A new diterpene synthase from the actinomycete Catenulispora acidiphila was identified and the structures of its products were elucidated, including the absolute configurations by an enantioselective ...deuteration approach. The mechanism of the cationic terpene cyclisation cascade was deeply studied through the use of isotopically labelled substrates and of substrate analogues with partially blocked reactivity, resulting in derailment products that gave further insights into the intermediates along the cascade. Their chemistry was studied, leading to the biomimetic synthesis of a diterpenoid analogue of a brominated sesquiterpene known from the red seaweed Laurencia microcladia.
A new diterpene synthase (CaCS) from Catenulispora acidiphila and its products were identified. The enzyme mechanism was studied by isotopic labelling experiments and usage of substrate analogues with blocked reactivity, resulting in a series of derailment products. Their chemistry was studied, leading to the biomimetic synthesis of a diterpenoid analogue of a brominated sesquiterpene known from the red seaweed Laurencia microcaldia.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Covering: July 2010 to August 2021
This article summarizes more than 200 cases of misassigned marine natural products reported between July 2010 and August 2021, sorting out errors according to the ...structural elements. Based on a comparative analysis of the original and the revised structures, major pitfalls still plaguing the structural elucidation of small molecules were identified, emphasizing the role of total synthesis, crystallography, as well as chemical- and biosynthetic logic to complement spectroscopic data. Distinct "trends" in natural product misassignment are evident between compounds of marine and plant origin, with an overall much lower incidence of "impossible" structures within misassigned marine natural products.
The article summarizes over 200 cases of misassigned MNPs, identifying major pitfalls still plaguing the structural elucidation of small molecules.
Covering: 2010 to 2020
The class of 2,11-cyclized cembranoids is particularly widespread in marine Octocorallia, especially Alcyonacea and Gorgonacea, and has been extensively studied. Following a ...previous review published in 2010, the accumulated knowledge from the past decade will be presented here. All 2,11-cyclized cembranoids share a bicyclo8.4.0tetradecane core that is in most of the known compounds oxidatively modified to result in the 15-oxatricyclo6.6.1.0
2,7
pentadecane system. Multiple further oxidation and acylation patterns can be observed, while halogenated compounds are surprisingly rare. One new sulfur-containing and a few
seco
-compounds have also been reported. The biosynthetic pathways to this fascinating class of natural products have not been studied to date, but a plausible biosynthetic hypothesis is presented that allows for a structured discussion of the compounds according to their carbon skeletons and oxidation patterns. Biological activities towards 2,11-cyclized diterpenes are also included.
This review summarises new marine 2,11-cyclized cembranoids from the past decade in a structured presentation according to their hypothetical biosynthesis.
Benzoxepane derivatives were designed and synthesized, and one hit compound emerged as being effective in vitro with low toxicity. In vivo, this hit compound ameliorated both sickness behavior ...through anti‐inflammation in LPS‐induced neuroinflammatory mice model and cerebral ischemic injury through anti‐neuroinflammation in rats subjected to transient middle cerebral artery occlusion. Target fishing for the hit compound using photoaffinity probes led to identification of PKM2 as the target protein responsible for anti‐inflammatory effect of the hit compound. Furthermore, the hit exhibited an anti‐neuroinflammatory effect in vitro and in vivo by inhibiting PKM2‐mediated glycolysis and NLRP3 activation, indicating PKM2 as a novel target for neuroinflammation and its related brain disorders. This hit compound has a better safety profile compared to shikonin, a reported PKM2 inhibitor, identifying it as a lead compound in targeting PKM2 for the treatment of inflammation‐related diseases.
