Milk thistle and prostate cancer: differential effects of pure flavonolignans

[Admin]

Milk thistle and prostate cancer: differential effects of pure flavonolignans from Silybum marianum on antiproliferative end points in human prostate carcinoma cells.

Extracts from the seeds of milk thistle, Silybum marianum, are known commonly as silibinin and silymarin and possess anticancer actions on human prostate carcinoma in vitro and in vivo. Seven distinct flavonolignan compounds and a flavonoid have been isolated from commercial silymarin extracts. Most notably, two pairs of diastereomers, silybin A and silybin B and isosilybin A and isosilybin B, are among these compounds. In contrast, silibinin is composed only of a 1:1 mixture of silybin A and silybin B. With these isomers now isolated in quantities sufficient for biological studies, each pure compound was assessed for antiproliferative activities against LNCaP, DU145, and PC3 human prostate carcinoma cell lines. Isosilybin B was the most consistently potent suppressor of cell growth relative to either the other pure constituents or the commercial extracts. Isosilybin A and isosilybin B were also the most effective suppressors of prostate-specific antigen secretion by androgen-dependent LNCaP cells. Silymarin and silibinin were shown for the first time to suppress the activity of the DNA topoisomerase IIalpha gene promoter in DU145 cells and, among the pure compounds, isosilybin B was again the most effective. These findings are significant in that isosilybin B composes no more than 5% of silymarin and is absent from silibinin. Whereas several other more abundant flavonolignans do ultimately influence the same end points at higher exposure concentrations, these findings are suggestive that extracts enriched for isosilybin B, or isosilybin B alone, might possess improved potency in prostate cancer prevention and treatment.

Davis-Searles PR, Nakanishi Y, Kim NC, Graf TN, Oberlies NH, Wani MC, Wall ME, Agarwal R, Kroll DJ.

Natural Products Laboratory, Research Triangle Institute, Research Triangle Park, North Carolina 27709-2194, USA.


PMID: 15899838 [PubMed - in process]

[Edwina Bilderback]

Hello
After reading your informative article on Milk Thistle, i.e. isosilybin B, I was wondering if I could find someone producing the product, who might target particularly the prostate cancer issue.
Any help would be much appreciated.
Edwina Bilderback

[Admin]

We've always had the best result with whole herb extracts vs. isolates of their active ingredients.  You may be able to find the isolate around, but clinically we have had great results with whole herb extracts and for prostatitis we have seen the best results with our combination formula over straight Milk Thistle.  We sell straight milk thistle extract, but the red clover in our combination extract also really helps with the inflammation as does the dandelion root.  You can see the product at our web store: Living Pharmacy.