The role of vanadium bromoperoxidase in the biosynthesis of halogenated marine natural products

Halogenated natural products are frequently reported metabolites in marine seaweeds. These compounds span a range from halogenated indoles, terpenes, acetogenins, phenols, etc., to volatile halogenated hydrocarbons that are produced on a very large scale. In many cases these halogenated marine metabolites possess biological activities of pharmacological interest. Given the abundance of halogenated marine natural products found in marine organisms and their potentially important biological activities, the biogenesis of these compounds has intrigued marine natural product chemists for decades. Over a quarter of a century ago, a possible role for haloperoxidase enzymes was first suggested in the biogenesis of certain halogenated marine natural products, although this was long before haloperoxidases were discovered in marine organisms. Since that time, FeHeme- and Vanadium-haloperoxidases (V-HPO) have been discovered in many marine organisms. The structure and catalytic activity of vanadium haloperoxidases is reviewed herein, including the importance of V-HPO-catalyzed bromination and cyclization of terpene substrates.     

Natural Products Produced in Culture by Biosynthetically Talented Salinispora arenicola Strains Isolated from Northeastern and South Pacific Marine Sediments

Laboratory cultures of two ‘biosynthetically talented’ bacterial strains harvested from tropical and temperate Pacific Ocean sediment habitats were examined for the production of new natural products. Cultures of the tropical Salinispora arenicola strain RJA3005, harvested from a PNG marine sediment, produced salinorcinol (3) and salinacetamide (4), which had previously been reported as products of engineered and mutated strains of Amycolatopsis mediterranei, but had not been found before as natural products. An S. arenicola strain RJA4486, harvested from marine sediment collected in the temperate ocean waters off British Columbia, produced the new aminoquinone polyketide salinisporamine (5). Natural products 3, 4, and 5 are putative shunt products of the widely distributed rifamycin biosynthetic pathway.     

The nature and role of pigments of marine invertebrates

Marine animals, especially those from tropical waters, are often brilliantly coloured, and bright colouration is widespread in both sessile and non-sessile invertebrates. These spectacular natural colours are common in species inhabiting shallow waters, and appear not only in animals exposed to bright light, but also in those living in dark areas where colours are visible only with artificial illumination. Marine organisms also show variation in colour with depth and geographical location, and display great variety in colour patterning. These colour characteristics are the result of several different processes, and serve various purposes - the distribution and function of pigments seems to vary between invertebrate groups. In addition to playing an important role in how marine organisms interact, pigments may be involved in physiological processes. Although nitrogenous pigments predominate, marine organisms contain pigments belonging to all the major structural classes of natural products, as well as some that are unique to the marine environment. This review discusses the nature and significance of such pigments, the chemical and biological processes involved, the factors responsible for and affecting bright colourations, as well as their evolution and speculation as to their function.     

新型海洋双吲哚类生物碱的研究进展

双吲哚类生物碱是近年来分离到的一类很重要的海洋天然产物。由于这类化合物具有新颖的化学结构和多种生理活性,因此它们引起了科学家极大的兴趣。本文综述了近年来新型海洋双吲哚类生物碱的研究进展。     

Marine bifunctional sphingolipids from the sponge Oceanapia ramsayi

During the course of our continuing studies on marine natural lipid products,two known sphingolipids have been isolated for the first time from a specimen of the marine sponge Oceanapia ramsayi collected at Itampolo on the west coast of Madagascar in the Indian Ocean. The structures were elucidated using NMR data and by comparison with literature data. The occurrence of these sphingolipids within other Oceanapia spp. is discussed.     

海洋天然产物研究新进展

海洋天然产物化学是目前天然产物化学中最活跃的研究领域之一。近年来,从海洋生物中分离到非常多的化学结构和生理活性上令人注目的新化合物,引起了有机化学家和药物化学家的关注。本文按萜类、太环内酯、聚醚类、生物碱,环肽、含氰化合物、甾醇、聚丙酸酯类化合物等化学结构来概述海洋天然产物研究近年来的进展。     

Status of Drug Discovery Research Based on Marine Organisms from Eastern Indonesia

Despite the vastness of Eastern Indonesian Waters (EIW), no review has been done on the status of drug discovery research based on marine organisms from this area. The aim of this paper is to briefly discuss the challenges and perspectives on drug discovery research based on marine organisms in these indigenous waters. The emphasis is on the last 20 year period (1993 to 2013). Research activities completed during this period suggest that marine organisms from EIW could be utilized as an important natural resource for future drug discovery and development. However, lack of facilities, as well as competent human resources, significantly hinder progress on drug discovery research. More in-depth study especially on deep-sea natural products needs to be carried out to solidify the research on the potential for marine organisms from EIW to contribute to the future of drug discovery.     

