scholarly journals Isolation and Structure Elucidation of New Secondary Metabolites from New Zealand Marine Red Algae

2021 ◽  
Author(s):  
◽  
Wendy Lynne Popplewell

<p>The natural product analysis of New Zealand red algae has been neglected in recent years, and there is obvious scope for the chemical re-evaluation of New Zealand marine red algae. This study describes the isolation and structure elucidation of 12 new and eight known compounds from four different genera of red algae. To aid in this process, 34 red algae were screened in order to generate a digital HSQC spectra mask, a screening tool developed by the VUW Marine Natural Products group to identify extracts of interest for further analysis. All 34 algal extracts were screened using the HSQC mask and four extracts were identified as interesting and analysed in detail. Examination of extracts of the red algae Plocamium costatum and Ballia callitricha lead to the isolation of three known metabolites. Eleven new oxylipins, labillarides A to K, are reported from the alga Phacelocarpus labillardieri. Labillarides A to H are polyunsaturated alpha-pyrone macrocycles, all of which show similarities to the previously reported compounds isolated from southern Australian collections of the algae. Labillarides E to H are of particular interest as they represent the two diastereomeric pairs associated with variation at the C-3 and C-8 chiral centres. Labillarides I and J are related enol macrocycles while labillaride K is a furan-3-one oxylipin, all of which have biogenic significance to the macrocyclic alpha-pyrones. Labillarides A, B and I exhibit moderate cytotoxicity while labillaride C shows moderate antibacterial activity. A new nitrogenous bromophenol, colensolide A, was isolated from the alga Osmundaria colensoi along with five known bromophenols. The presence of nitrogen-containing sidechains in bromophenols is unusual but not unprecedented. The bicyclic nitrogenous moiety observed in colensolide A is proposed to be of histidine origin. Several of the known bromophenols exhibit antibacterial activity and one shows moderate cytotoxicity.</p>

2021 ◽  
Author(s):  
◽  
Wendy Lynne Popplewell

<p>The natural product analysis of New Zealand red algae has been neglected in recent years, and there is obvious scope for the chemical re-evaluation of New Zealand marine red algae. This study describes the isolation and structure elucidation of 12 new and eight known compounds from four different genera of red algae. To aid in this process, 34 red algae were screened in order to generate a digital HSQC spectra mask, a screening tool developed by the VUW Marine Natural Products group to identify extracts of interest for further analysis. All 34 algal extracts were screened using the HSQC mask and four extracts were identified as interesting and analysed in detail. Examination of extracts of the red algae Plocamium costatum and Ballia callitricha lead to the isolation of three known metabolites. Eleven new oxylipins, labillarides A to K, are reported from the alga Phacelocarpus labillardieri. Labillarides A to H are polyunsaturated alpha-pyrone macrocycles, all of which show similarities to the previously reported compounds isolated from southern Australian collections of the algae. Labillarides E to H are of particular interest as they represent the two diastereomeric pairs associated with variation at the C-3 and C-8 chiral centres. Labillarides I and J are related enol macrocycles while labillaride K is a furan-3-one oxylipin, all of which have biogenic significance to the macrocyclic alpha-pyrones. Labillarides A, B and I exhibit moderate cytotoxicity while labillaride C shows moderate antibacterial activity. A new nitrogenous bromophenol, colensolide A, was isolated from the alga Osmundaria colensoi along with five known bromophenols. The presence of nitrogen-containing sidechains in bromophenols is unusual but not unprecedented. The bicyclic nitrogenous moiety observed in colensolide A is proposed to be of histidine origin. Several of the known bromophenols exhibit antibacterial activity and one shows moderate cytotoxicity.</p>


2021 ◽  
Author(s):  
◽  
Joanna M Wojnar

<p>This study describes the isolation and structure elucidation of several known and 13 new compounds from New Zealand marine organisms. Furthermore, it describes the development of a digital mask program for the analysis of HSQC spectra of crude sponge extracts. This was used as a screening tool to identify secondary metabolite producers that warranted further analysis. As reports of metabolites from New Zealand nudibranchs are poorly represented in the literature, a study of five New Zealand nudibranch species was undertaken. These coloured and seemingly undefended nudibranchs are known to concentrate or sequester toxic metabolites from their prey, facilitating rapid isolation and structure elucidation of these metabolites. This study resulted in the isolation of a variety of metabolite classes; two new compounds, 13alpha- acetoxypukalide diol (30) and lopholide diol (31) from the nudibranch Tritonia incerta, are described. Examination of the sponge Raspailia agminata resulted in the isolation of a novel family of partially acetylated glycolipids which contain up to six glucose residues. The chromatographic separation of these compounds was a challenge due to the similarity of the congeners and their lack of a chromophore. MSguided isolation eventually led to the purification of agminosides A-E (145-149). An unidentified sponge of the order Dictyoceratida was found to contain a new isomer (186) of the known sesterterpene variabilin. As variabilin-type compounds are predominantly found from sponges of the family Irciniidae, the unidentified sponge is most likely an irciniid. In addition, the sponge contained two prenylated quinones, one of which, 189, is a new isomer of a known sponge metabolite. The sponge Darwinella oxeata contained four new nitrogenous diterpenes of the aplysulphurane (rearranged spongian) skeleton, oxeatamide A (214), isooxeatamide A (215), oxeatamide A 23-methyl ester (216) and oxeatamide B (217).</p>


