Investigation and chemometric analysis of the changes in the chemical contents of Rosmarinus officinalis essential oils obtained under different conditions

In this thesis, the chemical composition of essential oils of Rosmarinus officinalis (Rosemary), cultured in Muğla, obtained under different conditions were determined using GC-MS. In addition, the inhibitory activities of acetylcholinesterase, butyrylcholinesterase, tyrosinase, α-amylase and α-glucosidase were also studied. Furthermore, the percentage composition data of 29 major compounds of essential oil and the bioactivities data were subjected to chemometric analyses. Rosmarinus officinalis (Rosemary), a member of the Lamiaceae family, is a cultivated plant grown in many parts of the world, both for ornamental, cosmetic and medicinal purposes. It is known as "Rosemary, Biberiye, Kuş dili" in our country, and its homeland is North Africa and Mediterranean countries. R. officinalis has needle-like thin leaves, purple flowers and a shrub-like appearance. The young shoots of the plant, a widely growing Mediterranean area, are used as a spice and an ornamental plant. A syrup by boiling its flowers, rosemary spirit and cologne from its flowers and leaves, etc., are prepared. It is known that a valuable essential oil is used in cosmetics, and especially in skincare products. Rosemary tea is known to be beneficial for the digestive system. Therefore, its essential oil is mentioned in various pharmacopoeias. It is available in the European pharmacopoeia as "Rosemary Leaf and Rosmarini folium". In general, the essential oil is obtained using the hydrodistillation method. To standardize the chemicals in the essential oil of this important species, which is cultivated in the broad Mediterranean climate in our country, the drying type of the plant and the pH of the water used for essential oil extraction should be known clearly. This study aims to investigate changes in the chemical composition of the essential oils of R. officinalis obtained using different methods for possible standardization. For this purpose, R. officinalis from Muğla was collected, divided into pieces, and left to dry under different conditions. Briefly, the plant samples, which were undried, dried under the sun and under the shadow on the 1st, 2nd, 3rd, and 4th days, and dried using a fruit dryer for one day, were used to obtain essential oils. The samples were also divided into three parts which each were submitted to hydrodistillation at pH=5.8, pH=7.0 and pH=8.0. The essential oils of the undried and dried parts of the plant were extracted with a Clevenger apparatus. Thus, 30 essential oils were obtained. The chemical contents of the essential oils obtained were analyzed using a GC-MS. In addition, acetylcholinesterase, butyrylcholinesterase, tyrosinase, α-glucosidase and α-amylase inhibitory activities of 30 essential were tested oils since the essential oil of R. officinalis is used in medicine and cosmetics. The composition of major compounds of essential oils were α-pinene (0.001% to 19.6%), ecaliptol (0.001% to 53.2%), camphor (0.13% to 18.6%), borneol (0.13% to 35%) ,4), verbenone (0.24% vs 98.1%), interestingly differed due to drying effects and pH effects. Other major components percentage included in the European Pharmacopoeia, namely, camphen (0.001% vs. 5.5%), β-pinene (0.001% vs. 4.9%), myrcene (0.001% vs. 1.9%), p-cymene (0.001% vs. 2.97), limonene (0.001% to 4.3%), α-terpineol (0.27% to 12.1%) and bornyl acetate (0.001% to 7.8%) also detected in different amounts. Within the scope of this thesis, it was seen that the composition of the essential oil of the R. officinalis changed with various factors, and depending on composition, the enzyme inhibitory activity results differed from each other. Both GC-MS data and bioactivities were subjected to chemometric methods, and the differences were explained. Since the results of this thesis study are important in terms of plant extraction and essential oil obtaining, we think that the results of this study are crucial for companies producing essential oil to protect public health.