Compounds isolated in nettle are scopoletin, ß-sitosterol and its glucoside, tannins as well as other sterol and steryl glucosides.
Other constituents are free amino acids. Furthermore, phenylpropanes, including homovanillyl alcohol, polyphenols, polysaccharides and their methyl ether and lignans such as neoolivil and lignans glucosides have been detected in the drug.
Other characteristic compounds are lectins, named UDA (Urtica dioica agglutinin), which can be divided in six isolectins. Plant lectins are small proteins, able to recognize and bind sugar residues.
UDA is able to agglutinate erythrocytes and is thought to play a major role in the antiprostatic effect of nettle extract.
Extracts of nettle are used in the treatment of prostatic diseases, especially benign prostatic hypertrophy (international stages I-II, stages II-III according to Vahlensick), and for the stabilization of the urodynamic of the patient.
The therapy with nettle results in relief of symptoms, such as pollakisuria (frequent urination), nocturia (frequent nocturnal urination) and urinary urgency. Residual urine is reduced and urinary outflow is improved.