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In vitro effects of new artemisinin derivatives in Neospora caninum-infected human fibroblasts. Int J Antimicrob Agents 2015; 46:88-93. [PMID: 25934265 DOI: 10.1016/j.ijantimicag.2015.02.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 11/21/2022]
Abstract
From a panel of 34 artemisinin derivatives tested in vitro, artemisone, GC007 and GC012 were most efficacious at inhibiting Neospora caninum replication (IC50 values of 3-54nM), did not notably impair the invasiveness of tachyzoites and were non-toxic for human foreskin fibroblasts (HFFs). Transmission electron microscopy of drug-treated N. caninum-infected HFFs demonstrated severe alterations in the parasite cytoplasm, changes in the composition of the matrix of the parasitophorous vacuole (PV) and diminished integrity of the PV membrane. To exert parasiticidal activity, parasites had to be cultured continuously in the presence of 5μM artemisone or GC007 for 3 weeks. N. caninum tachyzoites readily adapted to a stepwise increase in concentrations (0.5-10μM) of GC012, but not to artemisone or GC007. Drugs induced the expression of elevated levels of NcBAG1 and NcSAG4 mRNA, but only NcBAG1 could be detected by immunofluorescence. Thus, artemisinin derivatives represent interesting leads that should be investigated further.
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Shukla V, Pala Z, Alok A, Desai N. Screening of Different <i>Artemisia</i> spp. from Western Ghats of Maharashtra for an Anti-Malarial Compound—Artemisinin. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/ajps.2015.69162] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Spotlight on the in vitro effect of artemisinin-naphthoquine phosphate on Schistosoma mansoni and its snail host Biomphalaria alexandrina. Acta Trop 2015; 141:37-45. [PMID: 25291045 DOI: 10.1016/j.actatropica.2014.09.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 09/23/2014] [Accepted: 09/27/2014] [Indexed: 12/18/2022]
Abstract
Malaria and schistosomiasis are the two most important parasitic diseases in the tropics and sub-tropics with geographic overlap. Efforts have been made for developing new schistosomicidal drugs, or testing existing drugs originally used for non-related diseases. The antimalarial artemisinin-naphthoquine phosphate combination (CO-ArNp) was recently reported to be a promising novel antischistosomal therapy with potent in vivo activity against Schistosoma mansoni. In this work, we report the in vitro dose- and time-response effect of CO-ArNp against the Egyptian strain of S. mansoni, and its snail host, Biomphalaria alexandrina. Incubation of adult S. mansoni with CO-ArNp at 40 or 20 μg/ml for 48 or 72 h killed all worms. Exposure of S. mansoni miracidia and cercariae to the molluscicidal LC50 of CO-ArNp (16.8 μg/ml) resulted in 100% mortality of the free larval stages within 90 and 15 min, respectively. Moreover, incubation of adult B. alexandrina snails with this drug combination killed all snails at 40 μg/ml within 24h. Scanning electron microscope revealed marked morphological and tegumental alterations on the different stages of the parasite and its snail soft tissue. Our study highlights the schistosomicidal and molluscicidal effects of artemisinin-naphthoquine phosphate. No doubt more studies are needed to clarify its potential value to control schistosomiasis.
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Starkl Renar K, Pečar S, Iskra J. Activation of aqueous hydrogen peroxide for non-catalyzed dihydroperoxidation of ketones by azeotropic removal of water. Org Biomol Chem 2015; 13:9369-72. [DOI: 10.1039/c5ob01503k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyclic and acyclic ketones were selectively converted to gem-dihydroperoxides in 72–99% yield with 30% aq. hydrogen peroxide by azeotropic distillation of water from the reaction mixture without any catalyst.
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Affiliation(s)
- K. Starkl Renar
- Laboratory of Organic and Bioorganic Chemistry
- Department of Physical and Organic Chemistry
- Jožef Stefan Institute
- Ljubljana
- Slovenia
| | - S. Pečar
- Faculty of Pharmacy
- University of Ljubljana
- Slovenia
| | - J. Iskra
- Laboratory of Organic and Bioorganic Chemistry
- Department of Physical and Organic Chemistry
- Jožef Stefan Institute
- Ljubljana
- Slovenia
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Magenta D, Sangiovanni E, Basilico N, Haynes RK, Parapini S, Colombo E, Bosisio E, Taramelli D, Dell’Agli M. Inhibition of metalloproteinase-9 secretion and gene expression by artemisinin derivatives. Acta Trop 2014; 140:77-83. [PMID: 25149353 DOI: 10.1016/j.actatropica.2014.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/23/2014] [Accepted: 08/07/2014] [Indexed: 01/08/2023]
Abstract
Malaria remains one of the world's most common infectious diseases, being responsible for more deaths than any other communicable disease except tuberculosis. There is strong evidence that tumour necrosis factor α and interleukin-1β are important contributors to the systemic disease caused by the infection with Plasmodium falciparum. Circulating levels of TNFα are increased after infection, as a consequence of stimulation of monocyte-macrophages by infected red blood cells or parasite products, as shown in vitro for the malaria pigment haemozoin. TNFα in turn enhances the synthesis of metalloproteinase-9 in monocytes and macrophages. Metalloproteinase-9 acts on the extracellular matrix but also on non-traditional substrates, including precursors of inflammatory cytokines, which are proteolytically activated and contribute to the amplification of the inflammatory response. The aim of the present work was to establish whether artemisinin and its derivatives artemisone, artesunate and dihydroartemisinin possess immuno-modulatory properties. In particular, it is necessary to evaluate their effects on mRNA levels and secretion of MMP-9 by the human monocytic cell line (THP-1 cells) stimulated by hemozoin or TNFα. 5μM of each derivative, although not artemisinin itself, induced significantly inhibited TNFα production. Artesunate, artemisone and DHA antagonized haemozoin-induced MMP-9 secretion by 25%, 24% and 50%, respectively. mRNA levels were also depressed by 14%, 20% and 27%, respectively, thus reflecting in part the effect observed on protein production. The derivatives significantly inhibited both TNFα-induced MMP-9 secretion and mRNA levels to a greater extent than haemozoin itself. Both haemozoin and TNFα increased NF-κB driven transcription by 11 and 7.7 fold, respectively. Artesunate, artemisone and DHA inhibited haemozoin-induced NF-κB driven transcription by 28%, 34%, and 49%, respectively. Similarly the derivatives, but not artemisinin, prevented TNFα-induced NF-κB driven transcription by 47-51%. The study indicates that artemisinins may attenuate the inflammatory potential of monocytes in vivo. Thus, in addition to direct anti-parasitic activities, the beneficial clinical effects of artemisinins for the treatment of malaria include the apparent ability to attenuate the inflammatory response, thus limiting the risk of progression to the more severe form of the disease, including the onset of cerebral malaria.
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Transcriptome responses involved in artemisinin production in Artemisia annua L. under UV-B radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 140:292-300. [PMID: 25194528 DOI: 10.1016/j.jphotobiol.2014.08.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/01/2014] [Accepted: 08/05/2014] [Indexed: 11/23/2022]
Abstract
Artemisinin, an endoperoxide sesquiterpene lactone, is an effective antimalarial drug isolated from Artemisia annua L. In this study, a low dose (1.44 kJm(-2)d(-1)) of UV-B radiation (280-320 nm) for short-term (1h per day for 10 days) was applied to A. annua seedlings to stimulate artemisinin production. UV-B treatment not only induced the generation of reactive oxygen species (ROS), enhanced peroxidase activity and endogenous content of abscisic acid (ABA), but stimulated the biosynthesis of artemisinin in the seedlings. Here, transcriptomic changes during UV-B radiation in A. annua were detected using an Agilent GeneChip with 43,692 probe sets. In total, 358 transcripts were identified as differentially expressed under UV-B stress, of which 172 transcripts increased and 186 transcripts decreased in abundance. In terms of biological processes, gene ontology (GO) terms including primary carbohydrate and nitrogen compound metabolic processes were enriched in UV-B-repressed genes. The up-regulated genes were enriched in response to stress, ROS generation, hormone (ethylene, ABA) stimulus and cell cycle control. The expression of key enzymes such as amorpha-4,11-diene synthase (ADS) and cytochrome P450 dependent monooxygenase/hydroxylase (CYP71AV1), and related WRKY transcription factors was up-regulated significantly for artemisinin biosynthesis. This profile of global gene expression patterns during UV-B stress will be valuable for further identification of the enzymes involved in artemisinin biosynthesis.
