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Cheng W, Huang Y, Gao H, Bold B, Zhang T, Yang D. Marine Natural Products as Novel Treatments for Parasitic Diseases. Handb Exp Pharmacol 2024. [PMID: 38554166 DOI: 10.1007/164_2024_712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2024]
Abstract
Parasitic diseases including malaria, leishmaniasis, and trypanosomiasis have received significant attention due to their severe health implications, especially in developing countries. Marine natural products from a vast and diverse range of marine organisms such as sponges, corals, molluscs, and algae have been found to produce unique bioactive compounds that exhibit promising potent properties, including antiparasitic, anti-Plasmodial, anti-Leishmanial, and anti-Trypanosomal activities, providing hope for the development of effective treatments. Furthermore, various techniques and methodologies have been used to investigate the mechanisms of these antiparasitic compounds. Continued efforts in the discovery and development of marine natural products hold significant promise for the future of novel treatments against parasitic diseases.
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Affiliation(s)
- Wenbing Cheng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
- Guangxi Key Laboratory of Marine Natural Products and Combinatorial Biosynthesis Chemistry, Guangxi Academy of Marine Sciences, Guangxi Academy of Sciences, Nanning, Guangxi, China
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, Inner Mongolia Engineering Technology Research Center of Germplasm Resources Conservation and Utilization, School of Life Sciences, Inner Mongolia University, Hohhot, Inner Mongolia Autonomous Region, China
| | - Yanbing Huang
- Guangxi Key Laboratory of Marine Natural Products and Combinatorial Biosynthesis Chemistry, Guangxi Academy of Marine Sciences, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Haijun Gao
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
- Chengdu Fifth People's Hospital (Affiliated Fifth People's Hospital of Chengdu University of Traditional Chinese Medicine/The Second Clinical Medical College), Chengdu, Sichuan, China
| | - Bolor Bold
- National Center for Zoonotic Disease, Ulaanbaatar, Mongolia
| | - Ting Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China.
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, Inner Mongolia Engineering Technology Research Center of Germplasm Resources Conservation and Utilization, School of Life Sciences, Inner Mongolia University, Hohhot, Inner Mongolia Autonomous Region, China.
| | - Dengfeng Yang
- Guangxi Key Laboratory of Marine Natural Products and Combinatorial Biosynthesis Chemistry, Guangxi Academy of Marine Sciences, Guangxi Academy of Sciences, Nanning, Guangxi, China
- College of Food and Quality Engineering, Nanning University, Nanning, China
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Batista PJ, Nuzzo G, Gallo C, Carbone D, dell’Isola M, Affuso M, Barra G, Albiani F, Crocetta F, Virgili R, Mazzella V, Castiglia D, d’Ippolito G, Manzo E, Fontana A. Chemical and Pharmacological Prospection of the Ascidian Cystodytes dellechiajei. Mar Drugs 2024; 22:75. [PMID: 38393046 PMCID: PMC10890457 DOI: 10.3390/md22020075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/26/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Marine invertebrates are a traditional source of natural products with relevant biological properties. Tunicates are soft-bodied, solitary or colonial, sessile organisms that provide compounds unique in their structure and activity. The aim of this work was to investigate the chemical composition of the ascidian Cystodytes dellechiajei, selected on the basis of a positive result in biological screening for ligands of relevant receptors of the innate immune system, including TLR2, TLR4, dectin-1b, and TREM2. Bioassay-guided screening of this tunicate extract yielded two known pyridoacridine alkaloids, shermilamine B (1) and N-deacetylshermilamine B (2), and a family of methyl-branched cerebrosides (3). Compounds 2 and 3 showed selective binding to TREM2 in a dose-dependent manner. N-deacetylshermilamine B (2), together with its acetylated analogue, shermilamine B (1), was also strongly cytotoxic against multiple myeloma cell lines. TREM2 is involved in immunomodulatory processes and neurodegenerative diseases. N-deacetylshermilamine B (2) is the first example of a polycyclic alkaloid to show an affinity for this receptor.
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Affiliation(s)
- Pedro Jatai Batista
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Genoveffa Nuzzo
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Carmela Gallo
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Dalila Carbone
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Mario dell’Isola
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Mario Affuso
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Giusi Barra
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Federica Albiani
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Fabio Crocetta
- Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy; (F.C.); (R.V.)
