Yield and chemical composition of herb of four fireweed species (Epilobium sp.)

The effect of plant age and time of herb harvesting on the yield and chemical composition of herb of 4 Epilobium species (Epilobium hirsutum, E. montanum, E. parviflorum, E. tetragonum) was investigated. The content of main groups of biologically active compounds (phenolic acid, flavonoids and tannins) in dry herb was determined. The highest mass of herb, both in the first and second year of plant vegetation, was obtained from E. hirsutum and the lowest from E. montanum. The highest content of all determined biologically active compounds (phenolic acids, flavonoids, tannins) was observed in E. hirsutum. The main component of the fraction of free phenolic acids in the herb of this species was p-coumaric acid