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1.
Nanoscale ; 13(31): 13231-13240, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34477731

RESUMO

Although artemisinin (ART) has shown initial promise in cancer therapy, its therapeutic efficacy is limited by its low tumor inhibitory efficacy and unfavorable distribution. Considering the important role of heme in the specific parasite-killing effect of ART, we designed a liposomal nanostructure self-assembled from hemin-lipid (Hemesome) to co-deliver ART and hemin for cancer therapy. The synergistic chemotherapeutic and immunotherapeutic effects of hemin and ART were demonstrated both in vitro and in vivo. The liposome-like structure was relatively stable in the blood circulation and gastrointestinal tract environment, but dissociated in the tumor cell environment. The folic acid (FA) modification not only increased their efficiency for transport across the epithelium, but also increased their tumor accumulation. In mouse models, following oral administration of FA-Hemesome-ART nanoparticles (5 mg kg-1 ART in total) every other day and intraperitoneal injection with a programmed death-ligand 1 antibody (aPD-L1, 70 µg per mouse in total), MC38 tumors were completely inhibited within 30 days. The cured mice remained tumor-free 30 days after rechallenging them with another inoculation of MC38 cells due to the strong immune memory effect.


Assuntos
Artemisininas , Nanopartículas , Neoplasias , Animais , Linhagem Celular Tumoral , Hemina , Imunoterapia , Lipídeos , Camundongos , Neoplasias/tratamento farmacológico
2.
Front Cell Infect Microbiol ; 11: 680127, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34527599

RESUMO

Since the first reported case caused by the novel coronavirus SARS-CoV-2 infection in Wuhan, COVID-19 has caused serious deaths and an ongoing global pandemic, and it is still raging in more than 200 countries and regions around the world and many new variants have appeared in the process of continuous transmission. In the early stage of the epidemic prevention and control and clinical treatment, traditional Chinese medicine played a huge role in China. Here, we screened out six monomer compounds, including artemether, artesunate, arteannuin B, echinatin, licochalcone B and andrographolide, with excellent anti-SARS-CoV-2 and anti-GX_P2V activity from Anti-COVID-19 Traditional Chinese Medicine Compound Library containing 389 monomer compounds extracted from traditional Chinese medicine prescriptions "three formulas and three drugs". Our discovery preliminary proved the stage of action of those compounds against SARS-CoV-2 and provided inspiration for further research and clinical applications.


Assuntos
COVID-19 , SARS-CoV-2 , Artemeter , Artemisininas , Artesunato , Chalconas , Diterpenos , Humanos
3.
ACS Chem Neurosci ; 12(17): 3148-3156, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34465091

RESUMO

Artemisinin (ART), a well-known antimalarial medicine originally isolated from the plant Artemisia annua, exerts neuroprotective effects in the nervous system owing to an antioxidant effect. Here, we determined whether ART is capable of inhibiting the oxidative stress to enhance motoneuronal (MN) survival to promote motor function recovery of rats following brachial plexus root avulsion (BPRA) with reimplantation surgery. Rats following BPRA and reimplantation were subcutaneously injected with 500 µL of PBS or 16 mg/mL ART once daily for 7 days after surgery. Terzis grooming test (TGT), histochemical staining, real-time polymerase chain reaction, and Western blot were conducted to determine the recovery of motor function of the upper limb, the survival rate of MNs, the oxidative stress levels in the ventral horn of the spinal cord, the morphology of abnormal musculocutaneous nerve fibers, the remyelination of axons in musculocutaneous nerves, and the degree of bicep atrophy. ART significantly increased TGT score, improved the survival of MNs, inhibited the oxidative stress, ameliorated the abnormal morphology of fibers in the musculocutaneous nerve, promoted the remyelination of axons, and alleviated muscle atrophy. Take together, ART can improve the survival of MNs and axonal remyelination to promote the motor function recovery via inhibiting oxidative stress, suggesting that ART may represent a new approach to the therapy of spinal root avulsion.


