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

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).

New Polyketides and New Benzoic Acid Derivatives from the Marine Sponge-Associated Fungus Neosartorya quadricincta KUFA 0081

“…This identification was supported by sequence analysis of the β-tubulin, calmodulin and actin genes as described in the previous report [ 22 ]. Neosartorya quadricincta was also confirmed by the analysis sequence of the internal transcribed spacer (ITS) gene according the procedure previously described by us [ 7 ]. Its gene sequences were deposited in GenBank with Accession Numbers KM095492 and KT201525, respectively.…”

“…Certain species are also found to produce interesting bioactive secondary metabolites that can be considered to have potential for drug development [ 1 ]. For this reason, we have investigated the bioactive secondary metabolites produced from the cultures of four Neosartorya species collected from soil in Thailand, i.e., Neosartorya glabra KUFC 6311 [ 2 ], N. pseudofischeri KUFC 6422 [ 3 ], N. siamensis KUFC 6349 [ 4 ] and N. fischeri KUFC 6344 [ 5 ], as well as six marine-derived species of Neosartorya , including N. paulistensis KUFC 7898 [ 6 ], N. laciniosa KUFC 7896 [ 5 ], N. spinosa KUFC 8104, N. tsunodae KUFC 9213 [ 5 ], N. siamensis KUFA 0017 and N. takakii KUFC 7898 [ 7 ], as well as one marine-derived Aspergillus species ( Aspergillus similanensis KUFA 0013) [ 8 , 9 ]. Recently, we have also reported the antifungal activity of the crude extract of N. quadricincta KUFA 0064, isolated from an agricultural soil in Southern Thailand, against plant pathogenic fungi, which are causative agents of diseases of economically-important plants of Thailand [ 10 ].…”

A New Dihydrochromone Dimer and Other Secondary Metabolites from Cultures of the Marine Sponge-Associated Fungi Neosartorya fennelliae KUFA 0811 and Neosartorya tsunodae KUFC 9213

“…Chromatographic fractionation and further purification of the ethyl acetate extract of N. fennelliae KUFA 0811, yielded a previously undescribed 2,3-dihydro-4 H -chromen-4-one dimer which we have named paecilin E ( 1 ), in addition to the previously described dehydromevalonic acid lactone [ 6 ], byssochlamic acid [ 7 ], β-sitostenone [ 8 ], ergosta-4,6,8 (14), 22-tetraen-3-one [ 9 ], cyathisterone [ 10 ], dankasterone A ( 2 ) [ 11 ], chevalone B [ 12 ], helvolic acid [ 5 ], aszonalenin [ 13 ], secalonic acid A [ 14 ] and fellutanine A [ 13 ]. The ethyl acetate extract of N. tsunodae KUFC 9213 furnished, besides sartorypyrone B and helvolic acid which were previous isolated in our first study [ 5 ], byssochlamic acid [ 7 ], hopan-3β,22-diol ( 5 ) [ 15 ], chevalone C [ 16 ], a chromanol derivative ( 3 ) [ 17 , 18 ], (3β,5α,22 E )-3,5-dihydroxyergosta-7,22-dien-6-one ( 4 ) [ 19 ], the alkaloid harmane ( 7 ) [ 20 ], and lumichrome ( 6 ) [ 21 ].…”

New Cyclotetrapeptides and a New Diketopiperzine Derivative from the Marine Sponge-Associated Fungus Neosartorya glabra KUFA 0702

“…This identification was supported by sequence analysis of the β-tubulin, calmodulin and actin genes as described in the previous report [ 21 ]. Neosartorya glabra was also confirmed by sequence analysis of the internal transcribed spacer (ITS) gene, according the procedure previously described by us [ 11 ]. Its gene sequences were deposited in GenBank with accession numbers KU955860.…”

“…During our ongoing search for bioactive secondary metabolites from members of the genus Neosartorya and our pursuit for natural antibiotics from marine-derived fungi, we have investigated the secondary metabolites of a Thai collection of N. glabra KUFA 0702, isolated from the marine sponge Mycale sp., collected from the coral reef at Samaesarn Island in the Gulf of Thailand. The ethyl acetate extract of its culture furnished three new compounds including two new cyclotetrapeptides, sartoryglabramides A ( 5 ) and B ( 6 ), and a new analog of fellutanine A ( 8 ), in addition to the previously reported ergosta-4,6,8 (14), 22-tetraen-3-one [ 6 ], ergosterol 5, 8-endoperoxide [ 7 ], helvolic acid [ 8 ], aszonalenin ( 1 ) [ 9 ], (3 R )-3-(1 H -indol-3-ylmethyl)-3, 4-dihydro-1 H -1,4-benzodiazepine-2,5-dione ( 2 ) [ 10 ], takakiamide ( 3 ) [ 11 ], (11a R )-2,3-dihydro-1 H -pyrrolo[2,1- c ][1,4]benzodiazepine-5,11(10 H ,11a H )-dione ( 4 ) [ 12 ], and fellutanine A ( 7 ) [ 13 , 14 ] ( Figure 1 ). Compounds 1 – 8 were tested for their antibacterial activity against Gram-positive ( Escherichia coli ATCC 25922) and Gram-negative ( Staphyllococus aureus ATCC 25923) bacteria, as well as for their antifungal activity against filamentous ( Aspergillus fumigatus ATCC 46645), dermatophyte ( Trichophyton rubrum ATCC FF5) and yeast ( Candida albicans ATCC 10231).…”