scholarly journals Isolation of New Secondary Metabolites from New Zealand Marine Invertebrates

2021 ◽  
Author(s):  
◽  
Joanna M Wojnar
Keyword(s):  
New Zealand ◽  
Methyl Ester ◽  
Secondary Metabolites ◽  
Chromatographic Separation ◽  
Structure Elucidation ◽  
Screening Tool ◽  
Marine Invertebrates ◽  
Toxic Metabolites ◽  
The Family ◽  
New Compounds

<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>

scholarly journals Isolation of New Secondary Metabolites from New Zealand Marine Invertebrates

2021 ◽  
Author(s):  
◽  
Joanna M Wojnar
Keyword(s):  
New Zealand ◽  
Methyl Ester ◽  
Secondary Metabolites ◽  
Chromatographic Separation ◽  
Structure Elucidation ◽  
Screening Tool ◽  
Marine Invertebrates ◽  
Toxic Metabolites ◽  
The Family ◽  
New Compounds

<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>

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

2021 ◽  
Author(s):  
◽  
Wendy Lynne Popplewell
Keyword(s):  
Antibacterial Activity ◽  
Natural Products ◽  
New Zealand ◽  
Secondary Metabolites ◽  
Natural Product ◽  
Red Algae ◽  
Structure Elucidation ◽  
Screening Tool ◽  
Product Analysis ◽  
Algal Extracts

<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>

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

2021 ◽  
Author(s):  
◽  
Wendy Lynne Popplewell
Keyword(s):  
Antibacterial Activity ◽  
Natural Products ◽  
New Zealand ◽  
Secondary Metabolites ◽  
Natural Product ◽  
Red Algae ◽  
Structure Elucidation ◽  
Screening Tool ◽  
Product Analysis ◽  
Algal Extracts

<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>

scholarly journals The Isolation and Structure Elucidation of Secondary Metabolites from Tongan Marine Invertebrates

2021 ◽  
Author(s):  
◽  
Victoria Helen Woolner
Keyword(s):  
Antifungal Activity ◽  
Secondary Metabolites ◽  
Structure Elucidation ◽  
Sea Cucumber ◽  
Marine Invertebrates ◽  
Marine Sponges ◽  
Marine Organisms ◽  
New Members ◽  
Ic50 Values ◽  
New Compounds

<p>During the course of this study, Tongan marine organisms were investigated for new secondary metabolites. A combination of reversed- and normal-phase chromatographic techniques and NMR spectroscopy was employed, to aid in the isolation and structure elucidation of the five known and four new compounds isolated in this study. A brief investigation into the antifungal activity of Tongan holothurian saponins was instigated in order to compare the activity against saponins isolated from the common New Zealand sea cucumber, Australostichopus mollis. A yeast-based chemical genetics study, determined the antifungal activity, for four partially purified Tongan holothurian extracts, against Saccharomyces cerevisiae, to be similar to neothyonidioside (44), a saponin from A. mollis. This result suggested the antifungal activity to be a common characteristic to sea cucumber saponins. Further interest in secondary metabolites from Tongan marine organisms led this study towards the investigation of Tongan marine sponges. Five sponges were selected for screening, and two chosen for further study which yielded five known compounds (51–53, 61, 62) and four new fascaplysin derivatives; 7-bromoreticulatine,10-bromo-6,7-dimethoxyhomofascaplysin C,10-bromo-6, 7-dimethoxyhomofascaplysin D, and 10-bromohomofascaplysin A (63–66, respectively). Although 63 and 66 are new members of the fascaplysin family solely due to the position of the bromine, it appears that bromination on the A-ring is comparatively rare, with only three of the 24 literature examples displaying A-ring bromination. On the other hand, 64 and 65 present a new sub-class of fascaplysin derivatives due to the presence of a dimethoxy functionality. Both 7-bromoreticulatine (63) and 10-bromohomofascaplysin A (66) were found to be potently cytotoxic in the HL-60 cell line, exhibiting IC50 values of 33.8 and 498 nM, respectively. 10-Bromo-6,7-dimethoxyhomofascaplysins C (64) and D (65) were significantly less cytotoxic with respective IC₅₀ values of 2.7 and 6.0 μΜ. (Abstract continues with diagrams).</p>

scholarly journals The Isolation and Structure Elucidation of Secondary Metabolites from Tongan Marine Invertebrates