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Yamansarov EY, Kazakova OB, Medvedeva NI, Kazakov DV, Kukovinets OS, Tolstikov GA. First synthesis of steroidal 1,2,4-trioxolanes. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2014. [DOI: 10.1134/s1070428014070197] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Therapeutic effects of artesunate in hepatocellular carcinoma: repurposing an ancient antimalarial agent. Eur J Gastroenterol Hepatol 2014; 26:861-70. [PMID: 24987823 DOI: 10.1097/meg.0000000000000066] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVES Artemisinins are antimalarial drugs that exert potent anticancer activity. We evaluated the effects of artesunate, a semisynthetic derivative of artemisinin, on tumor growth, angiogenesis, the unfolded protein response, and chemoresistance in hepatocellular carcinoma. MATERIALS AND METHODS The effect of artesunate was examined in HepG2 and BWTG3 cells under normoxic and hypoxic conditions and in a diethylnitrosamine-induced mouse model. Histology was performed with hematoxylin/eosin and reticulin staining. The expression of chemoresistance-related transporters and angiogenic and unfolded protein response factors was determined. Cytotoxicity was assessed by alanine and aspartate transaminase, lactate dehydrogenase, water-soluble tetrazolium salt, and caspase-3 activity assays. Small animal imaging was performed using dynamic contrast-enhanced MRI and choline PET to assess tumor progression. RESULTS Artesunate dose dependently reduced cell viability (from 50 μmol/l; P<0.05) and increased caspase-3 activity (P<0.05) in HepG2 and BWTG3 cells. These effects were enhanced by hypoxia (from 12.5 μmol/l; P<0.01). Moreover, artesunate downregulated vascular endothelial growth factor and placental growth factor expression in vitro (both P<0.05) and in vivo (both P<0.01). In mice, artesunate decreased vessel density and tumor burden (both P<0.05). These in-vivo effects were enhanced by combination with sorafenib (P<0.05 and P=0.07, respectively), without apparent hepatotoxicity. Furthermore, artesunate modulated the unfolded protein response in vitro and in vivo, increasing proapoptotic signaling, and did not induce doxorubicin chemoresistance. CONCLUSION These findings indicate that artesunate could offer a new approach to the therapy of hepatocellular carcinoma. Clinical trials with artesunate as monotherapy or in combination with current hypoxia-inducing approaches are necessary.
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Analytical sample preparation strategies for the determination of antimalarial drugs in human whole blood, plasma and urine. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 962:109-131. [DOI: 10.1016/j.jchromb.2014.02.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 02/25/2014] [Accepted: 02/28/2014] [Indexed: 02/06/2023]
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Synthesis of Novel Conjugates of Tetraoxane Endoperoxide with Bis(Quaternary Ammonium Salts). Biosci Biotechnol Biochem 2014; 73:217-20. [DOI: 10.1271/bbb.80571] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Enhanced Photosynthesis and Carbon Metabolism Favor Arsenic Tolerance in Artemisia annua, a Medicinal Plant as Revealed by Homology-Based Proteomics. INTERNATIONAL JOURNAL OF PROTEOMICS 2014; 2014:163962. [PMID: 24868464 PMCID: PMC4020366 DOI: 10.1155/2014/163962] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 02/03/2014] [Indexed: 12/24/2022]
Abstract
This paper provides the first proteomic evidence of arsenic (As) tolerance and interactive regulatory network between primary and secondary metabolism in the medicinal plant, Artemisia annua. While chlorophyll fluorescence and photosynthetic rate depicted mild inhibition, there was a significant enhancement in PSI activity, whole chain, ATP, and NADPH contents in 100 μM As treatments compared to the control plants. However, a decrease in the above variables was recorded under 150 μM treatments. Proteomic decoding of the survival strategy of A. annua under As stress using 2-DE followed by MALDI-MS/MS revealed a total of 46 differentially expressed protein spots. In contrast to other plants where As inhibits photosynthesis, A. annua showed appreciable photosynthetic CO2 assimilation and allocation of carbon resources at 100 μM As concentration. While an increased accumulation of ATP synthase, ferredoxin-NADP(H) oxidoreductase, and FeS-rieske proteins supported the operation of cyclic electron transport, mdr ABC transporter protein and pcs gene might be involved in As detoxification. The most interesting observation was an increased accumulation of LEAFY like novel protein conceivably responsible for an early onset of flowering in A. annua under As stress. This study not only affirmed the role of energy metabolism proteins but also identified potential candidates responsible for As tolerance in plants.
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Suberu JO, Yamin P, Leonhard K, Song L, Chemat S, Sullivan N, Barker G, Lapkin AA. The effect of O-methylated flavonoids and other co-metabolites on the crystallization and purification of artemisinin. J Biotechnol 2014; 171:25-33. [DOI: 10.1016/j.jbiotec.2013.11.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 11/22/2013] [Accepted: 11/26/2013] [Indexed: 11/15/2022]
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Terent'ev AO, Borisov DA, Vil’ VA, Dembitsky VM. Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products. Beilstein J Org Chem 2014; 10:34-114. [PMID: 24454562 PMCID: PMC3896255 DOI: 10.3762/bjoc.10.6] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Accepted: 11/16/2013] [Indexed: 12/16/2022] Open
Abstract
The present review describes the current status of synthetic five and six-membered cyclic peroxides such as 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides), 1,2-dioxanes, 1,2-dioxenes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes. The literature from 2000 onwards is surveyed to provide an update on synthesis of cyclic peroxides. The indicated period of time is, on the whole, characterized by the development of new efficient and scale-up methods for the preparation of these cyclic compounds. It was shown that cyclic peroxides remain unchanged throughout the course of a wide range of fundamental organic reactions. Due to these properties, the molecular structures can be greatly modified to give peroxide ring-retaining products. The chemistry of cyclic peroxides has attracted considerable attention, because these compounds are used in medicine for the design of antimalarial, antihelminthic, and antitumor agents.
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Key Words
- 1,2,4,5-tetraoxanes
- 1,2,4-trioxanes
- 1,2,4-trioxolanes
- 1,2-dioxanes
- 1,2-dioxenes
- 1,2-dioxolanes
- cyclic peroxides
- ozonides
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Affiliation(s)
- Alexander O Terent'ev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russia
| | - Dmitry A Borisov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russia
| | - Vera A Vil’
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russia
| | - Valery M Dembitsky
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russia
- Institute for Drug Research, P.O. Box 12065, Hebrew University, Jerusalem 91120, Israel
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Suberu JO, Gorka AP, Jacobs L, Roepe PD, Sullivan N, Barker GC, Lapkin AA. Anti-plasmodial polyvalent interactions in Artemisia annua L. aqueous extract--possible synergistic and resistance mechanisms. PLoS One 2013; 8:e80790. [PMID: 24244716 PMCID: PMC3828274 DOI: 10.1371/journal.pone.0080790] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 10/07/2013] [Indexed: 12/11/2022] Open
Abstract
Artemisia annua hot water infusion (tea) has been used in in vitro experiments against P. falciparum malaria parasites to test potency relative to equivalent pure artemisinin. High performance liquid chromatography (HPLC) and mass spectrometric analyses were employed to determine the metabolite profile of tea including the concentrations of artemisinin (47.5±0.8 mg L(-1)), dihydroartemisinic acid (70.0±0.3 mg L(-1)), arteannuin B (1.3±0.0 mg L(-1)), isovitexin (105.0±7.2 mg L(-1)) and a range of polyphenolic acids. The tea extract, purified compounds from the extract, and the combination of artemisinin with the purified compounds were tested against chloroquine sensitive and chloroquine resistant strains of P. falciparum using the DNA-intercalative SYBR Green I assay. The results of these in vitro tests and of isobologram analyses of combination effects showed mild to strong antagonistic interactions between artemisinin and the compounds (9-epi-artemisinin and artemisitene) extracted from A. annua with significant (IC50 <1 μM) anti-plasmodial activities for the combination range evaluated. Mono-caffeoylquinic acids, tri-caffeoylquinic acid, artemisinic acid and arteannuin B showed additive interaction while rosmarinic acid showed synergistic interaction with artemisinin in the chloroquine sensitive strain at a combination ratio of 1:3 (artemisinin to purified compound). In the chloroquine resistant parasite, using the same ratio, these compounds strongly antagonised artemisinin anti-plasmodial activity with the exception of arteannuin B, which was synergistic. This result would suggest a mechanism targeting parasite resistance defenses for arteannuin B's potentiation of artemisinin.