- NBFC—National Biodiversity Future Center, Piazza Marina 61, 90133 Palermo, Italy;
| | - Riccardo Virgili
- Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy; (F.C.); (R.V.)
- NBFC—National Biodiversity Future Center, Piazza Marina 61, 90133 Palermo, Italy;
- Laboratory of Bio-Organic Chemistry and Chemical Biology, Department of Biology, University of Naples “Federico II”, Via Cupa Nuova Cinthia 21, 80126 Napoli, Italy
| | - Valerio Mazzella
- NBFC—National Biodiversity Future Center, Piazza Marina 61, 90133 Palermo, Italy;
- Ischia Marine Centre, Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, 80077 Naples, Italy
| | - Daniela Castiglia
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Giuliana d’Ippolito
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Emiliano Manzo
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
| | - Angelo Fontana
- Bio-Organic Chemistry Unit, Institute of Biomolecular Chemistry CNR, Via Campi Flegrei 34, 80078 Naples, Italy; (P.J.B.); (C.G.); (D.C.); (M.d.); (M.A.); (G.B.); (D.C.); (G.d.); (E.M.); (A.F.)
- Laboratory of Bio-Organic Chemistry and Chemical Biology, Department of Biology, University of Naples “Federico II”, Via Cupa Nuova Cinthia 21, 80126 Napoli, Italy
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Cooreman K, De Spiegeleer B, Van Poucke C, Vanavermaete D, Delbare D, Wynendaele E, De Witte B. Emerging pharmaceutical therapies of Ascidian-derived natural products and derivatives. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2023; 102:104254. [PMID: 37648122 DOI: 10.1016/j.etap.2023.104254] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/01/2023]
Abstract
In a growing multidrug-resistant environment, the identification of potential new drug candidates with an acceptable safety profile is a substantial crux in pharmaceutical discovery. This review discusses several aspects and properties of approved marine natural products derived from ascidian sources (phylum Chordata, subphylum Tunicata) and/or their deduced analogues including their biosynthetic origin, (bio)chemical preclinical assessments and known efficacy-safety profiles, clinical status in trials, but also translational developments, opportunities and final conclusions. The review also describes the preclinical assessments of a large number of other ascidian compounds that have not been involved in clinical trials yet. Finally, the emerging research on the connectivity of the ascidian hosts and their independent or obligate symbiotic guests is discussed. The review covers the latest information on the topic of ascidian-derived marine natural products over the last two decades including 2022, with the majority of publications published in the last decade.
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Affiliation(s)
- Kris Cooreman
- Aquatic Environment and Quality, Animal Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food, Jacobsenstraat 1, BE-8400 Ostend, Belgium
| | - Bart De Spiegeleer
- Faculty of Pharmaceutical Sciences, Drug Quality and Registration Group, Ghent University, Ottergemsesteenweg 460, BE-9000 Ghent, Belgium
| | - Christof Van Poucke
- Technology and Food Science Unit, Flanders Research Institute for Agriculture, Fisheries and Food, Brusselsesteenweg 370, BE-9090 Melle, Belgium
| | - David Vanavermaete
- Aquatic Environment and Quality, Animal Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food, Jacobsenstraat 1, BE-8400 Ostend, Belgium
| | - Daan Delbare
- Aquatic Environment and Quality, Animal Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food, Jacobsenstraat 1, BE-8400 Ostend, Belgium
| | - Evelien Wynendaele
- Faculty of Pharmaceutical Sciences, Drug Quality and Registration Group, Ghent University, Ottergemsesteenweg 460, BE-9000 Ghent, Belgium
| | - Bavo De Witte
- Aquatic Environment and Quality, Animal Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food, Jacobsenstraat 1, BE-8400 Ostend, Belgium.
