Steroid 5α-reductase inhibitory activity of condensed tannins from woody plants

Abstract

In humans, steroid 5α-reductase is involved in the development of benign prostatic hyperplasia (BPH). We tested the steroid 5α-reductase inhibitory activity of the 70% acetone extract of woody plants. The tannin polymer prepared from the 70% acetone extract showed the highest steroid 5α-reductase inhibitory activity. Furthermore, the steroid 5α-reductase inhibitory activity of tannins was not affected by the addition of superoxide dismutase or catalase. It was concluded that the steroid 5α-reductase inhibitory activity of condensed tannin was caused by binding to the steroid 5α-reductase, rather than from the peroxide/superoxide produced by tannins. The tannins, prepared from tree barks, with potential for steroid 5α-reductase inhibitory activity might be advantageous in therapy for steroid 5α-reductase diseases such as BPH or prostate cancer. © 2008 The Japan Wood Research Society.