Drimane Sesquiterpenoids from the Aspergillus oryzae QXPC‐4

Abstract

Three new drimane sesquiterpenoids, astellolides C-E (1-3, resp.), four new drimane sesquiterpenoid p-hydroxybenzoates, astellolides F-I (4-7, resp.), together with two known compounds astellolides A and B (8 and 9, resp.), have been isolated from the liquid culture of Aspergillus oryzae (strain No. QXPC-4). Their structures were established by comprehensive analysis of spectroscopic data. The relative and absolute configurations were determined on the basis of NOESY and CD data, together with single-crystal X-ray diffraction analyses of compounds 1-3. The metabolites were evaluated for their cytotoxic activities, however, no compounds showed a significant cytotoxicity against the tested cell lines at a concentration of 20 μM.

Oryzines A & B, Maleidride Congeners from Aspergillus oryzae and Their Putative Biosynthesis

“…Thus, A. oryzae produces kojic acid, the diterpene indoles aflavinines, the aflatrem precursor 13-desoxypaxilline, the sesquiterpenes parasiticolides and various alkaloids, e.g., ditryptoleucine and oryzamides [ 9 ]. Other compounds produced by A. oryzae have been reported recently [ 10 , 11 , 12 ]. However, identifications of the respective producing strains were solely based on morphological characteristics and ribosomal genes, which are insufficient to clearly differentiate them from A. flavus [ 13 ].…”

Drimane Sesquiterpenoids and Isochromone Derivative from the Endophytic Fungus Pestalotiopsis sp. M-23

“…The 13 C NMR spectrum (Table 1) showed the presence of 15 carbon resonances which were classified using DEPT experiments into three methyls ( δ C at 33.4, 23.0, and 15.8), three methylenes (including one oxygenated methylene at δ C 80.9), six methines (including a double bond group at δ C 130.4 and 129.4; an oxymethine δ C 64.8; and a hemiacetal methine at δ C 101.7), and three quaternary carbons (including an oxygen-bearing carbon at δ C 79.0). These data suggested that 1 was a drimane sesquiterpenoid [16, 17]. Comparing the NMR spectra (Table 1) of 1 with those of 2 α -hydroxyisodrimeninol ( 4 ) [17, 18], a drimane sesquiterpenoid also isolated from this fungus, revealed that the two compounds were similar.…”

“…2). The relative configuration of 1 was deduced from the results of ROESY experiment and comparison with the data in literature [16, 17]. The ROESY correlations of Me-15 ( δ H 0.88) with H-2 ( δ H 3.91), H-11 ( δ H 5.37) and H a -12 ( δ H 3.70) revealed that these protons were β -oriented, and the ROESY correlation between H-5 ( δ H 1.93) and H-9 ( δ H 2.07) suggested their α -oriented configuration (Fig.…”

Phytotoxic Metabolites Isolated from Aspergillus sp., an Endophytic Fungus of Crassula arborescens

“…Compounds 5-7 are drimane-type sesquiterpenoids with a furanone group without cytotoxic activity isolated from Aspergillus sp. [16]. Compared with astellolides B (6) and G (7), astellolide A (5) exhibited obvious phytotoxic activity, which may be related to the benzene ring without the phenol hydroxyl group.…”

“…Among these fractions, nine compounds were purified by repeated CC. Their structures were identified to be aspertamarinoic acid (1), (−)dihydrocanadensolide (2) [10], kojic acid (3) [11], citreoisocoumarin (4) [12,13], astellolide A (5) [14], astellolide B (6) [15], astellolide G (7) [16], cyclo-N-methylphenylalanyltryptophenyl (8) [17] and (−)-ditryptophenaline (9) [18] (Figure 2) on the basis of their HRESIMS, 1D and 2D NMR spectra (see Figures S1-S24) and compared with those reported in the previous literature. -3 ).…”