A qualitative and quantitative analysis of polyphenolic compounds in five Epilobium spp. with a possible potential to alleviate benign prostatic hyperplasia

Abstract

Benign prostatic hyperplasia (BPH) is a widespread male disease, affecting more than 50 % of men over the age of 60 years. Inhibition of the enzyme 5α-reductase is a common treatment strategy for this condition. Such potential can be found in willow flowers (Epilobium spp.), which are known in folk medicine for treating of prostate ailments, mainly benign prostatitis, hypertrophy and prostatitis. Smallflower hairy willowherb (E. parviflorum), which is rare, is the most recommended for treating BPH. The aim. The aim of the study was to investigate the qualitative and quantitative content of polyphenols in five Epilobium species (E. adenocaulon Hausskn., E. hirsutum L., E. montanum L., E. parviflorum Schreb. and E. palustre L.) growing in Estonia, to find the most promising species in terms of chemical composition to alleviate BPH. Materials and Methods. The qualitative and quantitative analyses of polyphenols in herbs of Epilobium spp. were performed using HPLC/MS. All five species were collected from the pond's shore in Pilkuse village (Otepää municipality, Valga county, Estonia) in July 2008. Research results. It was found that 20 % ethanol was optimal for extracting polyphenolic compounds from the herb Epilobium spp. with subsequent UV chromatogram analysis at 350 nm. In the analyzed Epilobium species, 12 polyphenolic compounds were identified. Oenothein B, myricetin rhamnoside and myricetin glucoside were the principal polyphenolic compounds among other identified constituents in the Epilobium spp. herbs. E. montanum had the highest content of oenothein B. The highest was the total content of myricetin glycosides for all five compared species, the total content of quercetin glycosides was slightly lower, and the total content of kaempferol glycosides was the lowest. Conclusions. The content of polyphenols is highest in E. adenocaulon and the lowest in E. parviflorum. Thus, E. parviflorum does not offer the best therapeutic potential for the to relief of BPH in terms of the quantitative content of polyphenolic compounds