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Description
The chemical composition of commercial marjoram (Origanum majorana) essential oils sourced from southeastern Serbia and Egypt was investigated using GC and GC-MS techniques. The major volatile compounds in both oils were terpinen-4-ol and γ-terpinene, constituting approximately 50% of the oils based on GC peak areas. However, there were significant differences between the two oils in terms of their cis- and trans-sabinene hydrate content, which are commercially important monoterpenes. The Egyptian oil contained 12.1% trans-sabinene hydrate and 3.5% cis-sabinene hydrate, while the Serbian oil contained a total of 7.2% cis- and trans-sabinene hydrates in a 1:1.7 ratio. Interestingly, we found that the literature NMR data on these compounds were mostly incomplete and usually lacked a thorough multiplet analysis. For that reason, we also performed a complete and comprehensive 1H and 13C NMR assignment of sabinene hydrates, that includes J-values obtained by computer spin simulation and molecular modeling.
This work was supported by the Ministry of Science, Technological Development and Innovations of the Republic of Serbia (Contract Number 451-03-47/2023-01/ 200124).
Keywords: Origanum majorana, trans-sabinene hydrate, cis-sabinene hydrate, NMR, spin simulation