2020 ◽  
Author(s):  
Joe Bracegirdle ◽  
Z Sohail ◽  
Michael Fairhurst ◽  
Monica Gerth ◽  
Giuseppe Zuccarello ◽  
...  

© 2019 by the authors Red algae of the genus Plocamium have been a rich source of halogenated monoterpenes. Herein, a new cyclic monoterpene, costatone C (7), was isolated from the extract of P. angustum collected in New Zealand, along with the previously reported (1E,5Z)-1,6-dichloro-2-methylhepta-1,5-dien-3-ol (8). Elucidation of the planar structure of 7 was achieved through conventional NMR and (−)-HR-APCI-MS techniques, and the absolute configuration by comparison of experimental and DFT-calculated ECD spectra. The absolute configuration of 8 was determined using Mosher’s method. Compound 7 showed mild antibacterial activity against Staphylococcus aureus and S. epidermidis. The state of Plocamium taxonomy and its implications upon natural product distributions, especially across samples from specimens collected in different countries, is also discussed.


Marine Drugs ◽  
2019 ◽  
Vol 17 (7) ◽  
pp. 418 ◽  
Author(s):  
Joe Bracegirdle ◽  
Zaineb Sohail ◽  
Michael J. Fairhurst ◽  
Monica L. Gerth ◽  
Giuseppe C. Zuccarello ◽  
...  

Red algae of the genus Plocamium have been a rich source of halogenated monoterpenes. Herein, a new cyclic monoterpene, costatone C (7), was isolated from the extract of P. angustum collected in New Zealand, along with the previously reported (1E,5Z)-1,6-dichloro-2-methylhepta-1,5-dien-3-ol (8). Elucidation of the planar structure of 7 was achieved through conventional NMR and (−)-HR-APCI-MS techniques, and the absolute configuration by comparison of experimental and DFT-calculated ECD spectra. The absolute configuration of 8 was determined using Mosher’s method. Compound 7 showed mild antibacterial activity against Staphylococcus aureus and S. epidermidis. The state of Plocamium taxonomy and its implications upon natural product distributions, especially across samples from specimens collected in different countries, is also discussed.


2021 ◽  
Author(s):  
◽  
Joanna M Wojnar

<p>This study describes the isolation and structure elucidation of several known and 13 new compounds from New Zealand marine organisms. Furthermore, it describes the development of a digital mask program for the analysis of HSQC spectra of crude sponge extracts. This was used as a screening tool to identify secondary metabolite producers that warranted further analysis. As reports of metabolites from New Zealand nudibranchs are poorly represented in the literature, a study of five New Zealand nudibranch species was undertaken. These coloured and seemingly undefended nudibranchs are known to concentrate or sequester toxic metabolites from their prey, facilitating rapid isolation and structure elucidation of these metabolites. This study resulted in the isolation of a variety of metabolite classes; two new compounds, 13alpha- acetoxypukalide diol (30) and lopholide diol (31) from the nudibranch Tritonia incerta, are described. Examination of the sponge Raspailia agminata resulted in the isolation of a novel family of partially acetylated glycolipids which contain up to six glucose residues. The chromatographic separation of these compounds was a challenge due to the similarity of the congeners and their lack of a chromophore. MSguided isolation eventually led to the purification of agminosides A-E (145-149). An unidentified sponge of the order Dictyoceratida was found to contain a new isomer (186) of the known sesterterpene variabilin. As variabilin-type compounds are predominantly found from sponges of the family Irciniidae, the unidentified sponge is most likely an irciniid. In addition, the sponge contained two prenylated quinones, one of which, 189, is a new isomer of a known sponge metabolite. The sponge Darwinella oxeata contained four new nitrogenous diterpenes of the aplysulphurane (rearranged spongian) skeleton, oxeatamide A (214), isooxeatamide A (215), oxeatamide A 23-methyl ester (216) and oxeatamide B (217).</p>


2020 ◽  
Author(s):  
Joe Bracegirdle ◽  
Z Sohail ◽  
Michael Fairhurst ◽  
Monica Gerth ◽  
Giuseppe Zuccarello ◽  
...  