2021 ◽  
Author(s):  
◽  
Victoria Helen Woolner
Keyword(s):  
Antifungal Activity ◽  
Secondary Metabolites ◽  
Structure Elucidation ◽  
Sea Cucumber ◽  
Marine Invertebrates ◽  
Marine Sponges ◽  
Marine Organisms ◽  
New Members ◽  
Ic50 Values ◽  
New Compounds

<p>During the course of this study, Tongan marine organisms were investigated for new secondary metabolites. A combination of reversed- and normal-phase chromatographic techniques and NMR spectroscopy was employed, to aid in the isolation and structure elucidation of the five known and four new compounds isolated in this study. A brief investigation into the antifungal activity of Tongan holothurian saponins was instigated in order to compare the activity against saponins isolated from the common New Zealand sea cucumber, Australostichopus mollis. A yeast-based chemical genetics study, determined the antifungal activity, for four partially purified Tongan holothurian extracts, against Saccharomyces cerevisiae, to be similar to neothyonidioside (44), a saponin from A. mollis. This result suggested the antifungal activity to be a common characteristic to sea cucumber saponins. Further interest in secondary metabolites from Tongan marine organisms led this study towards the investigation of Tongan marine sponges. Five sponges were selected for screening, and two chosen for further study which yielded five known compounds (51–53, 61, 62) and four new fascaplysin derivatives; 7-bromoreticulatine,10-bromo-6,7-dimethoxyhomofascaplysin C,10-bromo-6, 7-dimethoxyhomofascaplysin D, and 10-bromohomofascaplysin A (63–66, respectively). Although 63 and 66 are new members of the fascaplysin family solely due to the position of the bromine, it appears that bromination on the A-ring is comparatively rare, with only three of the 24 literature examples displaying A-ring bromination. On the other hand, 64 and 65 present a new sub-class of fascaplysin derivatives due to the presence of a dimethoxy functionality. Both 7-bromoreticulatine (63) and 10-bromohomofascaplysin A (66) were found to be potently cytotoxic in the HL-60 cell line, exhibiting IC50 values of 33.8 and 498 nM, respectively. 10-Bromo-6,7-dimethoxyhomofascaplysins C (64) and D (65) were significantly less cytotoxic with respective IC₅₀ values of 2.7 and 6.0 μΜ. (Abstract continues with diagrams).</p>

scholarly journals Validation of a Spectroscopic Screening Method for Secondary Metabolites from New Zealand Extremophilic Microbes

2021 ◽  
Author(s):  
◽  
Chriselle Deborah Braganza
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Biological Activity ◽  
New Zealand ◽  
Antifungal Activity ◽  
Secondary Metabolites ◽  
Marine Bacteria ◽  
Marine Invertebrates ◽  
Screening Method ◽  
Microbial Cultures ◽  
Anoxybacillus Flavithermus

<p>The existing protocol for the screening of natural products from marine invertebrates and macroalgae has been demonstrated successfully at VUW on multiple occasions. This study describes the evaluation of an adapted version of the protocol to screen liquid microbial cultures. The adapted protocol was carried out using an NMR-guided approach and was used to screen 10 New Zealand extremophilic microbes. Investigation of the bacteria Anoxybacillus flavithermus led to the isolation of the known compound 1-acetyl-β-carboline (25), which was briefly evaluated for its biological activity. A detailed investigation on the marine bacteria Shewanella sp. resulted in the isolation of indole-3-carboxaldehyde (93) and 14 known 2,5-diketopiperazines (36, 38, 41–44, 53, 54, 94–99). Three of the isolated 2,5-DKPs were tested against Saccharomyces cerevisiae to evaluate their antifungal activity, the results of which are also described. Overall, the use of the adapted screening method proved successful to guide the isolation of secondary metabolites from microbial cultures.</p>

scholarly journals New Halogenated Secondary Metabolites from Red Algae of the South Pacific

