Phytochemical composition of the essential oil, total phenolic content, antioxidant and antimicrobial activity in Iranian Satureja sahendica Bornm. at different ontogenesis conditions

摘要

The effects of different ontogenesis conditions (pre-flowering, full-flowering and post flowering) on the yield, essential oil composition, total phenolic content, antioxidant and antimicrobial activity ofSatureja sahendicaBornm. was investigated. The essential oil was obtained from the aerial parts of the plant by hydro distillation and analyzed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS). In total, 33 components were identified in the essential oil ofS. sahendicaunder different harvesting times, that represented 98.54 to 98.72% of the oils. The major components were thymol (28.76 to 42.24%),P-cymene (23.89 to 34.33%),γ-terpinene (13.78 to 19.37%) and myrcene (1.87 to 2.28). The highest essential oil yield was obtained in flowering stage. The highest thymol content was observed in the pre-flowering and the highestp-cymene andγ-terpinene contents as precursors of thymol and carvacrol were observed in flowering and post-flowering stages.Total phenolics and antioxidant activity of plant extracts were measured by the Folin-Ciocalteu and DPPH free radical scavenging assays, respectively. The total phenolic content under differentontogenesis conditionsvaried from 24.78 to 25.56(mg gallic acid equivalent/g dw).IC50values in the DPPH assay ranged from 7.85 to 8.34μg/ml and thehighestactivity was observed inpre-flowering stage. Antimicrobial activity of the essential oil ofS. sahendicawas evaluated using the disc diffusion method; andminimum inhibitory concentrations (MIC) and minimum fungicidal/bactericidalconcentrations (MFC/MBC) were recorded using the micro dilution method. This study confirms that the essential oil ofS. sahendicapossesses high antimicrobial activities inin vitroagainstCandida albicansandStaphylococcus aureus, two medically important pathogens. The maximum activity ofS. sahendicaoil was observed in the oil obtained at pre-flowering stage, against Gram-positive bacteria(S. aureus) and the yeast (C. albicans).