Aspewentins D-H, 20-Nor-isopimarane Derivatives from the Deep Sea Sediment-Derived Fungus Aspergillus wentii SD-310

Exploring the potential of Aspergillus wentii: secondary metabolites and biological properties

Fungi are of considerable importance due to their capacity to biosynthesize various secondary metabolites with bioactive properties that draw high attention in new drug discovery with beneficial uses for improving human well-being and life quality. Aspergillus genus members are widespread and cosmopolitan species with varying economic significance in the fields of industry, medicine, and agriculture. Its species are renowned for their biosynthesis of secondary metabolites, characterized by both potent biological activity and structural novelty, making them a substantial reservoir for the development of new pharmaceuticals. The current work aimed at focusing on one species of this genus, Aspergillus wentii Wehmer, including its reported secondary metabolites in the period from 1951 to November 2023. A total of 97 compounds, including nitro-compounds, terpenoids, anthraquinones, xanthones, benzamides, and glucans. A summary of their bioactivities, as well as their biosynthesis was highlighted. Additionally, the reported applications of this fungus and its enzymes have been discussed. This review offers a useful reference that can direct future research into this fungus and its active metabolites, as well as their possible pharmacological and biotechnological applications.

The incredible story of ophiobolin A and sphaeropsidin A: two fungal terpenes from wilt-inducing phytotoxins to promising anticancer compounds

Covering: 2000 to 2023This review presents the exceptional story of ophiobolin A (OphA) and sphaeropsidin A (SphA), a sesterterpene and a diterpene, respectively, which were initially isolated as fungal phytotoxins and subsequently shown to possess other interesting biological activities, including promising anticancer activities. Ophiobolin A is a phytotoxin produced by different fungal pathogens, all belonging to the Bipolaris genus. Initially, it was only known as a very dangerous phytotoxin produced by fungi attacking essential cereals, such as rice and barley. However, extensive and interesting studies were carried out to define its original carbon skeleton, which is characterized by a typical 5 : 8 : 5 ring system and shared with fusicoccins and cotylenins, and its phytotoxic activity on host and non-host plants. The biosynthesis of OphA was also defined by describing the different steps starting from mevalonate and through the rearrangement of the acyclic C-25 precursor lead the toxin is obtained. OphA was also produced as a bioherbicide from Drechslera gigantea and proposed for the biocontrol of the widespread and dangerous weed Digitaria sanguinaria. To date, more than sixty ophiobolins have been isolated from different fungi and their biological activities and structure-activity relationship investigated, which were also described using their hemisynthetic derivatives. In the last two decades, thorough studies have been performed on the potential anticancer activity of OphA and its original mode of action, attracting great interest from scientists. Sphaeropsidin A has a similar story. It was isolated as the main phytotoxin from Diplodia cupressi, the causal agent of Italian cypress canker disease, resulting in the loss of millions of plants in a few years in the Mediterranean basin. The damage to the forest, environment and ornamental heritage are noteworthy and economic losses are also suffered by tree nurseries and the wood industry. Six natural analogues of SphA were isolated and several interesting hemisynthetic derivatives were prepared to study its structure-activity relationship. Surprisingly, sphaeropsidin A showed other interesting biological activities, including antibiotic, antifungal, and antiviral. In the last decade, extensive studies have focused on the anticancer activity and original mode of action of SphA. Furthermore, specific hemisynthetic studies enable the preparation of derivatives of SphA, preserving its chromophore, which showed a noteworthy increase in anticancer activity. It has been demonstrated that ophiobolin A and sphaeropsidin A are promising natural products showing potent activity against some malignant cancers, such as brain glioblastoma and different melanomas.

