Isolation and Identification of Hexaketides from a Pigmented Monosporascus cannonballus Isolate

Abstract

Monosporascus cannonballus causes severe production losses to muskmelon and watermelon in the United States and other countries. Wild types of the fungus produce no pigments when grown on potato dextrose agar (PDA). After long-term storage on soil/oat hull mix, however, some isolates of the fungus produce yellow to brown pigments and no perithecia when grown on PDA. Five colored metabolites from pigmented cultures of M. cannonballus isolate TX923038 have now been identified. Two of these, monosporascone and dehydroxyarthrinone, have been isolated from other fungi, and three, demethylcerdarin, monosporascol A and azamonosporascone, have not previously been reported. The (1)H NMR and (13)C NMR of all five compounds are reported.

Advances in the Biology and Management of Monosporascus Vine Decline and Wilt of Melons and Other Cucurbits

“…The pigments become quite intense, and, along with a loss in perithecia production, the cultures are no longer recognizable as M. cannonballus; however, polymerase chain reaction (PCR) amplification of DNA with species-specific primers confirmed their identity as M. cannonballus . An investigation into the chemical nature of the pigments was conducted by Stipanovic et al (2004) and Wheeler et al (2004). Together they identified five related hexaketides in degenerative, pigmented cultures that were present in only minimal amounts in nonpigmented cultures.…”

“…The others were apparently new to Monosporascus. Stipanovic et al (2004) proposed the trivial name of monosporascone for 5-hydroy-7-methoxy-4, 9-dioxonaphthol [2,3-c] furan. An interesting note is that these pigments developed in a wildtype isolate, presumably without dsRNA, after long-term storage.…”

Biscogniauxone, a New Isopyrrolonaphthoquinone Compound from the Fungus Biscogniauxia mediterranea Isolated from Deep-Sea Sediments

“…Thus, another hydroxyl must locate at C-7 which was also confirmed by the HMBC cross-peaks of H-6,8/C-7. Although the 1 H NMR data of 1 exhibited good similarity to a number of isofuranonaphthoquinone compounds [12], two supposedly furan CH resonances at C-1 and C-3 were observed to upshift approximately 23 ppm, which implied a NH instead of an O linkage between C-1 and C-3. This inference also was supported by the HR-TOF-MS results and indicates the presence of an N atom in the molecule of 1 .…”

“…This inference also was supported by the HR-TOF-MS results and indicates the presence of an N atom in the molecule of 1 . Only few known compounds possess the N -containing isopyrrolonaphthoquinone structures, such as azamonosporascone [12], bhimamycin C and D [13] as well as bhimamycin F, H, and I [14]. According to the established data (Figure 3, Table 1), compound 1 was identified as a new N-atom-containing isopyrrolonaphthoquinone compound named biscogniauxone.…”

A New Synthesis of Benzo[f]isoindole‐4,9‐diones by Radical Alkylation and Bromomethylation of 1,4‐Naphthoquinones

“…[8] Azamonosporascone (8) has been isolated from Monosporascus cannonballus, a fungus responsible for crop losses of water and musk melons. [9] 1,2,3-Triaryl-substituted benzo[f]isoindole-4,9-diones have also attracted attention as modulators of the Pin 1 class of peptidyl-prolyl cis-trans isomerases for the treatment of cancer. [10] Owing to the significant biological activity of benzo[f]-isoindole-4,9-dione analogues 9, several pathways have been developed for their synthesis.…”