AUTHOR=Wang Ali , Yin Ruya , Zhou Zhiyao , Gu Gan , Dai Jungui , Lai Daowan , Zhou Ligang 

TITLE=Eremophilane-Type Sesquiterpenoids From the Endophytic Fungus Rhizopycnis vagum and Their Antibacterial, Cytotoxic, and Phytotoxic Activities

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.596889

DOI=10.3389/fchem.2020.596889

ISSN=2296-2646

ABSTRACT=<p>Fourteen new eremophilane-type sesquiterpenoids, named rhizoperemophilanes A~N (<bold>1</bold>~<bold>14</bold>), together with eight known congeners, were isolated from the culture of the endophytic fungus <italic>Rhizopycnis vagum</italic>. The structures of the new compounds were elucidated by extensive spectroscopic analyses, as well as ECD calculations and the modified Mosher's method for the assignment of the absolute configurations. Rhizoperemophilane J (<bold>10</bold>) contains an uncommon C-4/C-11 epoxy ring, while rhizoperemophilane N (<bold>14</bold>) features an unprecedented 3-nor-eremophilane lactone-lactam skeleton. These metabolites were evaluated for their antibacterial, cytotoxic, and phytotoxic activities. Among them, compounds <bold>11</bold>, <bold>16</bold>, and <bold>20</bold> displayed antibacterial activities, while <bold>14</bold> showed selective cytotoxicity against NCI-H1650 and BGC823 tumor cells. Moreover, compounds <bold>5</bold>, <bold>6</bold>, <bold>12</bold>, <bold>13</bold>, <bold>16</bold>, and <bold>19</bold> exhibited strong phytotoxic activities against the radicle elongation of rice seedlings.</p>