Content and Composition of Essential Oils from Solidago canadensis L. and Solidago virgaurea L. Growing in Estonia

Common goldenrod (S. virgaurea L., Asteraceae) is recognised in traditional medicine as a folk remedy for kidney, urinary tract, and liver diseases, among others; however, its pharmaceutical potential remains largely unexplored. The pharmaceutical potential of the invasive species Canadian goldenrod (S. canadensis L.) in Europe is also of practical interest. The aim of the study was to compare the yield and composition of essential oils (EO) of flowering tops (20 cm long) of S. canadensis and S. virgaurea. The yield of EOs, hydrodistilled from S. canadensis (8 samples) and S. virgaurea (5 samples) herbs using the European Pharmacopoeia method, ranged from 2.7 to 14.9 mL/kg. The average EO yield in both goldenrod species was similar, but the composition differed. A total of 81 constituents were identified and semiquantified by GC-MS in the EOs of both Solidago species, eight of which have been found in these species for the first time. α-Pinene, limonene, and (E)-β-ocimene were the principal compounds in S. canadensis herb EO, and α-pinene, β-pinene, β-myrcene, and α-humulene were the principal compounds in S. virgaurea EO. It contained, on average, 39 times more benzyl salicylate than the EO from S. canadensis. Also, the amounts of viridiflorol (more in S. virgaurea) or β-bourbonene and (E)-β-ocimene (more in S. canadensis) can be used as a chemical fingerprint of both goldenrod species studied. The EO compositions were largely similar, with species-related differences supported by the presence of α-muurolene in S. virgaurea and its absence in S. canadensis. The pharmaceutical potential of V. canadensis as an invasive species is not yet sufficiently clear and requires further pharmacological studies. The composition of the EO seems to support the traditional use of goldenrod in the urological field.