Pleosmaranes A-R, Isopimarane and 20-nor Isopimarane Diterpenoids with Anti-inflammatory Activities from the Mangrove Endophytic Fungus Pleosporales sp. HNQQJ-1

Pleosmaranes A-R (1-18), 18 new isopimarane-type diterpenoids, together with four known analogs (19-22), were isolated from the mangrove endophytic fungus Pleosporales sp. HNQQJ-1. Their structures and absolute configurations were established by analysis of their spectroscopic data and electronic circular dichroism (ECD) calculations. Compounds 1-9 possess an unusual aromatic B ring and a 20-nor-isopimarane skeleton. Compounds 15-17 contain a unique 2-oxabicyclo[2.2.2]octane moiety. Compound 18 features an unexpected 2-oxabicyclo[3.2.1]octane moiety. Compounds 8 and 12 exhibited a moderate inhibitory effect against LPS-induced NO production, with IC50 values of 19 and 25 μM, respectively.

Cytotoxic Compounds from Marine Fungi: Sources, Structures, and Bioactivity

Marine fungi, such as species from the Penicillium and Aspergillus genera, are prolific producers of a diversity of natural products with cytotoxic properties. These fungi have been successfully isolated and identified from various marine sources, including sponges, coral, algae, mangroves, sediment, and seawater. The cytotoxic compounds derived from marine fungi can be categorized into five distinct classes: polyketides, peptides, terpenoids and sterols, hybrids, and other miscellaneous compounds. Notably, the pre-eminent group among these compounds comprises polyketides, accounting for 307 out of 642 identified compounds. Particularly, within this collection, 23 out of the 642 compounds exhibit remarkable cytotoxic potency, with IC50 values measured at the nanomolar (nM) or nanogram per milliliter (ng/mL) levels. This review elucidates the originating fungal strains, the sources of isolation, chemical structures, and the noteworthy antitumor activity of the 642 novel natural products isolated from marine fungi. The scope of this review encompasses the period from 1991 to 2023.

A Comprehensive Review of the Classification, Sources, Phytochemistry, and Pharmacology of Norditerpenes

Norditerpenes are considered to be a common and widely studied class of bioactive compounds in plants, exhibiting a wide array of complex and diverse structural types and originating from various sources. Based on the number of carbons, norditerpenes can be categorized into C19, C18, C17, and C16 compounds. Up to now, 557 norditerpenes and their derivatives have been found in studies published between 2010 and 2023, distributed in 51 families and 132 species, with the largest number in Lamiaceae, Euphorbiaceae, and Cephalotaxaceae. These norditerpenes display versatile biological activities, including anti-tumor, anti-inflammatory, antimicrobial, and antioxidant properties, as well as inhibitory effects against HIV and α-glucosidase, and can be considered as an important source of treatment for a variety of diseases that had a high commercial value. This review provides a comprehensive summary of the plant sources, chemical structures, and biological activities of norditerpenes derived from natural sources, serving as a valuable reference for further research development and application in this field.

Editorial for Special Issue-''Research Progress and Applications of Natural Products"

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Isolation and characterization of three pairs of verrucosidin epimers from the marine sediment-derived fungus Penicillium cyclopium and configuration revision of penicyrone A and related analogues

Verrucosidins, a methylated α-pyrone class of polyketides rarely reported upon, have been implicated in one or more neurological diseases. Despite the significance of verrucosidins as neurotoxins, the absolute configurations of most of the derivatives have not been accurately characterized yet. In this study, three pairs of C-9 epimeric verrucosidin derivatives, including the known compounds penicyrones A and B (1a/1b) and 9-O-methylpenicyrones A and B (2a/2b), the new compounds 9-O-ethylpenicyrones A and B (3a/3b), together with the related known derivative verrucosidin (4), were isolated and identified from the culture extract of Penicillium cyclopium SD-413, which was obtained from the marine sediment collected from the East China sea. Their structures were established based on an in-depth analysis of nuclear magnetic resonances (NMR) and mass spectroscopic data. Determination of the absolute configurations of these compounds was accomplished by Mosher's method and time-dependent density functional theory (TDDFT) calculations of electronic circular dichroism (ECD) and optical rotation (OR). The configurational assignment of penicyrone A demonstrated that the previously reported C-6 absolute configuration of verrucosidin derivatives needs to be revised from (6S) to (6R). The 9R/9S epimers of compounds 1-3 were found to exhibit growth inhibition against some pathogenic bacteria, indicating that they have potential as lead compounds for the creation of antimicrobial agents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-023-00173-2.