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Affiliation(s)
- John O. Suberu
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Alexander P. Gorka
- Centre for Infectious Disease, Department of Chemistry, Georgetown University, Washington, District of Columbia, United States of America
| | - Lauren Jacobs
- Centre for Infectious Disease, Department of Chemistry, Georgetown University, Washington, District of Columbia, United States of America
| | - Paul D. Roepe
- Centre for Infectious Disease, Department of Chemistry, Georgetown University, Washington, District of Columbia, United States of America
| | - Neil Sullivan
- Sensapharm Ltd, Business and Innovation Centre, Sunderland, United Kingdom
| | - Guy C. Barker
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Alexei A. Lapkin
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
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A rapid method for the determination of artemisinin and its biosynthetic precursors in Artemisia annua L. crude extracts. J Pharm Biomed Anal 2013; 84:269-77. [PMID: 23867088 DOI: 10.1016/j.jpba.2013.06.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 11/23/2022]
Abstract
A rapid high-pressure liquid chromatography (HPLC) tandem mass spectrometry (TQD) method for the determination of artemisinin, 9-epi-artemisinin, artemisitene, dihydroartemisinic acid, artemisinic acid and arteannuin B in Artemisia annua extracts is described. Detection and quantification of 9-epi-artemisinin in crude extracts are reported for the first time. In this method all six metabolites are resolved and eluted within 6 min with minimal sample preparation. A recovery of between 96.25% and 103.59% was obtained for all metabolites analysed and the standard curves were linear (r(2)>0.99) over the concentration range of 0.15-10 μg mL(-1) for artemisinin, 9-epi-artemisinin, artemisitene and arteannuin B, and the range of 3.75-120 μg mL(-1) for dihydroartemisinic acid and artemisinic acid. All validation indices were satisfactory, showing the method to be robust, quick, sensitive and adequate for a range of applications including high throughput (HTP) analysis.
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Sharma P, Wollenberg K, Sellers M, Zainabadi K, Galinsky K, Moss E, Nguitragool W, Neafsey D, Desai SA. An epigenetic antimalarial resistance mechanism involving parasite genes linked to nutrient uptake. J Biol Chem 2013; 288:19429-40. [PMID: 23720749 DOI: 10.1074/jbc.m113.468371] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acquired antimalarial drug resistance produces treatment failures and has led to periods of global disease resurgence. In Plasmodium falciparum, resistance is known to arise through genome-level changes such as mutations and gene duplications. We now report an epigenetic resistance mechanism involving genes responsible for the plasmodial surface anion channel, a nutrient channel that also transports ions and antimalarial compounds at the host erythrocyte membrane. Two blasticidin S-resistant lines exhibited markedly reduced expression of clag genes linked to channel activity, but had no genome-level changes. Silencing aborted production of the channel protein and was directly responsible for reduced uptake. Silencing affected clag paralogs on two chromosomes and was mediated by specific histone modifications, allowing a rapidly reversible drug resistance phenotype advantageous to the parasite. These findings implicate a novel epigenetic resistance mechanism that involves reduced host cell uptake and is a worrisome liability for water-soluble antimalarial drugs.
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Affiliation(s)
- Paresh Sharma
- Laboratory of Malaria and Vector Research, Office of Cyber Infrastructure and Computational Biology, NIAID, National Institutes of Health, Bethesda, Maryland 20852, USA
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Liu Y, Barry BD, Yu H, Liu J, Liao P, Bi X. Regiospecific 6-Endo-Annulation of in Situ Generated 3,4-Dienamides/Acids: Synthesis of δ-Lactams and δ-Lactones. Org Lett 2013; 15:2608-11. [DOI: 10.1021/ol4007772] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ying Liu
- Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. of China, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. of China, and School of Chemistry and Life Science, Anshan Normal University, Anshan, Liaoning 114007, P. R. of China
| | - Badru-Deen Barry
- Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. of China, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. of China, and School of Chemistry and Life Science, Anshan Normal University, Anshan, Liaoning 114007, P. R. of China
| | - Haifeng Yu
- Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. of China, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. of China, and School of Chemistry and Life Science, Anshan Normal University, Anshan, Liaoning 114007, P. R. of China
| | - Jianquan Liu
- Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. of China, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. of China, and School of Chemistry and Life Science, Anshan Normal University, Anshan, Liaoning 114007, P. R. of China
| | - Peiqiu Liao
- Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. of China, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. of China, and School of Chemistry and Life Science, Anshan Normal University, Anshan, Liaoning 114007, P. R. of China
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. of China, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. of China, and School of Chemistry and Life Science, Anshan Normal University, Anshan, Liaoning 114007, P. R. of China
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Charrier C, Bertho G, Petigny O, Moneton P, Azerad R. A new derivative detected in accelerated ageing of artesunate-amodiaquine fixed dose combination tablets. J Pharm Biomed Anal 2013; 81-82:20-6. [PMID: 23603276 DOI: 10.1016/j.jpba.2013.03.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 03/14/2013] [Indexed: 11/18/2022]
Abstract
An unknown impurity detected in small amounts during the heat treatment of artesunate-amodiaquine bilayer tablets was purified by semipreparative HPLC and identified by MS and NMR as the tetrahydrofuranyl acetate-rearranged derivative of anhydrodihydroartemisinin. When anhydrodihydroartemisinin was treated with a Fe(II) salt in acetonitrile-water solution, the same product was generated, together with an isomeric 2-deoxy-4α-hydroxy-anhydrodihydroartemisinin derivative, as expected from the usual homolytic radical opening of the endoperoxide bond previously described for other artemisinin derivatives.
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Affiliation(s)
- Cedric Charrier
- Molecular Biodiversity Department, Bertin Pharma, Parc d'activités du Pas du Lac, 78180 Montigny-le-Bretonneux, France.
