AUTHOR=Tang Jun , Huang Xueshuang , Cao Ming-Hang , Wang Zhiyan , Yu Zhiyin , Yan Yijun , Huang Jian-Ping , Wang Li , Huang Sheng-Xiong 

TITLE=Mono-/Bis-Alkenoic Acid Derivatives From an Endophytic Fungus Scopulariopsis candelabrum and Their Antifungal Activity

JOURNAL=Frontiers in Chemistry

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.812564

DOI=10.3389/fchem.2021.812564

ISSN=2296-2646

ABSTRACT=<p>During a screening for antifungal secondary metabolites, six new mono-/bis-alkenoic acid derivatives (<bold>2</bold>–<bold>7</bold>) and one known alkenoic acid derivative (<bold>1</bold>) were isolated from an endophytic fungi <italic>Scopulariopsis candelabrum</italic>. Their chemical structures were identified by <sup>1</sup>H-NMR, <sup>13</sup>C-NMR, 2D NMR, and high-resolution mass spectrometry, as well as comparisons with previously reported literatures. Among them, fusariumesters C‒F (<bold>2</bold>–<bold>5</bold>) are bis-alkenoic acid derivatives dimerized by an ester bond, while acetylfusaridioic acid A (<bold>6</bold>) and fusaridioic acid D (<bold>7</bold>) are alkenoic acid monomers. All the isolates were submitted to an antifungal assay against <italic>Candida albicans</italic> and the corn pathogen <italic>Exserohilum turcicum</italic> using the filter paper agar diffusion method. As a result, only compound <bold>1</bold> decorating with <italic>β</italic>-lactone ring turned out to be active against these two tested fungi. The broth microdilution assay against <italic>Candida albicans</italic> showed the minimum inhibitory concentration (MIC) value of <bold>1</bold> to be 20 <italic>μ</italic>g/ml, while the minimum inhibitory concentration value of the positive control (naystatin) was 10 <italic>μ</italic>g/ml. And the half maximal inhibitory concentration (IC<sub>50</sub>) value (21.23 <italic>μ</italic>g/ml) of <bold>1</bold> against <italic>Exserohilum turcicum</italic> was determined by analyzing its inhibition effect on the mycelial growth, using cycloheximide (IC<sub>50</sub> = 46.70 <italic>μ</italic>g/ml) as the positive control.</p>