Anti-Vibrio potential of natural products from marine microorganisms

The emergence of drug-resistant Vibrio poses a serious threat to aquaculture and human health, thus there is an urgent need for the discovery of new related antibiotics. Given that marine microorganisms (MMs) are evidenced as important sources of antibacterial natural products (NPs), great attention has been gained to the exploration of potential anti-Vibrio agents from MMs. This review summarizes the occurrence, structural diversity, and biological activities of 214 anti-Vibrio NPs isolated from MMs (from 1999 to July 2022), including 108 new compounds. They were predominantly originated from marine fungi (63%) and bacteria (30%) with great structural diversity, including polyketides, nitrogenous compounds, terpenoids, and steroids, among which polyketides account for nearly half (51%) of them. This review will shed light on the development of MMs derived NPs as potential anti-Vibrio lead compounds with promising applications in agriculture and human health.

20-nor-Isopimarane and isopimarane diterpenoids produced by Aspergillus sp. WT03

Five new uncommon 20-nor-isopimarane diterpenoids, aspewentins N-R (1-5), and three related known congeners (6-8), along with an isopimarane diterpenoid, sphaeropsidin C (9), were isolated from a Coptis chinensis Franch. rhizosphere soil-derived fungal strain, Aspergillus sp. WT03. The structures of compounds 1-9 were characterized based on the comprehensive analysis of the spectroscopic data, and their absolute configurations were elucidated by single crystal X-ray diffraction and time-dependent density functional theory (TDDFT)-ECD calculations. Compounds 1-5 represent rare examples of 20-nor-isopimarane analogues featuring a 1,2,3,4-tetrahydronaphthalene and 3,4-dihydronaphthalen-1(2H)-one moiety. The biosynthetic pathway of these diterpenoids was also proposed. Additionally, compounds 1, 3 and 4 showed moderate cytotoxic activity against MCF-7, A549 and HT-29 cell lines.

A Review of Diterpenes from Marine-Derived Fungi: 2009-2021

Marine-derived fungi are important sources of novel compounds and pharmacologically active metabolites. As an important class of natural products, diterpenes show various biological activities, such as antiviral, antibacterial, anti-inflammatory, antimalarial, and cytotoxic activities. Developments of equipment for the deep-sea sample collection allow discoveries of more marine-derived fungi with increasing diversity, and much progress has been made in the identification of diterpenes with novel structures and bioactivities from marine fungi in the past decade. The present review article summarized the chemical structures, producing organisms and biological activities of 237 diterpenes which were isolated from various marine-derived fungi over the period from 2009 to 2021. This review is beneficial for the exploration of marine-derived fungi as promising sources of bioactive diterpenes.

Pimarane Diterpenes from Fungi

Pimarane diterpenes are a kind of tricyclic diterpene, generally isolated from plant and fungi. In nature, fungi distribute widely and there are nearly two to three million species. They provide many secondary metabolites, including pimarane diterpenes, with novel skeletons and bioactivities. These natural products from fungi have the potential to be developed into clinical medicines. Herein, the structures and bioactivities of 197 pimarane diterpenes are summarized and the biosynthesis and pharmacological researches of pimarane diterpenes are introduced. This review may be useful improving the understanding of pimarane diterpenes from fungi.

