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Gribble GW. Naturally Occurring Organohalogen Compounds-A Comprehensive Review. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2023; 121:1-546. [PMID: 37488466 DOI: 10.1007/978-3-031-26629-4_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
The present volume is the third in a trilogy that documents naturally occurring organohalogen compounds, bringing the total number-from fewer than 25 in 1968-to approximately 8000 compounds to date. Nearly all of these natural products contain chlorine or bromine, with a few containing iodine and, fewer still, fluorine. Produced by ubiquitous marine (algae, sponges, corals, bryozoa, nudibranchs, fungi, bacteria) and terrestrial organisms (plants, fungi, bacteria, insects, higher animals) and universal abiotic processes (volcanos, forest fires, geothermal events), organohalogens pervade the global ecosystem. Newly identified extraterrestrial sources are also documented. In addition to chemical structures, biological activity, biohalogenation, biodegradation, natural function, and future outlook are presented.
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Affiliation(s)
- Gordon W Gribble
- Department of Chemistry, Dartmouth College, Hanover, NH, 03755, USA.
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Menezes C, Thakur NL. Sea anemone venom: Ecological interactions and bioactive potential. Toxicon 2022; 208:31-46. [DOI: 10.1016/j.toxicon.2022.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 10/19/2022]
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Nematocyst types and venom effects of Aurelia aurita and Velella velella from the Mediterranean Sea. Toxicon 2020; 175:57-63. [DOI: 10.1016/j.toxicon.2019.12.155] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 12/06/2019] [Accepted: 12/21/2019] [Indexed: 01/10/2023]
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Chen D, Chen Y, Ma Z, Zou L, Li J, Liu Y. One-Pot Synthesis of Indole-3-acetic Acid Derivatives through the Cascade Tsuji-Trost Reaction and Heck Coupling. J Org Chem 2018; 83:6805-6814. [PMID: 29763306 DOI: 10.1021/acs.joc.8b01056] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A practical palladium-mediated cascade Tsuji-Trost reaction/Heck coupling of N-Ts o-bromoanilines with 4-acetoxy-2-butenonic acid derivatives using a Pd(OAc)2/P( o-tol)3/DIPEA system is described for a straightforward synthesis of indole-3-acetic acid derivatives. This methodology was successfully applied to synthesize various substituted indole/azaindole-3-acetic acid derivatives and Almotriptan, which is a drug for the acute treatment of migraines. Moreover, a plausible cyclization mechanism has been proposed.
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Affiliation(s)
- Dongsheng Chen
- Novel Technology Center of Pharmaceutical Chemistry , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China.,Shanghai Engineering Research Center of Pharmaceutical Process , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China
| | - Yuanyuan Chen
- Novel Technology Center of Pharmaceutical Chemistry , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China.,Shanghai Engineering Research Center of Pharmaceutical Process , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China
| | - Zhilong Ma
- Novel Technology Center of Pharmaceutical Chemistry , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China.,Shanghai Engineering Research Center of Pharmaceutical Process , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China
| | - Lei Zou
- Novel Technology Center of Pharmaceutical Chemistry , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China.,Shanghai Engineering Research Center of Pharmaceutical Process , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China
| | - Jianqi Li
- Novel Technology Center of Pharmaceutical Chemistry , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China.,Shanghai Engineering Research Center of Pharmaceutical Process , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China
| | - Yu Liu
- Novel Technology Center of Pharmaceutical Chemistry , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China.,Shanghai Engineering Research Center of Pharmaceutical Process , Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry , 285 Gebaini Road , Shanghai 201203 , People's Republic of China
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Peripheral 5-HT3 Receptors Are Involved in the Antinociceptive Effect of Bunodosine 391. Toxins (Basel) 2017; 10:toxins10010012. [PMID: 29280949 PMCID: PMC5793099 DOI: 10.3390/toxins10010012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/06/2017] [Accepted: 12/20/2017] [Indexed: 12/27/2022] Open
Abstract
Bunodosine 391 (BDS 391), a low molecular weight compound isolated from the sea anemone Bunodosoma cangicum, increases the nociceptive threshold and inhibits inflammatory hyperalgesia. Serotonin receptors are involved in those effects. In this study, we have expanded the characterization of the antinociceptive effect of BDS 391 demonstrating that, in rats: (a) the compound inhibits (1.2–12 ng/paw) overt pain, in the formalin test, and mechanical hyperalgesia (0.6–6.0 ng/paw) detected in a model of neuropathic pain; (b) intraplantar administration of ondansetron, a selective 5-HT3 receptor antagonist, blocks the effect of BDS 391, whereas ketanserin, a 5-HT2 receptor antagonist, partially reversed this effect, indicating the involvement of peripheral 5-HT2 and 5-HT3 receptors in BDS 391 antinociception; and (c) in binding assay studies, BDS 391 was not able to displace the selective 5-HT receptor antagonists, suggesting that this compound does not directly bind to these receptors. The effect of biguanide, a selective 5-HT3 receptor agonist, was also evaluated. The agonist inhibited the formalin’s nociceptive response, supporting an antinociceptive role for 5-HT3 receptors. Our study is the first one to show that a non-peptidic low molecular weight compound obtained from a sea anemone is able to induce antinociception and that activation of peripheral 5-HT3 receptors contributes to this effect.
