PDR for Herbal Medicines

HERBAL MONOGRAPHS SAW PALMETTO / 665

1.25 to 2.5 cm long and 1.25 cm in diameter. The hard seed

is pale brown, oval or globular, and has a hilum near the

base. The whole panicle can weigh up to 4 kg.

Leaves, Stem and Root: The plant is a bushy palm with a

A maximum height of 6 m. The large, yellow-green leaves

have up to 20 segments and form a crown.

Characteristics: The taste of the seeds is soapy and

unpleasant.

Habitat: The plant is indigenous to the coastal regions of the

southern states of the U.S., from South Carolina to Florida

and southern California.

Other Names: Sabal, Shrub Palmetto

ACTIONS AND PHARMACOLOGY

COMPOUNDS

Steroids: Sterols, including beta-sitosterol, beta-sitosterol-3-

O-glucosides, beta-sitosterol-3-O-diglucoside, beta-si toster-

ol-fatty acid esters and their glucosides, for example beta-

sitosterol-3-O-myristate, beta-sitosterol-3-O-(6-0-myristyl-

beta-glucosides)

Flavonoids: including isoquercitrin, kaempferol-3-O-gIuco-

^ sides, rhoifolin

Water-soluble polysaccharides (galactoarabane with uronic

acid)

Fatty oil: free fatty acids

The lipophilic components (fatty oil with phytosterines) can

be found in ethanolic and hexane-extracts. The anti-exuda-

tive components (polysaccharides) are found in aqueous

extracts. Ethanolic extracts contain both component groups.

EFFECTS

Anti-Androgenic Effects

The lipophilic extract of the herb 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 (Carilla, 1984; Goepel, 1999). 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
W* testosterone to DHT and for conversion of DHT to an
androgen compound, respectively (Sultan, 1984).

Anti-Estrogenic Effects

The herb 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 (DiSil-

verio, 1992). There is also some evidence with inhibition of

several steps involved in prolactin receptor signal transduc-

tion in ovary cells (Vacher, 1995).

Anti-Inflammatory Effects

The hexane extracts of the herb have demonstrated anti-

inflammatory activity (Champault, 1984). Inhibition of the

synthesis of arachidonic acid inflammatory metabolites,

through a double blocking of cyclooxygenas and 5-lipoxy-

genase pathways results in anti-inflammatory properties.

(Breu, 1992). The drug also contains anti-spasmodic proper-

ties by inhibiting calcium influx and activation of the

sodium/calcium ion exchanger. Induction of-protein synthe-

sis plays a role in the antispasmotic effect with cyclic AMP

as a possible mediator. Extracts of the drug may also

antagonize the contracting effect of acetylcholine on urinary

bladders. (Gutierrez, 1996).

CLINICAL TRIALS

Benign Prostatic Hyperplasia

The effect of Saw Palmetto on voiding symptoms and

urodynamic parameters was determined in men with lower

urinary tract symptoms (LUTS) presumed secondary to "

benign prostatic hyperplasia (BPH). The study was conduct-

ed over a 6-month period with Saw Palmetto 160 mg given

twice daily. Parameters evaluated included peak urinary flow

rate, postvoid residual urine volume, pressure-flow study and

serum prostate-specific antigen. The herb was well-tolerated

and significantly improved urinary tract symptoms. There

was no significant improvement in objective measures of

bladder outlet obstruction (Gerber, 1998).

A 6-month, double-blind, randomized equivalence study was

conducted to compare the effects of a Saw Palmetto extract

(320 mg Permixon) with those of a 5 alpha-reductase

inhibitor (5 mg finasteride). The study included 1098 men

with moderate benign prostate hypertrophy (BPH) using the

International Prostate Symptom Score (IPSS) as the primary

end-point. The finasteride and Permixon treatment groups

relieved the symptoms of BPH including a decrease in IPSS,

improved quality of life and increased peak urinary flow

rate. There was no statistical difference in improvement

between the two treatment groups. Finasteride markedly

decreased serum PSA levels and prostate volume while

Permixon had little effect on androgen-dependent parame-

ters. This conclusion suggests that other pathways might also

be involved in the symptomatology of BPH (Carraro, 1996).

Serenoa repens given 160 mg twice daily was compared to

alfuzosin 2.5 mg three times daily to determine the effect on

63 benign prostatic hyperplasia. The double-blind, compara-

tive, parallel-groups study determined efficacy by assess-

I ment of clinical symptoms (Boyarsky's nscale, visual