Marine fungal metabolites as a source of drug leads against aquatic pathogens

Aquatic pathogens, including Vibrio, Edwardsiella, Pseudomonas, and Aeromonas, which could result in bacterial diseases to aquaculture, have seriously threatened the world aquaculture production. Marine-derived fungi, which could produce novel secondary metabolites with significant antibacterial activity, may be an important source for finding effective agents against aquatic pathogens. In this review, a systematically overview of the harm of several aquatic pathogens, and 134 antibacterial secondary metabolites against aquatic pathogens from 13 genera of marine-derived fungi, were summarized and concluded. The aim of this review is to find out the relationships between activity and structural type, between bioactive compounds and their hosts, and so on. Altogether, 95 references published during 1997-2021 were cited. KEY POINTS: •Aquatic pathogens, which could result in bacterial diseases to aquaculture, were described. •Marine fungal metabolites with activities against aquatic pathogens were summarized. •The distributions of these bioactive marine fungal metabolites were analyzed.

Antibacterial Molecules from Marine Microorganisms against Aquatic Pathogens: A Concise Review

Antibiotic resistance and residues in aquaculture are a growing concern worldwide and consequently identifying favorable antibacterial compounds against aquatic pathogenic bacteria are gained more attention. Active compounds derived from marine microorganisms have shown great promise in this area. This review is aimed to make a comprehensive survey of anti-aquatic pathogenic bacterial compounds that were produced by marine microorganisms. A total of 79 compounds have been reported, covering literature from 1997 to 2021. The compounds are included in different structural classes such as polyketides, terpenoids, nitrogen compounds and others, and some of them present the potential to be developed into agents for the treatment of aquatic pathogenic bacteria.

Recent studies on terpenoids in Aspergillus fungi: Chemical diversity, biosynthesis, and bioactivity

Metabolites from fungi are a major source of natural small molecule drugs in addition to plants, while fungal derived terpenoids have been confirmed to have great potentials in many diseases. Aspergillus fungi are distributed in every corner of the earth, and their terpenoid metabolites exhibit promising diversity in term of both their chemistry and bioactivity. This review attempted to provide timely and comprehensive coverage of chemical, biosynthesis, and biological studies on terpenoids discovered from the genus Aspergillus, including mono-, sesqui-, di-, sester-, tri-, and meroterpenoids, in the last decade. The structural characteristics, biosynthesis, and pharmacological activities of 288 terpenoids were introduced.

Secondary metabolites of endophytic fungi isolated from Huperzia serrata

The natural product Huperzine A isolated from Huperzia serrata is a targeted inhibitor of acetylcholinesterase that has been approved for clinical use in the treatment of Alzheimer's disease. Given the large demand for natural sources of Huperzine A  (Hup. A), efforts have been made to explore whether it is also produced by endophytic fungi from H. serrata and, if so, identify its biosynthetic pathway. These studies have indicated that endophytic fungi from H. serrata represent a huge and largely untapped resource for natural products (including Hup. A) with chemical structures that have been optimized by evolution for biological and ecological relevance. To date, more than three hundred endophytic fungi have been isolated from H. serrata, of which 9 strains can produce Hup. A, whilst more than 20 strains produce other important metabolites, such as polyketones, xanthones, alkaloids, steroids, triterpenoids, furanone derivatives, tremulane sesquitepenes and diterpenoids. In total, 200 secondary metabolites have been characterized in endophytic fungi from H. serrata to date. Functionally, some have cholinesterase-inhibitory or antibacterial activity. This review also considers the different classes of secondary metabolites produced by endophytic fungi, along with their possible applications. We systematically describe the taxonomy, biology, and chemistry of these secondary metabolites. It also summarizes the biosynthetic synthesis of metabolites, including that of Hup. A. The review will aid researchers in obtaining a clearer understanding of this plant-endophyte relationship to better exploit the excellent resources it offers that may be utilized by pharmaceutical industries.