Highly efficient biomimetic total synthesis and structural verification of bistratamides E and J from Lissoclinum bistratum

The interesting biological activities of heterocycle-containing cyclic peptide-derived natural products, isolated from marine organisms over the past twenty years, have attracted the interest of many synthetic and natural products chemists. Bistratamides E-J, members of this class of natural products that were isolated very recently from Lissoclinum bistratum, exhibited cytotoxic activity against a human colon tumor (HCT-116) cell line. Here we report the first total syntheses of bistratamides E (1) and J (2) in overall yields of 19 and 34 %, respectively. The thiazole substructures have been synthesized by oxidation of their corresponding thiazoline substructures, which were obtained from cysteine containing peptides using a novel biomimetic approach wherein Val-Cys dipeptide units were converted to thiazolines by a bisphosphonium salt. The final macrocyclization was promoted efficiently using the combination of PyBOP and DMAP. This approach allows the use of readily available Fmoc-protected amino acids to make complex thiazole and oxazoline-containing natural products.     

Organic UV filters in marine environments: An update of analytical methodologies,occurrence and distribution

Ultraviolet filters (UV Filters) are compounds that are widely employed in personal care products such as sunscreens to protect the skin from sun damage, but they are also added to other products, such as food packaging, plastics, paints, textiles, detergents, etc. The continuous use of these products causes the release of a substantial amount of these products into the marine environment through direct input or wastewater discharge, and thus they are becoming an important class of contaminants of emerging concern. A correlation between their occurrence and different negative effects on marine biota has been reported.Taking into account all the possible impacts on the environment, knowledge of their presence and distribution in the different compartments of the ecosystems, ranging from waters and sediments to aquatic organisms, which potentially suffer from bioaccumulation and biomagnification processes, is essential. High concentrations of ultraviolet filters have been found in samples collected from across the entire planet, even in polar regions, revealing their global distribution.Therefore, interest in the sensitive determination of ultraviolet filters in several marine matrices has increased. In this article, an overall review of the more recently reported analytical chemistry methods for identifying and quantifying these compounds in marine environmental samples is presented. We compare and discuss the potential advantages and disadvantages of every step involved in the analytical procedure, including the pre-treatment, treatment and extraction processes that are required to avoid matrix effects. Moreover, we describe the worldwide occurrence and distribution of those most important UV filters.     

Recent developments in the synthesis of zoanthamine alkaloids

This review provides a compilation of the most recent synthetic approaches and total syntheses of zoanthamine alkaloids, which are structurally unique heptacyclic marine natural products that display a range of interesting biological activities. This review is focused on synthetic methodologies for the construction of the three adjacent quaternary asymmetric carbon atoms on the cyclohexane ring (C-ring) of these compounds. The literature covered in this review dates from 2008 to the end of 2013.     

Cytotoxic and antioxidant marine prenylated quinones and hydroquinones

Covering: 1972 to 2011. This review covers the literature of prenylated quinone, hydroquinone and naphthoquinone marine natural products with reported cytotoxic and/or antioxidant properties. The structures, biological activity and, where applicable, the syntheses of 159 cytotoxic/antioxidant compounds, isolated from various marine organisms, are presented, while trends in the distribution of these cytotoxic metabolites, across the different marine phyla, are highlighted. Marine prenylated quinones, hydroquinones and naphthoquinones are of mixed polyketide and terpenoid biogenesis and recent biosynthetic studies of selected compounds are discussed.     

Chemical Diversity and Biological Activity of Secondary Metabolites Isolated from Indonesian Marine Invertebrates

Marine invertebrates have been reported to be an excellent resource of many novel bioactive compounds. Studies reported that Indonesia has remarkable yet underexplored marine natural products, with a high chemical diversity and a broad spectrum of biological activities. This review discusses recent updates on the exploration of marine natural products from Indonesian marine invertebrates (i.e., sponges, tunicates, and soft corals) throughout 2007–2020. This paper summarizes the structural diversity and biological function of the bioactive compounds isolated from Indonesian marine invertebrates as antimicrobial, antifungal, anticancer, and antiviral, while also presenting the opportunity for further investigation of novel compounds derived from Indonesian marine invertebrates.     

Secondary metabolites from marine bryozoans. A review

Secondary metabolites from marine bryozoans are reviewed. Two ctenosome bryozoans are dealt with, one, Alcyonidium gelatinosum containing a sulfoxonium ion acting as hapten in an allergic contact dermatitis and the other, Zoobotryon verticillatum yielding bromogramines. Five cheilostome bryozoans have given rise to the isolation of unique secondary natural products. Bugula neritina is the source of the antineoplastic bryostatins and Bugula purple while Flustra foliacea have yielded an array of bromoindole alkaloids and a brominated quinoline. Chartella papyracea also have bromoindole alkaloids while Sessibugula translucens have ecological active bipyrroles. A biological active xanthine derivative has been reported from Phidolopora pacifica. The structure and chemistry of these compounds are discussed as are their origin, function and biological activity.     

Marine Natural Products as Lead Compound for New Drug Discovery

The study of natural product has long been motivated by a quest for some benefit to man, the discover. Recent years have witnessed growing attention to the isolation, identification and synthesis of the marine natural. Although marine organisms do not have a long history of medicine applications like terrestrial plants, some marine organisms have left an extensive record of hazard to mankind. The isolation and identification of saxtoxin, tetradotoxin and lyngbyatoxin resulted from such reported. The marine biosphere has long held great promise as source of anticancer compounds, while a number of screening efforts has indicated a much higher percentage of antineplastic and antitumor activity than terrestrial plants. Several marine natural products have made their appearance in clinical trials at the National Cancer Institute, such as the didemnis, , bryostatins, This finds marine invertebratehave reinvigorated interest and effort in anticancer agent from marine invertebrate.     