Assuntos
Artemisininas , Plexo Braquial , Remielinização , Animais , Axônios , Regeneração Nervosa , Ratos , Recuperação de Função Fisiológica
4.
Parasite ; 28: 67, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34569928

RESUMO

BACKGROUND: Artemisinin-based treatment in malaria patients with abnormal hemoglobin may be ineffective because of their genetic particularity, which could lead to resistance. The main purpose of this study was to assess the effect of artemisinin derivatives on in vivo parasite clearance according to erythrocyte variants. In vivo response was investigated through retrospective data obtained over a 42-day artemether-lumefantrine/artesunate amodiaquine efficacy protocol conducted from 2012 to 2016. RESULTS: A total of 770 patients in Côte d'Ivoire attending the hospitals of Anonkoua-koute (Abidjan), Petit Paris (Korhogo), Libreville (Man), Dar es salam (Bouaké), Ayamé and Yamoussoukro with acute uncomplicated falciparum malaria were selected for successful hemoglobin typing. HbAS, HbSS, HbAC, and HbSC genotypes were found. Parasite clearance time was obtained for 414 patients. In the population with abnormal hemoglobin, parasite densities on admission and parasite clearance rates were significantly lower in the HbSC group compared to HbAA (p = 0.02 and p = 0.007, respectively). After PCR correction on day 42, the acute treatment rate was 100% for each group. Parasite half-life and time for initial parasitaemia to decline by 50 and 99% were longer for the HbSC group (p < 0.05). The study also investigated the prevalence of K13-propeller polymorphisms across different hemoglobin genotype groups. A total of 185 and 63 samples were sequenced in the HbAA group and patients with abnormal Hb, respectively. Only two nonsynonymous mutations D559N and V510M were found in the HbAA group. CONCLUSION: Although this study proved good efficacy of artemether-lumefantrine and artesunate amodiaquine in the treatment of uncomplicated Plasmodium falciparum malaria in patients with abnormal hemoglobin, the increased delay of parasite clearance may represent a threat to health in these patients in relation with sickle cell crisis, which could support selection of parasites resistant to artemisinin.


Assuntos
Antimaláricos , Artemisininas , Hemoglobinas Anormais , Malária Falciparum , Antimaláricos/uso terapêutico , Artemeter/uso terapêutico , Combinação Arteméter e Lumefantrina , Artemisininas/uso terapêutico , Costa do Marfim/epidemiologia , Combinação de Medicamentos , Etanolaminas/uso terapêutico , Hemoglobinas Anormais/uso terapêutico , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Plasmodium falciparum/genética , Estudos Retrospectivos , Resultado do Tratamento
5.
Molecules ; 26(18)2021 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-34577011

RESUMO

Chemical and biological investigation of the Madagascar endemic plant Saldinia proboscidea led to the isolation of an isomer of artemisinin, (-)-6-epi-artemisinin (2). Its structure was elucidated using a combination of NMR and mass spectrometry. The absolute configuration was established by chemical syntheses of compound 2 as well as a new stereoisomer (3). The comparable bioactivities of artemisinin (1) and its isomer (-)-6-epi-artemisinin (2) revealed that this change in configuration was not critical to their biological properties. Bioactivity was assessed using an apoptosis induction assay, a SARS-CoV-2 inhibitor assay, and a haematin polymerization inhibitory activity (HPIA) assay. This is the first report of an artemisinin-related compound from a genus not belonging to Artemisia and it is the first isolation of an artemisinin-related natural product that is the opposite enantiomeric series relative to artemisinin from Artemisia annua.


Assuntos
Antimaláricos/química , Artemisininas/química , Extratos Vegetais/química , Rubiaceae/química , Madagáscar , Estereoisomerismo
6.
Zhongguo Zhong Yao Za Zhi ; 46(18): 4849-4864, 2021 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-34581097

RESUMO

As a unicellular organism, Plasmodium displays a panoply of lipid metabolism pathways that are seldom found together in a unicellular organism. These pathways mostly involve the Plasmodium-encoded enzymatic machinery and meet the requirements of membrane synthesis during the rapid cell growth and division throughout the life cycle. Different lipids have varied synthesis and meta-bolism pathways. For example, the major phospholipids are synthesized via CDP-diacylglycerol-dependent pathway in prokaryotes and de novo pathway in eukaryotes, and fatty acids are synthesized mainly via type Ⅱ fatty acid synthesis pathway. The available studies have demonstrated the impacts of artemisinin and its derivatives, the front-line compounds against malaria, on the lipid metabolism of Plasmodium. Therefore, this article reviewed the known lipid metabolism pathways and the effects of artemisinin and its derivatives on these pathways, aiming to deepen the understanding of lipid synthesis and metabolism in Plasmodium and provide a theoretical basis for the research on the mechanisms and drug resistance of artemisinin and other anti-malarial drugs.


