Evaluation of Phytochemical Composition of Sahandian Savory (Satureja sahendica Bornm.) Essential Oils at Different Phenological Stages

Sahandian Savory (Satureja sahandica Bornm.) is an indigenous perennial aromatic plant growing in the West and North West of Iran. Its growing season starts from March till end of September. Oil and its quality are abundantly variable among different Savory species (Ahmadi et al., 2009). Although, Thymol, p-Cymene and γ-Terpinen have been determined as the main components of Sahandian Savory oil by Sefidkon et al. (2004), little data on its Phytochemistry and phenology genealogy? is available. The present study investigated the phytochemical properties of essential oils of (S. sahendica Bornm.) at different harvest times from Pakal habitat and a specimen grown in greenhouse.
The aerial parts of plants were collected on one month intervals from 20th April till 20th September. A specimen cloned from the wild plants and grown in research greenhouse, college of Agriculture, Ilam, was harvested at full blooming stage in September. Essential oils were extracted using Clevenger apparatus by hydro-distillation. Isolation and identification of oil components were carried out by gas chromatography (GC) and coupled gas chromatography with mass spectrometer (GC/MS) at Medicinal Plants and Drug Research Institute, Shahid Beheshti Medical University, Tehran, Iran. Antioxidant activity and total phenol content were measured following Singleton et al. (1999) methods, respectively.
The ANOVA showed that harvest time significantly affected oil yield of samples at one percent of probability. Mean comparison analysis revealed that the maximum and minimum oil yield were belonged to May (0.42%) and September (0.19%) harvests, respectively. The essential oil percentage of plants grown in greenhouse were extremely low and negligible samples collected from their natural habitat. Analysis of variances for antioxidant activity and total phenol content showed that the traits were also significantly affected by harvest time. The highest and lowest antioxidant activity recorded for harvests in September (61.06%) and August (49.53%), respectively. On the other hand, maximum and minimum total phenol content recorded from samples harvested in September (432.71 mg Gallic acid/ ml essential oil) and June (191.28 mg Gallic acid/ml essential oil), respectively. Phytochemical analysis by coupling gas chromatography with mass spectrometer (GC/MS) identified 75 different components. ANOVA of oil compositions exhibited a highly significant difference between different harvest times. Borneol was the main component of oil at all harvests. In early stages (April and May), Borneol (29.34 and 34.58 percent), Bornyl acetate (12.96 and 9.42 percent), Linalool (7.64 and 9.35 percent) and α-Terpineol (7.09 and 8.26 percent) were the main components. By the end of spring (Mid June) Borneol and Camphor content was increased slowly so that Borneol reached to its peak (44.71 percent) in end of June, but the other main components were declined by the last harvest. On full flowering stage (mid-August and early-September) an increase was recorded for Bornyl acetate, the highest content of Camphor observed; Carvacrol was identified as the main oil component (4.92 percent) and Borneol content decreased. Phytochemical composition of oils extracted from greenhouse sample at flowering stage was significantly different from those obtained from wild plants at the same growing stage. Plants grown in the greenhouse were rich in Borneol, Bornyl acetate, Carvacrol, Camphor and Camphene (39.02, 9.54, 7.88, 7.56 and 5.93 percent, respectively), while oils extracted from wild plants, mostly formed by Borneol, Camphor, 4-Terpineol, Bornyl acetate and Carvacrol (29.30, 15.26, 11.82, 9.25 and 4.92 percent, respectively). The results showed that growing Sahandian savory in the greenhouse which is free from climatic stresses may be led to beneficial changes in its essential oil composition.
The study revealed that the highest essential oil can be achieved in May, the best quality essential oil regarding antioxidant activity and total phenol content should be obtained at the full blooming stage and to get the highest amount of Borneol, harvest must be done in July under Ilam province conditions.
Acknowledgments The authors acknowledge the financial support of the project by Dean, College of Agriculture; and Vice President for Research and Technology, Ilam University, Ilam, Iran.