Nitrogen fertilization and the essential oils profile of the rhizomes of different sweet flag populations (Acorus calamus L.)

Sweet flag rhizome (Acorus calamus L., Araceae) exhibits various biological activities such as sedative, anticonvulsant, immunosuppressant, antidiabetic, and anti-inflammatory. This plant is protected in Serbia, but due to its high market requirements, the cultivation of this species could be the final solution. The content and composition of essential oils from 24 cultivated samples and five samples of sweet flag from natural populations, as well as the influence of nitrogen fertilization on the composition of essential oils were studied. Essential oils were analysed using GC and GC/MS. Statistical analysis included the ANOVA and PCA analysis. The total content of essential oil was not significantly different between the natural (0.80–1.10%) and cultivated samples (1.15–1.30%). In all essential oils main compounds were β-asarone (4.82–17.98%), cadinadienol (10.14–13.95%), camphor (3.55–13.20%), and acorenone (9.68–12.64%). The cultivation of sweet flag showed significant (p < 0.05) impact on the composition of essential oil and the content of β-asarone (4.82–17.07%, mean 11.95±4.76 vs. 17.51–17.98%, mean 17.71 ± 2.23). The PCA analysis also separated the essential oils from natural and cultivated conditions based on the content of β-asarone. On the other hand, the amount of the fertilizer did not show any effect (p > 0.05) on the composition of investigated samples. The process of cultivation increased the level of active, but potentially genotoxic and carcinogenic compound β-asarone. It would be significant to determine the content of β-asarone routinely in the sweet flag rhizome, especially in the cultivated plants