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High-level semi-synthetic production of the potent antimalarial artemisinin. Nature 2013; 496:528-32. [PMID: 23575629 DOI: 10.1038/nature12051] [Citation(s) in RCA: 1265] [Impact Index Per Article: 115.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 03/04/2013] [Indexed: 12/28/2022]
Abstract
In 2010 there were more than 200 million cases of malaria, and at least 655,000 deaths. The World Health Organization has recommended artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria caused by the parasite Plasmodium falciparum. Artemisinin is a sesquiterpene endoperoxide with potent antimalarial properties, produced by the plant Artemisia annua. However, the supply of plant-derived artemisinin is unstable, resulting in shortages and price fluctuations, complicating production planning by ACT manufacturers. A stable source of affordable artemisinin is required. Here we use synthetic biology to develop strains of Saccharomyces cerevisiae (baker's yeast) for high-yielding biological production of artemisinic acid, a precursor of artemisinin. Previous attempts to produce commercially relevant concentrations of artemisinic acid were unsuccessful, allowing production of only 1.6 grams per litre of artemisinic acid. Here we demonstrate the complete biosynthetic pathway, including the discovery of a plant dehydrogenase and a second cytochrome that provide an efficient biosynthetic route to artemisinic acid, with fermentation titres of 25 grams per litre of artemisinic acid. Furthermore, we have developed a practical, efficient and scalable chemical process for the conversion of artemisinic acid to artemisinin using a chemical source of singlet oxygen, thus avoiding the need for specialized photochemical equipment. The strains and processes described here form the basis of a viable industrial process for the production of semi-synthetic artemisinin to stabilize the supply of artemisinin for derivatization into active pharmaceutical ingredients (for example, artesunate) for incorporation into ACTs. Because all intellectual property rights have been provided free of charge, this technology has the potential to increase provision of first-line antimalarial treatments to the developing world at a reduced average annual price.
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Kopetzki D, Lévesque F, Seeberger PH. A Continuous-Flow Process for the Synthesis of Artemisinin. Chemistry 2013; 19:5450-6. [DOI: 10.1002/chem.201204558] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/02/2013] [Indexed: 11/09/2022]
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Wang X, Dong Y, Wittlin S, Charman SA, Chiu FCK, Chollet J, Katneni K, Mannila J, Morizzi J, Ryan E, Scheurer C, Steuten J, Santo Tomas J, Snyder C, Vennerstrom JL. Comparative antimalarial activities and ADME profiles of ozonides (1,2,4-trioxolanes) OZ277, OZ439, and their 1,2-dioxolane, 1,2,4-trioxane, and 1,2,4,5-tetraoxane isosteres. J Med Chem 2013; 56:2547-55. [PMID: 23489135 DOI: 10.1021/jm400004u] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To ascertain the structure-activity relationship of the core 1,2,4-trioxolane substructure of dispiro ozonides OZ277 and OZ439, we compared the antimalarial activities and ADME profiles of the 1,2-dioxolane, 1,2,4-trioxane, and 1,2,4,5-tetraoxane isosteres. Consistent with previous data, both dioxolanes had very weak antimalarial properties. For the OZ277 series, the trioxane isostere had the best ADME profile, but its overall antimalarial efficacy was not superior to that of the trioxolane or tetraoxane isosteres. For the OZ439 series, there was a good correlation between the antimalarial efficacy and ADME profiles in the rank order trioxolane > trioxane > tetraoxane. As we have previously observed for OZ439 versus OZ277, the OZ439 series peroxides had superior exposure and efficacy in mice compared to the corresponding OZ277 series peroxides.
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Affiliation(s)
- Xiaofang Wang
- College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, Nebraska, USA
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Saleh G, Soave R, Lo Presti L, Destro R. Progress in the Understanding of the Key Pharmacophoric Features of the Antimalarial Drug Dihydroartemisinin: An Experimental and Theoretical Charge Density Study. Chemistry 2013; 19:3490-503. [DOI: 10.1002/chem.201202486] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 11/29/2012] [Indexed: 12/12/2022]
Affiliation(s)
- Gabriele Saleh
- Università degli Studi di Milano, Dipartimento di Chimica, Via Golgi 19, I‐20133 Milano (Italy), Fax: (+39) 02‐50314300
- Center for Materials Crystallography, Århus University, Langelandsgade 140, 8000 Århus (Denmark)
| | - Raffaella Soave
- Istituto di Scienze e Tecnologie Molecolari del CNR (CNR‐ISTM), Via Golgi 19 I‐20133 Milano (Italy), Fax: (+39) 02‐50314300
| | - Leonardo Lo Presti
- Università degli Studi di Milano, Dipartimento di Chimica, Via Golgi 19, I‐20133 Milano (Italy), Fax: (+39) 02‐50314300
- Center for Materials Crystallography, Århus University, Langelandsgade 140, 8000 Århus (Denmark)
- Istituto di Scienze e Tecnologie Molecolari del CNR (CNR‐ISTM), Via Golgi 19 I‐20133 Milano (Italy), Fax: (+39) 02‐50314300
| | - Riccardo Destro
- Università degli Studi di Milano, Dipartimento di Chimica, Via Golgi 19, I‐20133 Milano (Italy), Fax: (+39) 02‐50314300
- Istituto di Scienze e Tecnologie Molecolari del CNR (CNR‐ISTM), Via Golgi 19 I‐20133 Milano (Italy), Fax: (+39) 02‐50314300
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Lu X, Jiang W, Zhang L, Zhang F, Shen Q, Wang T, Chen Y, Wu S, Lv Z, Gao E, Qiu B, Tang K. Characterization of a novel ERF transcription factor in Artemisia annua and its induction kinetics after hormones and stress treatments. Mol Biol Rep 2012; 39:9521-7. [PMID: 22714923 DOI: 10.1007/s11033-012-1816-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Accepted: 06/10/2012] [Indexed: 10/28/2022]
Abstract
The full-length cDNA sequence of AaERF3 was cloned and characterized from Artemisia annua. The bioinformatic analysis and phylogenetic tree analysis implied that the AaERF3 encoded a putative protein of 193 amino acids which formed a closely related subgroup with AtERF1, ERF1 and ORA59 in Arabidopsis. The result of subcellular localization showed that AaERF3 targeted to both of the nuclei and the cytoplasm. The qRT-PCR analysis showed that Green young alabastrums had the highest expression level of AaERF3 in the 5-months-old plants. The qRT-PCR analysis also revealed that ABA, Wound and Cold treatments significantly enhanced the transcript expression of AaERF3. MeJA and Ethylene treatment could also slightly induce the accumulation of AaERF3 transcription.
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Affiliation(s)
- Xu Lu
- Plant Biotechnology Research Center, SJTU-Cornell Institute of Sustainable Agriculture and Biotechnology, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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Finaurini S, Basilico N, Corbett Y, D’Alessandro S, Parapini S, Olliaro P, Haynes RK, Taramelli D. Dihydroartemisinin inhibits the human erythroid cell differentiation by altering the cell cycle. Toxicology 2012; 300:57-66. [DOI: 10.1016/j.tox.2012.05.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 05/26/2012] [Accepted: 05/26/2012] [Indexed: 11/16/2022]
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Yu ZX, Li JX, Yang CQ, Hu WL, Wang LJ, Chen XY. The jasmonate-responsive AP2/ERF transcription factors AaERF1 and AaERF2 positively regulate artemisinin biosynthesis in Artemisia annua L. MOLECULAR PLANT 2012; 5:353-65. [PMID: 22104293 DOI: 10.1093/mp/ssr087] [Citation(s) in RCA: 273] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Plants of Artemisia annua produce artemisinin, a sesquiterpene lactone widely used in malaria treatment. Amorpha-4,11-diene synthase (ADS), a sesquiterpene synthase, and CYP71AV1, a P450 monooxygenase, are two key enzymes of the artemisinin biosynthesis pathway. Accumulation of artemisinin can be induced by the phytohormone jasmonate (JA). Here, we report the characterization of two JA-responsive AP2 family transcription factors--AaERF1 and AaERF2--from A. annua L. Both genes were highly expressed in inflorescences and strongly induced by JA. Yeast one-hybrid and electrophoretic mobility shift assay (EMSA) showed that they were able to bind to the CRTDREHVCBF2 (CBF2) and RAV1AAT (RAA) motifs present in both ADS and CYP71AV1 promoters. Transient expression of either AaERF1 or AaERF2 in tobacco induced the promoter activities of ADS or CYP71AV1, and the transgenic A. annua plants overexpressing either transcription factor showed elevated transcript levels of both ADS and CYP71AV1, resulting in increased accumulation of artemisinin and artemisinic acid. By contrast, the contents of these two metabolites were reduced in the RNAi transgenic lines in which expression of AaERF1 or AaERF2 was suppressed. These results demonstrate that AaERF1 and AaERF2 are two positive regulators of artemisinin biosynthesis and are of great value in genetic engineering of artemisinin production.