Computational studies of Fe(III) binding to bryostatins, bryostatin analogs, siderophores and marine natural products: arguments for ferric complexes in medicinal applications

In this computational study, geometric factors are calculated by applying semi-empirical methods (PM3) that support experimental evidence from this lab where bryostatins can bind trivalent iron with six Fe-O bonds forming an octahedral geometry. The geometric factors are calculated for all 20 structures (Fe3+ bound to bryostatin 1-20) as a neutral, monovalent, and divalent species. The average Fe-O bond distances and bond angles are compared to those of known marine and terrestrial siderophores. From these two data sets, we then examined other known marine natural products (MNPs) that can form a hexavalent complex with six Fe-O bonds and draw conclusions about their potential biological role as marine siderophores. This computational data indicates that Fe(III) strongly bonds to a host of MNPs, increasing their water solubility, contracting their structure, hence allowing transport through cell membranes more readily, and in some cases, stabilizing ester bonds that are susceptible to hydrolysis. It is argued that administering medicinally bryostatin, its analogs or other MNPs as a ferric complex, holds some fundamental chemical advantages compared to its administration as a neutral uncomplexed species.     

Actin-binding marine macrolides: total synthesis and biological importance

Marine organisms produce a fascinating range of structurally diverse secondary metabolites, which often possess unusual and sometimes unexpected biological activities. This structural diversity makes these marine natural products excellent molecular probes for the investigation of biochemical pathways. Recently, a number of novel and stereochemically complex macrolides, having a large macrolactone (22- to 44-membered) ring, that interact with the actin cycloskeleton have been isolated from different marine sources. Actin, like tubulin, is a major component of the cytoskeleton and has important cellular functions. Although the details of these interactions are still under investigation, these marine macrolides are becoming increasingly important as novel molecular probes to help elucidate the cellular functions of actin. Owing to their potent antitumor activities, these compounds, for example the aplyronines, also have potential for preclinical development in cancer chemotherapy. Their appealing molecular structures, with an abundance of stereochemistry, and biological significance, coupled with the extremely limited availability from the marine sources, have stimulated enormous interest in the synthesis of these compounds. This review summarizes the biological properties of these unusual marine natural products and features the recently completed total syntheses of swinholide A, scytophycin C, aplyronine A, mycalolide A--all of these being potent cytotoxic agents that target actin--and a diastereoisomer of ulapualide A. Rather than detailing each individual step of these multistep total syntheses, the different synthetic strategies, key reactions, and methods adopted for controlling the stereochemistry are compared.     

Marine natural products

This review covers the literature published in 2002 for marine natural products, with 579 citations (413 for the period January to December 2002) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (677 for 2002), together with their relevant biological activities, source organisms and country of origin. Syntheses that lead to the revision of structures or stereochemistries have been included (114), including any first total syntheses of a marine natural product.     

Biotechnical potential of natural products

The potential of natural products has been recognized since antiquity. They continue to contribute a great deal to modern industries by providing a wide range of chemicals; many of them now vital to modern life, such as antibiotics, cardiac drugs and insecticides, were discovered from living organisms.Traditionally, natural product research has primarily centred around the structural elucidation of compounds. However, in recent years, research has been directed towards the physiological and ecological significance of these chemicals. We have just begun to understand the role of naturally occurring chemicals in the biological interactions of organisms with their ecosystems. The study of natural products not only provides novel bioactive compounds, but also helps in the understanding of nature's way of tackling environmental problems. These processes, which may be called “Natural Technology”, might provide us with totally new means and agents for combating diseases, controlling pests or improving agricultural productivity.The extension of research to marine natural products has paid rich dividends. Polyoxygenated compounds such as tetrodotoxins, palytoxins and halichondrins show novel bioelectric properties which influence the ionic permeability of biological membranes. Some of these compounds show remarkable antitumour and immunomodulatory activities. So far, only a small proportion of the known flora has been subjected to chemical or biological investigations; the vast unexplored biotechnical potential of flora awaits discovery and exploitation.     

Marine natural products

This review covers the literature published in 2001 for marine natural products, with 497 citations (373 for the period January to December 2001) and includes 793 compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds and new stereochemical assignments (683 for 2001), together with relevant biological activities, source organisms and country of origin. Syntheses that confirm or revise structures or stereochemistries have been included (95), including any first total synthesis of a marine natural product.     

Marine natural products

This review covers the literature published in 2003 for marine natural products, with 619 citations (413 for the period January to December 2003) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (656 for 2003), together with their relevant biological activities, source organisms and country or origin. Biosynthetic studies or syntheses that lead to the revision of structures or stereochemistries have been included (78), including any first total syntheses of a marine natural product.