Determination of Oenothein B as the Active 5-α-Reductase-Inhibiting Principle of the Folk Medicine <i>Epilobium parviflorum</i>

Abstract

Several extracts from Epilobium parviflorum, a plant used in Central Europe for the treatment of prostate disorders, were evaluated in a biochemical assay with 5-alpha-reductase. The aqueous extract displaying inhibition of the enzyme was analyzed, the fraction responsible for this activity was purified, and the active compound identified as a macrocyclic tannin, oenothein B (1).