Reviewed: Veltri R, Marks L, Miller C, et al. Saw palmetto alters nuclear measurements reflecting DNA content in men with symptomatic BPH: Evidence for a possible molecular mechanism. Urology 2002;60(4):617-22.
Saw palmetto (Serenoa repens (W. Bartram) Small, Arecaceae) fruit extract is one of the most widely used treatments for symptomatic benign prostatic hyperplasia (BPH). In many men, BPH results in bothersome urinary symptoms. Based on the results of two previously published papers,1,2 a specific saw palmetto herbal blend (SPHB*) is associated with prostatic epithelial contraction (cells getting smaller) and decreases in tissue levels of dihydrotestosterone (DHT). (This is the third publication on the SPHB based on the same clinical trial that resulted in the two previous publications.)
Although the general mechanism of action is known, the molecular mechanisms for these findings are not known. The authors hypothesize that the molecular basis for the action might be due to alterations in DNA content and chromatin (genetic material in a cell) structure and organization of prostate epithelial cells. One way to measure genetic alterations in tissue is to determine the quantitative nuclear grade (QNG). QNG is a biomarker that describes the nuclear size, shape, and chromatin structure and organization. Changes in QNG may reflect alterations in gene expression in response to treatment or changes in disease state. This randomized, double-blind, placebo-controlled clinical trial examines the effects of SPHB on the epithelial nuclear chromatin structure of men with symptomatic BPH.
Forty-four men (mean age 65 years) with chronic symptoms of bladder outlet obstruction, prostate enlargement, and a positive prostate symptom score participated in the trial. Patients received either an inert placebo or SPHB. Both softgel capsules looked identical. Patients took one capsule 3 times daily with meals for 6 months. A prostate biopsy was performed at baseline and after 6 months of treatment. QNG was calculated by measuring 60 nuclear morphometric descriptors (NMDs). Examples of NMDs are perimeter, area, and cell class.
At baseline, there was no difference in the 60 NMDs between the placebo and SPHB treatment groups. After 6 months of placebo treatment, the NMDs did not significantly change. In contrast, after SPHB treatment, 25 of the 60 NMDs significantly changed. Therefore, according to the study, 6 months of SPHB treatment alters the DNA chromatin structure and organization in prostate epithelial cells.
The authors conclude that the clear-cut chromatin alterations suggest a molecular basis for the proprietary saw palmetto blend’s clinical effects. However, because of the multi-component nature of this herbal blend, it is not certain whether the benefits can be attributed solely to the saw palmetto extract or to the combined action of all the ingredients in the blend.
–Heather S. Oliff, PhD
* SPHB: 106 mg of standardized saw palmetto liposterolic extract combined with 80 mg nettle root extract (Urtica dioica L. ssp. dioica, Urticaceae), 160 mg pumpkin seed extract (Cucurbita pepo L., Cucurbitaceae), 33 mg lemon flavonoids, and 190 mg vitamin A (Nutrilite, Buena Park, CA).
1. Marks LS, Partin AW, Epstein JI, et al. Effects of a saw palmetto herbal blend in men with symptomatic benign prostatic hyperplasia. J Urol 2000;163:1451—6.
2. Marks LS, Hess DL, Dorey FJ, et al. Tissue effects of saw palmetto and finasteride: use of biopsy cores for in situ quantification of prostatic androgens. Urology 2001;57:999—1005