Daldinans D‒G, new isoindolinone antioxidants isolated from the ascomycete Daldinia concentrica.

Four new isoindolinone derivatives, daldinans D‒G (3‒6), together with two known compounds, daldinans A and B (1 and 2), were isolated from the stroma of the ascomycete Daldinia concentrica. Chemical structures of the isolated compounds were determined by spectroscopic methods. All of these compounds exhibited antioxidant activities with IC50 values of 3.21 to 39.67 µM in the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay.

New antioxidants from the culture broth of Coprinopsis echinospora.

During the search for natural antioxidants from fungal metabolites, three new sesquiterpene derivatives (1-3) have been isolated from the culture broth of Coprinopsis echinospora. Their structures were determined by spectroscopic methods, mainly NMR and mass spectrometric analyses. These compounds exhibited antioxidant activity with IC50 values in the range of 34.4-144.5 µM in the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging assay.

Chemical Constituents of the Culture Broth of Panus rudis.

In our ongoing search for new secondary metabolites from fungal strains, one novel compound (1) and nine known compounds (2-10) were isolated from the EtOAc-soluble layer of the culture broth of Panus rudis. The culture broth of P. rudis was extracted in acetone and fractionated by solvent partition; column chromatography using silica gel, Sephadex LH-20, and Sephadex G-10; MPLC; and HPLC. The structures of isolated compounds were elucidated by one- and two-dimensional NMR and LC-ESI-mass measurements. One new compound, panepoxydiol (1), and nine known compounds, (E)-3-(3-hydroxy-3-methylbut-1-en-1-yl)-7-oxabicyclo[4.1.0]hept-3-ene-2,5-diol (2), isopanepoxydone (3), neopanepoxydone (4), panepoxydone (5), panepophenanthrin (6), 4-hydroxy-2,2-dimethyl-6-methoxychromane (7), 6-hydroxy-2,2-dimethyl-3-chromen (8), 2,2-dimethyl-6-methoxychroman-4-one (9), 3,4-dihydroxy-2,2-dimethyl-6-methoxychromane (10), were isolated from the culture broth of P. rudis. This is the first report of isolation of a new compound panepoxydiol (1) and nine other chemical constituents (2-5, 7-10) from the culture broth of P. rudis.

Lipoxygenase Inhibitory Activity of Korean Indigenous Mushroom Extracts and Isolation of an Active Compound from Phellinus baumii.

We investigated a total of 335 samples of Korean native mushroom extracts as part of our lipoxygenase (LOX) inhibitor screening program. Among the mushroom-methanolic extracts we investigated, 35 exhibited an inhibitory activity greater than 30% against LOX at a concentration of 100 µg/mL. Especially, Collybia maculata, Tylopilus neofelleus, Strobilomyces confusus, Phellinus gilvus, P. linteus, P. baumii, and Inonotus mikadoi exhibited relatively potent LOX inhibitory activities of 73.3%, 51.6%, 52.4%, 66.7%, 59.5%, 100.0%, and 85.2%, respectively. Bioassay-guided fractionation led to the isolation of inoscavin A from the methanolic extract of P. baumii, which showed the most potent activity and was identified by spectroscopic methods. Specifically, inoscavin A exhibited potent LOX inhibitory activity with an IC50 value of 6.8 µM.

Bacillus sp. BS061 Suppresses Powdery Mildew and Gray Mold.

The use of a microorganism, or its secretions, to prevent plant disease offers an attractive alternative or supplement to synthetic fungicides for the management of plant disease without the negative effects of chemical control mechanisms. During a screening for microorganisms with the potential to be used as microbial fungicides, Bacillus sp. BS061 was isolated from a plant leaf. The strain BS061 potently inhibited the mycelial growth of Botrytis cinerea, and significantly reduced disease incidence of powdery mildew in cucumber and strawberry. We also found that the culture filtrate of BS061 inhibited the mycelial growth of various plant pathogens.

Bacillus sp. BS061 Suppresses Gray Mold and Powdery Mildew through the Secretion of Different Bioactive Substances.

A Bacillus sp. BS061 significantly reduced disease incidence of gray mold and powdery mildew. To identify the active principle, the culture filtrate was partitioned between butanol and water. The antifungal activity against B. cinerea was evident in the butanol-soluble portion, and active substances were identified as cyclic lipopeptides, iturin A series, by nuclear magnetic resonance spectrometry (NMR) and mass analysis. Interestingly, antifungal activity against powdery mildew was observed in the water-soluble portion, suggesting that cyclic lipopeptides have no responsibility to suppress powdery mildew. This finding reveals that biocontrol agents of Bacillus origin suppress gray mold and powdery mildew through the secretion of different bioactive substances.

New bioactive compounds from korean native mushrooms.

Mushrooms are ubiquitous in nature and have high nutritional attributes. They have demonstrated diverse biological effects and therefore have been used in treatments of various diseases, including cancer, diabetes, bacterial and viral infections, and ulcer. In particular, polysaccharides, including ß-glucan, are considered as the major constituents responsible for the biological activity of mushrooms. Although an overwhelming number of reports have been published on the importance of polysaccharides as immunomodulating agents, not all of the healing properties found in these mushrooms could be fully accounted for. Recently, many research groups have begun investigations on biologically active small-molecular weight compounds in wild mushrooms. In this mini-review, both structural diversity and biological activities of novel bioactive substances from Korean native mushrooms are described.

p-Terphenyls from fungus Paxillus curtisii chelate irons: a proposed role of p-terphenyls in fungus.

Diverse p-terphenyl compounds, named curtisians, have been isolated from the fungus Paxillus curtisii, and degradation of wood by this fungus is thought to be progressed by iron chelation of p-terphenyl curtisians. In this study, the iron chelation ability of p-terphenyls has been proved by chrome azurol S (CAS) assay, reducing power, and UV-visible spectroscopic analyses. The catechol moiety of p-terphenyl is an essential factor for the potent iron chelation ability, and thus deacylated curtisian with a tetrahydroxyl moiety in the central ring of p-terphenyl is more effective than acylated curtisians.

Mushrooms collected from deogyu mountain, muju, Korea and their antioxidant activity.

Mushrooms collected from Deogyu mountain, Korea, in 2011, were identified as four classes, four orders, 13 families, 22 genera, and 33 species. In particular, agaricales was most abundant and comprised more than 70%. Their antioxidant activities were estimated using three different bioassay methods, the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical scavenging assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, and reducing power assay. As a result, the methanol extracts of Stereum ostrea, Laetiporus sulphureus var. miniatus, and Tyromyces sambuceus exhibited potent antioxidant activity in all bioassays tested.