Fishing around: The benzoxepane derivative A was effective in vivo, ameliorating both sickness behavior through anti‐inflammation in LPS‐induced neuroinflammatory mice model and cerebral ischemic injury through anti‐neuroinflammation in rats subjected to transient middle cerebral artery occlusion. Target fishing identified PKM2 as the target protein for A. Furthermore, A exhibited an anti‐neuroinflammatory effect in vitro and in vivo by inhibiting PKM2‐mediated glycolysis and NLRP3 activation.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Placobranchus ocellatus is well known to produce diverse and complex γ‐pyrone polypropionates. In this study, the chemical investigation of P. ocellatus from the South China Sea led to the discovery ...and identification of ocellatusones A–D, a series of racemic non‐γ‐pyrone polyketides with novel skeletons, characterized by a bicyclo3.2.1octane (1, 2), a bicyclo3.3.1nonane (3) or a mesitylene‐substituted dimethylfuran‐3(2H)‐one core (4). Extensive spectroscopic analysis, quantum chemical computation, chemical synthesis, and/or X‐ray diffraction analysis were used to determine the structure and absolute configuration of the new compounds, including each enantiomer of racemic compounds 1–4 after chiral HPLC resolution. An array of new and diversity‐generating rearrangements is proposed to explain the biosynthesis of these unusual compounds based on careful structural analysis and comparison with six known co‐occurring γ‐pyrones (5–10). Furthermore, the successful biomimetic semisynthesis of ocellatusone A (1) confirmed the proposed rearrangement through an unprecedented acid induced cascade reaction.
A series of racemic polypropionates with novel polycyclic skeletons were discovered and structurally elucidated from the South China Sea photosynthetic sacoglossan mollusk Placobranchus ocellatus. An array of new and diversity‐generating rearrangements is proposed to explain the biosynthesis of these unusual compounds. Furthermore, the successful biomimetic semisynthesis of ocellatusone A confirmed the proposed rearrangement through an unprecedented acid induced cascade reaction.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Mangrove ecosystems are widely distributed in the intertidal zone of tropical and subtropical estuaries or coasts, containing abundant biological communities, for example, mangrove plants and diverse ...groups of microorganisms, featuring various bioactive secondary metabolites. We surveyed the literature from 2010 to 2022, resulting in a collection of 134 secondary metabolites, and classified them into two major families in terms of the biological sources and 15 subfamilies according to the chemical structures. To highlight the structural diversity and bioactivities of the mangrove ecosystem-associated secondary metabolites, we presented the chemical structures, bioactivities, biosynthesis, and chemical syntheses.
Covering: 2011-2021
Marine mollusks, which are well known as rich sources of diverse and biologically active natural products, have attracted significant attention from researchers due to their ...chemical and pharmacological properties. The occurrence of some of these marine mollusk-derived natural products in their preys, predators, and associated microorganisms has also gained interest in chemical ecology research. Based on previous reviews, herein, we present a comprehensive summary of the recent advances of interesting secondary metabolites from marine mollusks, focusing on their structural features, possible chemo-ecological significance, and promising biological activities, covering the literature from 2011 to 2021.
This review summarizes the recent advances on the interesting secondary metabolites from marine mollusks, focusing on their structural features, possible chemo-ecological significance, and promising biological activities.
Nowadays, various drugs on the market are becoming more and more resistant to numerous diseases, thus declining their efficacy for treatment purposes in human beings. Antibiotic resistance is one ...among the top listed threat around the world which eventually urged the discovery of new potent drugs followed by an increase in the number of deaths caused by cancer due to chemotherapy resistance as well. Accordingly, marine cyanobacteria, being the oldest prokaryotic microorganisms belonging to a monophyletic group, have proven themselves as being able to generate pharmaceutically important natural products. They have long been known to produce distinct and structurally complex secondary metabolites including peptides, polyketides, alkaloids, lipids, and terpenes with potent biological properties and applications. As such, this review will focus on recently published novel compounds isolated from marine cyanobacteria along with their potential bioactivities such as antibacterial, antifungal, anticancer, anti-tuberculosis, immunosuppressive and anti-inflammatory capacities. Moreover, various structural classes, as well as their technological uses will also be discussed.
This article provides an overview of approximately 300 secondary metabolites with inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), which were isolated from various natural sources ...or derived from synthetic process in the last decades. The structure-activity relationship and the selectivity of some compounds against other protein phosphatases were also discussed. Potential pharmaceutical applications of several PTP1B inhibitors were presented.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
