Content and Composition of Essential Oils from <em>Solidago canadensis</em> L. and <em>Solidago virgaurea</em> L. Growing in Estonia

Both invasive Canadian goldenrod (Solidago canadensis L.) and Common goldenrod (S. virgaurea L., Asteraceae) are recognised in traditional medicine as folk remedies for the treatment of kidney, urinary tract, and liver diseases, among others; however, their pharmaceutical potential remains largely unexplored. 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 (n=8) and S. virgaurea (n=5) 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. 82 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, (Z)-β-ocimene, D-limonene, and (E)-β-ocimene were the principal compounds in S. canadensis herb EO; and α-pinene, l-β-pinene, β-myrcene, and humulene 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 L-β-bourbonene and (E)-β-ocimene (more in S. canadensis) can be used as a chemical fingerprint of both goldenrod species studied. The qualitative composition of the EO of both goldenrods was very similar, only the content of α-muurolene may be a chemical marker for distinguishing them. The pharmaceutical perspective of V. canadensis as an invasive species is not yet sufficiently clear. Chemical composition of different species of goldenrod and their relationship to biological activity, as well as the potential for internal and external use, remains a topic of ongoing interest.