5.ALPHA.-Reductase Inhibitory Effect of Triterpenoids Isolated from Ganoderma lucidum

Abstract

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...

Ganoderic acids suppress growth and invasive behavior of breast cancer cells by modulating AP-1 and NF-κB signaling

“…The active GA-H is hydroxylated at position 3 and GA-A at position 7 and 15; whereas inactive GA-F is not hydroxylated. In addition, other triterpenes with hydroxyl or acetoxy groups at the positions 3, 7 and/or 15 such as ganoderic acid C1, ganoderic acid C2 (30), ganoderic acid D (31), ganoderic acid T (20), ganoderic acid X (19), ganoderic acid Y (32), ganoderiol A (31), ganoderol B (32,33), lucidumol B and ganodermadiol (30,31) were shown to have inhibitory biological activity. Shiao (34) demonstrated that several Ganoderma triterpenes with hydroxyl or acetoxy groups in these positions were cytotoxic to hepatoma cells and inhibited histamine release, cholesterol synthesis, and farnesylation of Ras protein.…”

Pharmacologically Relevant Receptor Binding Characteristics and 5.ALPHA.-Reductase Inhibitory Activity of Free Fatty Acids Contained in Saw Palmetto Extract

“…17,18,22) However, the use of radiolabeled compounds is inconvenient for routine assays. In addition, it is necessary to separate testosterone and radiolabeled DHT using HPLC or TLC.…”

“…Thus, we developed a method that utilizes electrospray ionization (ESI)-LC/MS without radiolabeled testosterone by modifying Liu's method. 17,18) 5a-Reductase activity was evaluated by measuring the ratio of DHT area to internal standard area. Figure 2 shows selected ion chromatograms of DHT and dexamethasone as an internal standard.…”

“…Protein concentrations were measured by the method of Lowry et al 16) Microsomal Preparation, 5a a-Reductase Activity, and LC/MS Analysis The liver microsomes of rats were prepared as reported by Liu et al with some modifications. 17,18) The liver was removed from female rats and homogenized in 4 volumes of medium A (0.32 M sucrose, 1 mM dithiothreitol, and 20 mM sodium phosphate, pH 6.5). The homogenate was then centrifuged at 10000ϫg for 10 min.…”

Isolation and Pharmacological Characterization of Fatty Acids from Saw Palmetto Extract

“…17 Rat liver microsome was prepared as reported by Liu et al 18 with some modifications. From a female rat, the liver was removed and minced tissue was homogenized in 4 volumes of medium A (0.32 M sucrose, 1 mM dithiothreitol, and 20 mM sodium phosphate, pH 6.5).…”