Since the aetiology of benign prostatic hyperplasia (BHP) is still unknown, the use of medicinal herb extracts
and products prepared thereof are recommended due to their antimicrobial activity, especially during early stages of BHP.
A comparison was performed of the in vitro antimicrobial activity (using broth microdilution assay) of flowers and leaves
of willowherb (Epilobium angustifolium L., Onagraceae) from Mt. Velebit (Croatia). The strains (standard ATCC and
clinical isolates) of Staphylococcus aureus (including MRSA), Bacillus subtilis, Escherichia coli (including p-fimbriae
positive strain), Pseudomonas aeruginosa, Proteus mirabilis, Candida albicans, C. tropicalis, C. dubliniensis and Saccharomyces
cerevisiae were susceptible with MIC values between 4.6±0.2 and 18.2±0.8 mg/mL. The results of in vitro
studies showed that no differences were found in the antimicrobial activity between the ethanol extracts of leaves and
flowers of E. angustifolium. Using the quantitative fluorescent assay with ethidium bromide and acridine orange, the viability
of C. albicans ATCC 10231 was assessed after in vitro exposure to E. angustifolium leaf and flower ethanol extracts.
Apoptosis of C. albicans blastospores dominated over necrosis in all treated samples after short-term exposure with
6 to 12 mg/mL of extracts. In addition to the valuable biological activity of E. angustifolium extracts, the data obtained
from the in vitro diffusion, the dilution assay and antifungal viability fluorescent assay suggest that leaf and flower ethanol
extracts of E. angustifolium L. are a promising complementary herbal therapy of conditions such as BHP.