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Characterising the enzymatic profile of crude tentacle extracts from the South Atlantic jellyfish Olindias sambaquiensis (Cnidaria: Hydrozoa). Toxicon 2016; 119:1-7. [PMID: 27169682 DOI: 10.1016/j.toxicon.2016.04.048] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 04/27/2016] [Accepted: 04/28/2016] [Indexed: 11/20/2022]
Abstract
Jellyfish venoms are of medical and biotechnological importance, with toxins displaying antimicrobial, analgesic and anti-tumor activities. Although proteolytic enzymes have also been described, detailed characterisation of these proteins is scant in Olindias spp. High throughput mass spectrometry profiling of cnidarian venoms has become increasingly popular since the first description of the proteomic profile of putative toxins isolated from nematocysts of the hydrozoan jellyfish Olindias sambaquiensis describing the presence of orthologous enzymes as presented in venoms of advanced species as snakes. Rigorous bioinformatics analyses can aid functional annotation, but biochemical assays are prerequisite to unambiguously assign toxic function to a peptide or protein. Here we present results that experimentally confirm previously predicted proteomic analysis that crude venom extracts from tentacles of O. sambaquiensis are composed of polypeptides with metalloproteinase, serine proteinase and phospholipases A2 activities. Surprisingly, levels of serine proteinase and phospholipase A2 activities were comparable to those observed in venoms of Bothrops snakes which were used as positive controls in this study. Hence, these data offer new opportunities to explore serine proteinase and phospholipase A2 activities in the clinical sequelae following O. sambaquiensis envenomation, with future possible biopharmaceutical applications.
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Abstract
Marine indole alkaloids comprise a large and steadily growing group of secondary metabolites. Their diverse biological activities make many compounds of this class attractive starting points for pharmaceutical development. Several marine-derived indoles were found to possess cytotoxic, antineoplastic, antibacterial and antimicrobial activities, in addition to the action on human enzymes and receptors. The newly isolated indole alkaloids of marine origin since the last comprehensive review in 2003 are reported, and biological aspects will be discussed.
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Affiliation(s)
- Natalie Netz
- Institute of Organic Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Till Opatz
- Institute of Organic Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
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Jouiaei M, Yanagihara AA, Madio B, Nevalainen TJ, Alewood PF, Fry BG. Ancient Venom Systems: A Review on Cnidaria Toxins. Toxins (Basel) 2015; 7:2251-71. [PMID: 26094698 PMCID: PMC4488701 DOI: 10.3390/toxins7062251] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/09/2015] [Accepted: 06/10/2015] [Indexed: 01/22/2023] Open
Abstract
Cnidarians are the oldest extant lineage of venomous animals. Despite their simple anatomy, they are capable of subduing or repelling prey and predator species that are far more complex and recently evolved. Utilizing specialized penetrating nematocysts, cnidarians inject the nematocyst content or "venom" that initiates toxic and immunological reactions in the envenomated organism. These venoms contain enzymes, potent pore forming toxins, and neurotoxins. Enzymes include lipolytic and proteolytic proteins that catabolize prey tissues. Cnidarian pore forming toxins self-assemble to form robust membrane pores that can cause cell death via osmotic lysis. Neurotoxins exhibit rapid ion channel specific activities. In addition, certain cnidarian venoms contain or induce the release of host vasodilatory biogenic amines such as serotonin, histamine, bunodosine and caissarone accelerating the pathogenic effects of other venom enzymes and porins. The cnidarian attacking/defending mechanism is fast and efficient, and massive envenomation of humans may result in death, in some cases within a few minutes to an hour after sting. The complexity of venom components represents a unique therapeutic challenge and probably reflects the ancient evolutionary history of the cnidarian venom system. Thus, they are invaluable as a therapeutic target for sting treatment or as lead compounds for drug design.
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Affiliation(s)
- Mahdokht Jouiaei
- Venom Evolution Lab, School of Biological Sciences, the University of Queensland, St. Lucia 4072, QLD, Australia.
