Omphaloprenol A: a new bioactive polyisoprenepolyol isolated from the mycelium of poisonous mushroom Omphalotus japonicus.

Mushrooms of the Omphalotus genus are known to be rich in secondary metabolites. In the quest for new bioactive compounds, we analyzed the compounds isolated from the mycelium of the poisonous mushroom Omphalotus japonicus. As a result, a new polyisoprenepolyol, which was named omphaloprenol A, was identified, along with known substances such as hypsiziprenol A10 and A11, illudin S, and ergosterol. The chemical structure of omphaloprenol A was elucidated by nuclear magnetic resonance and infrared spectroscopies and mass spectrometry, and its bioactivity was investigated. Omphaloprenol A showed growth promoting activity against the root of lettuce seeds and cytotoxicity against HL60 cells. To the best of our knowledge, this is the first report on the isolation of a polyisoprenepolyol compound from Omphalotaceae mushrooms.

Constituents of the Fruiting Body of Poisonous Mushroom Omphalotus japonicus.

Six new sesquiterpenes, tsukiyols A-C, neoilludin C, and 4-O-methylneoilludins A and B, were isolated from the fruiting body of Omphalotus japonicus (Kawam.) Kirchm. & O. K. Mill. Additionally, six known compounds, illudin S, neoilludins A-B, 5-hydroxydichomitol, ergosterolperoxide, and 3ß,5α,9α-trihydroxyergosta-7,22-diene-6-one, were also obtained. Their chemical structures were determined with MS, IR, and NMR spectra and the absolute configurations of neoilludins A-C, 4-O-methylneoilludins A, and B were determined with electronic circular dichroism (ECD). Illudin S and 3ß,5α,9α-trihydroxyergosta-7,22-diene-6-one showed cytotoxicity against human acute promyelocytic leukemia HL60 cells. Illudin S, 4-O-methylneoilludin A, B, and tsukiyol C showed growth-restoring activity against mutant yeast via Ca2+-signal transduction.