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Affiliation(s)
- Zong-Xia Yu
- National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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Antimalarial Effects of Iranian Flora Artemisia sieberi on Plasmodium berghei In Vivo in Mice and Phytochemistry Analysis of Its Herbal Extracts. Malar Res Treat 2012; 2012:727032. [PMID: 22315701 PMCID: PMC3270465 DOI: 10.1155/2012/727032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 12/31/2011] [Accepted: 01/05/2012] [Indexed: 11/18/2022] Open
Abstract
The aim of this study is pharmacochemistry of Iranian flora Artemisia sieberi and its antimalarial effects on Plasmodium berghei in vivo. This is the first application of A. sieberi for treatment of murine malaria. A. sieberi were collected at flowering stage from the Khorassan and Semnan provinces of Iran; the aerial parts were air-dried at room temperature and then powdered. The powder was macerated in methanol, filtered with Bokhner hopper and solvent was separated in rotary evaporator. Total herbal extract was subsequently processed for ether and chloroform extracts preparation. The toxicity of herbal extract was assessed on naive NMRI mice with high, average and low doses; then pathophysiological signs were assessed. Finally, the antimalarial efficacy was investigated on two groups of Plasmodium berghei infected mice. Percentage of parasitaemia and pathophysiology were also evaluated. The results of this assessment showed no toxicity even by high concentration of herbal extract. A significant reduction in percentage of parasitaemia was observed; no alterations of hepatosplenomegaly and body weight were indicated in study group. A. sieberi extracts showed antimalarial effects against murine malaria with some efficacies on reducing pathophysiology. However, there is requirement to find the major component of this herbal extract by further studies.
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78
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Galata M, Mahmoud S. Bioactive Plant Isoprenoids. STUDIES IN NATURAL PRODUCTS CHEMISTRY VOLUME 37 2012. [DOI: 10.1016/b978-0-444-59514-0.00005-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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79
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Antitumor activity of artemisinin and its derivatives: from a well-known antimalarial agent to a potential anticancer drug. J Biomed Biotechnol 2011; 2012:247597. [PMID: 22174561 PMCID: PMC3228295 DOI: 10.1155/2012/247597] [Citation(s) in RCA: 234] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 08/29/2011] [Indexed: 01/27/2023] Open
Abstract
Improvement of quality of life and survival of cancer patients will be greatly enhanced by the development of highly effective drugs to selectively kill malignant cells. Artemisinin and its analogs are naturally occurring antimalarials which have shown potent anticancer activity. In primary cancer cultures and cell lines, their antitumor actions were by inhibiting cancer proliferation, metastasis, and angiogenesis. In xenograft models, exposure to artemisinins substantially reduces tumor volume and progression. However, the rationale for the use of artemisinins in anticancer therapy must be addressed by a greater understanding of the underlying mechanisms involved in their cytotoxic effects. The primary targets for artemisinin and the chemical base for its preferential effects on heterologous tumor cells need yet to be elucidated. The aim of this paper is to provide an overview of the recent advances and new development of this class of drugs as potential anticancer agents.
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80
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Tilley L, Charman SA, Vennerstrom JL. Semisynthetic Artemisinin and Synthetic Peroxide Antimalarials. NEGLECTED DISEASES AND DRUG DISCOVERY 2011. [DOI: 10.1039/9781849733496-00033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Since the discovery of the endoperoxide sesquiterpene lactone artemisinin, numerous second-generation semisynthetic artemisinins and synthetic peroxides have been prepared and tested for their antimalarial properties. Using a case-study approach, we describe the discovery of the investigational semisynthetic artemisinins artelinic acid (8) and artemisone (9), and the structurally diverse synthetic peroxides arteflene (10), fenozan B07 (11), arterolane (12), PA1103/SAR116242 (13), and RKA182 (14).
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Affiliation(s)
- Leann Tilley
- Department of Biochemistry and Centre of Excellence for Coherent X-rayScience, La Trobe University Melbourne, Victoria 3086 Australia
| | - Susan A. Charman
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052 Australia
| | - Jonathan L. Vennerstrom
- College of Pharmacy University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha NE USA
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81
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Kumar N, Singh R, Rawat DS. Retracted: Tetraoxanes: synthetic and medicinal chemistry perspective. Med Res Rev 2011; 31:482. [PMID: 20027667 DOI: 10.1002/med.20189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Alam P, Abdin MZ. Over-expression of HMG-CoA reductase and amorpha-4,11-diene synthase genes in Artemisia annua L. and its influence on artemisinin content. PLANT CELL REPORTS 2011; 30:1919-28. [PMID: 21655998 DOI: 10.1007/s00299-011-1099-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 05/13/2011] [Accepted: 05/24/2011] [Indexed: 05/19/2023]
Abstract
Artemisinin, an endoperoxide sesquiterpene lactone, is a novel antimalarial natural product isolated from Artemisia annua L. plants. The low concentrations (0.01-1.1%) of this compound in A. annua L. plants is, however, a major constraint for commercialization of artemisinin-based combination therapies (ACTs) recommended by WHO for treating malaria caused by multidrug-resistant P. falciparum sp. In this context, in vivo yield improvement programs were undertaken by us. In the present study, HMG-Co A reductase gene (hmgr) from Catharanthus roseus (L) G. Don and amorpha-4,11-diene synthase (ads) gene from A. annua L. were over-expressed in A. annua L. plants to study their effects on artemisinin yields. The transgenic lines developed from putative transgenic regenerants were evaluated for integration and copy number of the transgenes using hptII gene probe, as it was a part of the expression cassette. The transgenic lines showed positive bands of hptII gene on Southern blots confirming the integration of transgenes. Some of the transgenic lines had single copy of the transgenes, while others had multiple copies. The expressions of hmgr and ads at the transcriptional level were also confirmed in each transgenic line employing RT-PCR assays. The HPLC analyses showed that the artemisinin contents were significantly increased in these transgenics. One of the transgenic lines, TR4, was found to contain 7.65-fold higher (1.73 mg/gDW) artemisinin than the non-transgenic plant (W). The increased artemisinin levels were found to be correlated with HMG-Co A reductase and amorpha-4,11-diene synthase enzymatic activities in the biochemical analyses.
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Affiliation(s)
- Pravej Alam
- Centre for Transgenic Plant Development, Department of Biotechnology, Faculty of Science, Jamia Hamdard, New Delhi, 110062, India
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Mishra BB, Tiwari VK. Natural products: An evolving role in future drug discovery. Eur J Med Chem 2011; 46:4769-807. [DOI: 10.1016/j.ejmech.2011.07.057] [Citation(s) in RCA: 565] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 07/29/2011] [Accepted: 07/30/2011] [Indexed: 11/16/2022]
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Artemisinins and immune system. Eur J Pharmacol 2011; 668:6-14. [PMID: 21756901 DOI: 10.1016/j.ejphar.2011.06.044] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 06/13/2011] [Accepted: 06/22/2011] [Indexed: 01/26/2023]
Abstract
Artemisinins in combination with other antimalarial drugs remain the mainstay of current antimalarial armamentarium. It is interesting to note that many traditional drugs with antiprotozoal background can wield immunomodulation on the recipient's immune system in a positive or negative direction. Artemisinins also attribute immunomodulatory distensions. For instance, they demonstrate predominant immunosuppressive traits toward different immune components by particularly regulating the cellular proliferation and cytokine release, which indicates that they possess some additional mechanisms and features demanding deliberate attentions. This article reviews the data-based immunomodulatory effects of artemisinins on different immune cells including neutrophils, macrophages, splenocytes, T and B cells in conjunction with their therapeutic prospective with regard to inflammation, autoimmunity and delayed-type hypersensitivity.
