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A New Meroditerpene and a New Tryptoquivaline Analog from the Algicolous Fungus Neosartorya takakii KUFC 7898.

Zin WW, Buttachon S, Buaruang J, Gales L, Pereira JA, Pinto MM, Silva AM, Kijjoa A - Mar Drugs (2015)

Bottom Line: A new meroditerpene sartorenol (1), a new natural product takakiamide (2) and a new tryptoquivaline analog (3) were isolated, together with nine known compounds, including aszonapyrone A, chevalone B, aszonalenin, acetylaszonalenin, 3'-(4-oxoquinazolin-3-yl) spiro[1H-indole-3,5'-oxolane]-2,2'-dione, tryptoquivalines L, F and H, and the isocoumarin derivative, 6-hydroxymellein, from the ethyl acetate extract of the culture of the algicolous fungus Neosartorya takakii KUFC 7898.The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and, in the case of sartorenol (1) and tryptoquivaline U (3), X-ray analysis was used to confirm their structures and to determine the absolute configuration of their stereogenic carbons.The three new compounds did not show any quorum sensing inhibition in the screening protocol based on the pigment production by Chromobacterium violaceum (ATCC 31532).

View Article: PubMed Central - PubMed

Affiliation: ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal. madalena@ff.up.pt.

ABSTRACT
A new meroditerpene sartorenol (1), a new natural product takakiamide (2) and a new tryptoquivaline analog (3) were isolated, together with nine known compounds, including aszonapyrone A, chevalone B, aszonalenin, acetylaszonalenin, 3'-(4-oxoquinazolin-3-yl) spiro[1H-indole-3,5'-oxolane]-2,2'-dione, tryptoquivalines L, F and H, and the isocoumarin derivative, 6-hydroxymellein, from the ethyl acetate extract of the culture of the algicolous fungus Neosartorya takakii KUFC 7898. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and, in the case of sartorenol (1) and tryptoquivaline U (3), X-ray analysis was used to confirm their structures and to determine the absolute configuration of their stereogenic carbons. Compounds 1, 2 and 3 were evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria, and multidrug-resistant isolates from the environment; however, none exhibited antibacterial activity (MIC ˃ 256 mg/mL). The three new compounds did not show any quorum sensing inhibition in the screening protocol based on the pigment production by Chromobacterium violaceum (ATCC 31532).

No MeSH data available.


Ortep view of tryptoquivaline U (3).
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marinedrugs-13-03776-f005: Ortep view of tryptoquivaline U (3).

Mentions: Compound 3 was isolated as white crystals (mp, 208–209 °C), and its molecular formula C23H21N4O4 was established on the basis of the [M + H]+ peak at m/z 417.1563 (calculated 417.1563) in the (+)-HRESIMS. The 1H and 13C NMR spectra of compound 3 (Table 3, Supplementary Figures S13 and S15) resembled those of tryptoquivaline L [9]. The 13C NMR, DEPT and HSQC spectra (Table 3, Supplementary Figures S15 and S16) displayed signals of three carbonyls (δC 176.0, 170.7, 159.6), four quaternary sp2 (δC 147.5, 139.8, 132.0, 121.4), nine methine sp2 (δC 147.4, 135.0, 131.6, 127.6, 127.3, 126.1, 125.7, 125.7, 116.2), two quaternary sp3 (δC 84.7 and 64.6), two methine sp3 (δC 82.0 and 56.9), one methylene sp3 (δC 31.6) and two methyl (δC 26.9 and 26.5) carbons. The 1H NMR and COSY spectra (Table 3, Supplementary Figures S13 and S14) revealed the presence of two 1,2-disubstituted benzene rings of the gem-dimethyl imidazoindolone ring system and quinazolin-4(3H)-one moiety as well as the protons of the five-membered spirolactone ring, similar to those of tryptoquivaline L [9]. However, contrary to tryptoquivaline L, H-2 of compound 3 appeared as a doublet at δH 5.55 (J = 8.4 Hz) instead of a singlet at δH 5.25 [9]. Moreover, the COSY spectrum exhibited a correlation between H-2 signal and a doublet at δH 3.76 (J = 8.4 Hz). Consequently, this signal was attributed to NH-16. Interestingly, both CH3-27 (δC 26.5) and CH3-28 (δC 26.9) resonated at higher chemical shift values than their counterparts in tryptoquivaline L (δC 16.4 and 22.8) while C-15 exhibited lower chemical shift value (δC 64.6) than the corresponding carbon (δC 70.0) of tryptoquivaline L [9]. Thus, the only difference between the structure of compound 3 and that of tryptoquivaline L is the presence of a hydrogen atom on N-16 instead of a hydroxyl group. This was supported by the molecular formula of compound 3 (C23H20N4O4), which has one oxygen atom less than that of tryptoquivaline L. In order to verify if the stereochemistry of compound 3 is the same as that of tryptoquivaline L, X-ray analysis of compound 3 was performed. The ORTEP diagram of compound 3 (Figure 5) showed unambiguously that the absolute configurations of C-2, C-3 and C-12 are S, S and R, the same as that of the corresponding carbons of tryptoquivaline L. Since compound 3 is a new analog of tryptoquivalines, and in accordance with the names given to the tryptoquivaline series, we have named compound 3 tryptoquivaline U.