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Cadelis MM, Copp BR. Marine pyridoacridine, pyridoacridone and pyrroloacridine alkaloids. THE ALKALOIDS. CHEMISTRY AND BIOLOGY 2023; 90:97-157. [PMID: 37716797 DOI: 10.1016/bs.alkal.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/18/2023]
Abstract
The families of pyridoacridine, pyridoacridone, and pyrroloacridine alkaloids are fascinating classes of natural products that have attracted the attention of chemists for over 80 years. Since the first purification of a brightly colored molecule isolated from the sea anemone Calliactis parasitica in 1940, over 110 examples of these alkaloids have been reported from marine organisms. While the paucity of numbers of protons relative to carbons and nitrogens in these molecules presents challenges in structure solution, the chemist is rewarded by their bright pigmented colors and typically diverse biological activities. In the past, several authors have proposed biosynthetic relationships within the pyridoacridine family of alkaloids, formulating a family tree derived from the reaction of dopaminequinone and kynuramine to tie together over 75 alkaloids. Inclusion of two additional quinones, and one homologous diamine, building blocks, for which there is biomimetic synthesis support, is suggestive of a more expansive connected biogenesis that encompasses not only pyridoacridines, but also pyridoacridone, and pyrroloacridine alkaloids. This review covers the isolation, structure elucidation, and proposed biosynthesis and biogenesis of pyridoacridine, pyridoacridone and pyrroloacridine marine alkaloids published to the end of 2022. Biomimetic or bio-inspired syntheses of the compound classes are described and new biological activities reported since 2004 are updated.
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Affiliation(s)
- Melissa M Cadelis
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Brent R Copp
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Tempone AG, Pieper P, Borborema SET, Thevenard F, Lago JHG, Croft SL, Anderson EA. Marine alkaloids as bioactive agents against protozoal neglected tropical diseases and malaria. Nat Prod Rep 2021; 38:2214-2235. [PMID: 34913053 PMCID: PMC8672869 DOI: 10.1039/d0np00078g] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Indexed: 01/09/2023]
Abstract
Covering: 2000 up to 2021Natural products are an important resource in drug discovery, directly or indirectly delivering numerous small molecules for potential development as human medicines. Among the many classes of natural products, alkaloids have a rich history of therapeutic applications. The extensive chemodiversity of alkaloids found in the marine environment has attracted considerable attention for such uses, while the scarcity of these natural materials has stimulated efforts towards their total synthesis. This review focuses on the biological activity of marine alkaloids (covering 2000 to up to 2021) towards Neglected Tropical Diseases (NTDs) caused by protozoan parasites, and malaria. Chemotherapy represents the only form of treatment for Chagas disease, human African trypanosomiasis, leishmaniasis and malaria, but there is currently a restricted arsenal of drugs, which often elicit severe adverse effects, show variable efficacy or resistance, or are costly. Natural product scaffolds have re-emerged as a focus of academic drug discovery programmes, offering a different resource to discover new chemical entities with new modes of action. In this review, the potential of a range of marine alkaloids is analyzed, accompanied by coverage of synthetic efforts that enable further studies of key antiprotozoal natural product scaffolds.
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Affiliation(s)
- Andre G Tempone
- Centre for Parasitology and Mycology, Instituto Adolfo Lutz, São Paulo, 01246-000, Brazil.
| | - Pauline Pieper
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
| | - Samanta E T Borborema
- Centre for Parasitology and Mycology, Instituto Adolfo Lutz, São Paulo, 01246-000, Brazil.
| | - Fernanda Thevenard
- Centre of Natural Sciences and Humanities, Federal University of ABC, Sao Paulo, 09210-580, Brazil
| | - Joao Henrique G Lago
- Centre of Natural Sciences and Humanities, Federal University of ABC, Sao Paulo, 09210-580, Brazil
| | - Simon L Croft
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK.
| | - Edward A Anderson
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
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Chabowska G, Barg E, Wójcicka A. Biological Activity of Naturally Derived Naphthyridines. Molecules 2021; 26:4324. [PMID: 34299599 PMCID: PMC8306249 DOI: 10.3390/molecules26144324] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 11/16/2022] Open
Abstract
Marine and terrestrial environments are rich sources of various bioactive substances, which have been used by humans since prehistoric times. Nowadays, due to advances in chemical sciences, new substances are still discovered, and their chemical structures and biological properties are constantly explored. Drugs obtained from natural sources are used commonly in medicine, particularly in cancer and infectious diseases treatment. Naphthyridines, isolated mainly from marine organisms and terrestrial plants, represent prominent examples of naturally derived agents. They are a class of heterocyclic compounds containing a fused system of two pyridine rings, possessing six isomers depending on the nitrogen atom's location. In this review, biological activity of naphthyridines obtained from various natural sources was summarized. According to previous studies, the naphthyridine alkaloids displayed multiple activities, i.a., antiinfectious, anticancer, neurological, psychotropic, affecting cardiovascular system, and immune response. Their wide range of activity makes them a fascinating object of research with prospects for use in therapeutic purposes.