Assuntos
Antimaláricos , Artemisininas , Malária , Plasmodium , Antimaláricos/farmacologia , Artemisininas/farmacologia , Artemisininas/uso terapêutico , Humanos , Metabolismo dos Lipídeos , Malária/tratamento farmacológico
7.
Nat Microbiol ; 6(9): 1163-1174, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34400833

RESUMO

Periodic fever is a characteristic clinical feature of human malaria, but how parasites survive febrile episodes is not known. Although the genomes of Plasmodium species encode a full set of chaperones, they lack the conserved eukaryotic transcription factor HSF1, which activates the expression of chaperones following heat shock. Here, we show that PfAP2-HS, a transcription factor in the ApiAP2 family, regulates the protective heat-shock response in Plasmodium falciparum. PfAP2-HS activates the transcription of hsp70-1 and hsp90 at elevated temperatures. The main binding site of PfAP2-HS in the entire genome coincides with a tandem G-box DNA motif in the hsp70-1 promoter. Engineered parasites lacking PfAP2-HS have reduced heat-shock survival and severe growth defects at 37 °C but not at 35 °C. Parasites lacking PfAP2-HS also have increased sensitivity to imbalances in protein homeostasis (proteostasis) produced by artemisinin, the frontline antimalarial drug, or the proteasome inhibitor epoxomicin. We propose that PfAP2-HS contributes to the maintenance of proteostasis under basal conditions and upregulates specific chaperone-encoding genes at febrile temperatures to protect the parasite against protein damage.


Assuntos
Febre/parasitologia , Malária Falciparum/parasitologia , Plasmodium falciparum/fisiologia , Proteínas de Protozoários/metabolismo , Fatores de Transcrição/metabolismo , Antimaláricos/farmacologia , Artemisininas/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Resposta ao Choque Térmico , Temperatura Alta , Humanos , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/genética , Plasmodium falciparum/crescimento & desenvolvimento , Proteostase/efeitos dos fármacos , Proteínas de Protozoários/genética , Fatores de Transcrição/genética
8.
Free Radic Biol Med ; 174: 157-170, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34403740

RESUMO

Tumor hypoxia is a major biological factor that drives resistance to chemotherapy and radiotherapy. We previously demonstrated that the pro-oxidative drug dihydroartemisinin (DHA) efficiently targeted normoxic and hypoxic cancer cells. Although well studied in normoxia, the mechanism behind DHA-mediated cytotoxicity in hypoxia is insufficiently explored. Here, we analyzed the effect of DHA in HCT116 wild type (wt) cells and in HCT116 Bax-/-Baksh cells with a defective intrinsic apoptosis pathway. Normoxic HCT116 wt cells underwent apoptosis shortly after treatment with DHA. Autophagy-associated cell death contributes to short-term cytotoxicity of DHA in normoxia. These cells switched to an apoptosis- and autophagy-independent cell death after treatment with DHA in hypoxia and displayed similar long-term survival in response to DHA in normoxia and hypoxia. In HCT116 Bax-/-Baksh cells, DHA induced cell cycle arrest shortly after treatment irrespective of oxygen levels. Later, HCT116 Bax-/-Baksh cells induced a delayed cell death after treatment with DHA in hypoxia followed by return to normoxia, while treatment with DHA in normoxia was hardly toxic. We identified lower glutathione levels in hypoxic HCT116 cells which correlated with higher lipid peroxidation after treatment with DHA. Moreover, insufficient expression of Bax/Bak counteracted hypoxia-mediated downregulation of mitochondrial function, thereby adding to DHA-induced ROS production and lipid peroxidation in hypoxia. In summary, DHA-mediated cytotoxicity in normoxia depended on Bax/Bak expression, while cytotoxicity after treatment with DHA in hypoxia was regulated independently of Bax/Bak in HCT116 colorectal cancer cells.


Assuntos
Apoptose , Neoplasias Colorretais , Artemisininas , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Células HCT116 , Humanos , Hipóxia , Proteína X Associada a bcl-2/genética
9.
Comput Biol Med ; 136: 104758, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34411900

RESUMO

Covid-19 is an emerging infectious disease caused by coronavirus SARS-CoV-2. Due to the rapid rise in deaths resulted from this infection all around the world, the identification of drugs against this new coronavirus is an important requirement. Among the drugs that can fight this type of infection; natural products are substances that serve as sources of beneficial chemical molecules for the development of effective therapies. In this study, Camphor, Artemisinin and 14 Sumac phytochemicals were docked in the active site of SARS-CoV-2 main protease (PDB code: 6LU7). We have also performed molecular dynamic simulation at 100 ns with MM-GBSA/PBSA analysis for the structures with the best affinity in the binding site of the studied enzyme (Hinokiflavone and Myricetin) after docking calculations to consider parameters like RMSD, covariance, PCA, radius of gyration, potential energy, temperature and pressure. The result indicates that Hinokiflavone and Myricetin are the structures with best affinity and stability in the binding site of the studied enzyme and they respect the conditions mentioned in Lipinski's rule and have acceptable ADMET proprieties; so, these compounds have important pharmacokinetic properties and bioavailability, and they could have more potent antiviral treatment of COVID-19 than the other studied compounds.


