Materia Medica

Serenoa repens Bartram, (Arecaceae).  Previously Serenoa serrulata and Sabal serrulata  (Palmae, Palmaceae)  Common name is saw palmetto.

History: Serenoa, being indigenous to the Southeastern United States, has a short medicinal history.  The Native Americans and early settlers used the berry for food and medicine, believing it to be strengthening to the system.  The center core of the fan palm plant was in great demand for was eating and considered delicious.

The Eclectics of the 18^th century were using Serenoa for upper and lower respiratory problems, atrophy of the breast, ovaries and testes and for BPH.  It was also used as an aphrodisiac.  The berries were official in the United States Pharmacopoeia from 1906 to 1916, and in the National Formulary from 1926 to 1950.

During the 1960s, it was discovered that there were relatively high concentrations of free and bound sitosterols in the dried berries.  b-sitosterols and other Serenoa extracts injected into female mice showed fairly high activity, compared to other plant estrogens.¹  Since that time Serenoa has been extensively studied in Europe for treatment of BPH and for the chemical explanation of its efficiency.

Serenoa belongs to the palm fans (Arecaceae), and S. repens is the only species within its genus.  It is a shrub or small tree that grows up to ten feet, with a crown of large, fan-like leaves and a reddish to blackish berry about the size of an olive.  It is native to the Southeastern United States from Southern Carolina to Southeastern Louis

The ripe berry is the part used.  Serenoa is available as a bulk herb, but the active ingredients are not water soluble, so a tea would be ineffective for most purposes.  The studies have all used a liposterolic extract prepared primarily with hexane.  Liposterolic extracts can also be prepared with 90% ethanol or by a supercritical carbon dioxide process.   The extract should contain 85 to 95% fatty acids and 0.2 to 0.4% total sterols.  It is also available in hydroalcoholic extracts and capsules.

Serenoa has received a great deal of attention as a treatment for early stages of benign prostatic hyperplasia (BPH.)  There are a number of pharmacodynamic effects, suggesting multiple mechanisms of action that give the favorable results in BPH.  These are primarily inhibition of 5 alpha-reductase^2,3 and the binding of androgen receptors (testosterone, but also estrogen and progesterone indicating antiestogenic effect.)^4,5  Studies have determined it does help with dysuria, nocturia, frequency of urination and other urinary difficulties.⁶  It has some anti-inflammatory action⁷ and spasmolytic activity.  Serenoa has compared favorably with finasteride,⁸ with less side effects.  There is some evidence that Serenoa does reduce the size of the prostate.^9,10.

It is most commonly used for treatment of BPH, but contemporary herbals also recommend it for asthma, bronchitis, wasting conditions, impotence and frigidity.

The berries contain approximately 1.5 percent essential oil, of which 63 percent are free fatty acids and 38 percent are ethyl esters of those fatty acids.  The fatty acids include: caproic, capric, lauric, palmitic and oleic acids, and ethyl esters of these.  They also contain b-sitosterol and its glucoside, b-sitosterol D-glucoside, as well as ferulic acid.¹¹   

The liposterolic extract dosage is 160 mg twice a day.  This would correspond to about 3 or 4 g of dried berries per day. Men using Serenoa for BPH should consult with his health care professional on a regular basis. The mechanism of action is similar to finasteride and there could be an additive effect, therefore, it is not recommended to use them concurrently.  It is possible that the antiandrogenic actions of  Serenoa may diminish the effects of therapeutic androgens.

No significant side effects have been reported in clinical studies except for occasional  upset stomach.  It is not recommended during pregnancy.