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The composition of hydro-distilled essential oils from fresh leaves of wild growing Juniperus polycarpos var. turcomanica, collected from northeaste of Iran, were investigated by GC and GC-MS analysis during growing season 2012-2013. The oil yields depend on the month of collecting and ranged between 1.5 and 2.1% (v/w). Analysis of the essential oil identified 49 components that representing 89.7-94.6% of the total oil. Results indicated that the predominant presence of monoterpene constituents, representing 56.9-85.6% of the essential oil. The main constituent was α-pinene (41.8-75.4%), followed by germacrene B (1-5.8%), camphor (0.7-4.5%) and α-cadinol (0.4-4.8%). Regarding essential oil composition, quantitative and qualitative variations were recorded for 12 different collection periods. The best time for harvesting juniper leaves seems to be from mid-autumn to mid-winter. [ABSTRACT FROM AUTHOR]

Influence of microwave power on dehydration kinetics as well as quantity, chemical composition and antioxidant potential of peppermint essential oil was evaluated. The leaves were dried using microwave powers of 200, 400 and 800 W, and the essential oils extracted by hydro-distillation. The antioxidant potential of the essential oils was quantified by DPPH radical-scavenging activity method. The obtained results showed that increasing microwave power caused significant decrement (p ≤ 0.01) in drying duration. Drying over the considered microwave powers reduced essential oil yield significantly (p ≤ 0.01). In total, 36 compounds were identified in the essential oils belonging mainly to oxygenated monoterpenes. The main constituents namely menthol, menthone and menthyl acetate showed significant variation (p ≤ 0.01 or p ≤ 0.05) with the drying process. Antioxidant assaying indicated significant effect (p ≤ 0.05) on radical scavenging activity of the essential oil by drying and essential oil concentration. Compared to the fresh samples (with an IC50 of 103 μg/ml), the leaves dried at microwave power levels of 200, 400 and 800 W resulted in significant lower antioxidant activities with IC50 values of 201, 291 and 615 μg/ml, respectively. [ABSTRACT FROM AUTHOR]

Essential oils from the aerial parts of three populations ofNepeta crassifolia(Lamiaceae), which are Iranian endemic species and four populations ofN. nudagrown in northwestern Iran were obtained by hydro-distillation and examined by gas chromatography (GC) and GC–mass spectrometry (GC/MS). Overall, 37 compounds were identified in the essential oils from different populations ofN. crassifoliaandN. nuda. The essential oils consisted mainly of oxygenated monoterpenes and sesquiterpene aldehydes. The major components in the oils of three populations ofN. crassifoliawere 4aβ, 7α, 7aβ-nepetalactone (16.46–27.45%), 4aα, 7α, 7aβ-nepetalactone (13.45–17.54%), 1,8-cineole (8.15–9.70%) and elemol (14.38–22.14%), while 7aβ-nepetalactone (61–72.21%), 4aα, 7α, 7aβ-nepetalactone (8.72–12.63%), pulegone (7.36%) and piperitenone oxide (4.12%) were identified as the main constituents in the oils of four populations ofN. nuda. The essential oils from the aerial parts of two species ofNepetasourced in northwestern Iran were rich in oxygenated monoterpenes. In conclusion, the present study indicated the essential oil components of wild populations of bothNepetaspecies varied with chemotypes, environmental conditions, and geographic origin. [ABSTRACT FROM AUTHOR]

Jasmonic acid (JA) and its volatile methyl ester (MJ) are regarded as endogenous regulators that play important roles in regulating stress responses, plant growth and development. Salicylic acid (SA) has been identified as an important signaling element involved in establishing the local and systemic disease resistance response of plants after pathogen attack. Growth, oil yield and chemical components ofSatureja hortensisL. grown in greenhouse conditions were investigated. Experimental treatments, included (i) water foliar application, (ii) water + ethanol foliar application, (iii–v) 50, 100, and 200 ?L JA and (vi–ix) 50, 100, and 200 M SA. The hydro-distilled oil yields of studied treatments ranged between 0.74 and 0.91 mL/100 g dry matter. The major components of the oil were carvacrol, ?-terpinene, (Z)-?-ocimene, ?-pinene, and ?-terpinene. The result indicated that different levels of JA and SA had significant impacts on chemical components ofS. hortensisoils, whereas they had no significant effects on oil yield and dry herbage. Foliar application of 50 ?L SA increased monoterpene hydrocarbons inS. hortensisoil, whereas oxygenated monoterpenes and sesquiterpenes decreased. Finally, some of secondary metabolites inS. hortensiscould be partially changed by supplementation of different elicitors. [ABSTRACT FROM PUBLISHER]

Thymus (thyme) is one of the most important genera with regard to the number of species within the family Lamiaceae. Kerman thyme (Thymus carmanicus Jalas) is an endemic Iranian species, intensively utilized because of its wide ranging medicinal and culinary properties. Aerial parts of T. carmanicus collected from various altitudes including 2000-2500, 2500-3000, and 3000-3500 m above sea level in Zagros Mountains, Kerman province, South Iran. The yellow oil yields ranged between 0.80 to 1.10% (v/w) for populations collected from various elevations and for the populations collected from various regions ranged between 0.55-1.61% (v/w). GC-MS analyses revealed compounds, constituting 92.2-99.9% of total essential oils. The major constituents of essential oils were carvacrol (47.6-57.9%), thymol (8.3-19.0%), γ-terpinene (7.3-7.9%) and p-cymene (4.4-7.6%), that monoterpenes, especially oxygenated monoterpenes was the main constituent group in essential oil from the aerial parts of T. carmanicus. The results of current study indicated that increasing elevation decreased thymol content in essential oils of the wild populations of T. carmanicus. [ABSTRACT FROM AUTHOR]

Jasmonic acid (JA) is regarded as endogenous regulator that plays important roles in regulating stress responses, plant growth, and development. Salicylic acid (SA) has been identified as an important signaling element involved in establishing the local and systemic disease resistance response of plants after pathogen attack. A field experiment was conducted to assess the foliar applications effect of JA and SA on quantity and quality yields of essential oil of lemon balm (Melissa officinalis L.). Experimental treatments were: I) water foliar application; II) water + 1% ethanol foliar application (as a solvent); III-V) JA at 0.05–0.40 mg L−1; VI-IX) SA at 0.14–14.00 g L−1. The essential oil contents of the treatments ranged between 0.55 to 0.61% (v/w). The results of analysis of the essential oils by GC-FID and GC/MS indicated that monoterpene oxygenated and sesquiterpenes were the major components. There were no significant differences among treatments for essential oil content, dry matter weight, and some of volatile components (neral and geranial). The foliar spray JA significantly improved the amounts of two phenolic monoterpenes compounds such as thymol from 0.42% in control to 4.37% in JA at 0.40 mg L−1 and carvacrol from 0.77% in control to 14.76% in JA at 0.40 mg L−1. In addition, the highest percentages of β-caryophyllene and caryophyllene oxide were obtained from the foliar application of SA and JA. In conclusion, the exogenous application of JA and SA can considerably improve some secondary metabolites especially monoterpene oxygenated and sesquiterpenes in lemon balm plants under filed conditions. Image 1 • Foliar sprays effects of JA and SA on essential oil of lemon balm were studied. • JA significantly improved phenolic monoterpenes contents in lemon balm oil. • SA increased sesquiterpenes concentrations in lemon balm essential oil. [ABSTRACT FROM AUTHOR]