Extracts from Epilobium sp. herbs, their components and gut microbiota metabolites of Epilobium ellagitannins, urolithins, inhibit hormone-dependent prostate cancer cells-(LNCaP) proliferation and PSA secretion

Phytother Res. 2013 Dec;27(12):1842-8. doi: 10.1002/ptr.4941. Epub 2013 Feb 25.

Abstract

Extracts from Epilobium sp. herbs have been traditionally used in the treatment of prostate-associated ailments. Our studies demonstrated that the extracts from Epilobium angustifolium, Epilobium parviflorum and Epilobium hirsutum herbs are potent prostate cancer cells (LNCaP) proliferation inhibitors with IC50 values around 35 µg/ml. The tested extracts reduced prostate specific antigen (PSA) secretion (from 325.6 ± 25.3 ng/ml to ~90 ng/ml) and inhibited arginase activity (from 65.2 ± 1.1 mUnits of urea/mg of protein to ~40 mUnits of urea/mg protein). Selected constituents of extracts (oenothein B, quercetin-3-O-glucuronide, myricetin-3-O-rhamnoside) were proven to be active in relation to LNCaP cells. However, oenothein B was the strongest inhibitor of cells proliferation (IC50 = 7.8 ± 0.8 μM), PSA secretion (IC50 = 21.9 ± 3.2 μM) and arginase activity (IC50 = 19.2 ± 2.0 μM). Additionally, ellagitannins from E. hirustum extract were proven to be transformed by human gut microbiota into urolithins. Urolithin C showed the strongest activity in the inhibition of cell proliferation (IC50 = 35.2 ± 3.7 μM), PSA secretion (reduced PSA secretion to the level of 100.7 ± 31.0 ng/ml) and arginase activity (reduced to the level of 27.9 ± 3.3 mUnits of urea/mg of protein). Results of the work offer an explanation of the activity of Epilobium extracts and support the use of Epilobium preparations in the treatment of prostate diseases.

Keywords: Epilobium sp; LNCaP; arginase; oenothein B; prostate specific antigen; urolithins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arginase / antagonists & inhibitors
  • Biotransformation
  • Cell Line, Tumor
  • Cell Proliferation / drug effects*
  • Epilobium / chemistry*
  • Humans
  • Hydrolyzable Tannins / pharmacokinetics
  • Hydrolyzable Tannins / pharmacology
  • Male
  • Mannosides / pharmacology
  • Microbiota*
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology*
  • Prostate-Specific Antigen / metabolism
  • Prostatic Neoplasms / metabolism
  • Quercetin / analogs & derivatives
  • Quercetin / pharmacology

Substances

  • Hydrolyzable Tannins
  • Mannosides
  • Plant Extracts
  • myricetin-3-O-rhamnoside
  • quercetin 3-O-glucuronide
  • urolithin C
  • oenothein B
  • Quercetin
  • Prostate-Specific Antigen
  • Arginase