抄録
In the course of our search for natural biologically active materials from mushrooms, we found that an ethanol extract from the fruiting body of Ganoderma lucidum (Reishi, Mannentake) showed anti-androgenic activity (5α-reductase inhibitory activity) and estrogen-like activity [the proliferation activity of MCF-7 cells (human breast cancer)]. The inhibitory effects of methanol extracts of 19 edible and medicinal mushrooms on 5α-reductase activity were examined. The extract of G. lucidum showed the strongest 5α-reductase inhibitory activity. The effects of 102 methanol extracts of 40 mycelia, 9 culture fluids and 53 fruiting bodies of 40 strains of G. lucidum on 5α-reductase were investigated. The extract from the fruiting body of each strain was found to show the strongest 5α-reductase inhibitory activity among them. 5α-Reductase inhibitory activity-guided fractionation of the extract from the fruiting body of G. lucidum led to the isolation of two active compounds which were ganoderic acid DM and 5a-lanosta-7,9(11),24-triene-15α,26-dihydroxy-3-one with IC50 of 10.6μM and 41.9μM respectively. A carboxyl group of the side chain of ganoderic acid DM is essential to elicit the inhibitory activity because there is much less activity from its methyl ester. The treatment of the fruiting body of G. lucidum or the extract prepared from it significantly inhibited the growth of the ventral prostate induced by testosterone in rats. Also, we found that ethanol extract from the fruiting body of G. lucidum showed significant effects on the proliferation of MCF-7 cells. This proliferation effect is related to the estrogenic activity of G. lucidum, because this proliferation activity was inhibited by the addition of the antiestrogenic compound ICI182,780. The ethanol extract of G. lucidum prevented ovariectomy-induced bone loss and decreased the concentration of osteocalcin in the blood serum, similar to the action of 17β- estradiol. The present data provide evidence that the ethanol extract of G. lucidum protects against bone loss caused by estrogen deficiency, without a substantial effect on the uterus. These results showed that G. lucidum might be a useful ingredient for the treatment of sex-hormone-related aging diseases such as benign prostatic hyperplasia (BPH) and osteoporosis.
