Quellenin, a new anti-Saprolegnia compound isolated from the deep-sea fungus, Aspergillus sp. YK-76

Abstract

Saprolegnia parasitica, belonging to oomycetes, is one of virulent pathogen of fishes such as salmon and trout, and causes tremendous damage and losses in commercial aquacultures by saprolegniasis. Previously, malachite green, an effective medicine, had been used to control saprolegniasis. However, this drug has been banned around the world due to its mutagenicity. Therefore, novel anti-saprolegniasis compounds are urgently needed. As a new frontier to discover bioactive compounds, we focused on the deep-sea fungi for the isolation of anti-saprolegniasis compounds. In this paper, on the course of anti-saprolegniasis agents from 546 cultured broths of 91 deep-sea fungal strains, we report a new compound, named quellenin (1) together with three known compounds, diorcinol (2), violaceol-I (3) and violaceol-II (4), from deep-sea fungus Aspergillus sp. YK-76. This strain was isolated from an Osedax sp. annelid, commonly called bone-eating worm, collected at the São Paulo Ridge in off Brazil. Compounds 2, 3 and 4 showed anti-S. parasitica activity. Our results suggest that diorcinol and violaceol analogs and could be good lead candidates for the development of novel agents to prevent saprolegniasis.

Biosynthesis of Diphenyl Ethers in Fungi

“…8−12 Fungal DPEs possess broad biological activities including antimalarial, antitubercula, antisaprolegnia, antifungal, and anti-Aβ 42 aggregation. 11,13 They are therefore usually used as a platform to design and synthesize analogues for the development of highly useful drug leads. 14,15 A distinguished example is diorcinol (1) (Figure 1), one of the most universal DPEs among fungus, the postmodifications of which such as hydroxylation, methylation, and prenylation have enlarged its structural and bioactive diversity (Figure S1).…”

“…Fungi are another rich source of DPEs. Plenty of OH-/MeO-DPEs and chlorinated DPEs (chloro-DPEs) (Figure and Figure S1) have been isolated from different fungi, including Aspergillus sp., Simpilcillium sp., Pestalotiopsis sp., Phomopsis sp., and Cordyceps sp. − Fungal DPEs possess broad biological activities including antimalarial, antitubercula, antisaprolegnia, antifungal, and anti-Aβ 42 aggregation. , They are therefore usually used as a platform to design and synthesize analogues for the development of highly useful drug leads. , A distinguished example is diorcinol ( 1 ) (Figure ), one of the most universal DPEs among fungus, the postmodifications of which such as hydroxylation, methylation, and prenylation have enlarged its structural and bioactive diversity (Figure S1).…”

Recent updates on the bioactive compounds of the marine-derived genusAspergillus

“…These compounds showed anti-S. parasitica activity, suggesting that diorcinol (18) and violaceol analogs could have their potential to be used as saprolegniasis preventing candidates. 109 Chitinase enzyme (307) was produced from unconventional sources, the marine-derived fungus Aspergillus griseoaurantiacus KX010988 by solid state fermentation of potato shells. Chitinase enzyme (307) showed good antifungal activity against F. solani with inhibition zone diameter ¼ 23 AE 1.20.…”

Marine-derived fungi as a source of bioactive indole alkaloids with diversified structures

“…YK-76, which was isolated from an Osedax sp. annelid, commonly called bone-eating worm, collected at the São Paulo Ridge off the Brazilian coastline (Takahashi et al 2018). An analog of fellutanine A (41) was isolated from the ethyl acetate extract of a culture of the sponge-associated fungus Neosartorya glabra KUFA 0702 (May Zin et al 2016).…”