of antimalarial agents derived from artemisinin. In this review, we aim to provide an updated overview of the evolution of natural and natureinspired compounds related to the genus Artemisia that have been proven, in vitro and in vivo, to possess antimalarial properties. An overview of the chemical composition and a description of the ethnopharmacological aspects will be presented, as well as an updated report on in vitro and in vivo evidence that allowed the translation of artemisinin and its derivatives from traditional chemistry into modern medicinal chemistry. The biological and structural properties will be discussed, also dedicating attention to the challenging tasks that still are open, such as the identification of optimal combination strategies, the routes of administration, and the full assessment of the mechanism of action.

Loss of glycerol catabolism confers carbon-source-dependent artemisinin resistance in Mycobacterium tuberculosis.

In view of the urgent need for new antibiotics to treat human infections caused by multidrug-resistant pathogens, drug repurposing is gaining strength due to the relatively low research costs and shorter clinical trials. Such is the case of artemisinin, an antimalarial drug that has recently been shown to display activity against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. To gain insight into how Mtb is affected by artemisinin, we used RNAseq to assess the impact of artemisinin on gene expression profiles, revealing the induction of several efflux pumps and the KstR2 regulon. To anticipate the artemisinin resistance-conferring mutations that could arise in clinical Mtb strains, we performed an in vitro evolution experiment in the presence of lethal concentrations of artemisinin. We obtained artemisinin-resistant isolates displaying different growth kinetics and drug phenotypes, suggesting that resistance evolved through different pathways. Whole-genome sequencing of nine isolates revealed alterations in the glpK and glpQ1 genes, both involved in glycerol metabolism, in seven and one strains, respectively. We then constructed a glpK mutant and found that loss of glpK increases artemisinin resistance only when glycerol is present as a major carbon source. Our results suggest that mutations in glycerol catabolism genes could be selected during the evolution of resistance to artemisinin when glycerol is available as a carbon source. These results add to recent findings of mutations and phase variants that reduce drug efficacy in carbon-source-dependent ways.

A countrywide survey of hrp2/3 deletions and kelch13 mutation co-occurrence in Ethiopia.

Malaria elimination relies on detection of Plasmodium falciparum Histidine-Rich Proteins 2/3 (HRP2/3) through rapid diagnostic tests (RDTs) and treatment with artemisinin-combination therapies (ACTs). Data from the Horn of Africa suggest increasing hrp2/3 gene deletions and ACT partial resistance kelch13 (k13) mutations. To assess this, 233 samples collected during a national survey from 7 regions of Ethiopia were studied for hrp2/3 deletions by droplet digital dPCR and k13 mutations by DNA sequencing. Approximately 22% of the study population harbored complete hrp2/3 deletions by ddPCR. Thirty-two of 42 of k13 SNPs identified were R622I associated with ACT partial resistance. Both hrp2/3 deletions and k13 mutations associated with ACT partial resistance appear to be co-occurring especially in Northwest Ethiopia. Ongoing national surveillance relying on accurate laboratory methods are required to fully elaborate the genetic diversity of P. falciparum to inform public health policy makers.

Preparation and In-Vitro Characterization of Solid Lipid Nanoparticles Containing Artemisinin and Curcumin.

BACKGROUND: Malaria remains a formidable public health obstacle across Africa, Southeast Asia, and portions of South America, exacerbated by resistance to antimalarial medications, such as artemisinin-based combinations. The combination of curcumin and artemisinin shows promise due to its potential for dose reduction, reduced toxicity, synergistic effects, and suitability for drug delivery improvement. OBJECTIVE: This research aims to enhance the solubility and dissolution rates of curcumin and artemisinin by employing Solid Lipid Nanoparticles (SLNs). Oral delivery of both drugs faces challenges due to their poor water solubility, inefficient absorption, and rapid metabolism and elimination. METHOD: The study focuses on formulating and optimizing Solid Lipid Nanoparticles (SLNs) encapsulating artemisinin (ART) and curcumin (CUR). SLNs were developed using the hot homogenization method, incorporating ultrasonication. Drug-excipient compatibility was evaluated using Differential Scanning Calorimetry (DSC). Lipid and surfactant screening was performed to select suitable components. A 3² full factorial design was utilized to investigate the influence of lipid and surfactant concentrations on key parameters, such as entrapment efficiency (%EE) and cumulative drug release (%CDR). Additionally, evaluations of % entrapment efficiency, drug loading, particle size, zeta potential, and in-vitro drug release were conducted. RESULTS: Successful development of artemisinin and curcumin SLNs was achieved using a full factorial design, demonstrating controlled drug release and high entrapment efficiency. The optimized nanoparticles exhibited a size of 114.7nm, uniformity (PDI: 0.261), and a zeta potential of -9.24 mV. Artemisinin and curcumin showed %EE values of 79.1% and 74.5%, respectively, with cumulative drug release of 85.1% and 80.9%, respectively. The full factorial design indicated that increased lipid concentration improved %EE, while higher surfactant concentration enhanced drug release and %EE. Stability studies of the optimized batch revealed no alterations in physical or chemical characteristics. CONCLUSION: The study successfully developed Solid Lipid Nanoparticles (SLNs) for artemisinin and curcumin, achieving controlled drug release, high entrapment efficiency, and desired particle size and uniformity. This advancement holds promise for enhancing drug delivery of herbal formulations.

Synthesis, molecular modelling studies of artemisinin-chalcone derivatives and their antimalarial activity evaluation.

Twenty-two monomers and dimers of artemisinin having chalcone as a linker were synthesised, and their antimalarial activity against Plasmodium falciparum was determined, and a quantitative structure-activity relationship (QSAR) was developed. Artemisinin is a frontline antimalarial drug known worldwide but is threatened because of the rapidly emerging artemisinin-resistant strain Plasmodium falciparum. In vitro, antimalarial IC50 (half-maximal inhibitory concentration) activity of a molecule against malaria parasites provides a good first screen for identifying the antimalarial potential of a particular molecule. The most active compound was artemisinin dimer dimethoxy chalcone as a linker (22) with IC50 of 4.34 nM. The molecular mechanism was explored through in silico docking & ADMET studies for the active compounds.