Assuntos
Artemisininas , COVID-19 , Rhus , Cânfora , Humanos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Compostos Fitoquímicos/farmacologia , Inibidores de Proteases , SARS-CoV-2
10.
BMJ Glob Health ; 6(6)2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34193475

RESUMO

INTRODUCTION: To reduce malaria transmission in very low-endemic settings, screening and treatment near index cases (reactive case detection (RACD)), is widely practised, but the rapid diagnostic tests (RDTs) used miss low-density infections. Reactive focal mass drug administration (rfMDA) may be safe and more effective. METHODS: We conducted a pragmatic cluster randomised controlled trial in Eswatini, a very low-endemic setting. 77 clusters were randomised to rfMDA using dihydroartemisin-piperaquine (DP) or RACD involving RDTs and artemether-lumefantrine. Interventions were delivered by the local programme. An intention-to-treat analysis was used to compare cluster-level cumulative confirmed malaria incidence among clusters with cases. Secondary outcomes included safety and adherence. RESULTS: From September 2015 to August 2017, 222 index cases from 47 clusters triggered 46 RACD events and 64 rfMDA events. RACD and rfMDA were delivered to 1455 and 1776 individuals, respectively. Index case coverage was 69.5% and 62.4% for RACD and rfMDA, respectively. Adherence to DP was 98.7%. No serious adverse events occurred. For rfMDA versus RACD, cumulative incidences (per 1000 person-years) of all malaria were 2.11 (95% CI 1.73 to 2.59) and 1.97 (95% CI 1.57 to 2.47), respectively; and of locally acquired malaria, they were 1.29 (95% CI 1.00 to 1.67) and 0.97 (95% CI 0.71 to 1.34), respectively. Adjusting for imbalance in baseline incidence, incidence rate ratio for rfMDA versus RACD was 0.95 (95% CI 0.55 to 1.65) for all malaria and 0.82 (95% CI 0.40 to 1.71) for locally acquired malaria. Similar results were obtained in a per-protocol analysis that excluded clusters with <80% index case coverage. CONCLUSION: In a very low-endemic, real-world setting, rfMDA using DP was safe, but did not lower incidence compared with RACD, potentially due to insufficient coverage and/or power. To assess impact of interventions in very low-endemic settings, improved coverage, complementary interventions and adaptive ring trial designs may be needed. TRIAL REGISTRATION NUMBER: NCT02315690.


Assuntos
Antimaláricos , Malária , Antimaláricos/efeitos adversos , Artemeter/uso terapêutico , Combinação Arteméter e Lumefantrina/uso terapêutico , Artemisininas , Essuatíni , Humanos , Malária/tratamento farmacológico , Malária/epidemiologia , Malária/prevenção & controle , Administração Massiva de Medicamentos , Quinolinas
11.
Int J Mol Sci ; 22(11)2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34205228

RESUMO

BACKGROUND: Artemether-lumefantrine is a highly effective artemisinin-based combination therapy that was adopted in Mali as first-line treatment for uncomplicated Plasmodium falciparum malaria. This study was designed to measure the efficacy of artemether-lumefantrine and to assess the selection of the P. falciparum chloroquine resistance transporter (pfcrt) and P. falciparum multi-drug resistance 1 (pfmdr1) genotypes that have been associated with drug resistance. METHODS: A 28-day follow-up efficacy trial of artemether-lumefantrine was conducted in patients aged 6 months and older suffering from uncomplicated falciparum malaria in four different Malian areas during the 2009 malaria transmission season. The polymorphic genetic markers MSP2, MSP1, and Ca1 were used to distinguish between recrudescence and reinfection. Reinfection and recrudescence were then grouped as recurrent infections and analyzed together by PCR-restriction fragment length polymorphism (RFLP) to identify candidate markers for artemether-lumefantrine tolerance in the P. falciparum chloroquine resistance transporter (pfcrt) gene and the P. falciparum multi-drug resistance 1 (pfmdr1) gene. RESULTS: Clinical outcomes in 326 patients (96.7%) were analyzed and the 28-day uncorrected adequate clinical and parasitological response (ACPR) rate was 73.9%. The total PCR-corrected 28-day ACPR was 97.2%. The pfcrt 76T and pfmdr1 86Y population prevalence decreased from 49.3% and 11.0% at baseline (n = 337) to 38.8% and 0% in patients with recurrent infection (n = 85); p = 0.001), respectively. CONCLUSION: Parasite populations exposed to artemether-lumefantrine in this study were selected toward chloroquine-sensitivity and showed a promising trend that may warrant future targeted reintroduction of chloroquine or/and amodiaquine.


