1-1-diphenyl-2-picrylhydrazyl and thiocyanic-acid

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.

Topics: Antioxidants; Biphenyl Compounds; Flowers; Free Radical Scavengers; Fruit; Gas Chromatography-Mass Spectrometry; Hydrazines; Inhibitory Concentration 50; Magnoliopsida; Oils, Volatile; Picrates; Plant Extracts; Thiocyanates; Time Factors