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85
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Synthesis and in vitro antimalarial activity of tetraoxane-amine/amide conjugates. Eur J Med Chem 2011; 46:2816-27. [DOI: 10.1016/j.ejmech.2011.04.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 04/01/2011] [Accepted: 04/01/2011] [Indexed: 11/17/2022]
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Characterization of the first specific Jasmonate biosynthetic pathway gene allene oxide synthase from Artemisia annua. Mol Biol Rep 2011; 39:2267-74. [PMID: 21643745 DOI: 10.1007/s11033-011-0976-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 05/26/2011] [Indexed: 01/01/2023]
Abstract
Allene oxide synthase (AOS) is the first committed step in the biosynthetic pathway of Jasmonate. In this study, a full-length cDNA of AOS gene (named as AaAOS) was cloned from Artemisia annua. The gene was 1891 bp in size containing an open reading frame (1581 bp) encoding 526 amino acids. Comparative and bioinformatic analysis revealed that the deduced protein of AaAOS was highly homologous to AOSs from other plant species. Phylogenetic analysis indicated that the protein of AaAOS belonged to the dicotyledonous group, which was consistent with the category of A. annua. Southern blot analysis revealed that it was a low-copy gene. Quantitative Real-time PCR (qRT-PCR) analysis showed that AaAOS mRNA accumulated most abundantly in leaves and flowers. The qRT-PCR analysis revealed that MeJA, ABA and ethylene treatments significantly enhanced AaAOS transcript expression.
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Weathers PJ, Arsenault PR, Covello PS, McMickle A, Teoh KH, Reed DW. Artemisinin production in Artemisia annua: studies in planta and results of a novel delivery method for treating malaria and other neglected diseases. PHYTOCHEMISTRY REVIEWS : PROCEEDINGS OF THE PHYTOCHEMICAL SOCIETY OF EUROPE 2011; 10:173-183. [PMID: 21643453 PMCID: PMC3106422 DOI: 10.1007/s11101-010-9166-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Artemisia annua L. produces the sesquiterpene lactone, artemisinin, a potent antimalarial drug that is also effective in treating other parasitic diseases, some viral infections and various neoplasms. Artemisinin is also an allelopathic herbicide that can inhibit the growth of other plants. Unfortunately, the compound is in short supply and thus, studies on its production in the plant are of interest as are low cost methods for drug delivery. Here we review our recent studies on artemisinin production in A. annua during development of the plant as it moves from the vegetative to reproductive stage (flower budding and full flower formation), in response to sugars, and in concert with the production of the ROS, hydrogen peroxide. We also provide new data from animal experiments that measured the potential of using the dried plant directly as a therapeutic. Together these results provide a synopsis of a more global view of regulation of artemisinin biosynthesis in A. annua than previously available. We further suggest an alternative low cost method of drug delivery to treat malaria and other neglected tropical diseases.
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Affiliation(s)
- Pamela J. Weathers
- Department of Biology/Biotechnology, Worcester Polytechnic Institute, 100 Institute Rd, Worcester, MA 01609, USA
| | - Patrick R. Arsenault
- Department of Biology/Biotechnology, Worcester Polytechnic Institute, 100 Institute Rd, Worcester, MA 01609, USA
| | - Patrick S. Covello
- Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, SK S7N OW9, Canada
| | | | - Keat H. Teoh
- Arkansas Bioscience Institute, Jonesboro, AR 72401, USA
| | - Darwin W. Reed
- Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, SK S7N OW9, Canada
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Lacaze C, Kauss T, Kiechel JR, Caminiti A, Fawaz F, Terrassin L, Cuart S, Grislain L, Navaratnam V, Ghezzoul B, Gaudin K, White NJ, Olliaro PL, Millet P. The initial pharmaceutical development of an artesunate/amodiaquine oral formulation for the treatment of malaria: a public-private partnership. Malar J 2011; 10:142. [PMID: 21605361 PMCID: PMC3128010 DOI: 10.1186/1475-2875-10-142] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 05/23/2011] [Indexed: 11/10/2022] Open
Abstract
Background Artemisinin-based combination therapy is currently recommended worldwide for the treatment of uncomplicated malaria. Fixed-dose combinations are preferred as they favour compliance. This paper reports on the initial phases of the pharmaceutical development of an artesunate-amodiaquine (ASAQ) bilayer co-formulation tablet, undertaken following pre-formulation studies by a network of scientists and industrials from institutions of both industrialized and low income countries. Methods Pharmaceutical development was performed by a research laboratory at the University Bordeaux Segalen, School of Pharmacy, for feasibility and early stability studies of various drug formulations, further transferred to a company specialized in pharmaceutical development, and then provided to another company for clinical batch manufacturing. The work was conducted by a regional public-private not-for-profit network (TropiVal) within a larger Public Private partnership (the FACT project), set up by WHO/TDR, Médecins Sans Frontières and the Drugs for Neglected Disease initiative (DNDi). Results The main pharmaceutical goal was to combine in a solid oral form two incompatible active principles while preventing artesunate degradation under tropical conditions. Several options were attempted and failed to provide satisfactory stability results: incorporating artesunate in the external phase of the tablets, adding a pH regulator, alcoholic wet granulation, dry granulation, addition of an hydrophobic agent, tablet manufacturing in controlled conditions. However, long-term stability could be achieved, in experimental batches under GMP conditions, by physical separation of artesunate and amodiaquine in a bilayer co-formulation tablet in alu-alu blisters. Conduction of the workplan was monitored by DNDi. Conclusions Collaborations between research and industrial groups greatly accelerated the process of development of the bi-layered ASAQ tablet. Lack of public funding was the main obstacle hampering the development process, and no intellectual property right was claimed. This approach resulted in a rapid technology transfer to the drug company Sanofi-Aventis, finalizing the process of development, registration and WHO pre-qualification of the fixed-dose co-formulation together with DNDi. The bi-layered tablet is made available under the names of Coarsucam® and Artesunate amodiaquine Winthrop®, Sanofi-Aventis. The issue related to the difficulty of public institutions to valorise their participation in such initiative by lack of priority and funding of applied research is discussed.
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Feng TS, Guantai EM, Nell M, van Rensburg CEJ, Ncokazi K, Egan TJ, Hoppe HC, Chibale K. Effects of highly active novel artemisinin-chloroquinoline hybrid compounds on β-hematin formation, parasite morphology and endocytosis in Plasmodium falciparum. Biochem Pharmacol 2011; 82:236-47. [PMID: 21596024 DOI: 10.1016/j.bcp.2011.04.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 04/27/2011] [Accepted: 04/29/2011] [Indexed: 11/25/2022]
Abstract
4-Aminoquinolines were hybridized with artemisinin and 1,4-naphthoquinone derivatives via the Ugi-four-component condensation reaction, and their biological activities investigated. The artemisinin-containing compounds 6a-c and its salt 6c-citrate were the most active target compounds in the antiplasmodial assays. However, despite the potent in vitro activities, they also displayed cytotoxicity against a mammalian cell-line, and had lower therapeutic indices than chloroquine. Morphological changes in parasites treated with these artemisinin-containing hybrid compounds were similar to those observed after addition of artemisinin. These hybrid compounds appeared to share mechanism(s) of action with both chloroquine and artemisinin: they exhibited potent β-hematin inhibitory activities; they caused an increase in accumulation of hemoglobin within the parasites that was intermediate between the increase observed with artesunate and chloroquine; and they also appeared to inhibit endocytosis as suggested by the decrease in the number of transport vesicles in the parasites. No cross-resistance with chloroquine was observed for these hybrid compounds, despite the fact that they contained the chloroquinoline moiety. The hybridization strategy therefore appeared to be borrowing the best from both classes of antimalarials.
