Effects of Schisandra chinensis extract on the relaxation of isolated human prostate tissue and smooth muscle cell.

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE: Schisandra chinensis has been commonly used as a

traditional herbal medicine to treat various diseases including body weakness,

dysentery, impotence, enuresis and frequent urination in many countries including

Korea, China and Russia. Benign prostate hyperplasia is a common disease for the

elderly men and it induces lower urinary tract symptoms which hinder general

activity and quality of life. We evaluated the therapeutic potential of

Schisandra chinensis extract (SCE) in benign prostate hyperplasia using human

prostate tissue. MATERIALS AND METHODS: Schisandra chinensis fruit was collected

and extracted with ethanol. Human prostate tissues were obtained from 14 prostate

cancer patients. Macroscopically normal tissue was excised from the transition

zone and the periurethral regions. Isolated prostate tissue strips were mounted

in an organ-bath system, and the relaxation effect of SCE was evaluated by

cumulative addition to prostate strips pre-contracted with 10(-5)M

norepinephrine. The effect of tamsulosin was compared, and the additive effect

was evaluated. Electrophysiological studies using cultured human prostate smooth

muscle cells (HPrSMC) were conducted. RESULTS: Cumulative dosing of SCE induced

concentration-dependent relaxation in contracted prostate tissue (n=18, P<0.05).

Simultaneous dosing of SCE and tamsulosin showed an additive relaxation effect.

The relaxation effect of SCE was abolished by inhibition of K+ channels by

pre-treatment with tetraethylammonium. In HPrSMC, extracellular application of

100 mug/mL SCE significantly increased outward currents, and this effect was

significantly attenuated by treatment with 100 nM Iberiotoxin. CONCLUSIONS: SCE

showed a dose dependent relaxation effect on human prostate tissue as well as an

additive effect with tamsulosin. The relaxation effects of SCE on HPrSMC were, in

part, due to the activation of K+ channels.