2021 ◽  
Author(s):  
◽  
Victoria Woolner
Keyword(s):  
New Zealand ◽  
Secondary Metabolites ◽  
Structure Elucidation ◽  
Detailed Examination ◽  
Red Alga ◽  
Marine Natural Product ◽  
Extensive Investigation ◽  
Ic50 Value ◽  
Mass Spectrometric Evidence ◽  
Related Compounds

<p>An NMR- and MS-directed study led to the isolation and structure elucidation of several halogenated secondary metabolites from a New Zealand and a Tongan red alga. An extensive investigation was carried out on the New Zealand red alga Rhodophyllis membranacea following mass spectrometric evidence for an unusual tetrahalogenated indole with the exceptionally rare inclusion of bromine, chlorine and iodine within a fraction of a semi-purified extract. Due to the difficulty associated with the structure elucidation of proton deficient molecules, a strategic isolation and structure elucidation of several polyhalogenated indoles was employed in order to unequivocally assign the halogen positions on the indolic core. This resulted in the isolation and characterisation of 11 new tetrahalogenated indoles (123–133), four of which contain bromine, chlorine and iodine (124 and 129–131) and represent the first isolation of such compounds. Additionally, four new pentahalogenated indoles (134–137) and an uncharacterised tribromotrichloroindole were isolated. The synthetically known compound 4-chloroisatin (138) was isolated as a new marine natural product, while 4-chloro-3-hydroxyl-3-(2-oxopropyl)-2-oxindole (139) was established to be an artefact of isolation. Several compounds were found to exhibit antifungal properties against Saccharomyces cerevisiae.  A detailed examination of the Tongan alga Callophycus serratus led to the isolation of six new meroditerpenoids: callophycol C (227), iodocallophycols E (228) and F (229), iodocallophycoic acid B (230), deiodocallophycoic B (231) and callophycoic acid I (232). The relative configurations in compounds 228–231 are proposed to differ from closely related compounds in the literature. Iodocallophycol E (228) exhibited moderate cytotoxicity against the HL-60 cell line with an IC50 value of 6.0 μM.</p>

scholarly journals Secondary Metabolites of Aeromonas veronii Strain A134 Isolated from a Microcystis aeruginosa Bloom

Metabolites ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 110 ◽  
Author(s):  
Gad Weiss ◽  
Dimitry Kovalerchick ◽  
Omer Murik ◽  
Assaf Sukenik ◽  
Aaron Kaplan ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Microcystis Aeruginosa ◽  
Structure Elucidation ◽  
Large Scale ◽  
Culture Media ◽  
2D Nmr ◽  
X Ray ◽  
Aeromonas Veronii ◽  
Large Scale Culture ◽  
New Compounds

Aeromonas veronii strain A134 was isolated from Microcystis aeruginosa colonies collected from Lake Kinneret (Sea of Galilee), Israel. The Aeromonas culture media inhibited the growth of M. aeruginosa (strain MGK). The crude extract of a large-scale culture of A. veronii A134 was separated in a few chromatographic steps to yield three new secondary metabolites, 9-chlorolumichrome (1), veronimide (2) and veronipyrazine (3), along with a known lumichrome and several known diketopiperazines. The structures of the new compounds were established by analyses of the data from 1D and 2D NMR experiments and HRMS data of the compounds, as well as a single-crystal X-ray analysis of synthetic 1. The structure elucidation and proposed biogenesis of the new compounds are described below.

scholarly journals Validation of a Spectroscopic Screening Method for Secondary Metabolites from New Zealand Extremophilic Microbes

