Metabolites with phytopathogenic fungi inhibitory activities from the mangrove endophytic fungus Botryosphaeria ramose.

To check whether the endophytic fungus from the host plant could produce novel bioactive metabolites induced by the host-derived chemical components, a strategy called "Induction of Endophyte Metabolism by Adding Host Components" (IEMAHC) was put up and applied. Cultivation of the endophytic fungus Botryosphaeria ramosa L29 derived from Myoporum bontioides after adding (2R, 3R)-3, 5, 7-trihydroxyflavanone 3-acetate, a constituent of the same plant, into the culture medium, led to the separation of three new chromones, 5-hydroxy-2, 3-dihydroxymethyl-7-methoxychromone (1), 5-hydroxy-3-acetoxymethyl-2-methyl-7- methoxychromone (2), 5, 7-dihydroxy-3-hydroxymethyl-2-methylchromone (3), one new isocoumarin, 8-hydroxy-3-hydroxymethyl-6-methoxy-7-methylisocoumarin (4), two new δ-lactones, botryopyrone (8) and (5S, 8R)-simplicilopyrone (9), one new naturally rare 2 (7H)-oxepinone, botroxepinone (10), and three known compounds (5-7). They were identified through comprehensive analysis of spectroscopic data. HPLC comparative analysis indicated that compounds 8-10 were induced products after adding (2R, 3R)-3, 5, 7-trihydroxyflavanone 3-acetate as an inducer. Compound 3 exhibited more potent inhibitory activities on Fusarium oxysporum, Fusarium graminearum, Penicillium italicum, and Colletotrichum musae than triadimefon. Compounds 1, 2, 4-7 and 9 displayed potent antifungal activities towards two or three tested fungi with MIC values equal or superior to triadimefon. The induced products 9 and 10 both showing strong inhibitory activity against C. musae, might play a role in strengthening the host defense against the common mangrove invasive pathogenic fungal genera Colletotrichum.

Sesquiterpenes with Phytopathogenic Fungi Inhibitory Activities from Fungus Trichoderma virens from Litchi chinensis Sonn.

A new monosesquiterpene diacetylgliocladic acid (1), a new dimeric sesquiterpene divirensol H (9), and two exceptionally novel trimeric sesquiterpene trivirensols A and B (11 and 12), together with another eight known congeners, were purified from an endophytic fungus Trichoderma virens FY06, derived from Litchi chinensis Sonn. whose fruit is a delicious and popular food. All of them were identified by comprehensive spectroscopic analysis, combined with biosynthetic considerations. Trivirensols A and B are unprecedented trimers of which three subunits are connected by two ester bonds of the sesquiterpene class. Relative to the positive control triadimefon, all the tested metabolites showed strong inhibitory activities against at least one phytopathogenic fungus among Penicillium italicum, Fusarium oxysporum, Fusarium graminearum, Colletotrichum musae, and Colletotrictum gloeosporioides. Notably, as metabolites of the endophytic fungus from L. chinensis, they all presented strong antifungal activities against C. gloeosporioides which causes anthracnose in L. chinensis.