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Structure Elucidation and in Vitro Toxicity of New Azaspiracids Isolated from the Marine Dinoflagellate Azadinium poporum.

Krock B, Tillmann U, Potvin É, Jeong HJ, Drebing W, Kilcoyne J, Al-Jorani A, Twiner MJ, Göthel Q, Köck M - Mar Drugs (2015)

Bottom Line: Two strains of Azadinium poporum, one from the Korean West coast and the other from the North Sea, were mass cultured for isolation of new azaspiracids.Approximately 0.9 mg of pure AZA-36 (1) and 1.3 mg of pure AZA-37 (2) were isolated from the Korean (870 L) and North Sea (120 L) strains, respectively.The structures were determined to be 3-hydroxy-8-methyl-39-demethyl-azaspiracid-1 (1) and 3-hydroxy-7,8-dihydro-39-demethyl-azaspiracid-1 (2) by ¹H- and (13)C-NMR.

View Article: PubMed Central - PubMed

Affiliation: Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, Bremerhaven 27570, Germany. Bernd.Krock@awi.de.

ABSTRACT
Two strains of Azadinium poporum, one from the Korean West coast and the other from the North Sea, were mass cultured for isolation of new azaspiracids. Approximately 0.9 mg of pure AZA-36 (1) and 1.3 mg of pure AZA-37 (2) were isolated from the Korean (870 L) and North Sea (120 L) strains, respectively. The structures were determined to be 3-hydroxy-8-methyl-39-demethyl-azaspiracid-1 (1) and 3-hydroxy-7,8-dihydro-39-demethyl-azaspiracid-1 (2) by ¹H- and (13)C-NMR. Using the Jurkat T lymphocyte cell toxicity assay, (1) and (2) were found to be 6- and 3-fold less toxic than AZA-1, respectively.

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Structures of AZA-1 (top), AZA-36 (1) (bottom, left), and AZA-37 (2) (bottom, right).
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marinedrugs-13-06687-f001: Structures of AZA-1 (top), AZA-36 (1) (bottom, left), and AZA-37 (2) (bottom, right).

Mentions: The chemical shifts (1H and 13C) of (1) and (2) are listed in Table 3. The corresponding spectra are given as supplementary material. Compared to AZA-1, the 1H-NMR spectrum of (1) (Table 3) showed an extra oxymethine signal at δ 4.43, an allylic methyl signal at δ 1.70, and the loss of the 39-methyl signal. The 1H,1H-COSY correlations between H-2/H-3 and H-3/H-4 confirmed the neighborhood of H-2 and H-4 to the oxymethine (H-3). The 13C signal of C-3 at δ 71.4 indicated that C-3 of (1) was substituted by a hydroxyl group. The 1H,13C-HMBC spectrum showed correlations from H-47 (δ 1.70) to C-7 (123.4), C-8 (132.1), and C-9 (41.1), and the 1H,1H-COSY spectrum showed correlations between H-47/H-7 (δ 5.36) and H-47/H-6 (δ 4.79). These correlations allowed the assignment of the new allylic methyl group. Moreover, the methyl group at C-39 was substituted by a proton according to the 1H,1H-COSY spectrum. The other subunits in (1) were assigned on the basis of the 1D and 2D NMR experiments. Based on these results, the structure of AZA-36 was deduced to be 3-hydroxy-8-methyl-39-demethyl-azaspiracid-1 (1), as shown in Figure 1.


Structure Elucidation and in Vitro Toxicity of New Azaspiracids Isolated from the Marine Dinoflagellate Azadinium poporum.

Krock B, Tillmann U, Potvin É, Jeong HJ, Drebing W, Kilcoyne J, Al-Jorani A, Twiner MJ, Göthel Q, Köck M - Mar Drugs (2015)

Structures of AZA-1 (top), AZA-36 (1) (bottom, left), and AZA-37 (2) (bottom, right).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663548&req=5

marinedrugs-13-06687-f001: Structures of AZA-1 (top), AZA-36 (1) (bottom, left), and AZA-37 (2) (bottom, right).
Mentions: The chemical shifts (1H and 13C) of (1) and (2) are listed in Table 3. The corresponding spectra are given as supplementary material. Compared to AZA-1, the 1H-NMR spectrum of (1) (Table 3) showed an extra oxymethine signal at δ 4.43, an allylic methyl signal at δ 1.70, and the loss of the 39-methyl signal. The 1H,1H-COSY correlations between H-2/H-3 and H-3/H-4 confirmed the neighborhood of H-2 and H-4 to the oxymethine (H-3). The 13C signal of C-3 at δ 71.4 indicated that C-3 of (1) was substituted by a hydroxyl group. The 1H,13C-HMBC spectrum showed correlations from H-47 (δ 1.70) to C-7 (123.4), C-8 (132.1), and C-9 (41.1), and the 1H,1H-COSY spectrum showed correlations between H-47/H-7 (δ 5.36) and H-47/H-6 (δ 4.79). These correlations allowed the assignment of the new allylic methyl group. Moreover, the methyl group at C-39 was substituted by a proton according to the 1H,1H-COSY spectrum. The other subunits in (1) were assigned on the basis of the 1D and 2D NMR experiments. Based on these results, the structure of AZA-36 was deduced to be 3-hydroxy-8-methyl-39-demethyl-azaspiracid-1 (1), as shown in Figure 1.

Bottom Line: Two strains of Azadinium poporum, one from the Korean West coast and the other from the North Sea, were mass cultured for isolation of new azaspiracids.Approximately 0.9 mg of pure AZA-36 (1) and 1.3 mg of pure AZA-37 (2) were isolated from the Korean (870 L) and North Sea (120 L) strains, respectively.The structures were determined to be 3-hydroxy-8-methyl-39-demethyl-azaspiracid-1 (1) and 3-hydroxy-7,8-dihydro-39-demethyl-azaspiracid-1 (2) by ¹H- and (13)C-NMR.

View Article: PubMed Central - PubMed

Affiliation: Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, Bremerhaven 27570, Germany. Bernd.Krock@awi.de.

ABSTRACT
Two strains of Azadinium poporum, one from the Korean West coast and the other from the North Sea, were mass cultured for isolation of new azaspiracids. Approximately 0.9 mg of pure AZA-36 (1) and 1.3 mg of pure AZA-37 (2) were isolated from the Korean (870 L) and North Sea (120 L) strains, respectively. The structures were determined to be 3-hydroxy-8-methyl-39-demethyl-azaspiracid-1 (1) and 3-hydroxy-7,8-dihydro-39-demethyl-azaspiracid-1 (2) by ¹H- and (13)C-NMR. Using the Jurkat T lymphocyte cell toxicity assay, (1) and (2) were found to be 6- and 3-fold less toxic than AZA-1, respectively.

Show MeSH
Related in: MedlinePlus