Effect of Organic Cultivation on the Chemical Composition and Antioxidant Activity of Rosmarinus Officinalis L. Essential Oil

Background: Rosemary (Rosmarinus officinalis L.) is a medicinal and aromatic plant of considerable pharmacological interest, mainly due to its essential oil, which is rich in bioactive compounds exhibiting significant antioxidant activity and other therapeutic properties. The chemical composition of this oil can be influenced by several factors, including geographical origin, climate, and cultivation practices. Therefore, this study aimed to compare the effects of organic and conventional cultivation on the yield, chemical composition, and antioxidant activity of Rosmarinus officinalis essential oil.

Materials and methods: Essential oils were obtained from rosemary samples using hydrodistillation. GC-MS analysis was carried out to determine the chemical composition of the two oil samples, and the antioxidant activity was evaluated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay in 96 microplates.

Results: GC-MS analysis revealed that the essential oil extracted from organically grown rosemary was distinguished by higher contents of 1,8-cineol (38.96 %) and camphor (17.08 %), while the essential oil obtained from conventionally grown rosemary was distinguished by higher content of α-pinene (276 %) and lower content of 1,8-cineol (15.26 %). The organic sample showed a free radical scavenging activity (IC₅₀ = 0.429 ± 0.006 ml/ml) comparable to the conventional sample (IC₅₀ = 0.447 ± 0.002 ml/ml).

Conclusion: Organic cultivation improved the essential oil yield and increased the concentration of specific bioactive compounds compared to conventional cultivation, indicating enhanced chemical quality. However, antioxidant activities were comparable between both cultivation methods, showing no significant difference.