title: Comparison of antioxidant and free radical scavenging activities of the essential oils from flowers and fruits of Otostegia persica Boiss.
abstract: The aerial parts of the endemic plant of Otostegia persica Boiss. in two different stages of flowering and fruiting were hydro-distilled to extract oils in the yields of 0.3 and 0.15% (v/w), respectively. The oils were analyzed by GC and GC/MS. Twenty-eight and thirty-one components were identified, representing 97.59 and 94.61% of the oils, respectively. The main compounds of the essential oil flowers (EOFL) were alpha-pinene (17.21%), 1-octen,3-ol (13.44%) and cubenol (7.27%), whereas diisooctyl phthalate (45%) and hexadecanoic acid (11.07%) were the major constituents of the essential oil of the fruits (EOFR). The oils were screened for their possible antioxidant activities by two complementary test systems, namely DPPH free radical-scavenging and ammonium thiocyanate. In both tested systems, EOFL exerted greater antioxidant and radical scavenging activity. In the first case, EOFL exerted antioxidant activity with an IC50 19.8 +/- 1.8 microg mL(-1) almost similar to BHA and ascorbic acid (15.2 +/- 1.1 and 17.4 +/- 1.3), respectively. In the ammonium thiocyanate system, the inhibition rate of oxidation of linoleic acid for EOFL was estimated 93.5 +/- 2.8. The higher activity of this oil in comparison to EOFR may be attributed to its high content of monoterpenes, especially oxygenated ones in the oil of the flowers.
authors.affiliation: Department of Pharmacognosy, School of Pharmacy, Kerman University of Medical Science, Kerman, Iran.
authors.forename: Fariba
authors.initials: F
authors.lastname: Sharififar
authors.forename: Valiolah
authors.initials: V
authors.lastname: Mozaffarian
authors.forename: Shirin
authors.initials: S
authors.lastname: Moradkhani
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism*; D001713:Biphenyl Compounds / Q000737:chemistry; D035264:Flowers / Q000378:metabolism*; D016166:Free Radical Scavengers; D005638:Fruit / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006834:Hydrazines / Q000737:chemistry; D020128:Inhibitory Concentration 50; D019684:Magnoliopsida / Q000378:metabolism*; D009822:Oils, Volatile / Q000378:metabolism*; D010851:Picrates; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D013861:Thiocyanates / Q000737:chemistry; D013997:Time Factors
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D006834:Hydrazines; D009822:Oils, Volatile; D010851:Picrates; D010936:Plant Extracts; D013861:Thiocyanates; C026976:thiocyanic acid; C004931:1,1-diphenyl-2-picrylhydrazyl