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Affiliation(s)
- Gabriela Chabowska
- Department of Basic Medical Sciences, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211A, 50-556 Wrocław, Poland;
| | - Ewa Barg
- Department of Basic Medical Sciences, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211A, 50-556 Wrocław, Poland;
| | - Anna Wójcicka
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211A, 50-556 Wrocław, Poland
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Synthesis and Evaluation of the Tetracyclic Ring-System of Isocryptolepine and Regioiso-Mers for Antimalarial, Antiproliferative and Antimicrobial Activities. Molecules 2021; 26:molecules26113268. [PMID: 34070798 PMCID: PMC8198049 DOI: 10.3390/molecules26113268] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/18/2021] [Accepted: 05/26/2021] [Indexed: 12/04/2022] Open
Abstract
A series of novel quinoline-based tetracyclic ring-systems were synthesized and evaluated in vitro for their antiplasmodial, antiproliferative and antimicrobial activities. The novel hydroiodide salts 10 and 21 showed the most promising antiplasmodial inhibition, with compound 10 displaying higher selectivity than the employed standards. The antiproliferative assay revealed novel pyridophenanthridine 4b to be significantly more active against human prostate cancer (IC50 = 24 nM) than Puromycin (IC50 = 270 nM) and Doxorubicin (IC50 = 830 nM), which are used for clinical treatment. Pyridocarbazoles 9 was also moderately effective against all the employed cancer cell lines and moreover showed excellent biofilm inhibition (9a: MBIC = 100 µM; 9b: MBIC = 100 µM).
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Haider S, Chittiboyina AG, Khan IA. Isolation, Synthesis and Medicinal Significance of Marine Pyridoacridine Alkaloids. CURR ORG CHEM 2019. [DOI: 10.2174/1385272823666190725093517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pyridoacridine alkaloids, distributed in marine organisms have emerged as an
important class of compounds due to their uniqure chemical architecture, diversity and
medicinal significance. These alkaloids are reported to exhibit a wide array of biological
activities like anti-cancer, anti-bacterial, ant-viral, anti-fungal and anti-parasitic activities.
The present review highlights the isolation, synthesis and medicinal significance of this
important class of pyridoacridine alkaloids.
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Affiliation(s)
- Saqlain Haider
- National Center for Natural Products Research, University of Mississippi, University, MS-38677, United States
| | - Amar G. Chittiboyina
- National Center for Natural Products Research, University of Mississippi, University, MS-38677, United States
| | - Ikhlas A. Khan
- National Center for Natural Products Research, University of Mississippi, University, MS-38677, United States
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Kanishcheva EА, Bedareva VO, Vasilin VK, Stroganova TА, Krapivin GD. Thermolysis of 3-azido-4-aryl(hetaryl)thieno[2,3-b]pyridines: 2,7-naphthyridines or 1,4-diazepines? Chem Heterocycl Compd (N Y) 2019. [DOI: 10.1007/s10593-019-02552-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Affiliation(s)
- John A. Joule
- Chemistry Department; The University of Manchester; Manchester M13 9PL UK
| | - Mercedes Álvarez
- Pharmacology; Toxicology and Medicinal Chemistry; Universitat de Barcelona; Joan XXIII, s/n E-08028 Barcelona Spain
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Rampelotto PH, Trincone A. Anti-infective Compounds from Marine Organisms. GRAND CHALLENGES IN MARINE BIOTECHNOLOGY 2018. [PMCID: PMC7123853 DOI: 10.1007/978-3-319-69075-9_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Pabulo H. Rampelotto
- Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Antonio Trincone
- Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Pozzuoli, Naples, Italy
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12
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Steroid Alkaloids from Holarrhena africana with Strong Activity against Trypanosoma brucei rhodesiense. Molecules 2017; 22:molecules22071129. [PMID: 28684718 PMCID: PMC6152089 DOI: 10.3390/molecules22071129] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/04/2017] [Accepted: 07/05/2017] [Indexed: 11/16/2022] Open
Abstract