Assuntos
Combinação Arteméter e Lumefantrina/administração & dosagem , Malária Falciparum/tratamento farmacológico , Proteínas de Membrana Transportadoras/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Proteínas de Protozoários/genética , Alelos , Combinação Arteméter e Lumefantrina/efeitos adversos , Artemisininas/administração & dosagem , Artemisininas/efeitos adversos , Criança , Pré-Escolar , Cloroquina/administração & dosagem , Cloroquina/efeitos adversos , Resistência a Medicamentos/genética , Feminino , Humanos , Malária Falciparum/genética , Malária Falciparum/parasitologia , Malária Falciparum/patologia , Masculino , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/patogenicidade
12.
Cancer Invest ; 39(8): 675-684, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34241563

RESUMO

The major problems with cancer therapy are drug-induced side effects. There is an urgent need for safe anti-tumor drugs. Artemisinin is a Chinese herbal remedy for malaria with efficacy and safety. However, several studies reported that artemisinin causes neurotoxicity and cardiotoxicity in animal models. Recently, nanostructured drug delivery systems have been designed to improve therapeutic efficacy and reduce toxicity. Artemisinin has been reported to show anticancer properties. The anticancer effects of artemisinin appear to be mediated by inducing cell cycle arrest, promoting ferroptosis and autophagy, inhibiting cell metastasis. Therefore, the review is to concentrate on mechanisms and molecular targets of artemisinin as anti-tumor agents. We believe these will be important topics in realizing the potential of artemisinin and its derivatives as potent anticancer agents.


Assuntos
Antineoplásicos/uso terapêutico , Artemisininas/uso terapêutico , Neoplasias/tratamento farmacológico , Antineoplásicos/farmacologia , Artemisininas/farmacologia , Humanos
13.
Cochrane Database Syst Rev ; 7: CD011525, 2021 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-34273901

RESUMO

BACKGROUND: Intermittent preventive treatment could help prevent malaria in infants (IPTi) living in areas of moderate to high malaria transmission in sub-Saharan Africa. The World Health Organization (WHO) policy recommended IPTi in 2010, but its adoption in countries has been limited. OBJECTIVES: To evaluate the effects of intermittent preventive treatment (IPT) with antimalarial drugs to prevent malaria in infants living in malaria-endemic areas. SEARCH METHODS: We searched the following sources up to 3 December 2018: the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library), MEDLINE (PubMed), Embase (OVID), LILACS (Bireme), and reference lists of articles. We also searched the metaRegister of Controlled Trials (mRCT) and the WHO International Clinical Trials Registry Platform (ICTRP) portal for ongoing trials up to 3 December 2018. SELECTION CRITERIA: We included randomized controlled trials (RCTs) that compared IPT to placebo or no intervention in infants (defined as young children aged between 1 to 12 months) in malaria-endemic areas. DATA COLLECTION AND ANALYSIS: The primary outcome was clinical malaria (fever plus asexual parasitaemia). Two review authors independently assessed trials for inclusion, evaluated the risk of bias, and extracted data. We summarized dichotomous outcomes and count data using risk ratios (RR) and rate ratios respectively, and presented all measures with 95% confidence intervals (CIs). We extracted protective efficacy values and their 95% CIs; when an included trial did not report this data, we calculated these values from the RR or rate ratio with its 95% CI. Where appropriate, we combined data in meta-analyses and assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS: We included 12 trials that enrolled 19,098 infants; all were conducted in sub-Saharan Africa. Three trials were cluster-RCTs. IPTi with sulfadoxine-pyrimethamine (SP) was evaluated in 10 trials from 1999 to 2013 (n = 15,256). Trials evaluating ACTs included dihydroartemisinin-piperaquine (1 trial, 147 participants; year 2013), amodiaquine-artesunate (1 study, 684 participants; year 2008), and SP-artesunate (1 trial, 676 participants; year 2008). The earlier studies evaluated IPTi with SP, and were conducted in Tanzania (in 1999 and 2006), Mozambique (2004), Ghana (2004 to 2005), Gabon (2005), Kenya (2008), and Mali (2009). One trial evaluated IPTi with amodiaquine in Tanzania (2000). Later studies included three conducted in Kenya (2008), Tanzania (2008), and Uganda (2013), evaluating IPTi in multiple trial arms that included artemisinin-based combination therapy (ACT). Although the effect size varied over time and between drugs, overall IPTi impacts on the incidence of clinical malaria overall, with a 30% reduction (rate ratio 0.70, 0.62 to 0.80; 10 studies, 10,602 participants). The effect of SP appeared to attenuate over time, with trials conducted after 2009 showing little or no effect of the intervention. IPTi with SP probably resulted in fewer episodes of clinical malaria (rate ratio 0.78, 0.69 to 0.88; 8 trials, 8774 participants, moderate-certainty evidence), anaemia (rate ratio 0.82, 0.68 to 0.98; 6 trials, 7438 participants, moderate-certainty evidence), parasitaemia (rate ratio 0.66, 0.56 to 0.79; 1 trial, 1200 participants, moderate-certainty evidence), and fewer hospital admissions (rate ratio 0.85, 0.78 to 0.93; 7 trials, 7486 participants, moderate-certainty evidence). IPTi with SP probably made little or no difference to all-cause mortality (risk ratio 0.93, 0.74 to 1.15; 9 trials, 14,588 participants, moderate-certainty evidence). Since 2009, IPTi trials have evaluated ACTs and indicate impact on clinical malaria and parasitaemia. A small trial of DHAP in 2013 shows substantive effects on clinical malaria (RR 0.42, 0.33 to 0.54; 1 trial, 147 participants, moderate-certainty evidence) and parasitaemia (moderate-certainty evidence). AUTHORS' CONCLUSIONS: In areas of sub-Saharan Africa, giving antimalarial drugs known to be effective against the malaria parasite at the time to infants as IPT probably reduces the risk of clinical malaria, anaemia, and hospital admission. Evidence from SP studies over a 19-year period shows declining efficacy, which may be due to increasing drug resistance. Combinations with ACTs appear promising as suitable alternatives for IPTi.


