AUTHOR=Liu Peng , Tan Yue , Yang Jian , Wang Yan-Duo , Li Qi , Sun Bing-Da , Xing Xiao-Ke , Sun Di-An , Yang Sheng-Xiang , Ding Gang 

TITLE=Bioactive secondary metabolites from endophytic strains of Neocamarosporium betae collected from desert plants

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1142212

DOI=10.3389/fpls.2023.1142212

ISSN=1664-462X

ABSTRACT=<p>Endophytic fungi from desert plants belong to a unique microbial community that has been scarcely investigated chemically and could be a new resource for bioactive natural products. In this study, 13 secondary metabolites (<bold>1–13</bold>) with diverse carbon skeletons, including a novel polyketide (1) with a unique 5,6-dihydro-4<italic>H</italic>,7<italic>H</italic>-2,6-methanopyrano[4,3-<italic>d</italic>][1,3]dioxocin-7-one ring system and three undescribed polyketides (<bold>2</bold>, <bold>7</bold>, and <bold>11</bold>), were obtained from the endophytic fungus <italic>Neocamarosporium betae</italic> isolated from two desert plant species. Different approaches, including HR-ESI-MS, UV spectroscopy, IR spectroscopy, NMR, and CD, were used to determine the planar and absolute configurations of the compounds. The possible biosynthetic pathways were proposed based on the structural characteristics of compounds <bold>1–13</bold>. Compounds <bold>1</bold>, <bold>3</bold>, <bold>4</bold>, and <bold>9</bold> exhibited strong cytotoxicity toward HepG2 cells compared with the positive control. Several metabolites (<bold>2</bold>, <bold>4–5</bold>, <bold>7–9</bold>, and <bold>11–13</bold>) were phytotoxic to foxtail leaves. The results support the hypothesis that endophytic fungi from special environments, such as desert areas, produce novel bioactive secondary metabolites.</p>