Metabolites of Marine Sediment-Derived Fungi: Actual Trends of Biological Activity Studies

Marine sediments are characterized by intense degradation of sedimenting organic matter in the water column and near surface sediments, combined with characteristically low temperatures and elevated pressures. Fungi are less represented in the microbial communities of sediments than bacteria and archaea and their relationships are competitive. This results in wide variety of secondary metabolites produced by marine sediment-derived fungi both for environmental adaptation and for interspecies interactions. Earlier marine fungal metabolites were investigated mainly for their antibacterial and antifungal activities, but now also as anticancer and cytoprotective drug candidates. This review aims to describe low-molecular-weight secondary metabolites of marine sediment-derived fungi in the context of their biological activity and covers research articles published between January 2016 and November 2020.

Marine Pharmacology in 2016-2017: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis and Antiviral Activities; Affecting the Immune and Nervous Systems, and Other Miscellaneous Mechanisms of Action

The review of the 2016-2017 marine pharmacology literature was prepared in a manner similar as the 10 prior reviews of this series. Preclinical marine pharmacology research during 2016-2017 assessed 313 marine compounds with novel pharmacology reported by a growing number of investigators from 54 countries. The peer-reviewed literature reported antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral activities for 123 marine natural products, 111 marine compounds with antidiabetic and anti-inflammatory activities as well as affecting the immune and nervous system, while in contrast 79 marine compounds displayed miscellaneous mechanisms of action which upon further investigation may contribute to several pharmacological classes. Therefore, in 2016-2017, the preclinical marine natural product pharmacology pipeline generated both novel pharmacology as well as potentially new lead compounds for the growing clinical marine pharmaceutical pipeline, and thus sustained with its contributions the global research for novel and effective therapeutic strategies for multiple disease categories.

Advances in regioselective functionalization of 9-phenanthrenols

Various approaches are discussed for regioselective functionalization and transformation of 9-phenanthrenol and its ether derivatives, which are readily available from phenanthrene in coal tar.

Molecules derived from the extremes of life: a decade later

Covering: Early 2008 until the end of 2019Microorganisms which survive (extreme-tolerant) or even prefer (extremophilic) living at the limits of pH, temperature, salinity and pressure found on earth have proven to be a rich source of novel structures. In this update we summarise the wide variety of new molecules which have been isolated from extremophilic and extreme-tolerant microorganisms since our original 2009 review, highlighting the range of bioactivities these molecules have been reported to possess.

xOPBE: A Specialized Functional for Accurate Prediction of 13C Chemical Shifts

In this study, we present a new hybrid functional denoted as xOPBE, which is optimized at the 6-311+G(2d,p) basis set and designed with a specific aim of providing accurate ¹³C chemical shifts. By mixing the Hartree-Fock exchange into the OPBE functional, xOPBE provides a significantly improved overall performance as compared to its parent OPBE functional, while OPBE was shown previously as an excellent functional for ¹³C chemical shifts. Even in the case of the 1-adamantyl cation, for which OPBE completely fails in reproducing the experimental results, xOPBE still performs very well with similar accuracy as the standard CCSD(T) method with a large basis set. Our results also demonstrate that xOPBE not only can improve quantitatively the description of the correct assignments given by OPBE but also can revert OPBE's incorrect assignments qualitatively. Thus, we would like to recommend the use of xOPBE for routine evaluations of ¹³C chemical shifts.

Cytotoxic Thiodiketopiperazine Derivatives from the Deep Sea-Derived Fungus Epicoccum nigrum SD-388

Four new thiodiketopiperazine alkaloids, namely, 5’-hydroxy-6’-ene-epicoccin G (1), 7-methoxy-7’-hydroxyepicoccin G (2), 8’-acetoxyepicoccin D (3), and 7’-demethoxyrostratin C (4), as well as a pair of new enantiomeric diketopiperazines, (±)-5-hydroxydiphenylalazine A (5), along with five known analogues (6–10), were isolated and identified from the culture extract of Epicoccum nigrum SD-388, a fungus obtained from deep-sea sediments (−4500 m). Their structures were established on the basis of detailed interpretation of the NMR spectroscopic and mass spectrometric data. X-ray crystallographic analysis confirmed the structures and established the absolute configurations of compounds 1–3, while the absolute configurations for compounds 4 and 5 were determined by ECD calculations. Compounds 4 and 10 showed potent activity against Huh7.5 liver tumor cells, which were comparable to that of the positive control, sorafenib, and the disulfide bridge at C-2/C-2’ is likely essential for the activity.

