The microsomal enzyme steroid 5a-reductase [EC 1.3.99.5] catalyzes the NADPH-dependent reduction of D 4,5 double bond of a variety of 3-oxo-D 4 steroids.1) The principal circulating androgen is testosterone. In several androgen target tissues, like the prostate, testosterone is converted to 5a-dihydrotestosterone (DHT), which is the most potent natural androgen. This process amplifies of the androgenic response, perhaps because of the higher affinity of the androgen receptor for DHT than for testosterone.2) Both 5a-reductase and DHT perform critical roles physiologically and pathologically in man. The plasma level of DHT has been reported to be elevated in patients with either benign prostatic hyperplasia (BPH) or prostatic cancer. As a result, the inhibition of 5a-reductase has become a pharmacological strategy for the treatment of BPH as well as other DHT-related disorders such as acne and male pattern baldness.3)The study of the inhibition of 5a-reductase with organic molecules has lasted more than two decades; consequently, numerous nonsteroidal and steroidal compounds have been designed and synthesized as competitive, noncompetitive, and uncompetitive inhibitors of 5a-reductase. However, it should be noted that these inhibitors have the potential to cause adverse effects such as those reported for finasteride 4) -i.e., gynecomastia, impairment of muscle growth, and severe myopathy. Hence, the emergence of therapeutic materials having fewer side effects-preferably, edible natural products-would be highly desirable if their safety could be guaranteed.For thousands of years, mushrooms have been known as a source of medicine. In our previous screening of mushrooms, we discovered that the EtOH extract of Ganoderma lucidum (LEYSS.:FR.) KARST. (Ganodermataceae) (Fig. 1) showed the strongest 5a-reductase inhibitory activity. Also, the treatment of G. lucidum itself or the EtOH extract prepared from it significantly inhibited the growth of the ventral prostate induced by testosterone in rat. 5,6) In this paper, we report the isolation of the oxygenated lanostane-type triterpenoids with 5a-reductase inhibition, ganoderic acid DM (1) and 5a-lanosta-7,9(11),24-triene15a,26-dihydroxy-3-one (2) from G. lucidum and their inhibitory effects on 5a-reductase. EtOH Eextracts of Ganoderma lucidum Dried and chipped G. lucidum (15 kg) was extracted with 95% EtOH (126 l) at room temperature for 24 h by using blender. The extracts were filtered through ADVANTEC No. 2 filter paper, concentrated under vacuum, and then freeze-dried. The extracts (571.1 g) were stored in Ϫ20°C before assay.
MATERIALS AND METHODS
MaterialsDried and chipped G. lucidum (200 g) was extracted with 30% EtOH at room temperature for 24 h by using blender. The extracts were filtered through ADVANTEC No. 2 filter paper, concentrated under vacuum, and then freeze-dried. The extracts (10 g) were stored in Ϫ20°C before assay.The 95% EtOH extracts (571 g) was fractionated into three fractions 5a a-Reductase inhibitory activity-guided fractionation of the EtOH ext...
