Interspecific morphological and phytochemical variations in the willow herb (Epilobium spp.) medicinal plant

Willow herb (Epilobium sp.) is a medicinal plant that is used for various purposes in the traditional medicine and food industries. In this research, an attempt was made to assess morphological and phytochemical variations in eight Epilobium species (E. hirsutum, E. Parviflorum, E. roseum, E. algidum, E. anatolicum, E. confusum, E. frigidum, and E. lanceolatum). The species were collected from natural habitats during the flowering period. Analysis of variance showed a significant variation among the studied species for measured morphological and phytochemical traits. Total phenolic content varied from 194.64 ± 1.17 to 309.10 ± 5.59 mg g-1 DW, total flavonoids ranged from 39.03 ±0.21 to 56.14 ±0.67 mg g-1 DW, and antioxidant activity differed from 43.03 ± 2.20 to 101.36 ± 3.68 mg g-1 DW. The results showed that E. frigidum is the richest source of natural antioxidants among the studied species, and also has the highest seed and leaf lengths. Antioxidant activity was significantly correlated with bioclimatic variables. However, the dendrogram based on morphological traits was relatively different from that based on all phytochemical variables. In conclusion, the remarkable variation among species for the morphological and phytochemical traits may be exploited in the breeding programs of the genus Epilobium.