Mushrooms are widely consumed not only as foods but also as alternative medicines. The fungus-specific constituents of mushrooms are thought to be effective against cancer and other lifestyle-related diseases. Mushroom polysaccharides belonging to the b-glucans possess the antitumor and immunomodulating actions in vivo, and some clinical trials have been carried out with these agents. 1,2) Steroids are abundantly present in mushrooms 3,4) and were reported to have diverse physiological functions, such as anti-oxidant effects, anti-inflammatory activity and inhibitory effects on cancer cell growth.5-7) One major mushroom steroid is the provitamin D 2 ergosterol. Vitamin D 2 was shown to contribute to the prevention of prostate and colon cancer. 8,9) Peroxide of ergosterol, 5a,8a-epidioxy-22E-ergosta-6,22-dien-3b-ol (1) is also widely distributed in mushrooms such as Hypsizigus marmoreus, Pleurotus eringii and Ganoderma lipsiense. 4,6,7,10,11) Ergosterol peroxide (EP) inhibits the growth of some cancer cells and decreases lipid peroxidation of rat liver microsomes.7,10) These constituents may decrease the risk of cancer and other lifestyle diseases through dietary intake of mushrooms.In our previous study, the suppressive effects of extracts of Japanese edible mushrooms were screened on HL60 leukemia cell growth, and an apoptosis-inducing property of Sarcodon aspratus (BERK.) S. ITO (S. aspratus) was found.
12)We have isolated EP as a major apoptosis inducing component from the S. aspratus acetone extract.12) However, EP was not the only apoptosis inducing component in the active fraction. In the present study, we purified another antitumor sterol from S. aspratus using preparative HPLC and subsequently identified it as 5a,8a-epidioxy-22E-ergosta-6,9 (11),22-trien-3b-ol (9,11-dehydroergosterol peroxide (9(11)-DHEP)) (2). The effects of this compound on apoptosis in HL60 cells and growth of HT29 human colon adenocarcinoma cells and WI38 normal embryonic human fibroblasts were investigated.
MATERIALS AND METHODS
InstrumentsMeasurements of 1 H-NMR spectra, including two-dimensional NMR experiments, i.e. double quantum filtered-correlation spectroscopy (DQF-COSY), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC), were performed on an Avance 800 spectrometer (Bruker, Karlsruhe, Germany) at 800.30 MHz at 298 K.
13C-NMR spectra including DEPT were recorded on a DRX 600 (Bruker) or Avance 500 (Bruker) spectrometers at 150.92 or 125.77 MHz at 298 K. Tetramethylsilane (TMS) was used as the standard for chemical shift calculations. Mass spectral measurement was performed on a JMS-HX/HX-110A (JEOL, Tokyo Japan) mass spectrometer by electron ionization (EI).Material Sarcodon aspratus (BERK.) S. ITO grown in the South Aizu area, Fukushima, Japan was purchased from a local market as fresh or air-dried foodstuffs.Isolation of Ergosterol Peroxide and 9,11-Dehydroergosterol Peroxide from S. aspratus Dried fruiting bodies of S. aspratus (20 g) were extracted with acetone. The ace- 75...