- Institute for Molecular Bioscience, the University of Queensland, St. Lucia 4072, QLD, Australia.
| | - Angel A Yanagihara
- Pacific Cnidaria Research Lab, Department of Tropical Medicine, University of Hawaii, Honolulu, HI 96822, USA.
| | - Bruno Madio
- Institute for Molecular Bioscience, the University of Queensland, St. Lucia 4072, QLD, Australia.
| | - Timo J Nevalainen
- Department of Pathology, University of Turku, Turku FIN-20520, Finland.
| | - Paul F Alewood
- Institute for Molecular Bioscience, the University of Queensland, St. Lucia 4072, QLD, Australia.
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, the University of Queensland, St. Lucia 4072, QLD, Australia.
- Institute for Molecular Bioscience, the University of Queensland, St. Lucia 4072, QLD, Australia.
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Abstract
This review covers the isolation, chemical structure, biological activity, structure activity relationships including synthesis of chemical probes, and pharmacological characterization of neuroactive marine natural products; 302 references are cited.
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Affiliation(s)
- Ryuichi Sakai
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan.
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10
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Abstract
This review covers the literature published in 2011 for marine natural products, with 870 citations (558 for the period January to December 2011) 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 (1152 for 2011), 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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Orts DJB, Peigneur S, Madio B, Cassoli JS, Montandon GG, Pimenta AMC, Bicudo JEPW, Freitas JC, Zaharenko AJ, Tytgat J. Biochemical and electrophysiological characterization of two sea anemone type 1 potassium toxins from a geographically distant population of Bunodosoma caissarum. Mar Drugs 2013; 11:655-79. [PMID: 23466933 PMCID: PMC3705364 DOI: 10.3390/md11030655] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 01/23/2013] [Accepted: 02/15/2013] [Indexed: 12/12/2022] Open
Abstract
Sea anemone (Cnidaria, Anthozoa) venom is an important source of bioactive compounds used as tools to study the pharmacology and structure-function of voltage-gated K+ channels (KV). These neurotoxins can be divided into four different types, according to their structure and mode of action. In this work, for the first time, two toxins were purified from the venom of Bunodosoma caissarum population from Saint Peter and Saint Paul Archipelago, Brazil. Sequence alignment and phylogenetic analysis reveals that BcsTx1 and BcsTx2 are the newest members of the sea anemone type 1 potassium channel toxins. Their functional characterization was performed by means of a wide electrophysiological screening on 12 different subtypes of KV channels (KV1.1-KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; hERG and Shaker IR). BcsTx1 shows a high affinity for rKv1.2 over rKv1.6, hKv1.3, Shaker IR and rKv1.1, while Bcstx2 potently blocked rKv1.6 over hKv1.3, rKv1.1, Shaker IR and rKv1.2. Furthermore, we also report for the first time a venom composition and biological activity comparison between two geographically distant populations of sea anemones.
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Affiliation(s)
- Diego J. B. Orts
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, SP, 05508-090, Brazil; E-Mails: (D.J.B.O.); (B.M.); (J.E.P.W.B.); (J.C.F.)
- Center of Marine Biology, University of São Paulo, São Sebastião, SP, 11600-000, Brazil
| | - Steve Peigneur
- Laboratory of Toxicology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium; E-Mail:
| | - Bruno Madio
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, SP, 05508-090, Brazil; E-Mails: (D.J.B.O.); (B.M.); (J.E.P.W.B.); (J.C.F.)
| | - Juliana S. Cassoli
- Laboratory of Venoms and Animals Toxins, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil; E-Mails: (J.S.C.); (G.G.M.); (A.M.C.P.)
| | - Gabriela G. Montandon
- Laboratory of Venoms and Animals Toxins, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil; E-Mails: (J.S.C.); (G.G.M.); (A.M.C.P.)
| | - Adriano M. C. Pimenta
- Laboratory of Venoms and Animals Toxins, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil; E-Mails: (J.S.C.); (G.G.M.); (A.M.C.P.)
| | - José E. P. W. Bicudo
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, SP, 05508-090, Brazil; E-Mails: (D.J.B.O.); (B.M.); (J.E.P.W.B.); (J.C.F.)
| | - José C. Freitas
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, SP, 05508-090, Brazil; E-Mails: (D.J.B.O.); (B.M.); (J.E.P.W.B.); (J.C.F.)
| | - André J. Zaharenko
- Laboratorio de Genetica, Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Jan Tytgat
- Laboratory of Toxicology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium; E-Mail:
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Ishikura M, Abe T, Choshi T, Hibino S. Simple indole alkaloids and those with a non-rearranged monoterpenoid unit. Nat Prod Rep 2013; 30:694-752. [DOI: 10.1039/c3np20118j] [Citation(s) in RCA: 269] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Li JL, Xiao B, Park M, Yoo ES, Shin S, Hong J, Chung HY, Kim HS, Jung JH. PPAR-γ agonistic metabolites from the ascidian Herdmania momus. JOURNAL OF NATURAL PRODUCTS 2012. [PMID: 23189988 DOI: 10.1021/np300401g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Seven new amino acid derivatives (1-4 and 6-8) were isolated from MeOH extracts of the marine ascidian Herdmania momus. Planar structures were established on the basis of NMR, IR, and MS spectroscopic analyses. Absolute configurations of these compounds were derived from specific rotation and CD analysis. The peroxisome proliferator-activated receptor (PPAR)-γ agonistic activities of the compounds were investigated due to the similarity of the structural motif to that of the antidiabetic drug rosiglitazone. Analogues with indoleglyoxyl moieties (5, 6, and 8) showed significant PPAR-γ activation in Ac2F rat liver cells.
