Administration of extract of mushroom Phellinus linteus induces prostate enlargement with increase in stromal component in experimentally developed rat model of benign prostatic hyperplasia.

Objectives: To clarify the effect of the mushroom extract Phellinus linteus on noncancerous prostate cells using an experimentally developed rat benign prostatic hyperplasia model. A growing number of people take some natural herbal extracts for maintenance of their health. Among them, the extracts of certain mushrooms are believed to have a marked tumoricidal effect but low toxicity for normal tissues, and they are being drunk widely in Japan and Korea. However, until now, their effect on noncancerous benign prostate growth has not been examined.

Methods: The mushroom extract was administered daily for 5 weeks to experimentally developed benign prostatic hyperplasia rats. Prostate organ weight, histologic composition, and gene expression levels of sex hormone receptors, transforming growth factor-beta, vascular endothelial growth factor, and endothelial nitric oxide synthase were examined.

Results: Prostate weight increased significantly by 37% owing to treatment with the mushroom extract (P < 0.05). In particular, the stromal component of the prostate increased significantly by 80% (P < 0.05). A suppression of transforming growth factor-beta1 expression by 56% was observed with the mushroom extract treatment (P < 0.05).

Conclusions: We found that the mushroom extract enlarged the prostate. The effect was suggested to be on the prostate stroma, which may be involved in transforming growth factor-beta1 regulation. Administration of mushroom extract should be considered carefully by those with an enlarged prostate.