AUTHOR=Zhao Dong-Lin , Wang Hai-Su , Gao Li-Wei , Zhang Peng 

TITLE=Tennessenoid A, an Unprecedented Steroid−Sorbicillinoid Adduct From the Marine-Derived Endophyte of Aspergillus sp. Strain 1022LEF

JOURNAL=Frontiers in Marine Science

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.923128

DOI=10.3389/fmars.2022.923128

ISSN=2296-7745

ABSTRACT=<p>Marine natural products, characterized by fascinating drug-like functionalities and promising biological activities, are important base materials for innovative drugs and agrochemicals. Chemical investigations of the marine-algal-derived endophytic fungus <italic>Aspergillus</italic> sp. 1022LEF residing in the inner tissue of marine red alga yielded a novel polyketide-terpene hybrid metabolite, namely tennessenoid A (<bold>1</bold>), as well as six known biosynthetic congeners including two steroids, ergosta-4,6,8(14),22-tetraen-3-one (<bold>2</bold>) and (22<italic>E</italic>,24<italic>R</italic>)-3α-ureido-ergosta-4,6,8(14),22-tetraene (<bold>3</bold>), and four sorbicillinoid-based compounds, saturnispol G (<bold>4</bold>), trichodimerol (<bold>5</bold>), and dihydrotrichodimer ethers A and B (<bold>6</bold> and <bold>7</bold>). Their structures were unambiguously determined based on extensive 1D/2D NMR and HRESIMS spectroscopic analyses. Tennessenoid A (<bold>1</bold>) was characterized as an unprecedented steroid−sorbicillinoid adduct <italic>via</italic> a C−C bond, which was rarely-observed in natural products. All of the isolated compounds were evaluated for their antifungal activities against eight plant pathogenetic fungi. <bold>1</bold>, in particular, demonstrated broad-spectrum activities against <italic>Sclerotium rolfsii</italic> Sacc., <italic>Fusarium oxysporum</italic> (Schl.) F.sp <italic>cucumerinum</italic> Owen, <italic>Coniella diplodiella</italic> Petrak et Sydow, <italic>Physalospora piricola</italic> Nose., <italic>Fusarium graminearum</italic> schw., <italic>Alternaria mali</italic> rob., <italic>Colletotrichum orbiculare</italic> Arx., and <italic>Alternaria porri</italic> (E11iott) Cifed., with the inhibition zone diameters ranging from 2 to 7 mm.</p>