In our continued search for natural compounds with activity against Trypanosoma brucei, causative agent of human African trypanosomiasis (HAT, “sleeping sickness”), we have investigated extracts from the leaves and bark of the West African Holarrhenaafricana (syn. Holarrhena floribunda; Apocynaceae). The extracts and their alkaloid-enriched fractions displayed promising in vitro activity against bloodstream forms of T. brucei rhodesiense (Tbr; East African HAT). Bioactivity-guided chromatographic fractionation of the alkaloid-rich fractions resulted in the isolation of 17 steroid alkaloids, one nitrogen-free steroid and one alkaloid-like non-steroid. Impressive activities (IC50 in µM) against Tbr were recorded for 3β-holaphyllamine (0.40 ± 0.28), 3α-holaphyllamine (0.37 ± 0.16), 3β-dihydroholaphyllamine (0.67 ± 0.03), N-methylholaphyllamine (0.08 ± 0.01), conessimine (0.17 ± 0.08), conessine (0.42 ± 0.09), isoconessimine (0.17 ± 0.11) and holarrhesine (0.12 ± 0.08) with selectivity indices ranging from 13 to 302. Based on comparison of the structures of this congeneric series of steroid alkaloids and their activities, structure-activity relationships (SARs) could be established. It was found that a basic amino group at position C-3 of the pregnane or pregn-5-ene steroid nucleus is required for a significant anti-trypanosomal activity. The mono-methylated amino group at C-3 represents an optimum for activity. ∆5,6 unsaturation slightly increased the activity while hydrolysis of C-12β ester derivatives led to a loss of activity. An additional amino group at C-20 engaged in a pyrrolidine ring closed towards C-18 significantly increased the selectivity index of the compounds. Our findings provide useful empirical data for further development of steroid alkaloids as a novel class of anti-trypanosomal compounds which represent a promising starting point towards new drugs to combat human African trypanosomiasis.
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Palanisamy SK, Rajendran NM, Marino A. Natural Products Diversity of Marine Ascidians (Tunicates; Ascidiacea) and Successful Drugs in Clinical Development. NATURAL PRODUCTS AND BIOPROSPECTING 2017; 7:1-111. [PMID: 28097641 PMCID: PMC5315671 DOI: 10.1007/s13659-016-0115-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 12/14/2016] [Indexed: 06/06/2023]
Abstract
This present study reviewed the chemical diversity of marine ascidians and their pharmacological applications, challenges and recent developments in marine drug discovery reported during 1994-2014, highlighting the structural activity of compounds produced by these specimens. Till date only 5% of living ascidian species were studied from <3000 species, this study represented from family didemnidae (32%), polyclinidae (22%), styelidae and polycitoridae (11-12%) exhibiting the highest number of promising MNPs. Close to 580 compound structures are here discussed in terms of their occurrence, structural type and reported biological activity. Anti-cancer drugs are the main area of interest in the screening of MNPs from ascidians (64%), followed by anti-malarial (6%) and remaining others. FDA approved ascidian compounds mechanism of action along with other compounds status of clinical trials (phase 1 to phase 3) are discussed here in. This review highlights recent developments in the area of natural products chemistry and biotechnological approaches are emphasized.
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Affiliation(s)
- Satheesh Kumar Palanisamy
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, 98166, Messina, Italy.
| | - N M Rajendran
- Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Angela Marino
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, 98166, Messina, Italy
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14
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Stępień M, Gońka E, Żyła M, Sprutta N. Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications. Chem Rev 2016; 117:3479-3716. [PMID: 27258218 DOI: 10.1021/acs.chemrev.6b00076] [Citation(s) in RCA: 878] [Impact Index Per Article: 109.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.
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Affiliation(s)
- Marcin Stępień
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Elżbieta Gońka
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Marika Żyła
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Natasza Sprutta
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
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15
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Ibrahim SRM, Mohamed GA. Marine Pyridoacridine Alkaloids: Biosynthesis and Biological Activities. Chem Biodivers 2016; 13:37-47. [PMID: 26765351 PMCID: PMC7162015 DOI: 10.1002/cbdv.201400434] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/22/2015] [Indexed: 12/05/2022]
Abstract
Pyridoacridines are a class of strictly marine-derived alkaloids that constitute one of the largest chemical families of marine alkaloids. During the last few years, both natural pyridoacridines and their analogues have constituted excellent targets for synthetic works. They have been the subject of intense study due to their significant biological activities; cytotoxic, antibacterial, antifungal, antiviral, insecticidal, anti-HIV, and anti-parasitic activities. In the present review, 95 pyridoacridine alkaloids isolated from marine organisms are discussed in term of their occurrence, biosynthesis, biological activities, and structural assignment.
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Affiliation(s)
- Sabrin R M Ibrahim
- Department of Pharmacognosy and Pharmaceutical Chemistry, College of Pharmacy, Taibah University, Al Madinah , Al Munawwarah 30078, Saudi Arabia (phone: +966-581-183034; fax:+966-484-75027).