2021 ◽  
Author(s):  
◽  
Chriselle Deborah Braganza
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Biological Activity ◽  
New Zealand ◽  
Antifungal Activity ◽  
Secondary Metabolites ◽  
Marine Bacteria ◽  
Marine Invertebrates ◽  
Screening Method ◽  
Microbial Cultures ◽  
Anoxybacillus Flavithermus

<p>The existing protocol for the screening of natural products from marine invertebrates and macroalgae has been demonstrated successfully at VUW on multiple occasions. This study describes the evaluation of an adapted version of the protocol to screen liquid microbial cultures. The adapted protocol was carried out using an NMR-guided approach and was used to screen 10 New Zealand extremophilic microbes. Investigation of the bacteria Anoxybacillus flavithermus led to the isolation of the known compound 1-acetyl-β-carboline (25), which was briefly evaluated for its biological activity. A detailed investigation on the marine bacteria Shewanella sp. resulted in the isolation of indole-3-carboxaldehyde (93) and 14 known 2,5-diketopiperazines (36, 38, 41–44, 53, 54, 94–99). Three of the isolated 2,5-DKPs were tested against Saccharomyces cerevisiae to evaluate their antifungal activity, the results of which are also described. Overall, the use of the adapted screening method proved successful to guide the isolation of secondary metabolites from microbial cultures.</p>

scholarly journals Natural Products Analysis  of South Pacific Marine  Sponges

2021 ◽  
Author(s):  
◽  
Taitusi Taufa
Keyword(s):  
Natural Products ◽  
New Zealand ◽  
Secondary Metabolites ◽  
Optical Rotation ◽  
Screening Method ◽  
Marine Sponges ◽  
Ic50 Value ◽  
Products Analysis ◽  
New Compounds ◽  
Cacospongia Mycofijiensis

<p>This thesis describes the isolation and structure elucidation of 15 new secondary metabolites from Tongan and New Zealand marine sponges. A total of 18 sponge specimens were subjected to an NMR-based screening method, of which four were analysed in detail. Examination of a two-sponge association, Stelletta crater and Desmacella dendyi from New Zealand, resulted in the isolation of two new 4-methylenesterols, craterols A (94) and B (95). To the best of the author’s knowledge, compounds 94 and 95 represent the first secondary metabolites to be reported from either species. Both 94 and 95 possess a double bond between C-5 and C-6, a feature that is unprecedented in this subgroup of marine natural products. An investigation of a Tongan sponge Zyzzya fuliginosa afforded two new pyrroloquinoline alkaloids, 6-bromodamirone B (182) and makaluvamine W (183). Makaluvamine W (183) contains an oxazole moiety, which is uncommon in this group of natural products. Both 182 and 183 lacked activity against the human promyelocytic leukemia cells (HL-60). Five new compounds were isolated from a Tongan sponge of the genus Leucetta, including two glycerol lipids (238 and 239), three glycerol ethers (244–246) and an imidazole alkaloid (243). Naamidine K (243) is a new addition to the naamidine family, while the glycerol metabolites are non-imidazole alkaloid additions to the group of compounds reported from this genus. A spectroscopic investigation into the Tongan sponge Cacospongia mycofijiensis yielded four new zampanolide analogues (282–285) and a new oxygenated sesquiterpene, isodictyodendrillin A (280). The isolation of the zampanolide analogues gives insight into the structure-activity relationship (SAR) in this family of compounds. Zampanolides B–D (282–284) displayed potent antiproliferative activity towards HL-60 cell lines in the low nanomolar range (3–5 nM), while zampanolide E (285) was significantly less potent with an IC50 value of 306 nM. In addition, the re-isolation of dactylolide (281) and zampanolide A (278) from this sponge, established a firm conclusion regarding the controversial configuration of dactylolide (281), which possesses the same absolute configuration as (–)-zampanolide A (278) and has a levorotatory optical rotation.</p>

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