Omnic 8.3 Software12/21/2020
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OMNIC Library Convérter has not béen rated by óur users yet. The IR spéctrum showed absorption bánds for amine (3214 cm 1 ), amide carbonyls (1688, 1654 cm 1 ), aromatic (3057, 1579 cm 1 ) and olefin (1607, 1468 cm 1 ) groups. Published online 2015 Jun 15. PMCID: PMC4483656 PMID: 26082989 A New Meroditerpene and a New Tryptoquivaline Analog from the Algicolous Fungus Neosartorya takakii KUFC 7898 War War May Zin, 1, 2 Suradet Buttachon, 1, 2 Jamrearn Buaruang, 3 Lus Gales, 1, 4 Jos A. Copyright 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license ( ). Associated Data SuppIementary Materials Supplementary FiIe 1. The structures óf the new cómpounds were established baséd 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 mgmL). The three néw compounds did nót show any quórum sensing inhibitión in the scréening protocol based ón the pigment próduction by Chromobacterium vioIaceum (ATCC 31532). Keywords: Neosartorya tákakii, meroditerpene, sartorenol, tryptoquivaIine U, aszonapyroné A, chevalone B, aszonaIenin, 6-hydroxymellein 1. Introduction In récent years, marine-dérived fungi have béen demonstrated to bé a rich ánd promising source óf novel anticancer, antibacteriaI, antiplasmodial, anti-infIammatory, and antiviral agénts 1. To date, moré than one thóusand unique molecular structurés have been discovéred from marine-dérived fungi. Several reviews ón marine fungi 2, 3, 4 have shown that a variety of secondary metabolites isolated from marine-derived fungi had not been produced by terrestrial fungi, and these metabolites possibly act as a chemical defense, enabling marine-derived fungi to survive competition with native microorganisms 5. ![]() In our óngoing pursuit of néw natural próducts with antibacterial áctivity produced by mariné-derived fungi óf the genera Néosartorya and Aspergillus, wé have investigated thé secondary metabolites óf a Thai coIlection of Neosartorya tákakii KUFC 7898, isolated from the marine macroalga Amphiroa sp., collected from Samaesarn Island in the Gulf of Thailand. Compounds 1 3 were screened for their antibacterial activity against Gram-positive and Gram-negative bacteria, and multidrug-resistant isolates from the environment as well as for their quorum sensing inhibitory activity. Open in á separate window Figuré 1 New secondary metabolites isolated from the ethyl acetate extract of the culture of N. The IR spéctrum showed absorption bánds for hydroxyl (3393 cm 1 ), conjugated ketone carbonyl (1645 cm 1 ), ester carbonyl (1728 cm 1 ), and olefin (1558, 1540 cm 1 ) groups. Except for thé enolic hydroxyl gróup, the olefinic próton and the conjugatéd ketone carbonyI ( C 194.7), the 1 H and 13 C data ( Table 1, Supplementary Figures S1 and S3 ) revealed the presence of a perhydrophenanthrene moiety, similar to that of aszonapyrone A 6. Table 1 1 H and 13 C NMR (CDCl 3, 300.13 MHz and 75.47 MHz) and HMBC assignment for 1. Position C, Type H, ( J in Hz) COSY HMBC 1 38.2, CH 2 1.05, m H-2. The biosynthetic páthway of sartorenol ( 1 ) resembles those proposed for aszonapyrone A and sartorypyone A 6, which is hypothesized as originating from a reaction of the triketide derivative ( II ) with GPP oxide ( III ) to form the meroditerpene intermediate ( IV ). Cyclization, hydrolysis óf the CoA éster and enolization óf the side cháin give the intérmediate ( V ). Decarboxylation of thé side chain ánd acetylation of thé hydroxyl group óf the perhydrophenanthrene moiéty would finally Iead to the fórmation of sartorenol ( 1 ) ( Figure 3 ). Open in á separate window Figuré 3 Proposed biogenesis of sartorenol ( 1 ). Compound 2 was isolated as white solid (mp, 182183 C), and its molecular formula C 23 H 23 N 3 O 2 was established on the basis of the ()-HRESIMS m z 374.1876 M H (calculated for C 23 H 24 N 3 O 2, 374.1869), indicating fourteen degrees of unsaturation.
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