- Department of Pharmacognosy, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt, (phone: +20-88-2411330; fax: +20-88-2332776).
| | - Gamal A Mohamed
- Department of Natural Products and Alternative Medicine, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia (phone: +966-597-636182).
- Department of Pharmacognosy, Faculty of Pharmacy, Al-Azhar University, Assiut Branch, Assiut 71524, Egypt, (phone: +20-88-2181191; fax: +20-88-2181191).
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16
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Imperatore C, Aiello A, D'Aniello F, Senese M, Menna M. Alkaloids from marine invertebrates as important leads for anticancer drugs discovery and development. Molecules 2014; 19:20391-423. [PMID: 25490431 PMCID: PMC6270949 DOI: 10.3390/molecules191220391] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 11/07/2014] [Accepted: 11/27/2014] [Indexed: 11/27/2022] Open
Abstract
The present review describes research on novel natural antitumor alkaloids isolated from marine invertebrates. The structure, origin, and confirmed cytotoxic activity of more than 130 novel alkaloids belonging to several structural families (indoles, pyrroles, pyrazines, quinolines, and pyridoacridines), together with some of their synthetic analogs, are illustrated. Recent discoveries concerning the current state of the potential and/or development of some of them as new drugs, as well as the current knowledge regarding their modes of action, are also summarized. A special emphasis is given to the role of marine invertebrate alkaloids as an important source of leads for anticancer drug discovery.
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Affiliation(s)
- Concetta Imperatore
- The NeaNat Group, Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, Napoli 80131, Italy.
| | - Anna Aiello
- The NeaNat Group, Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, Napoli 80131, Italy.
| | - Filomena D'Aniello
- The NeaNat Group, Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, Napoli 80131, Italy.
| | - Maria Senese
- The NeaNat Group, Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, Napoli 80131, Italy.
| | - Marialuisa Menna
- The NeaNat Group, Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, Napoli 80131, Italy.
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17
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Tran TD, Pham NB, Quinn RJ. Structure Determination of Pentacyclic Pyridoacridine Alkaloids from the Australian Marine OrganismsAncorina geodidesandCnemidocarpa stolonifera. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402372] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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18
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Drug discovery and human African trypanosomiasis: a disease less neglected? Future Med Chem 2014; 5:1801-41. [PMID: 24144414 DOI: 10.4155/fmc.13.162] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Human African trypanosomiasis (HAT) has been neglected for a long time. The most recent drug to treat this disease, eflornithine, was approved by the US FDA in 2000. Current treatments exhibit numerous problematic side effects and are often ineffective against the debilitating CNS resident stage of the disease. Fortunately, several partnerships and initiatives have been formed over the last 20 years in an effort to eradicate HAT, along with a number of other neglected diseases. This has led to an increasing number of foundations and research institutions that are currently working on the development of new drugs for HAT and tools with which to diagnose and treat patients. New biochemical pathways as therapeutic targets are emerging, accompanied by increasing numbers of new antitrypanosomal compound classes. The future looks promising that this collaborative approach will facilitate eagerly awaited breakthroughs in the treatment of HAT.
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19
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Chemoinformatic analysis as a tool for prioritization of trypanocidal marine derived lead compounds. Mar Drugs 2014; 12:1169-84. [PMID: 24599097 PMCID: PMC3967203 DOI: 10.3390/md12031169] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 01/22/2014] [Accepted: 01/30/2014] [Indexed: 11/17/2022] Open
Abstract
Marine trypanocidal natural products are, most often, reported with trypanocidal activity and selectivity against human cell lines. The triaging of hits requires a consideration of chemical tractability for drug development. We utilized a combined Lipinski's rule-of-five, chemical clustering and ChemGPS-NP principle analysis to analyze a set of 40 antitrypanosomal natural products for their drug like properties and chemical space. The analyses identified 16 chemical clusters with 11 well positioned within drug-like chemical space. This study demonstrated that our combined analysis can be used as an important strategy for prioritization of active marine natural products for further investigation.
