Plant-associated microorganisms are known to produce a variety of metabolites with novel structures and interesting biological activities. An endophytic fungus FJBJ11, isolated from the plant tissue of Brucea javanica (L.) Merr. (Simaroubaceae), was proven to be significantly effective in producing metabolites with anti-Tobacco mosaic virus (TMV) activities. The isolate was identified as Aspergillus tubingensis FJBJ11 based on morphological characteristics and ITS sequence. Bioassay-guided isolation led to the identification of a cycli penta-peptide, malformin A1, along with two cyclic dipeptides, cyclo (Gly-l-Pro) and cyclo (Ala-Leu). Malformin A1 showed potent inhibitory effect against the infection and replication of TMV with IC50 values of 19.7 and 45.4 μg·mL−1, as tested using local lesion assay and leaf-disc method, respectively. The results indicated the potential use of malformin A1 as a leading compound or a promising candidate of new viricide.
Four novel compounds—two phenylpropionamides, one piperidine, and one phenolic derivatives—were isolated and identified from the fruit of a medicinal plant, Ailanthus altissima (Mill.) Swingle (Simaroubaceae), together with one known phenylpropionamide, 13 known phenols, and 10 flavonoids. The structures of the new compounds were elucidated as 2-hydroxy-N-[(2-O-β-d-glucopyranosyl)phenyl]propionamide (1), 2-hydroxy-N-[(2-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl)phenyl]propionamide (2), 2β-carboxyl-piperidine-4β-acetic acid methyl ester (4), and 4-hydroxyphenyl-1-O-[6-(hydrogen-3-hydroxy-3-methylpentanedioate)]-β-d-glucopyranoside (5) based on spectroscopic analysis. All the isolated compounds were evaluated for their inhibitory activity against Tobacco mosaic virus (TMV) using the leaf-disc method. Among the compounds isolated, arbutin (6), β-d-glucopyranosyl-(1→6)-arbutin (7), 4-methoxyphenylacetic acid (10), and corilagin (18) showed moderate inhibition against TMV with IC50 values of 0.49, 0.51, 0.27, and 0.45 mM, respectively.
Two new compounds named fischeacid (1) and fischexanthone (2), together with eight known compounds, were obtained from the culture of a marine-derived fungus Neosartorya fischeri strain 1008F1. The structures of the new compounds were elucidated based on the spectroscopic data. Bioassays indicated that AGI-B4 (5) and 3,4-dihydroxybenzoic acid (10) showed potent inhibitory effect on the replication of tobacco mosaic virus, and AGI-B4 also possessed an inhibition of the cell proliferation of human gastric cancer cell line SGC-7901 and hepatic cancer cells BEL-7404.
The fermentation and isolation of metabolites produced by an endophytic fungus, which was identified as Phomopsis sp. FJBR-11, based on phylogenetic analysis, led to the identification of six compounds, including dothiorelones A–C, and H, and cytosporones C and U. Among these compounds, cytosporone U exhibited potent inhibitory activity against Tobacco mosaic virus (TMV). Moreover, the crude and a purified exopolysaccharide were proved to possess strong inhibitory effects against the virus infection.
A new phenolic derivative, 4-hydroxyphenol-1-O-[6-O-(E)-feruloyl-β-d-glucopyranosyl]-(1→6)-β-d-glucopyranoside (1), and a new terpenylated coumarin, named altissimacoumarin H (2) were identified from the fruit of Ailanthus altissima (Mill.) Swingle (Simaroubaceae), together with ten known compounds (3–12), including two coumarins and eight phenylpropanoids. Their structures were determined on the basis of chemical method and spectroscopic data. Antiviral effect against Tobacco mosaic virus (TMV) of all the compounds obtained were evaluated using leaf-disc method.