Assuntos
Antimaláricos/uso terapêutico , Doenças Endêmicas/prevenção & controle , Malária/prevenção & controle , África ao Sul do Saara , Amodiaquina/uso terapêutico , Artemisininas/uso terapêutico , Viés , Intervalos de Confiança , Erradicação de Doenças , Combinação de Medicamentos , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Parasitemia/tratamento farmacológico , Pirimetamina/uso terapêutico , Quinolinas/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Sulfadoxina/uso terapêutico
14.
Cell Death Dis ; 12(7): 705, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34262021

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is an extremely lethal cancer with limited treatment options. Cisplatin (DDP) is used as a mainstay of chemotherapeutic agents in combination with other drugs or radiotherapy for PDAC therapy. However, DDP exhibits severe side-effects that can lead to discontinuation of therapy, and the acquired drug resistance of tumor cells presents serious clinical obstacles. Therefore, it is imperative to develop a more effective and less toxic therapeutic strategy. We and others have previously discovered that dihydroartemisinin (DHA) represents a safe and promising therapeutic agent to preferentially induce cancer cell ferroptosis. In the present study, we find that DHA could intensively strengthen the cytotoxicity of DDP and significantly reduce its effective concentrations both in vitro and in vivo. Combination of DHA and DDP synergistically inhibits the proliferation and induces DNA damage of PDAC cells. Mechanically, the combinative treatment impairs mitochondrial homeostasis, characterized by destroyed mitochondrial morphology, decreased respiratory capacity, reduced ATP production, and accumulated mitochondria-derived ROS. Further studies show that ferroptosis contributes to the cytotoxic effects in PDAC cells under the challenge of DHA and DDP, together with catastrophic accumulation of free iron and unrestricted lipid peroxidation. Moreover, pharmacologic depleting of the free iron reservoir or reconstituted expression of FTH contributes to the tolerance of DHA/DDP-induced ferroptosis, while iron addition accelerates the ferroptotic cell death. In summary, these results provide experimental evidence that DHA acts synergistically with DDP and renders PDAC cells vulnerable to ferroptosis, which may act as a promising therapeutic strategy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Artemisininas/farmacologia , Carcinoma Ductal Pancreático/tratamento farmacológico , Cisplatino/farmacologia , Ferroptose/efeitos dos fármacos , Ferro/metabolismo , Neoplasias Pancreáticas/tratamento farmacológico , Trifosfato de Adenosina/metabolismo , Animais , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Dano ao DNA , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Humanos , Camundongos Endogâmicos BALB C , Camundongos Nus , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Invasividade Neoplásica , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Espécies Reativas de Oxigênio/metabolismo , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Antimicrob Agents Chemother ; 65(9): e0090121, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34228534

RESUMO

Plasmodium falciparum multidrug resistance-1 gene (pfmdr1) polymorphisms associate with altered antimalarial susceptibility. Between 2010 and 2018/2019, we observed that the prevalence of the wild-type allele N86 and the wild-type combination NYD increased 10-fold (4% versus 40%) and more than 2-fold (18% versus 44%), respectively. Haplotypes other than NYD or NFD declined by up to >90%. Our molecular data suggest the pfmdr1 pattern shifted toward one associated with artemether-lumefantrine resistance.