Deep-Sea Fungi Could Be the New Arsenal for Bioactive Molecules

Growing microbial resistance to existing drugs and the search for new natural products of pharmaceutical importance have forced researchers to investigate unexplored environments, such as extreme ecosystems. The deep-sea (>1000 m below water surface) has a variety of extreme environments, such as deep-sea sediments, hydrothermal vents, and deep-sea cold region, which are considered to be new arsenals of natural products. Organisms living in the extreme environments of the deep-sea encounter harsh conditions, such as high salinity, extreme pH, absence of sun light, low temperature and oxygen, high hydrostatic pressure, and low availability of growth nutrients. The production of secondary metabolites is one of the strategies these organisms use to survive in such harsh conditions. Fungi growing in such extreme environments produce unique secondary metabolites for defense and communication, some of which also have clinical significance. Despite being the producer of many important bioactive molecules, deep-sea fungi have not been explored thoroughly. Here, we made a brief review of the structure, biological activity, and distribution of secondary metabolites produced by deep-sea fungi in the last five years.

Induced terreins production from marine red algal-derived endophytic fungus Aspergillus terreus EN-539 co-cultured with symbiotic fungus Paecilomyces lilacinus EN-531

The coculture of marine red algal-derived endophytic fungi Aspergillus terreus EN-539 and Paecilomyces lilacinus EN-531 induced the production of a new terrein derivative, namely asperterrein (1) and a known dihydroterrein (2), which were not detected in the axenic cultures of both strains. The production of the known secondary metabolites terrein (3), butyrolactone I (4), and dankasterone (6), derived from A. terreus EN-539, were depressed significantly in the coculture. Compounds 1-3 exhibited inhibitory activity against Alternaria brassicae, Escherichia coli, Physalospora piricola, and Staphylococcus aureus with MIC values ranging from 4 to 64 μg ml^-1.

HPLC-DAD-Directed Isolation of Linearly Fused Prenylated Indole Alkaloids from a Soil-Derived Aspergillus versicolor

An HPLC-DAD-directed chemical investigation of the soil-derived fungus Aspergillus versicolor QC812 resulted in the isolation and identification of eight new linearly fused prenylated indole alkaloids, asperversiamides I-P (1-8), along with a congener, asperversiamide H (9). Their structures and absolute configurations were determined by spectroscopic analysis including HRESIMS and 1D and 2D NMR, electronic circular dichroism analysis, and single-crystal X-ray diffraction. Asperversiamide I (1), the first diketopiperazine derived from d-proline and l-tryptophan, possesses an unprecedented C-11-spiro-fused 6/6/5/5/6/5 hexacyclic ring system. Asperversiamide J (2) is the first linearly fused 6/6/5 tricyclic prenylated indole alkaloid to be reported. 1 and 2 showed moderate inhibitory activities against HeLa cells with IC₅₀ values of 7.3 and 6.4 μM, respectively.

