Saw Palmetto (Serenoa repens)
One of the most interesting palms utilized by humans for food and as a valuable herbal remedy is the saw palmetto (Serenoa repens). This palm is native to the southeastern United States, from Florida to North Carolina. Unlike most palms, the stem is typically prostrate with erect palmate leaves. It grows in coastal dune areas and inland pine woodlands, often forming dense, impenetrable thickets in the understory of pines, such as slash pine (Pinus elliottii) and longleaf pine (Pinus palustris). The common name is derived from the leaf stalks (petioles) which are armed with rows of sharp teeth resembling a saw blade.
Left: Forest of slash pines (Pinus elliottii) with dense understory of saw palmetto (Serenoa repens). Right: Leaf stalks (petioles) of saw palmetto showing rows of sharp, sawlike teeth.
The juicy black fruits (drupes) were an important food for native Americans of this region, such as the Seminoles. Early settlers also made a soothing tea from the dried fruits. Therapeutic benefits from saw palmetto tea has been known for decades. It was prescribed for frequency of urination and excessive night urination due to inflammation of the bladder and prostate enlargement. Recent studies indicate that the use of saw palmetto may be more than folklore. The fruit mesocarp is rich in steroidal compounds called sitosterols. According to Herbs That Heal by M.A. Weiner and J.A. Weiner (1994), benign prostate enlargement is caused by testosterone accumulation in the prostate. The testosterone is then converted into dihydrotestosterone (DHT), which causes cellular proliferation and enlargement of the prostate. Saw palmetto extract from the dried fruits prevents the conversion of testosterone into DHT because it inhibits the action of the enzyme testosterone-5-alpha-reductase. This is essentially the same action of the prescription drug finasteride (Proscar). Several double blind studies have been conducted that indicate an improvement in men suffering from enlarged prostates; however, there is considerable disagreement among urologists whether this herbal remedy is really an effective cure for this condition. Until more data is available, saw palmetto may be a useful herb to take as a relatively inexpensive preventive therapy.
The ripe fruits (top) and herbal extract capsules (bottom) of saw palmetto (Serenoa repens). At maturity the fruits (drupes) are shiny black. The extract made from dried fruits is taken by men as preventive therapy for prostate enlargement.
References About Saw Palmetto:
Blumenthal, M. 2000. “Saw Palmetto.” Herbalgram Number 50: 32-37.
Duke, J.A. 1997. The Green Pharmacy. Rodale Press, Emmaus, Pennsylvania.
Weiner, M.A. and J. Weiner. 1994. Herbs That Heal. Quantum Books, Mill Valley, California.