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20
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Jones AJ, Grkovic T, Sykes ML, Avery VM. Trypanocidal activity of marine natural products. Mar Drugs 2013; 11:4058-82. [PMID: 24152565 PMCID: PMC3826150 DOI: 10.3390/md11104058] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 10/09/2013] [Accepted: 10/10/2013] [Indexed: 12/21/2022] Open
Abstract
Marine natural products are a diverse, unique collection of compounds with immense therapeutic potential. This has resulted in these molecules being evaluated for a number of different disease indications including the neglected protozoan diseases, human African trypanosomiasis and Chagas disease, for which very few drugs are currently available. This article will review the marine natural products for which activity against the kinetoplastid parasites; Trypanosoma brucei brucei, T.b. rhodesiense and T. cruzi has been reported. As it is important to know the selectivity of a compound when evaluating its trypanocidal activity, this article will only cover molecules which have simultaneously been tested for cytotoxicity against a mammalian cell line. Compounds have been grouped according to their chemical structure and representative examples from each class were selected for detailed discussion.
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Affiliation(s)
- Amy J Jones
- Eskitis Institute for Drug Discovery, Griffith University, Nathan, Brisbane 4111, Australia.
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21
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Camp D, Campitelli M, Carroll AR, Davis RA, Quinn RJ. Front-Loading Natural-Product-Screening Libraries for logP:Background, Development, and Implementation. Chem Biodivers 2013; 10:524-37. [DOI: 10.1002/cbdv.201200302] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Indexed: 01/22/2023]
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22
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Jones AJ, Avery VM. Whole-organism high-throughput screening against Trypanosoma brucei brucei. Expert Opin Drug Discov 2013; 8:495-507. [PMID: 23540598 DOI: 10.1517/17460441.2013.783816] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Human African trypanosomiasis (HAT) occurs as a result of infection with the protozoan parasites Trypanosoma brucei gambiense and T.b. rhodesiense and is nearly always fatal without treatment. However, current therapeutic options are severely limited and there is a desperate need for new compounds to treat the disease. Whole-cell high-throughput screening (HTS) is a technique frequently used to identify compounds with trypanocidal activity. AREAS COVERED The authors examine the development of whole-organism HTS assays for T.b. brucei. The authors describe the successes achieved through HTS and discuss the advantages and disadvantages of whole-organism HTS. EXPERT OPINION Despite hundreds of trypanocidal molecules being identified by whole-organism HTS, very few have progressed into preclinical development. The failure of molecules identified by HTS to progress along the drug development pathway is due to a multitude of factors including undrug-like molecules and molecules having poor pharmacodynamics/kinetic properties. Future studies should focus on screening libraries that contain drug-like molecules that possess some of the properties required in the final compound.
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Affiliation(s)
- Amy J Jones
- Discovery Biology, Eskitis Institute (N27), Griffith University, Brisbane, 4111, Australia
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23
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Petersen IN, Crestey F, Kristensen JL. Total synthesis of ascididemin via anionic cascade ring closure. Chem Commun (Camb) 2012; 48:9092-4. [PMID: 22864261 DOI: 10.1039/c2cc34725c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new and convergent synthesis of ascididemin is presented. Using an anionic cascade ring closure as the key step, this natural product is obtained in 45% overall yield in just 6 steps starting from 2'-fluoroacetophenone. This new approach was extended to the synthesis of a new isomer of ascididemin.
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Affiliation(s)
- Ida Nymann Petersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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24
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Abstract
Natural products (NPs) have historically been a fertile source of new drugs for the pharmaceutical industry. However, this once-popular approach has waned considerably over the past two decades as the high-throughput screening of megalibraries comprised mainly of molecules with non-natural (synthetic) motifs has unfolded. Contemporary high-throughput screening libraries contain molecules compliant with physicochemical profiles considered essential for downstream development. Until recently, there was no strategy that aligned NP screening with the same physicochemical profiles. An approach based on Log P has addressed these concerns and, together with advances in isolation, afforded NP leads in timelines compatible with pure compound screening. Concomitant progress related to access of biological resources has provided long-awaited legal certainty to further facilitate NP drug discovery.
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25
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Feng Y, Davis RA, Sykes ML, Avery VM, Quinn RJ. Iotrochamides A and B, antitrypanosomal compounds from the Australian marine sponge Iotrochota sp. Bioorg Med Chem Lett 2012; 22:4873-6. [PMID: 22677313 DOI: 10.1016/j.bmcl.2012.05.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 05/04/2012] [Accepted: 05/08/2012] [Indexed: 10/28/2022]
Abstract
Bioassay-guided isolation of the CH(2)Cl(2)/MeOH extract from the Australian sponge Iotrochota sp. resulted in the purification of two new N-cinnamoyl-amino acids, iotrochamides A (1) and B (2). The chemical structures of 1 and 2 were determined by 1D/2D NMR and MS data analyses. Compounds 1 and 2 were shown to inhibit Trypanosoma brucei brucei with IC(50) values of 3.4 and 4.7 μM, respectively.
