Saw Palmetto in the treatment of Benign Prostatic Hyperplasia (BPH)
What is BPH?
Benign prostatic hyperplasia is an enlargement of the prostate gland. After age 50, most men develop enlarged prostates. The prostate is located below the bladder. As the prostate enlarges, it may slowly restrict the flow of urine. This can lead to symptoms such as:
Since cancer of the prostate may cause similar symptoms, you should be evaluated by your doctor to rule out prostate cancer. Your doctor will likely examine your prostate gland manually to detect abnormalities and may measure prostate-specific antigen (PSA) in your blood to help in evaluating for the presence of prostate cancer. Saw Palmetto does not affect PSA levels.
CLINICAL PHARMACOLOGY
The symptoms associated with benign prostatic hyperplasia (BPH) are related to bladder outlet obstruction, which is comprised of two underlying components: static and dynamic. The static component is related to an increase in prostate size caused, in part, by a proliferation of smooth muscle cells in the prostatic stroma, which may be caused by an accumulation of dhydrotestosterone (DHT). However the severity of BPH symptoms and the degree of urethral obstruction do not correlate well with the size of the prostrate. The dynamic component is a function of an increase in smooth muscle tone in the prostate and bladder neck leading to constriction of the bladder outlet. Smooth muscle tone is mediated by the sympathetic nervous stimulation of alpha 1 adrenoceptors, which are abundant in the prostate, prostatic capsules, prostatic urethra, and bladder neck. Blockage of these adrenoceptors can cause smooth muscle in the bladder neck and prostate to relax , resulting in an improvement in urine flow rate and a reduction in symptoms of BPH.
EFFECTS OF SAW PALMETTO
Anti-Androgenic effects:
The lipophilic extract of the Saw Palmetto inhibits binding of dihydrotestosterone (DHT) to the cytosolic androgenic receptor and alpha 1-adrenoceptor in the prostate, thus preventing accumulation of the steroid, which may lead to prostate hyperplasia. Anti-androgenic effects of the lipophilic extract also consist of 5-alpha-reductase and 3-ketosteroid reductase inhibition. These enzymes are responsible for the conversion of testosterone to DHT and for the conversion of DHT to an androgen compound, respectively.
Anti-Estrogenic Effects
Saw Palmetto lowers cytosol and nuclear receptor values for estrogen which result in an anti-estrogen effect since progesterone receptor content is linked to estrogenic activity. Anti-estrogenic agents inhibit stromatic prostate mass growth in patients with benign prostate hypertrophy. There is also some evidence with inhibition of several steps involved in prolactin receptor signal transduction ovary cells.
Anti-Inflammatory Effects The extracts of Saw Palmetto herb have demonstrated anti-inflammatory activity. Inhibition of the synthesis of arachidonic acid inflammatory metobolits, through a double blocking of cycloxygenas and 5-lipoxy-genase pathways results in anti-inflammatory properties. The drug also contains anti-spasmodic properties by inhibiting calcium influx and activation of the sodium/calcium ion exchanger. Induction of the protein syntheses plays a role in the antispasmotic effect with cyclic AMP as a possible mediator. Extracts of the drug may also antagonized the contracting effect of acetycholine on urinary bladder.
IN CONCLUSION, Saw Palmetto has been shown to inhibit the conversion of testosterone to DHT thus preventing the enlargement of the prostrate gland. Secondly, Saw Palmetto's Anti-Estrogenic effect inhibits stromatic prostate mass growth, and third, Saw Palmetto has anti-spasmodic properties that cause smooth muscles in the bladder neck and prostate to relax, resulting in an improvement in urine flow rate and a reduction in symptoms of BPH.
For more information click on the Saw Palmetto monograph or view the clinical studies.