Volatile profile in herbs of Epilobium angustifolium, Epilobium hirsutum, and Epilobium parviflorum growing in Estonia

Epilobium species have garnered attention for their potential use in benign prostatic hyperplasia; however, their polyphenolic composition has been primarily investigated. This study aimed to perform a comparative qualitative analysis and relative comparison based on gas chromatography‒mass spectrometry (GC–MS) peak area percentages of the volatile profile in three Epilobium species growing in Estonia. The volatile profiles of E. angustifolium, E. hirsutum, and E. parviflorum were obtained by hydrodistillation. The yield of the volatile fraction in the studied Epilobium species ranged from 0.24 to 0.78 mL/kg. Qualitative and semi-quantitative analyses of the volatile profile by GC‒MS revealed the presence of 98 components, with a range of 87.12% to 92.93%. The most significant proportion of the volatile profile was made up of aliphatic hydrocarbons, 40.75%‒43.09% for E. angustifolium and 34.29%‒45.04% for E. hirsutum, and aliphatic acids, 15.79%‒29.29% for E. angustifolium and 7.44%‒22.45% for E. hirsutum. E. hirsutum also had a significant content of aldehydes and ketones, 7.08%‒9.03%. Within the volatile profile, monoterpenoids in E. parviflorum accounted for 51.92%, aliphatic acids for 19.43%, and sesquiterpenes for 6.76%. Thus, aliphatic hydrocarbons and fatty acids generally prevailed in E. angustifolium and E. hirsutum, while monoterpenoids predominated in E. parviflorum. Numerous volatile profiles (22‒50) were identified for the first time in the investigated species. Although the yield of volatile profiles in Epilobium species is low, due to their biological activity, they may have a beneficial effect in benign prostatic hyperplasia, which requires further investigation.