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Affiliation(s)
- Yunjiang Feng
- Eskitis Institute, Griffith University, Brisbane, QLD 4111, Australia
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26
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Camp D, Davis RA, Campitelli M, Ebdon J, Quinn RJ. Drug-like properties: guiding principles for the design of natural product libraries. JOURNAL OF NATURAL PRODUCTS 2012; 75:72-81. [PMID: 22204643 DOI: 10.1021/np200687v] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
While natural products or their derivatives and mimics have contributed around 50% of current drugs, there has been no approach allowing front-loading of chemical space compliant with lead- and drug-like properties. The importance of physicochemical properties of molecules in the development of orally bioavailable drugs has been recognized. Classical natural product drug discovery has only been able to undertake this analysis retrospectively after compounds are isolated and structures elucidated. The present approach addresses front-loading of both extracts and subsequent fractions with desired physicochemical properties prior to screening for drug discovery. The physicochemical profiles of natural products active against two neglected disease targets, malaria and African trypanosomiasis, are presented based on this strategy. This approach can ensure timely development of natural product leads at a hitherto unachievable rate.
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Affiliation(s)
- David Camp
- Eskitis Institute, Griffith University, Brisbane, QLD 4111, Australia
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27
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Abstract
Covering: 2010. Previous review: Nat. Prod. Rep., 2011, 28, 196. This review covers the literature published in 2010 for marine natural products, with 895 citations (590 for the period January to December 2010) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1003 for 2010), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.
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Affiliation(s)
- John W Blunt
- Department of Chemistry, University of Canterbury, Christchurch, New Zealand.
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28
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Davis RA, Sykes M, Avery VM, Camp D, Quinn RJ. Convolutamines I and J, antitrypanosomal alkaloids from the bryozoan Amathia tortusa. Bioorg Med Chem 2011; 19:6615-9. [DOI: 10.1016/j.bmc.2011.06.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 05/04/2011] [Accepted: 06/02/2011] [Indexed: 11/28/2022]
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29
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Watts KR, Tenney K, Crews P. The structural diversity and promise of antiparasitic marine invertebrate-derived small molecules. Curr Opin Biotechnol 2010; 21:808-18. [PMID: 20956079 DOI: 10.1016/j.copbio.2010.09.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 09/22/2010] [Accepted: 09/22/2010] [Indexed: 02/01/2023]
Abstract
This review focuses on six important parasitic diseases that adversely affect the health and lives of over one billion people worldwide. In light of the global human impact of these neglected tropical diseases (NTDs), several initiatives and campaigns have been mounted to eradicate these infections once and for all. Currently available therapeutics summarized herein are either ineffective and/or have severe and deleterious side effects. Resistant strains continue to emerge and there is an overall unmet and urgent need for new antiparasitic drugs. Marine-derived small molecules (MDSMs) from invertebrates comprise an extremely diverse and promising source of compounds from a wide variety of structural classes. New discoveries of marine natural product privileged structures and compound classes that are being made via natural product library screening using whole cell in vitro assays are highlighted. It is striking to note that for the first time in history the entire genomes of all six parasites have been sequenced and additional transcriptome and proteomic analyses are available. Furthermore, open and shared, publicly available databases of the genome sequences, compounds, screening assays, and druggable molecular targets are being used by the worldwide research community. A combined assessment of all of the above factors, especially of current discoveries in marine natural products, implies a brighter future with more effective, affordable, and benign antiparasitic therapeutics.
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Affiliation(s)
- Katharine R Watts
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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30
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Pseudoceratinazole A: a novel bromotyrosine alkaloid from the Australian sponge Pseudoceratina sp. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.07.052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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32
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Davis RA, Demirkiran O, Sykes ML, Avery VM, Suraweera L, Fechner GA, Quinn RJ. 7′,8′-Dihydroobolactone, a typanocidal α-pyrone from the rainforest tree Cryptocarya obovata. Bioorg Med Chem Lett 2010; 20:4057-9. [DOI: 10.1016/j.bmcl.2010.05.091] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 05/20/2010] [Accepted: 05/21/2010] [Indexed: 11/24/2022]
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