Evidence that Serenoa repens extract displays an antiestrogenic activity in prostatic tissue of benign prostatic hypertrophy patients

Inhibitory effects of Serenoa repens on the kinetic of pig prostatic microsomal 5alpha-reductase activity

The pathogenesis of benign prostatic hyperplasia is linked to the accumulation of dihydrotestosterone (DHT), the active form of testosterone (T), in prostatic tissue. We have defined characteristics of 5alpha-reductase enzyme which catalyzes the conversion of T into DHT in prostatic microsomes of growing pigs. Peaks for the 5alpha-reductase activity were found at pH 5.5 and 8.0, which indicates the presence of both type 1 and type 2 isozymes. Kinetic parameters of porcine 5alpha-reductase in the presence of Serenoa repens extracts revealed uncompetitive, noncompetitive, and mixed types of inhibitions. Our results show the inhibitory action of S. repens on prostate porcine microsomal 5alpha-reductase activity.

Saw palmetto (Serenoa repens) in men with lower urinary tract symptoms: effects on urodynamic parameters and voiding symptoms

OBJECTIVES

To assess the effects of saw palmetto on voiding symptoms and urodynamic parameters in men with lower urinary tract symptoms (LUTS) presumed secondary to benign prostatic hyperplasia (BPH).

METHODS

Fifty men with previously untreated LUTS and a minimum International Prostate Symptom Score (IPSS) of 10 or greater were treated with a commercially available form of saw palmetto (160 mg twice per day) for 6 months. The initial evaluation included measurement of peak urinary flow rate, postvoid residual urine volume, pressure-flow study, and serum prostate-specific antigen (PSA) level. Patients completed an IPSS, serum PSA was determined, and flow rate was measured every 2 months during the course of the study. A urodynamic evaluation was repeated at the completion of the 6-month trial.

RESULTS

The mean IPSS (+/-SD) improved from 19.5+/-5.5 to 12.5+/-7.0 (P <0.001) among the 46 men who completed the study. Significant improvement in the symptom score was noted after treatment with saw palmetto for 2 months. An improvement in symptom score of 50% or greater after treatment with saw palmetto for 2, 4, and 6 months was noted in 21% (10 of 48), 30% (14 of 47), and 46% (21 of 46) of patients, respectively. There was no significant change in peak urinary flow rate, postvoid residual urine volume, or detrusor pressure at peak flow among patients completing the study. No significant change in mean serum PSA level was noted.

CONCLUSIONS

Saw palmetto is a well-tolerated agent that may significantly improve lower urinary tract symptoms in men with BPH. However, we were unable to demonstrate any significant improvement in objective measures of bladder outlet obstruction. Placebo-controlled trials of saw palmetto are needed to evaluate the true effectiveness of this compound.

Comparison of phytotherapy (Permixon) with finasteride in the treatment of benign prostate hyperplasia: a randomized international study of 1,098 patients

BACKGROUND

Controversy regarding the relative efficacy of treatments for the relief of the symptoms of benign prostatic hyperplasia (BPH).

METHODS

This was a 6-month double-blind randomized equivalence study that compared the effects of a plant extract (320 mg Permixon) with those of a 5 alpha-reductase inhibitor (5 mg finasteride) in 1,098 men with moderate BPH using the International Prostate Symptom Score (IPSS) as the primary end-point.

RESULTS

Both Permixon and finasteride decreased the IPSS (-37% and -39%, respectively), improved quality of life (by 38 and 41%), and increased peak urinary flow rate (+25% and +30%, P = 0.035), with no statistical difference in the percent of responders with a 3 ml/sec improvement. Finasteride markedly decreased prostate volume (-18%) and serum PSA levels (-41%); Permixon improved symptoms with little effect on volume (-6%) and no change in PSA levels. Permixon fared better than finasteride in a sexual function questionnaire and gave rise to less complaints of decreased libido and impotence.

CONCLUSIONS

Both treatments relieve the symptoms of BPH in about two-thirds of patients but, unlike finasteride, Permixon has little effect on so-called androgen-dependent parameters. This suggests that other pathways might also be involved in the symptomatology of BPH.

Effects of the lipidosterolic extract of Serenoa repens (Permixon) on human prostatic cell lines

BACKGROUND

Permixon is a drug used in the treatment of benign prostatic hyperplasia. We studied its androgenic and antiandrogenic effects in the prostatic cell lines LNCaP and PC3, respectively responsive and unresponsive to androgen stimulation.

METHODS

We performed FACScan analysis to investigate toxicity, 3H thymidine and 35S methionine incorporation to determine antiproliferative and metabolic effects, electron microscopy to study ultrastructural changes and cotransfection experiments to elucidate the role of wild type androgen receptor.

RESULTS

In LNCaP cell line, Permixon induced a double proliferative/differentiative effect, not observed in PC3 cells. In PC3 cells cotransfected with wild-type androgen receptors and CAT reporter genes under the control of a androgen responsive element, the drug inhibited androgen-induced CAT transcription.

CONCLUSIONS

Our data indicate a role of the androgen receptor in mediating the effects of Permixon in LNCaP cells. Cotransfection experiments in PC3 cells support a clear antiandrogenic action of the drug.

Phytotherapy in treatment of benign prostatic hyperplasia: a critical review

Phytotherapeutic agents have enjoyed widespread use, especially in Europe, for the treatment of BPH. With the recent proliferation of nutrition and vitamin stores in the United States, use of these agents has greatly increased. Although SPB extract is the most extensively studied of the phytotherapeutic agents used for BPH, no well-defined mechanism of action has been proposed. Evidence for an antiandrogenic or antiestrogenic effect is conflicting, and there are no clinical data suggesting an effect on 5-alpha-reductase activity. Furthermore, clinical trials with SPB have largely been uncontrolled and are thus of limited value in ascertaining the true clinical impact of this agent. Double-blind, controlled studies with SPB also have limitations in that most were of very short duration (none longer than 3 months) and did not provide entry or exclusion criteria. In addition, standardized symptom scores were not utilized. Only two of seven studies showed an appropriate placebo response, and the results and conclusions of both these studies were contradictory. The best and most convincing study of the efficacy of phytotherapeutic agents (using Harzol) was recently published in the Lancet. This study was rigorous and matched in design and format with pharmaceutical industry trials. A mild but appropriate placebo response was detected, which further validates the study. However, a prior placebo-controlled study showed no efficacy of beta-sitosterol-beta-D-glucoside. This dichotomy of results possibly reflects the different composition of the agents tested. This is a major confounding factor in this field of study, especially because the active ingredients are unknown. Standardization of the compounds is needed to compare and assess accurately the effect of the different extracts.