Thiocladospolides A-D, 12-Membered Macrolides from the Mangrove-Derived Endophytic Fungus Cladosporium cladosporioides MA-299 and Structure Revision of Pandangolide 3

Four new 12-membered macrolides, thiocladospolides A-D (1-4), each possessing a sulfur substitution at C-2, along with the known congener pandangolide 3 (5) and the possible hydrolysis product seco-patulolide C (6), were isolated and identified from the culture extract of Cladosporium cladosporioides MA-299, an endophytic fungus obtained from the leaves of the mangrove plant Bruguiera gymnorrhiza. Their structures were established by interpretation of the NMR spectroscopic and mass spectrometric data. X-ray crystallographic analysis of compound 1, which represents the first crystal structure described for a sulfur-containing 12-membered macrolide, confirmed its structure and absolute configuration. The proposed sulfur side chain at C-3 in pandangolide 3 (5) was revised to be at C-2 by detailed analysis of the NMR data and by a comparison with data for thiocladospolide A (1). The structures for pandangolides 2 and 4 should also be considered for revisions. The isolated compounds were evaluated for the antimicrobial activities against aquatic bacteria and plant pathogens.

20-Nor-Isopimarane Epimers Produced by Aspergillus wentii SD-310, a Fungal Strain Obtained from Deep Sea Sediment

Four new uncommon 20-nor-isopimarane diterpenoid epimers, aspewentins I−L (1–4), together with a new methylated derivative of 3, aspewentin M (5), were isolated from the deep sea sediment-derived fungus Aspergillus wentii SD-310. The very similar structures of these epimers made the separation and purification procedures difficult. The structures of compounds 1–5 were illustrated based on spectroscopic analysis, and the absolute configurations of compounds 1–5 were unambiguously determined by the combination of NOESY, time-dependent density functional (TDDFT)-ECD calculations, and X-ray crystallographic analysis. These metabolites represented the rare examples of 20-nor-isopimarane analogues possessing a cyclohexa-2,5-dien-1-one moiety. These compounds were tested for antimicrobial activities against human and aquatic pathogenic bacteria, as well as plant-pathogenic fungi. While compounds 1 and 2 exhibited inhibitory activities against zoonotic pathogenic bacteria such as Escherichia coli, Edwardsiella tarda, Vibrio harveyi, and V. parahaemolyticus, compound 5 showed potent activity against the plant pathogen Fusarium graminearum.

Highly Substituted Benzophenone Aldehydes and Eremophilane Derivatives from the Deep-Sea Derived Fungus Phomopsis lithocarpus FS508

Five new benzophenone derivatives named tenellones D–H (1–5), sharing a rare naturally occurring aldehyde functionality in this family, and a new eremophilane derivative named lithocarin A (7), together with two known compounds (6 and 8), were isolated from the deep marine sediment-derived fungus Phomopsis lithocarpus FS508. All of the structures for these new compounds were fully characterized and established on the basis of extensive spectroscopic interpretation and X-ray crystallographic analysis. Compound 5 exhibited cytotoxic activity against HepG-2 and A549 cell lines with IC₅₀ values of 16.0 and 17.6 μM, respectively.

Bioactive Pimarane Diterpenes from the Arctic Fungus Eutypella sp. D-1

Two new pimarane diterpenes, libertellenone M (1) and libertellenone N (2), together with five known compounds were isolated from the culture extract of Eutypella sp. D-1 derived from high-latitude soil of the Arctic. The structures of these compounds were determined by spectroscopic data as well as experimental and calculated electronic circular dichroism (ECD) analysis. Antimicrobial and cytotoxic activities of the isolated compounds were evaluated. Compound 3 exhibited weak antibacterial activity against Escherichia coli, Bacillus subtilis, and Vibrio vulnificus, each with MIC values of 16 μg/mL. Compounds 2 and 3 showed moderate cytotoxic activity against K562 and MCF-7 cell lines with IC₅₀ values of 7.67 and 9.57 μm, respectively.

Marine natural products

Covering: 2016. Previous review: Nat. Prod. Rep., 2017, 34, 235-294This review covers the literature published in 2016 for marine natural products (MNPs), with 757 citations (643 for the period January to December 2016) 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 (1277 in 432 papers for 2016), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included.

