EFFECTS OF STINGING NETTLE ROOT EXTRACTS AND THEIR STEROIDAL COMPONENTS ON THE NA+,K+-ATPASE OF THE BENIGN PROSTATIC HYPERPLASIA

The effects of organic-solvent extracts of Urtica dioica (Urticaceae) on the Na+,K+-ATPase of the tissue of benign prostatic hyperplasia (BPH) were investigated. The membrane Na+,K+-ATPase fraction was prepared from a patient with BPH by a differential centrifugation ofthe tissue homogenate. The enzyme activity was inhibited by 10(-4)-10(-5) M of ouabain. The hexane extract, the ether extract, the ethyl acetate extract, and the butanol extract of the roots caused 27.6-81.5 % inhibition of the enzyme activity at 0.1 mg/ml. In addition, a column extraction of stinging nettle roots using benzene as an eluent afforded efficient enzyme inhibiting activity. Steroidal components in stinging nettle roots, such as stigmast-4-en-3-one, stigmasterol, and campesterol inhibited the enzyme activity by 23.0-67.0% at concentrations ranging from 10(-3)-10(-6)M. These results suggest that some hydrophobic constituents such as steroids in the stinging nettle roots inhibited the membrane Na+,K+-ATPase activity of the prostate, which may subsequently suppress prostate-cell metabolism and growth.