Extracts from Epilobium Sp. herbs inhibit proliferation, PSA secretion and induce apoptosis in prostate cancer cells (LNCaP)

Extracts from Epilobium sp. herbs (Onagraceae) have traditionally been used in the treatment of prostate diseases. The aim of the study was to investigate the effect of standardized aqueous extracts from Epilobium angustifolium L., Epilobium parviflorum Schreb. and Epilobium hirsutum L. herbs on hormone-dependent prostate cancer cells (LNCaP). The extracts were characterized by the HPLC-DAD-MS/MS method. LNCaP cells were incubated with increasing concentration of the extracts (20–70µg/ml). Cell proliferation was measured using bisbenzimide (Hoechst 33258). Apoptosis was detected using Annexin V-FITC. PSA secretion and caspase-3 activity were quantified by ELISA assays. Extracts from Epilobium sp. herbs contained significant amounts of oenothein B as well as flavonoids (derivatives of quercetin, kaempferol, myricetin) and phenolic acids. Exposure of LNCaP cells to the extracts resulted in a significant decrease of cell proliferation (IC₅₀˜35µg/mL) and increase of cells apoptosis (from the level 26,9±3,3% to 80%). The tested extracts reduced PSA secretion from the level of 19.9±0.9 to 4.3±1.3ng/mL. The extracts increased the activity of caspase-3 from the level of 0.3±0.07 to 1.26±0.32ng/mg of protein. Extracts from Epilobium sp. herbs inhibit LNCaP cells proliferation, PSA secretion and induce apoptosis via caspase-dependent pathway. Our results partly confirm the use of Epilobium sp. herbs in the treatment of prostate diseases.