Structure and Fungicidal Activity of Secondary Metabolites Isolated from Trichoderma hamatum b-3

Two new harziane diterpenes (<b>1</b>-<b>2</b>), five undescribed cyclonerane sesquiterpenes (<b>3</b>-<b>7</b>), and three known compounds, 11-cycloneren-3, 7, 10-triol (<b>8</b>), harziandione (<b>9</b>), and dehydroacetic acid (<b>10</b>), were isolated from <i>Trichoderma hamatum</i> b-3. Their structures were elucidated via comprehensive inspection of spectral evidence in HRESIMS and 1D and 2D NMR, and the absolute configuration of <b>1</b>-<b>8</b> was confirmed by NMR, ECD calculation, as well as Mosher's method. In vitro fungicidal activity showed that some compounds showed great inhibitory activity against pathogenic fungi, including <i>Fusarium graminearum</i>, <i>Sclerotinia sclerotiorum</i>, <i>Botrytis cinerea</i>, and <i>Rhizoctonia solani</i>, among which compound <b>10</b> showed 100% inhibition of <i>S. sclerotiorum</i> and <i>B. cinerea</i>. The in vivo activity test showed that compound <b>10</b> was 65.8% effective against <i>B. cinerea</i> and compound <b>10</b> can be used as a lead compound for the development of biopesticides that inhibit <i>B. cinerea</i>. This study elucidated the bioactivity of secondary metabolites of <i>T. hamatum</i> and indicated the direction for the subsequent development of the biological control activity of <i>T. hamatum</i>.