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Affiliation(s)
- Tzu-Shean Feng
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
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Artesunate tolerance in transgenic Plasmodium falciparum parasites overexpressing a tryptophan-rich protein. Antimicrob Agents Chemother 2011; 55:2576-84. [PMID: 21464256 DOI: 10.1128/aac.01409-10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Due to their rapid, potent action on young and mature intraerythrocytic stages, artemisinin derivatives are central to drug combination therapies for Plasmodium falciparum malaria. However, the evidence for emerging parasite resistance/tolerance to artemisinins in southeast Asia is of great concern. A better understanding of artemisinin-related drug activity and resistance mechanisms is urgently needed. A recent transcriptome study of parasites exposed to artesunate led us to identify a series of genes with modified levels of expression in the presence of the drug. The gene presenting the largest mRNA level increase, Pf10_0026 (PArt), encoding a hypothetical protein of unknown function, was chosen for further study. Immunodetection with PArt-specific sera showed that artesunate induced a dose-dependent increase of the protein level. Bioinformatic analysis showed that PArt belongs to a Plasmodium-specific gene family characterized by the presence of a tryptophan-rich domain with a novel hidden Markov model (HMM) profile. Gene disruption could not be achieved, suggesting an essential function. Transgenic parasites overexpressing PArt protein were generated and exhibited tolerance to a spike exposure to high doses of artesunate, with increased survival and reduced growth retardation compared to that of wild-type-treated controls. These data indicate the involvement of PArt in parasite defense mechanisms against artesunate. This is the first report of genetically manipulated parasites displaying a stable and reproducible decreased susceptibility to artesunate, providing new possibilities to investigate the parasite response to artemisinins.
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91
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Feng TS, Guantai EM, Nell MJ, van Rensburg CEJ, Hoppe HC, Chibale K. Antiplasmodial and antitumor activity of dihydroartemisinin analogs derived via the aza-Michael addition reaction. Bioorg Med Chem Lett 2011; 21:2882-6. [PMID: 21489789 DOI: 10.1016/j.bmcl.2011.03.090] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 03/21/2011] [Accepted: 03/22/2011] [Indexed: 11/25/2022]
Abstract
A series of dihydroartemisinin derivatives were synthesized via an aza-Michael addition reaction to a dihydroartemisinin-based acrylate and were evaluated for antiplasmodial and antitumor activity. The target compounds showed excellent antiplasmodial activity, with dihydroartemisinin derivatives 5, 7, 9 and 13 exhibiting IC(50) values of ≤10 nM against both D10 and Dd2 strains of Plasmodium falciparum. Derivative 4d was the most active against the HeLa cancer cell line, with an IC(50) of 0.37 μM and the highest tumor specificity.
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Affiliation(s)
- Tzu-Shean Feng
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
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92
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Guantai E, Chibale K. How can natural products serve as a viable source of lead compounds for the development of new/novel anti-malarials? Malar J 2011; 10 Suppl 1:S2. [PMID: 21411013 PMCID: PMC3059460 DOI: 10.1186/1475-2875-10-s1-s2] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Malaria continues to be an enormous global health challenge, with millions of new infections and deaths reported annually. This is partly due to the development of resistance by the malaria parasite to the majority of established anti-malarial drugs, a situation that continues to hamper attempts at controlling the disease. This has spurred intensive drug discovery endeavours geared towards identifying novel, highly active anti-malarial drugs, and the identification of quality leads from natural sources would greatly augment these efforts. The current reality is that other than compounds that have their foundation in historic natural products, there are no other compounds in drug discovery as part of lead optimization projects and preclinical development or further that have originated from a natural product start-point in recent years. This paper briefly presents both classical as well as some more modern, but underutilized, approaches that have been applied outside the field of malaria, and which could be considered in enhancing the potential of natural products to provide or inspire the development of anti-malarial lead compounds.
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Affiliation(s)
- Eric Guantai
- Department of Chemistry, University of Cape Town, Rondebosch, 7701, South Africa
| | - Kelly Chibale
- Department of Chemistry, University of Cape Town, Rondebosch, 7701, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch, 7701, South Africa
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93
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Cabri W, D’Acquarica I, Simone P, Di Iorio M, Di Mattia M, Gasparrini F, Giorgi F, Mazzanti A, Pierini M, Quaglia M, Villani C. Stereolability of Dihydroartemisinin, an Antimalarial Drug: A Comprehensive Thermodynamic Investigation. Part 1. J Org Chem 2011; 76:1751-8. [DOI: 10.1021/jo102391s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Walter Cabri
- Analytical Development, R&D Department, sigma-tau S.p.A., Via Pontina km 30.400, 00040 Pomezia, Italy
| | - Ilaria D’Acquarica
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Patrizia Simone
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Marta Di Iorio
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Michela Di Mattia
- Analytical Development, R&D Department, sigma-tau S.p.A., Via Pontina km 30.400, 00040 Pomezia, Italy
| | - Francesco Gasparrini
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Fabrizio Giorgi
- Analytical Development, R&D Department, sigma-tau S.p.A., Via Pontina km 30.400, 00040 Pomezia, Italy
| | | | - Marco Pierini
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Marco Quaglia
- Analytical Development, R&D Department, sigma-tau S.p.A., Via Pontina km 30.400, 00040 Pomezia, Italy
| | - Claudio Villani
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
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94
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Bartoli G, Marcantoni E, Marcolini M, Sambri L. Applications of CeCl(3) as an environmental friendly promoter in organic chemistry. Chem Rev 2011; 110:6104-43. [PMID: 20731375 DOI: 10.1021/cr100084g] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Giuseppe Bartoli
- Department of Organic Chemistry A. Mangini, University of Bologna, viale Risorgimento 4, I-40156 Bologna, Italy
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95
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Maes L, Van Nieuwerburgh FCW, Zhang Y, Reed DW, Pollier J, Vande Casteele SRF, Inzé D, Covello PS, Deforce DLD, Goossens A. Dissection of the phytohormonal regulation of trichome formation and biosynthesis of the antimalarial compound artemisinin in Artemisia annua plants. THE NEW PHYTOLOGIST 2011; 189:176-89. [PMID: 20874804 DOI: 10.1111/j.1469-8137.2010.03466.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
• Biosynthesis of the sesquiterpene lactone and potent antimalarial drug artemisinin occurs in glandular trichomes of Artemisia annua plants and is subjected to a strict network of developmental and other regulatory cues. • The effects of three hormones, jasmonate, gibberellin and cytokinin, were studied at the structural and molecular levels in two different A. annua chemotypes by microscopic analysis of gland development, and by targeted metabolite and transcript profiling. Furthermore, a genome-wide cDNA-amplified fragment length polymorphism (AFLP)-based transcriptome profiling was carried out of jasmonate-elicited leaves at different developmental stages. • Although cytokinin and gibberellin positively affected at least one aspect of gland formation, these two hormones did not stimulate artemisinin biosynthesis. Only jasmonate simultaneously promoted gland formation and coordinated transcriptional activation of biosynthetic gene expression, which ultimately led to increased sesquiterpenoid accumulation with chemotype-dependent effects on the distinct pathway branches. Transcriptome profiling revealed a trichome-specific fatty acyl- coenzyme A reductase, trichome-specific fatty acyl-CoA reductase 1 (TFAR1), the expression of which correlates with trichome development and sesquiterpenoid biosynthesis. • TFAR1 is potentially involved in cuticular wax formation during glandular trichome expansion in leaves and flowers of A. annua plants. Analysis of phytohormone-modulated transcriptional regulons provides clues to dissect the concerted regulation of metabolism and development of plant trichomes.
