(Serenoa repens)
Historical and cultural backgrounds :
When compared with other plants (for example Papaver somniferum) Serenoa repens doesn't have a very long history of being a 'medicinal plant'. The medicinal qualities were noticed for the first time in 1879 by a self experiment of Dr. J. B. Read, of Savannah, Georgia; he published his experience in 'American Journal of Pharmacy': "By its peculiar soothing power on the mucous membrane it induces sleep, relieves the most troublesome coughs, promotes expectoration, improves digestion, and increases fat, flesh and strength. Its sedative and diuretic properties are remarkable. . . . Considering the great and diversified power of the saw palmetto as a therapeutic agent, it seems strange that it should have so long escaped the notice of the medical profession.".
Apart from the sexual stimulating properties that are ascribed to the saw palmetto berries, they have also been a common additive of palmwine in South East america. Effects
The plant material and lipophilic extracts possess sexual stimulating properties3. In addition, both appear to be an effective treatment for the symptoms of benign prostatic hyperplasia (enlarged prostate) and associated lower urinary tract symptoms.
Preparation and dosage :
Saw palmetto plant material can be eaten, prepared as an infusion or as an (n-hexane) lipid soluble extract. Although this latter manner of administration is dominant in investigational studies (usually in doses of 320 mg daily), the daily dosage of the berries is 1-2 g. To prepare an infusion, 2 g of plant material should be taken with 150 ml of water.
Many of the commercial preparations may be standardized to the active constituent content.
 Figure: Fresh saw palmetto berries
Geographical distribution and botany :
Serenoa repens [syn: S. Rerrulata and Sabal serrulata] is a member of Palmae. This species has originated from South East united states1; it grows naturally from the coast of South Carolina to Georgia, west to coastal Alabama, south throughout Florida4, but it is cultivated for commercial purposes mainly in Florida.
S. repens is a woody palmtree with fan-shaped leaves (about two feet in width) and thick, tough, leaf stems with very sharp, saw-like teeth (it is this latter characteistic appearance that gives the plant its popular name) and small white flowers. The berries require a high humidity and heat to ripen and are harvested in the fall.
Phytochemistry :
The plant material also contains an oil with consisting of fatty acids (including caprylic-, capric-, palmitic- caproic-, lauric-, and oleic acid, and their ethyl esters), phytosterols (beta-sitosterol, stigmasterol, cycloartenol, lupeol, lupenone and 24-methyl-cycloartenol), steroidal saponin, resins, tannin and polysaccharides. The saw palmetto berries also contain monoacylglycerides (i.e. 1-monolaurin and 1-monomyristin).
Pharmacology :
Pharmacodynamical data has demonstrated that the lipidosterolic extract of saw palmetto exerts its effects through multiple biochemical alterations; in vitro studies suggest that saw palmetto is an inhibitor of both type 1 and type 2 isoenzymes of 5 alpha-reductase (the enzyme responsible for the conversion of testosterone to dihydrotestosterone (DHT)) and interference with binding of dihydrotestosterone to cytosolic androgen receptors in prostate cells. It also possesses inhibitory effects towards growth factors and inflammatory substances that may contribute to benign prostatic hyperplasia (enlarged prostate).
The monoacylglycerides were moderately bioactive against renal (A-498) and pancreatic (PACA-2) human tumor cells; borderline cytotoxicity was exhibited against human prostatic (PC-3) cells.
Pharmacokinetical data concerning the active constituents of saw palmetto is scarce (and perhaps never investigated).
Modifiers of biological activty :
Little information about modifiers of saw palmetto and adverse reactions are known.
Toxicity :
Toxicity and long-term effects of saw plametto are unknown.
References
1. [2002 Healthnotes, Inc, 2002]
2. [Plosker, Brogden, 1996]
3. [Ratsch, 1998]
4. [Foster, 2000]
5. [Philips, 2000]
6. [Shimada, Tyler, McLaughlin, 1997]
7. [Gerber, Zagaja, Bales, Chodak, Contreras, 1998]
(Text by Wout.) |
