Inhibition of the DHT-induced PSA secretion by Verbascum xanthophoeniceum and Serenoa repens extracts in human LNCaP prostate epithelial cells.

BACKGROUND

Verbascum xanthophoeniceum is a mullein plant, typical of Balkan region and some parts of Turkey, traditionally used as phytotherapeutic agent due to its anti-inflammatory properties. It is rich in phenylethanoid and iridoid metabolites whose anti-inflammatory properties are under characterization.

METHODS

The role of Verbascum xanthophoeniceum crude methanolic extract and its isolated phenylethanoid glycoside verbascoside have been evaluated, in comparison to a saw palmetto extract, on a human in vitro model of androgen-regulated prostate epithelium, the LNCaP cell line. Cytotoxicity and DHT-induced free and total PSA secretion have been thoroughly studied.

RESULTS

We have found that similar to saw palmetto, Verbascum xanthophoeniceum extract and its isolated phenylethanoid glycoside verbascoside have no cytotoxicity in human LNCaP prostate epithelial cells, whereas an inhibitory effect on the DHT-induced free and total PSA secretion, a recognized anti-androgen like activity, has been shown in case of both Verbascum xanthophoeniceum extract and pure verbascoside. Furthermore, in the absence of the endogenous androgen DHT, an androgen-like activity in Verbascum xanthophoeniceum is detectable as it is for saw palmetto, suggesting that a mixed androgen-antiandrogen activity is present.

CONCLUSIONS

For the first time, Serenoa repens and Verbascum xanthophoeniceum extracts have shown an absence of cytotoxicity and an inhibitory effect on DHT-induced PSA secretion in an in vitro model of human prostate epithelium, whereas the phenylethanoid glycoside verbascoside appeared to explain only part of the Verbascum xanthophoeniceum inhibitory activity on PSA secretion.