Michimasa Ikeda

Three Oxygenated Cyclohexenone Derivatives Produced by an Endophytic Fungus

Three cyclohexenone derivatives, (4S,5S,6S)-5,6-epoxy-4-hydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one (1), (4R,5R)-4,5-dihydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one (2), and (4R,5S,6R)-4,5,6-trihydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one (3), were isolated from unpolished rice fermented with an xylariaceous endophytic fungus (strain YUA-026). The structures of three compounds were established on the basis of spectroscopic analyses and chemical conversion. The minimum inhibitory concentrations of 1 and 3 were 100 μg/ml and 400 μg/ml against Staphylococcus aureus, 100 μg/ml and 200 μg/ml against Pseudomonas aeruginosa, and 200 μg/ml and >400 μg/ml against Candida albicans, respectively. In addition, 1 and 3 exhibited phytotoxic activity against lettuce.

A new fungal morphogenic substance, pyrenolide a from Pyrenophora teres

Abstract A new ten-membered lactone, pyrenolide A, was identified as a new fungal morphogenic substance and its structure including absolute stereochemistry was elucidated.

Structural Confirmation of Cotylenin A, a Novel Fusicoccane-diterpene Glycoside with Potent Plant Growth-regulating Activity from Cladosporium Fungus sp. 501-7W

The structure of cotylenin A, a potent plant-growth stimulant with the most complex molecule in cotylenins from Cladosporium fungus sp. 501-7W, was analyzed again by HMBC experiments and X-ray crystallography of its diacetyl-dihydroderivative. The previously proposed stereostructure of cotylenin A was thus completely confirmed.

New Monoterpentriols from the Fruiting Body of Flammulina velutipes

Two monoterpentriols were isolated from the stipe segment without either the pileus or apical growth zone of the harvested fruiting body of F. velutipes. The structures of these monoterpentriols were elucidated as (1R, 2R, 4R, 8S)-(-)-p-menthane-2,8,9-triol (1) and its 8-epimer (2) based on a spectroscopic analysis and stereoselective chemical transformation from an authentic monoterpene alcohol. These monoterpentriols showed growth-promoting activities on the excised stipe with the pileus segment, which had been excised from a fruiting body just under the growth zone before the middle stage of the rapid growth period, at concentrations below 10 ppm, while the growth of the segment was inhibited at concentrations of 100 ppm and above.

Isolation and Identification of New Antifungal Macrophorins E, F and G as Malonyl Meroterpenes from Botryosphaeria berengeriana

Macrophorins E, F and G were newly isolated from Botryosphaeria berengeriana, each showing potent antifungal activity similar to that of macrophorin A against phytopathogenic fungi B. berengeriana and Gibberella fujikuroi. Macrophorins E and G were identified as novel malonylated derivatives of macrophorin A, and F as a macrophorin E congener with a hydroxy-cyclohexenedione moiety instead of its epoxy-cyclohexenone one.

N-Phenethylhexadecanamide from the edible mushroom Laetiporus sulphureus.

N-Phenethylhexadecanamide was isolated from the MeOH extract of the fruiting bodies of the mushroom Laetiporus sulphureus together with eburicoic acid. Their structures were elucidated by spectroscopic methods.

Protoilludane-Type Sesquiterpenes, Echinocidins A and B, from a Mycelial Culture of Echinodontium tsugicola

Abstract Two novel protoilludane sesquiterpenoids, echinocidins A (3) and B, (4) have been isolated from an artificial liquid culture of the basidiomycetous fungus Echinodontium tsugicola and their structures clarified spectroscopically. Echinocidin A (3) accelerated primary root growth to 117% and echinocidin B to 180% of controls at a concentration of 100 ppm.

Three sesquiterpenoids, fascicularones E, F, and G produced by the fungus Hypholoma fasciculare

Three new sesquiterpenoids, fascicularones E, F, and G, were isolated from the liquid culture extract of the fungus Hypholoma fasciculare. Their structures were established based on spectroscopic data.

Three lanostane triterpenoids from the fruiting bodies of Stropharia aeruginosa

Three new lanostane triterpenoids, aeruginosic acid derivatives, were isolated from the fruiting bodies of Stropharia aeruginosa and their structures were determined on the basis of spectral data.

Protoilludane sequiterpenoids, echinocidins C and D produced by a decay causing fungal strain Echinodontium tsugicola

New protoilludane sequiterpenoids, echinocidins C (3) and D (4) have been isolated from liquid culture of Echinodontium tsugicola. Their structures have been established on the basis of spectral analysis. The biological activities of 3 and 4 were examined by bioassay with lettuce seedlings