A New Meroditerpene and a New Tryptoquivaline Analog from the Algicolous Fungus Neosartorya takakii KUFC 7898.

Zin WW, Buttachon S, Buaruang J, Gales L, Pereira JA, Pinto MM, Silva AM, Kijjoa A - Mar Drugs (2015)

Ortep view of tryptoquivaline U (3).
© Copyright Policy
Related In: Results  -  Collection

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marinedrugs-13-03776-f005: Ortep view of tryptoquivaline U (3).
Mentions: Compound 3 was isolated as white crystals (mp, 208–209 °C), and its molecular formula C23H21N4O4 was established on the basis of the [M + H]+ peak at m/z 417.1563 (calculated 417.1563) in the (+)-HRESIMS. The 1H and 13C NMR spectra of compound 3 (Table 3, Supplementary Figures S13 and S15) resembled those of tryptoquivaline L [9]. The 13C NMR, DEPT and HSQC spectra (Table 3, Supplementary Figures S15 and S16) displayed signals of three carbonyls (δC 176.0, 170.7, 159.6), four quaternary sp2 (δC 147.5, 139.8, 132.0, 121.4), nine methine sp2 (δC 147.4, 135.0, 131.6, 127.6, 127.3, 126.1, 125.7, 125.7, 116.2), two quaternary sp3 (δC 84.7 and 64.6), two methine sp3 (δC 82.0 and 56.9), one methylene sp3 (δC 31.6) and two methyl (δC 26.9 and 26.5) carbons. The 1H NMR and COSY spectra (Table 3, Supplementary Figures S13 and S14) revealed the presence of two 1,2-disubstituted benzene rings of the gem-dimethyl imidazoindolone ring system and quinazolin-4(3H)-one moiety as well as the protons of the five-membered spirolactone ring, similar to those of tryptoquivaline L [9]. However, contrary to tryptoquivaline L, H-2 of compound 3 appeared as a doublet at δH 5.55 (J = 8.4 Hz) instead of a singlet at δH 5.25 [9]. Moreover, the COSY spectrum exhibited a correlation between H-2 signal and a doublet at δH 3.76 (J = 8.4 Hz). Consequently, this signal was attributed to NH-16. Interestingly, both CH3-27 (δC 26.5) and CH3-28 (δC 26.9) resonated at higher chemical shift values than their counterparts in tryptoquivaline L (δC 16.4 and 22.8) while C-15 exhibited lower chemical shift value (δC 64.6) than the corresponding carbon (δC 70.0) of tryptoquivaline L [9]. Thus, the only difference between the structure of compound 3 and that of tryptoquivaline L is the presence of a hydrogen atom on N-16 instead of a hydroxyl group. This was supported by the molecular formula of compound 3 (C23H20N4O4), which has one oxygen atom less than that of tryptoquivaline L. In order to verify if the stereochemistry of compound 3 is the same as that of tryptoquivaline L, X-ray analysis of compound 3 was performed. The ORTEP diagram of compound 3 (Figure 5) showed unambiguously that the absolute configurations of C-2, C-3 and C-12 are S, S and R, the same as that of the corresponding carbons of tryptoquivaline L. Since compound 3 is a new analog of tryptoquivalines, and in accordance with the names given to the tryptoquivaline series, we have named compound 3 tryptoquivaline U.

Bottom Line: A new meroditerpene sartorenol (1), a new natural product takakiamide (2) and a new tryptoquivaline analog (3) were isolated, together with nine known compounds, including aszonapyrone A, chevalone B, aszonalenin, acetylaszonalenin, 3'-(4-oxoquinazolin-3-yl) spiro[1H-indole-3,5'-oxolane]-2,2'-dione, tryptoquivalines L, F and H, and the isocoumarin derivative, 6-hydroxymellein, from the ethyl acetate extract of the culture of the algicolous fungus Neosartorya takakii KUFC 7898.The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and, in the case of sartorenol (1) and tryptoquivaline U (3), X-ray analysis was used to confirm their structures and to determine the absolute configuration of their stereogenic carbons.The three new compounds did not show any quorum sensing inhibition in the screening protocol based on the pigment production by Chromobacterium violaceum (ATCC 31532).

View Article: PubMed Central - PubMed

Affiliation: ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal. madalena@ff.up.pt.

ABSTRACT
A new meroditerpene sartorenol (1), a new natural product takakiamide (2) and a new tryptoquivaline analog (3) were isolated, together with nine known compounds, including aszonapyrone A, chevalone B, aszonalenin, acetylaszonalenin, 3'-(4-oxoquinazolin-3-yl) spiro[1H-indole-3,5'-oxolane]-2,2'-dione, tryptoquivalines L, F and H, and the isocoumarin derivative, 6-hydroxymellein, from the ethyl acetate extract of the culture of the algicolous fungus Neosartorya takakii KUFC 7898. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and, in the case of sartorenol (1) and tryptoquivaline U (3), X-ray analysis was used to confirm their structures and to determine the absolute configuration of their stereogenic carbons. Compounds 1, 2 and 3 were evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria, and multidrug-resistant isolates from the environment; however, none exhibited antibacterial activity (MIC ˃ 256 mg/mL). The three new compounds did not show any quorum sensing inhibition in the screening protocol based on the pigment production by Chromobacterium violaceum (ATCC 31532).

No MeSH data available.