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Affiliation(s)
- Lies Maes
- Department of Plant Systems Biology, VIB, Gent, Belgium
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96
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Teja-Isavadharm P, Siriyanonda D, Siripokasupkul R, Apinan R, Chanarat N, Lim A, Wannaying S, Saunders D, Fukuda MM, Miller RS, Weina PJ, Meléndez V. A simplified liquid chromatography-mass spectrometry assay for artesunate and dihydroartemisinin, its metabolite, in human plasma. Molecules 2010; 15:8747-68. [PMID: 21124272 PMCID: PMC6259473 DOI: 10.3390/molecules15128747] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 11/13/2010] [Accepted: 11/27/2010] [Indexed: 11/16/2022] Open
Abstract
Artesunate (AS) is a potent antimalarial that is used worldwide for the treatment of malaria. A simple method with a total run time of 12 min was developed and validated for the quantification of AS and dihydroartemisinin (DHA), its active metabolite, in human (heparinized) plasma based on one-step protein precipitation in acetonitrile using artemisinin (ARN) as an internal standard, followed by liquid chromatography with a single quadrupole mass spectrometry system connected to a C18 column. Peak area ratio responses were fitted to the 2nd-order curve type, polynomial equation with weighting (1/concentration) over a quantification range between 3.20/5.33-3,000/5,000 nM (1.23/1.52-1153/1422 ng/mL) of AS/DHA showing linearity with very good correlation (r2>0.999). Single ion recordings of 5 µL injections of plasma extracts allowed for limits of detection of 1.02 nM (0.39 ng/mL) for AS and 0.44 nM (0.13 ng/mL) for DHA. The inter-assay and intra-assay accuracy and precision of the method was very good with an inaccuracy of ±12.4% and coefficients of variation of ≤10.7% at all tested concentrations. The recovery of the analytes from plasma was ≥95%. Other commonly used antimalarials including mefloquine, quinine, and chloroquine, did not interfere with the analysis. Post-preparative tests over 24 h in an autosampler (10 °C) showed that the DHA response was only 2.1% of AS from auto-hydrolysis, and β-DHA was the major, stable epimer that was used for quantification of DHA. In contrast, α-DHA increased steadily up to 600%. Artesunate and DHA in plasma were stable through three freeze/thaw cycles for up to 6 h at room temperature and up to one year at -80 °C.
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Affiliation(s)
- Paktiya Teja-Isavadharm
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
- Author to whom correspondence should be addressed: ; Tel.: +1-662-6962795; Fax: +1-662-6444784
| | - Duangsuda Siriyanonda
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
| | - Raveewan Siripokasupkul
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
| | - Roongnapa Apinan
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
| | - Nitima Chanarat
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
| | - Apassorn Lim
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
| | - Srisombat Wannaying
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
| | - David Saunders
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
| | - Mark M. Fukuda
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
| | - Robert S. Miller
- Department of Pharmacology, Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA; (R.S.M.); (P.J.W.)
| | - Peter J. Weina
- Department of Pharmacology, Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA; (R.S.M.); (P.J.W.)
| | - Victor Meléndez
- Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok 10400, Thailand
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97
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Kumar N, Singh R, Rawat DS. Tetraoxanes: Synthetic and Medicinal Chemistry Perspective. Med Res Rev 2010. [PMID: 22675731 DOI: 10.1002/med.20223] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Diwan S. Rawat
- University of Delhi; Department of Chemistry; Delhi 110007 India
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98
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Brown GD. The biosynthesis of artemisinin (Qinghaosu) and the phytochemistry of Artemisia annua L. (Qinghao). Molecules 2010; 15:7603-98. [PMID: 21030913 PMCID: PMC6259225 DOI: 10.3390/molecules15117603] [Citation(s) in RCA: 186] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 10/17/2010] [Indexed: 12/27/2022] Open
Abstract
The Chinese medicinal plant Artemisia annua L. (Qinghao) is the only known source of the sesquiterpene artemisinin (Qinghaosu), which is used in the treatment of malaria. Artemisinin is a highly oxygenated sesquiterpene, containing a unique 1,2,4-trioxane ring structure, which is responsible for the antimalarial activity of this natural product. The phytochemistry of A. annua is dominated by both sesquiterpenoids and flavonoids, as is the case for many other plants in the Asteraceae family. However, A. annua is distinguished from the other members of the family both by the very large number of natural products which have been characterised to date (almost six hundred in total, including around fifty amorphane and cadinane sesquiterpenes), and by the highly oxygenated nature of many of the terpenoidal secondary metabolites. In addition, this species also contains an unusually large number of terpene allylic hydroperoxides and endoperoxides. This observation forms the basis of a proposal that the biogenesis of many of the highly oxygenated terpene metabolites from A. annua - including artemisinin itself - may proceed by spontaneous oxidation reactions of terpene precursors, which involve these highly reactive allyllic hydroperoxides as intermediates. Although several studies of the biosynthesis of artemisinin have been reported in the literature from the 1980s and early 1990s, the collective results from these studies were rather confusing because they implied that an unfeasibly large number of different sesquiterpenes could all function as direct precursors to artemisinin (and some of the experiments also appeared to contradict one another). As a result, the complete biosynthetic pathway to artemisinin could not be stated conclusively at the time. Fortunately, studies which have been published in the last decade are now providing a clearer picture of the biosynthetic pathways in A. annua. By synthesising some of the sesquiterpene natural products which have been proposed as biogenetic precursors to artemisinin in such a way that they incorporate a stable isotopic label, and then feeding these precursors to intact A. annua plants, it has now been possible to demonstrate that dihydroartemisinic acid is a late-stage precursor to artemisinin and that the closely related secondary metabolite, artemisinic acid, is not (this approach differs from all the previous studies, which used radio-isotopically labelled precursors that were fed to a plant homogenate or a cell-free preparation). Quite remarkably, feeding experiments with labeled dihydroartemisinic acid and artemisinic acid have resulted in incorporation of label into roughly half of all the amorphane and cadinane sesquiterpenes which were already known from phytochemical studies of A. annua. These findings strongly support the hypothesis that many of the highly oxygenated sesquiterpenoids from this species arise by oxidation reactions involving allylic hydroperoxides, which seem to be such a defining feature of the chemistry of A. annua. In the particular case of artemisinin, these in vivo results are also supported by in vitro studies, demonstrating explicitly that the biosynthesis of artemisinin proceeds via the tertiary allylic hydroperoxide, which is derived from oxidation of dihydroartemisinic acid. There is some evidence that the autoxidation of dihydroartemisinic acid to this tertiary allylic hydroperoxide is a non-enzymatic process within the plant, requiring only the presence of light; and, furthermore, that the series of spontaneous rearrangement reactions which then convert this allylic hydroperoxide to the 1,2,4-trioxane ring of artemisinin are also non-enzymatic in nature.
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Affiliation(s)
- Geoffrey D Brown
- Department of Chemistry, The University of Reading, Whiteknights, Reading, RG6 6AD, UK.
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99
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Jambou R, Le Bras J, Randrianarivelojosia M. Pitfalls in new artemisinin-containing antimalarial drug development. Trends Parasitol 2010; 27:82-90. [PMID: 21030307 DOI: 10.1016/j.pt.2010.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 09/16/2010] [Accepted: 09/23/2010] [Indexed: 11/26/2022]
Abstract
Artemisinin combination therapy (ACT) paves the way for new opportunities to eliminate malaria in the tropics. However, the huge increase of ACT consumption raises major concerns about their availability over the next few years. At the same time a decrease in their efficacy has already been reported. Alongside the deployment of multifocal control programs, the process ranging from artemisia crop production to accreditation of new ACT combinations urgently needs to be strengthened to supply sufficient quantities of high-quality drugs. New suppliers will have the opportunity to enter this market to develop new formulations, and bioequivalence studies are required to validate these new formulations. It is thus crucial for national malaria control teams to be able to better scrutinize the dossier of these new formulations.
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Affiliation(s)
- Ronan Jambou
- Institut Pasteur, Departement of Parasitology and Mycology, Paris, France.
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100
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Comparative oral bioavailability of non-fixed and fixed combinations of artesunate and amodiaquine in healthy Indian male volunteers. Eur J Clin Pharmacol 2010; 67:267-75. [DOI: 10.1007/s00228-010-0911-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Accepted: 09/27/2010] [Indexed: 10/19/2022]
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