Assuntos
Antimaláricos , Artemisininas , Malária Falciparum , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Artemeter/uso terapêutico , Combinação Arteméter e Lumefantrina , Artemisininas/farmacologia , Artemisininas/uso terapêutico , Resistência a Medicamentos/genética , Humanos , Malária Falciparum/tratamento farmacológico , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Plasmodium falciparum/genética , Polimorfismo Genético/genética , Ruanda
16.
Planta ; 254(2): 29, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-34263417

RESUMO

MAIN CONCLUSION: This review analyses the most recent scientific research conducted for the purpose of enhancing artemisinin production. It may help to devise better artemisinin enhancement strategies, so that its production becomes cost effective and becomes available to masses. Malaria is a major threat to world population, particularly in South-East Asia and Africa, due to dearth of effective anti-malarial compounds, emergence of quinine resistant malarial strains, and lack of advanced healthcare facilities. Artemisinin, a sesquiterpene lactone obtained from Artemisia annua L., is the most potent drug against malaria and used in the formulation of artemisinin combination therapies (ACTs). Artemisinin is also effective against various types of cancers, many other microbes including viruses, parasites and bacteria. However, this specialty metabolite and its derivatives generally occur in low amounts in the source plant leading to its production scarcity. Considering the importance of this drug, researchers have been working worldwide to develop novel strategies to augment its production both in vivo and in vitro. Due to complex chemical structure, its chemical synthesis is quite expensive, so researchers need to devise synthetic protocols that are economically viable and also work on increasing the in-planta production of artemisinin by using various strategies like use of phytohormones, stress signals, bioinoculants, breeding and transgenic approaches. The focus of this review is to discuss these artemisinin enhancement strategies, understand mechanisms modulating its biosynthesis, and evaluate if roots play any role in artemisinin production. Furthermore, we also have a critical analysis of various assays used for artemisinin measurement. This may help to develop better artemisinin enhancement strategies which lead to decreased price of ACTs and increased profit to farmers.


Assuntos
Antimaláricos , Artemisia annua , Artemisininas , Artemisia annua/genética , Melhoramento Vegetal
17.
Bull Environ Contam Toxicol ; 107(2): 343-350, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34251462

RESUMO

The inhibitory mechanisms of artemisinin anti-algae sustained-release granules (AASG) on algal cells at cytoplasmic level were investigated. The results showed that 0.2 g L-1 AASG could effectively inhibit the growth of Microcystis aeruginosa (M.aeruginosa). The stress of 0.2 g L-1 AASG changed the excitation energy distribution pattern of Photosystem II (PSII) of algal cells, which showed the increase of heat dissipation share and the inhibition of physiological activities related to PSII. At the same time, AASG induced a large amount of reactive oxygen species (ROS), which aggravated the membrane lipid peroxidation and caused serious damage to algae cell membrane. AASG also resulted in the decrease of esterase activity and alkaline phosphatase activity (APA) in algal cells. Results showed that AASG inhibited algal growth by exerting adverse effects on PSII, ROS and metabolic activity of M.aeruginosa.


Assuntos
Artemisininas , Microcystis , Preparações de Ação Retardada , Complexo de Proteína do Fotossistema II , Espécies Reativas de Oxigênio
18.
Sci Rep ; 11(1): 14571, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34272426

RESUMO

Effective and affordable treatments for patients suffering from coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are needed. We report in vitro efficacy of Artemisia annua extracts as well as artemisinin, artesunate, and artemether against SARS-CoV-2. The latter two are approved active pharmaceutical ingredients of anti-malarial drugs. Concentration-response antiviral treatment assays, based on immunostaining of SARS-CoV-2 spike glycoprotein, revealed that treatment with all studied extracts and compounds inhibited SARS-CoV-2 infection of VeroE6 cells, human hepatoma Huh7.5 cells and human lung cancer A549-hACE2 cells, without obvious influence of the cell type on antiviral efficacy. In treatment assays, artesunate proved most potent (range of 50% effective concentrations (EC50) in different cell types: 7-12 µg/mL), followed by artemether (53-98 µg/mL), A. annua extracts (83-260 µg/mL) and artemisinin (151 to at least 208 µg/mL). The selectivity indices (SI), calculated based on treatment and cell viability assays, were mostly below 10 (range 2 to 54), suggesting a small therapeutic window. Time-of-addition experiments in A549-hACE2 cells revealed that artesunate targeted SARS-CoV-2 at the post-entry level. Peak plasma concentrations of artesunate exceeding EC50 values can be achieved. Clinical studies are required to further evaluate the utility of these compounds as COVID-19 treatment.