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Affiliation(s)
- Jian Lin Li
- College of Pharmacy, Pusan National University, Busan 609-735, Korea
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Abstract
This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
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Combining multidimensional liquid chromatography and MALDI-TOF-MS for the fingerprint analysis of secreted peptides from the unexplored sea anemone species Phymanthus crucifer. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 903:30-9. [PMID: 22824729 DOI: 10.1016/j.jchromb.2012.06.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Revised: 06/17/2012] [Accepted: 06/18/2012] [Indexed: 11/23/2022]
Abstract
Sea anemones are sources of biologically active proteins and peptides. However, up to date few peptidomic studies of these organisms are known; therefore most species and their peptide diversity remain unexplored. Contrasting to previous venom peptidomic works on sea anemones and other venomous animals, in the present study we combined pH gradient ion-exchange chromatography with gel filtration and reversed-phase chromatography, allowing the separation of the 1-10 kDa polypeptides from the secretion of the unexplored sea anemone Phymanthus crucifer (Cnidaria/Phymanthidae). This multidimensional chromatographic approach followed by MALDI-TOF-MS detection generated a peptide fingerprint comprising 504 different molecular mass values from acidic and basic peptides, being the largest number estimated for a sea anemone exudate. The peptide population within the 2.0-3.5 kDa mass range showed the highest frequency whereas the main biomarkers comprised acidic and basic peptides with molecular masses within 2.5-6.9 kDa, in contrast to the homogeneous group of 4-5 kDa biomarkers found in sea anemones such as B. granulifera and B. cangicum (Cnidaria/Actiniidae). Our study shows that sea anemone peptide fingerprinting can be greatly improved by including pH gradient ion-exchange chromatography into the multidimensional separation approach, complemented by MALDI-TOF-MS detection. This strategy allowed us to find the most abundant and unprecedented diversity of secreted components from a sea anemone exudate, indicating that the search for novel biologically active peptides from these organisms has much greater potential than previously predicted.
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Abstract
Once considered to be isolation artifacts or chemical "mistakes" of nature, the number of naturally occurring organohalogen compounds has grown from a dozen in 1954 to >5000 today. Of these, at least 25% are halogenated alkaloids. This is not surprising since nitrogen-containing pyrroles, indoles, carbolines, tryptamines, tyrosines, and tyramines are excellent platforms for biohalogenation, particularly in the marine environment where both chloride and bromide are plentiful for biooxidation and subsequent incorporation into these electron-rich substrates. This review presents the occurrence of all halogenated alkaloids, with the exception of marine bromotyrosines where coverage begins where it left off in volume 61 of The Alkaloids. Whereas the biological activity of these extraordinary compounds is briefly cited for some examples, a future volume of The Alkaloids will present full coverage of this topic and will also include selected syntheses of halogenated alkaloids. Natural organohalogens of all types, especially marine and terrestrial halogenated alkaloids, comprise a rapidly expanding class of natural products, in many cases expressing powerful biological activity. This enormous proliferation has several origins: (1) a revitalization of natural product research in a search for new drugs, (2) improved compound characterization methods (multidimensional NMR, high-resolution mass spectrometry), (3) specific enzyme-based and other biological assays, (4) sophisticated collection methods (SCUBA and remote submersibles for deep ocean marine collections), (5) new separation and purification techniques (HPLC and countercurrent separation), (6) a greater appreciation of traditional folk medicine and ethobotany, and (7) marine bacteria and fungi as novel sources of natural products. Halogenated alkaloids are truly omnipresent in the environment. Indeed, one compound, Q1 (234), is ubiquitous in the marine food web and is found in the Inuit from their diet of whale blubber. Given the fact that of the 500,000 estimated marine organisms--which are the source of most halogenated alkaloids--only a small percentage have been investigated for their chemical content, it is certain that myriad new halogenated alkaloids are awaiting discovery. For example, it is estimated that nearly 4000 species of bryozoans have not been examined for their chemical content. The few species that have been studied contain some extraordinary halogenated alkaloids, such as hinckdentine A (610) and the chartellines (611-613). Of the estimated 1.5 million species of fungi, secondary metabolites have been characterized from only 5000 species. The future seems bright for the collector of halogenated alkaloids!
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Affiliation(s)
- Gordon W Gribble
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA.
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