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New antimicrobial bromotyrosine analogues from the sponge Pseudoceratina purpurea and its predator Tylodina corticalis.

Gotsbacher MP, Karuso P - Mar Drugs (2015)

Bottom Line: Bioassay-guided fractionation of extracts from temperate Australian collections of the marine sponge Pseudoceratina purpurea resulted in the isolation and characterisation of two new and six known bromotyrosine-derived alkaloids with antibiotic activity.Surprisingly, a single specimen of the mollusc Tylodina corticalis, which was collected while feeding on P. purpurea, contained only a few of the compounds found in the sponge suggesting selective accumulation and chemical modification of sponge metabolites.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry & Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia. michael.gotsbacher@sydney.edu.au.

ABSTRACT
Bioassay-guided fractionation of extracts from temperate Australian collections of the marine sponge Pseudoceratina purpurea resulted in the isolation and characterisation of two new and six known bromotyrosine-derived alkaloids with antibiotic activity. Surprisingly, a single specimen of the mollusc Tylodina corticalis, which was collected while feeding on P. purpurea, contained only a few of the compounds found in the sponge suggesting selective accumulation and chemical modification of sponge metabolites.

No MeSH data available.


Structure and selected 2D-NMR correlations of new bromotyrosine compound (2). (Colours: red (HMBC), green (ROESY), black (COSY)).
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marinedrugs-13-01389-f005: Structure and selected 2D-NMR correlations of new bromotyrosine compound (2). (Colours: red (HMBC), green (ROESY), black (COSY)).

Mentions: The 13C NMR spectrum of our compound indicated the presence of 21 carbons, one O-methyl (δ 60.4), six methylenes (δ 71.3, 39.4, 36.2, 31.5, 29.6, 27.9), four sp2 methines (δ 133.2 × 2, 132.9 × 2), nine sp2 quaternary (δ 151.8, 151.3, 151.0, 136.8, 136.3, 117.6 × 2, 117.1 × 2) and one amide carbonyl (δ 163.0). All protonated carbons were assigned by HSQC experiment. Use of one and two-dimensional NMR data (Table 3) enabled the construction of three substructures (Figure 5). Inspection of 1H, 13C, and 1H-1H COSY NMR spectra suggested that the following proton signals belonged to substructure A: δH 12.02 (oxime), 7.44 (sp2 methine), 3.76 (sp3 methine) and 3.75 (OMe). HMBC correlations from H-2 to C-2, C-3, H-6 to C-4, and H-7a/b to C-8 and C-11 provided good evidence for the oxime-tyrosine unit A. The connection between substructures A and B was obtained by HMBC correlations from H-7a/b to carbonyl C-11 and from the amide proton H-13 to oxime carbon C-8. C-8 and C-11 could be easily distinguished by their typical chemical shifts as reported in the literature [51]. The geometry of the oxime was determined as E from the up-field 13C chemical shift of C-7 (δC 27.9), c.f. δC 35.7 for Z-oximes as observed in (E, Z)-N,N′-bis-[3-(3′-bromo-4′-hydroxyphenyl)-2-oximidopropionyl] cystamine [4].


New antimicrobial bromotyrosine analogues from the sponge Pseudoceratina purpurea and its predator Tylodina corticalis.

Gotsbacher MP, Karuso P - Mar Drugs (2015)

Structure and selected 2D-NMR correlations of new bromotyrosine compound (2). (Colours: red (HMBC), green (ROESY), black (COSY)).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4377990&req=5

marinedrugs-13-01389-f005: Structure and selected 2D-NMR correlations of new bromotyrosine compound (2). (Colours: red (HMBC), green (ROESY), black (COSY)).
Mentions: The 13C NMR spectrum of our compound indicated the presence of 21 carbons, one O-methyl (δ 60.4), six methylenes (δ 71.3, 39.4, 36.2, 31.5, 29.6, 27.9), four sp2 methines (δ 133.2 × 2, 132.9 × 2), nine sp2 quaternary (δ 151.8, 151.3, 151.0, 136.8, 136.3, 117.6 × 2, 117.1 × 2) and one amide carbonyl (δ 163.0). All protonated carbons were assigned by HSQC experiment. Use of one and two-dimensional NMR data (Table 3) enabled the construction of three substructures (Figure 5). Inspection of 1H, 13C, and 1H-1H COSY NMR spectra suggested that the following proton signals belonged to substructure A: δH 12.02 (oxime), 7.44 (sp2 methine), 3.76 (sp3 methine) and 3.75 (OMe). HMBC correlations from H-2 to C-2, C-3, H-6 to C-4, and H-7a/b to C-8 and C-11 provided good evidence for the oxime-tyrosine unit A. The connection between substructures A and B was obtained by HMBC correlations from H-7a/b to carbonyl C-11 and from the amide proton H-13 to oxime carbon C-8. C-8 and C-11 could be easily distinguished by their typical chemical shifts as reported in the literature [51]. The geometry of the oxime was determined as E from the up-field 13C chemical shift of C-7 (δC 27.9), c.f. δC 35.7 for Z-oximes as observed in (E, Z)-N,N′-bis-[3-(3′-bromo-4′-hydroxyphenyl)-2-oximidopropionyl] cystamine [4].

Bottom Line: Bioassay-guided fractionation of extracts from temperate Australian collections of the marine sponge Pseudoceratina purpurea resulted in the isolation and characterisation of two new and six known bromotyrosine-derived alkaloids with antibiotic activity.Surprisingly, a single specimen of the mollusc Tylodina corticalis, which was collected while feeding on P. purpurea, contained only a few of the compounds found in the sponge suggesting selective accumulation and chemical modification of sponge metabolites.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry & Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia. michael.gotsbacher@sydney.edu.au.

ABSTRACT
Bioassay-guided fractionation of extracts from temperate Australian collections of the marine sponge Pseudoceratina purpurea resulted in the isolation and characterisation of two new and six known bromotyrosine-derived alkaloids with antibiotic activity. Surprisingly, a single specimen of the mollusc Tylodina corticalis, which was collected while feeding on P. purpurea, contained only a few of the compounds found in the sponge suggesting selective accumulation and chemical modification of sponge metabolites.

No MeSH data available.