Assuntos
Artemisininas/farmacologia , Extratos Vegetais/farmacologia , SARS-CoV-2/efeitos dos fármacos , Células A549 , Animais , Artemisia annua/química , COVID-19/tratamento farmacológico , Chlorocebus aethiops , Humanos , Células Vero
19.
Nat Commun ; 12(1): 4563, 2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34315897

RESUMO

The emergence and spread of Plasmodium falciparum parasites resistant to front-line antimalarial artemisinin-combination therapies (ACT) threatens to erase the considerable gains against the disease of the last decade. Here, we develop a large-scale phenotypic screening pipeline and use it to carry out a large-scale forward-genetic phenotype screen in P. falciparum to identify genes allowing parasites to survive febrile temperatures. Screening identifies more than 200 P. falciparum mutants with differential responses to increased temperature. These mutants are more likely to be sensitive to artemisinin derivatives as well as to heightened oxidative stress. Major processes critical for P. falciparum tolerance to febrile temperatures and artemisinin include highly essential, conserved pathways associated with protein-folding, heat shock and proteasome-mediated degradation, and unexpectedly, isoprenoid biosynthesis, which originated from the ancestral genome of the parasite's algal endosymbiont-derived plastid, the apicoplast. Apicoplast-targeted genes in general are upregulated in response to heat shock, as are other Plasmodium genes with orthologs in plant and algal genomes. Plasmodium falciparum parasites appear to exploit their innate febrile-response mechanisms to mediate resistance to artemisinin. Both responses depend on endosymbiont-derived genes in the parasite's genome, suggesting a link to the evolutionary origins of Plasmodium parasites in free-living ancestors.


Assuntos
Apicoplastos/metabolismo , Artemisininas/farmacologia , Resistência a Medicamentos , Febre/parasitologia , Malária Falciparum/parasitologia , Parasitos/fisiologia , Animais , Apicoplastos/efeitos dos fármacos , Resistência a Medicamentos/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Resposta ao Choque Térmico/efeitos dos fármacos , Mutação/genética , Parasitos/efeitos dos fármacos , Fenótipo , Plasmodium falciparum/genética , Transdução de Sinais/efeitos dos fármacos , Temperatura , Terpenos/metabolismo , Transcrição Genética/efeitos dos fármacos , Resposta a Proteínas não Dobradas/efeitos dos fármacos
20.
Molecules ; 26(14)2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34299438

RESUMO

An efficient synthesis of rac-6-desmethyl-5ß-hydroxy-d-secoartemisinin 2, a tricyclic analog of R-(+)-artemisinin 1, was accomplished and the racemate was resolved into the (+)-2b and (-)-2a enantiomers via their Mosher Ester diastereomers. Antimalarial activity resided with only the artemisinin-like enantiomer R-(-)-2a. Several new compounds 9-16, 19a, 19b, 22 and 29 were synthesized from rac-2 but the C-5 secondary hydroxyl group was surprisingly unreactive. For example, the formation of carbamates and Mitsunobu reactions were unsuccessful. In order to assess the unusual reactivity of 2, a single crystal X-ray crystallographic analysis revealed a close intramolecular hydrogen bond from the C-5 alcohol to the oxepane ether oxygen (O-11). All products were tested in vitro against the W-2 and D-6 strains of Plasmodium falciparum. Several of the analogs had moderate activity in comparison to the natural product 1. Iron (II) bromide-promoted rearrangement of 2 gave, in 50% yield, the ring-contracted tetrahydrofuran 22, while the 5-ketone 15 provided a monocyclic methyl ketone 29 (50%). Neither 22 nor 29 possessed in vitro antimalarial activity. These results have implications in regard to the antimalarial mechanism of action of artemisinin.


Assuntos
Antimaláricos/química , Artemisininas/química , Plasmodium falciparum/efeitos dos fármacos , Animais , Antimaláricos/farmacologia , Artemisininas/síntese química , Artemisininas/farmacologia , Cristalografia por Raios X/métodos , Compostos Heterocíclicos , Ligação de Hidrogênio , Cetonas , Sesquiterpenos/química , Estereoisomerismo , Relação Estrutura-Atividade
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