• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.985-987
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• 2010

The biological transformation of the bioactive dihydroisocoumarin, (-)-mellein, isolated from the marinederived fungus Cladosporium sp., was studied. The preparativescale culture of (-)-mellein with a marine isolate of a bacterium Stappia sp. resulted in the isolation of its oxidized metabolite, (3R,4S)-4-hydroxymellein. The stereostructure of the metabolite obtained was assigned on the basis of detailed physicochemical data analyses.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.118-123
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• 1998

Lasiodiplodia theobrorme is a pathogen of Java black rot on sweet potato. This fungus infects the tuberous root during storage after harvest. Invasion of the fungus results in the expansion of necrosis sites into the tuberous roots. The resultant necrotic symptom of the tissue is also induced by application of acetone extract of the fungus growing on potato sucrose agar (PSA) culture. The active principles to induce the necrosis are purified from the acetone extract as follows. After evaporation of hexane-benzene-EtOAc (1:2:1, v/v/v) the extract was fractioned on silica gel column, using a solvent gradient system from n-hexane to EtOAc and then to MeOH. The active fractions were purified with HPLC on Nucleosil 50-5 column by eluting n-hexane to EtOAc. Their structures are established by using spectroscopic techniques and synthesis to 4-hydroxymellein and mellein, respectively. Application of small amount of these compounds induce expansion of the necrotic symptom into the tissue and accumulated ipomeamarone. Conclusively, these compounds acted as phytotoxins (inducing necrosis) and as elicitors (eliciting the phytoalexin).

• Natural Product Sciences
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• v.25 no.3
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• pp.228-232
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• 2019

Five secondary metabolites, including a new isopimarane derivative xylaroisopimaranin A (1), were isolated from the endophytic fungus Xylaralyce sp. (HM-1), and their structures were elucidated by 1D, 2D NMR, MS and CD spectra. Their bioactivities were performed to antibacterial, Hep G2 cells cytotoxicity and brine shrimp inhibition. The biological evaluation results showed that the xylaroisopimaranin A (1), xylabisboein B (2), griseofulvin (3), 5-methylmellein (4) and mellein-5-carboxlic acid (5) displayed no significant Hep G2 cells cytotoxicity and antibacterial acitivity, but they inhibited the brine shrimp with $IC_{50}$ from 0.5 to $25{\mu}mol/mL$.