© 2019 by the authors Red algae of the genus Plocamium have been a rich source of halogenated monoterpenes. Herein, a new cyclic monoterpene, costatone C (7), was isolated from the extract of P. angustum collected in New Zealand, along with the previously reported (1E,5Z)-1,6-dichloro-2-methylhepta-1,5-dien-3-ol (8). Elucidation of the planar structure of 7 was achieved through conventional NMR and (−)-HR-APCI-MS techniques, and the absolute configuration by comparison of experimental and DFT-calculated ECD spectra. The absolute configuration of 8 was determined using Mosher’s method. Compound 7 showed mild antibacterial activity against Staphylococcus aureus and S. epidermidis. The state of Plocamium taxonomy and its implications upon natural product distributions, especially across samples from specimens collected in different countries, is also discussed.


Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 107
Author(s):  
Rafael de Felício ◽  
Patricia Ballone ◽  
Cristina Freitas Bazzano ◽  
Luiz F. G. Alves ◽  
Renata Sigrist ◽  
...  

Bacterial genome sequencing has revealed a vast number of novel biosynthetic gene clusters (BGC) with potential to produce bioactive natural products. However, the biosynthesis of secondary metabolites by bacteria is often silenced under laboratory conditions, limiting the controlled expression of natural products. Here we describe an integrated methodology for the construction and screening of an elicited and pre-fractionated library of marine bacteria. In this pilot study, chemical elicitors were evaluated to mimic the natural environment and to induce the expression of cryptic BGCs in deep-sea bacteria. By integrating high-resolution untargeted metabolomics with cheminformatics analyses, it was possible to visualize, mine, identify and map the chemical and biological space of the elicited bacterial metabolites. The results show that elicited bacterial metabolites correspond to ~45% of the compounds produced under laboratory conditions. In addition, the elicited chemical space is novel (~70% of the elicited compounds) or concentrated in the chemical space of drugs. Fractionation of the crude extracts further evidenced minor compounds (~90% of the collection) and the detection of biological activity. This pilot work pinpoints strategies for constructing and evaluating chemically diverse bacterial natural product libraries towards the identification of novel bacterial metabolites in natural product-based drug discovery pipelines.


RSC Advances ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 2596-2607
Author(s):  
R. P. Vivek-Ananth ◽  
Ajaya Kumar Sahoo ◽  
Kavyaa Kumaravel ◽  
Karthikeyan Mohanraj ◽  
Areejit Samal

First dedicated manually curated resource on secondary metabolites and therapeutic uses of medicinal fungi. Cheminformatics based analysis of the chemical space of fungal natural products.


2014 ◽  
Vol 10 ◽  
pp. 1228-1232 ◽  
Author(s):  
Jens Schmidt ◽  
Zeinab Khalil ◽  
Robert J Capon ◽  
Christian B W Stark

The heronapyrroles A–C have first been isolated from a marine-derived Streptomyces sp. (CMB-0423) in 2010. Structurally, these natural products feature an unusual nitropyrrole system to which a partially oxidized farnesyl chain is attached. The varying degree of oxidation of the sesquiterpenyl subunit in heronapyrroles A–C provoked the hypothesis that there might exist other hitherto unidentified metabolites. On biosynthetic grounds a mono-tetrahydrofuran-diol named heronapyrrole D appeared a possible candidate. We here describe a short asymmetric synthesis of heronapyrrole D, its detection in cultivations of CMB-0423 and finally the evaluation of its antibacterial activity. We thus demonstrate that biosynthetic considerations and the joint effort of synthetic and natural product chemists can result in the identification of new members of a rare class of natural products.


Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 853 ◽  
Author(s):  
Mei-Mei Cheng ◽  
Xu-Li Tang ◽  
Yan-Ting Sun ◽  
Dong-Yang Song ◽  
Yu-Jing Cheng ◽  
...  

Marine sponges are well known as rich sources of biologically natural products. Growing evidence indicates that sponges harbor a wealth of microorganisms in their bodies, which are likely to be the true producers of bioactive secondary metabolites. In order to promote the study of natural product chemistry and explore the relationship between microorganisms and their sponge hosts, in this review, we give a comprehensive overview of the structures, sources, and activities of the 774 new marine natural products from sponge-derived microorganisms described over the last two decades from 1998 to 2017.


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