Résumé
Chemical investigation on the rice culture of Corynespora cassiicola J9, an endophyte inhabiting in Blumea balsamifera (L.) DC. resulted in isolation of eight compounds, including a new depsidone derivative, corynether C (1), and seven analogues, corynether B (2), corynetherlactone A (3), corynether A (4), diaryl ether (5), corynesidone C (6), corynesidone D (7), and corynesidone A (8). Their structures were deduced based on 1D and 2D NMR spectroscopy, and HR-ESI-MS data. All of the isolated compounds were evaluated for inhibitory activities against Lissorhoptrus oryzophilus Kuschel by the leaf spray assay. Unfortunately, none of them showed inhibitory effects.
Résumé
Phytochemical investigation of the culture of Epicoccum nigrum,an endolichenic fungus inhabiting Leptogium masiaticum,led to the isolation of 11 compounds. Based on NMR spectroscopy and HRESIMS data,their structures were determined as one alkaloid fusaricide( 1),and seven benzofuran derivatives including epicoccone( 2),4,6-dihydroxy-5-methoxy-7-methyl-1,3-dihydro isobenzofuran( 3),5-methyl-epicoccone B( 4),3,6,7-trihydroxy-5-methoxy-4-methylisobenzo furan-1( 3 H)-one( 5),3-methoxyepicoccone B( 6),2,3,4-trihydroxy-6-( hydroxymethyl)-5-methylbenzyl-alcohol( 7),and isoochracinic acid( 8),together with three epicoccolide analogs epicocconigrones A( 9),epicoccolide B( 10),and epicocconigrones B( 11). Compounds 1,9 and 10 showed potent microorganism inhibitory effects. These results indicated the potential perspective of this endophytic fungus as an eco-friendly biocide.