1,3-Dioxepine and spiropyran derivatives of viomellein and other dimeric naphthopyranones from cultures of Aspergillus elegans KUFA0015 and their antibacterial activity

Metabolites from Marine-Derived Fungi as Potential Antimicrobial Adjuvants

“…However, 8, 9, 12, and 19 displayed cytotoxicity in the tested cell line, inhibiting more than 50% of cell growth at the concentration they displayed efficacy at in the various assays. On the other hand, 6, 17, and 18 displayed relevant activity at non-cytotoxic concentrations for the tested cell line, highlighting meroditerpene chevalone C (6) as a promising efflux pump inhibitor and vioxanthin (17) and viomellein (18) as antimicrobials with a biofilm formation inhibitory mechanism.…”

“…The results presented herein reinforce the importance of the marine environment as a source of bioactive compounds with remarkably varied applications. From a library of 19 compounds, nine compounds, i.e., two meroditerpenes (6 and 8), two alkaloids (9 and 10), two mycotoxins (13 and 14), and three dimeric naphthopyranones (17)(18)(19) exhibited antibacterial activity in an oxacillin-and methicillin-resistant strain of S. aureus.…”

“…A meroditerpene, aszonapyrone B (11), was obtained from N. laciniosa [34]. Finally, eight compounds including ochratoxin A (12) and its methyl ester derivative (13), ochratoxin B ( 14), the dimeric naphthopyranones rubrosulphin (15) and its diacetate derivative (16), vioxanthin (17), viomellein (18), and xanthomegnin (19) were obtained from A. elegans [17]. It is worth mentioning that 17-19 present a similar scaffold to that of xanthones, which were previously described as potential efflux pump inhibitors [35].…”

“…Specifically, the Aspergillus and Neosartorya genera have been extensively studied and recognized for the bioactive compounds they are able to produce [10][11][12][13][14][15]. Our group has been studying the potential of compounds isolated from these marine-derived fungi as potential antimicrobial agents, some of which have shown antibacterial activity against susceptible and resistant strains of clinically relevant bacteria [16][17][18][19].…”

“…The compounds studied herein were isolated from four different strains of fungi: six compounds from a soil fungus Neosartorya siamensis (KUFC 6349) [ 16 ]; four compounds from a marine-derived fungus N. takakii (KUFC 7898), which was isolated from the marine macroalga Amphiroa sp. [ 19 ]; one compound from the diseased coral-derived fungus N. laciniosa (KUFC 7869) [ 34 ], and eight compounds from a marine-derived Aspergillus elegans (KUFA 0015), which was isolated from the marine sponge Monanchora unguiculata [ 17 ].…”