Lithocarpins A–D: four tenellone-macrolide conjugated [4 + 2] hetero-adducts from the deep-sea derived fungus Phomopsis lithocarpus FS508

Lithocarpins A–D, four novel tenellone-macrolide conjugated dimers containing a fascinating 9,14-epoxynaphtho[2,3-e]oxecin-3(2H)-one skeleton.

Gold-Catalyzed Oxidation Terminal Alkyne: An Approach to Synthesize Substituted Dihydronaphthalen-2(1H)-ones and Phenanthrenols

A facile gold-catalyzed oxidation terminal alkynes to synthesize substituted dihydronaphthalen-2(1H)-ones 3 and phenanthrenols 5 was realized. Various useful structures and drug precursors were generated in up to 99% yield under mild condition and low catalyst loading.

Biotechnological Potential of Cold Adapted Pseudoalteromonas spp. Isolated from 'Deep Sea' Sponges

The marine genus Pseudoalteromonas is known for its versatile biotechnological potential with respect to the production of antimicrobials and enzymes of industrial interest. We have sequenced the genomes of three Pseudoalteromonas sp. strains isolated from different deep sea sponges on the Illumina MiSeq platform. The isolates have been screened for various industrially important enzymes and comparative genomics has been applied to investigate potential relationships between the isolates and their host organisms, while comparing them to free-living Pseudoalteromonas spp. from shallow and deep sea environments. The genomes of the sponge associated Pseudoalteromonas strains contained much lower levels of potential eukaryotic-like proteins which are known to be enriched in symbiotic sponge associated microorganisms, than might be expected for true sponge symbionts. While all the Pseudoalteromonas shared a large distinct subset of genes, nonetheless the number of unique and accessory genes is quite large and defines the pan-genome as open. Enzymatic screens indicate that a vast array of enzyme activities is expressed by the isolates, including β-galactosidase, β-glucosidase, and protease activities. A β-glucosidase gene from one of the Pseudoalteromonas isolates, strain EB27 was heterologously expressed in Escherichia coli and, following biochemical characterization, the recombinant enzyme was found to be cold-adapted, thermolabile, halotolerant, and alkaline active.

Wentinoids A–F, six new isopimarane diterpenoids from Aspergillus wentii SD-310, a deep-sea sediment derived fungus

Wentinoids A–F (1–6), presented as the first examples of isopimarane analogues from the fungus Aspergillus wentii, were isolated and identified.

Diterpenoids of terrestrial origin

This review covers the isolation and chemistry of diterpenoids from terrestrial as opposed to marine sources and includes labdanes, clerodanes, abietanes, pimaranes, kauranes, cembranes and their cyclization products. The literature from January to December, 2016 is reviewed.

Cold-water marine natural products, 2006 to 2016

This is an update report on marine natural products isolated from cold-water organisms in the last decade, following the previous review that covered the literature up to 2005. Emphasis is on structural assignments and biological activity.

Pyran Rings Containing Polyketides from Penicillium raistrickii

Five new pyran rings containing polyketides, penicipyrans A–E (1–5), together with the known pestapyrone A (6), were isolated from the saline soil-derived Penicillium raistrickii. Their structures were determined by interpretation of NMR and HRESIMS data. The absolute configurations of compounds 4 and 5 were established by the modified Mosher’s method and single-crystal X-ray diffraction analysis, respectively. These compounds possessed high structural diversity including two α-pyrones (1, 2), three isocoumarins (3, 4, 6), and one dihydropyran derivative (5). Among them, Compound 5 exhibited cytotoxicity against HL-60 and K562 cell lines with IC₅₀ values of 4.4 and 8.5 μM, respectively.

20-Nor-isopimarane cycloethers from the deep-sea sediment-derived fungus Aspergillus wentii SD-310

Five new 20-nor-isopimaranes, asperethers A–E (1–5), were isolated from the deep-sea derived fungus Aspergillus wentii SD-310. These compounds possess a unique 6/6/6/5 tetracyclic system and exhibited cytotoxicity against several tumor cell lines.