Cytotoxic Polyketides from a Marine-derived Fungus Aspergillus glaucus

Abstract

Eight new aromatic polyketides (2, 4-6, 8, 14, 16, and 17) together with eight known analogues (3, 7, 9-13, and 15) were isolated from the marine-derived fungus Aspergillus glaucus. The structures and stereochemistry of the new compounds were elucidated by spectroscopic and chemical methods, and their cytotoxicities were evaluated against the HL-60 and A-549 cell lines.

Polygonumnolides A1–B3, minor dianthrone derivatives from the roots of Polygonum multiflorum Thunb

“…The relative structure of dianthrone derivatives was unable to be confirmed by NOESY experiments (Lenta et al 2008; Haasnoot et al 1980; Spassov 1971). Indeed, the ROESY spectrum correlations of H-10 with H-4, H-5, H-4′ and H-5′, and H-10′ with H-4, H-5, H-4′ and H-5′ indicated that the relative structure of 1 cannot be confirmed by NOESY.…”

“…Comparison of the 1D NMR spectrum of 1 with those of physcion dianthrones, emodin dianthrones, and physcion-emodin dianthrones (Donald et al 1976; Du et al 2008; Monache et al 1991) suggested 1 could be a C-10/C-10′ isomer of physcion-emodin dianthrone glycosides. The 13 C NMR and DEPT spectra (Table 2) exhibited 37 carbon signals, including 31 carbon signals of physcion-emodin dianthrones that were categorized by DEPT and HSQC techniques into 18 quaternary carbons, including with two carbonyl groups [ δ C 191.3 (C-9′) and 188.5 (C-9)], 10 methine groups [ δ C 117.3 (C-2), 121.8 (C-4), 112.5 (C-5), 107.7 (C-7), 117.7 (C-2′), 122.2 (C-4′), 109.7 (C-5′), 100.7 (C-7′), 57.7 (C-10) and 56.7 (C-10′)], two methyl groups [ δ C 21.8 ( Me -3) and 22.1 ( Me -3′)], one methoxy group δ C 56.5 (O Me -6′)] and six carbon signals characteristic of glucose [ δ C 106.1, 74.9, 78.8, 71.2, 77.4, 62.7].…”

A rule to distinguish diastereomeric bianthrones by 1H NMR

“…[1][2][3][4][5][6][7][8][9][10] They are also regarded as important intermediates in the biosyntheses of photosensory pigments with ingestion-deterrent, antiviral, and sedative properties, and some have been obtained as intermediates in the chemical syntheses of these pigments. 11,12 Additionally, the photochromic derivatives with a double bond between C-10 and C-10 0 have attracted much attention for molecular electronics, and they may be taken as potential structural elements in supramolecular assemblages due to the conductance-switching property.…”

Bioactive Diphenyl Ethers and Isocoumarin Derivatives from a Gorgonian-Derived Fungus Phoma sp. (TA07-1)

“…Detailed inspection of the NMR data (Table 1) of 2 with those of 1 revealed that these two compounds were very similar, except for the sugar moiety. The sugar residue in 2 was defined as a ribose by comparing the NMR data (Table 1) with those of naphthyl ribofuranoside, isotorachrysone-6- O -α- d -ribofuranoside [20], chromene glycoside, and sterin A [21]. The key HMBC correlation from H-1″ to C-3′ (Figure 2) established the connection between the ribose and diphenyl ether moiety.…”