Effect of D-004, a lipid extract from Cuban royal palm fruit, on histological changes of prostate hyperplasia induced with testosterone in rats.

Benign prostatic hyperplasia (BPH) is the nonmalignant, uncontrolled growth of prostate gland cells and stroma leading to difficulty in urinating. Lipid extracts from Saw palmetto (Arecaceae) fruits are used to treat BPH. The Cuban royal palm (Roystonea regia) is a member of this family and D-004, a lipid extract from its fruits, prevents prostate hyperplasia (PH) induced with testosterone, as opposed to dihydrotestosterone, in rodents. This study investigated whether D-004 could prevent the histological features of testosterone-induced PH in rats. Rats were distributed into six groups (10 rats per group): A negative control group receiving subcutaneous injections of soy oil and treated with vehicle, and five groups injected subcutaneously with testosterone and treated with the vehicle (positive control), D-004 (100, 200 and 400 mg/kg) or Saw palmetto (400 mg/kg). Treatments were given orally for 14 days. At sacrifice, prostates were removed and processed for light microscopy. The histopathological findings of PH were assessed according to a score-chart protocol. D-004 200 and 400 mg/kg, but not 100 mg/kg, significantly and moderately in a dose-dependent manner prevented prostate enlargement and the testosterone-induced histological changes. Compared with positive controls, D-004 200 and 400 mg/kg inhibited prostate size increases and the histological score up to 56.1% and 60.7%, respectively, while Saw palmetto 400 mg/kg reduced such variables by 45.8% and 49.0%, respectively. The effects of D-004 400 mg/kg on the histological changes, not on prostate size, were greater (p < 0.05) than those of Saw palmetto. D-004 and Saw palmetto did not affect body weight values. In conclusion, D-004 200 and 400 mg/kg administered orally for 14 days prevented the increase of prostate size and the testosterone-induced histological changes in rats, its effects being comparable or mildly better than those of Saw palmetto. These results extend previous data showing preventive effects of D-004 on testosterone-induced prostate enlargement with in rodents, and further studies are required to explore the mechanisms underlying such effects.