Chemical composition, radical scavenging and anti-oxidant capacity of <i>Ocimum Basilicum</i> essential oil

<p><i>Ocimum basilicum</i> has several functional characteristics including carminative, stimulant, diuretic, antiseptic, anesthetic, anti-spasmodic, analgesic and anti-tussive properties. <i>O. basilicum</i> essential oil (basil oil) was tested for chemical composition and in vitro and ex vivo anti-oxidant activities. The in vitro anti-oxidant capacity of basil oil was examined using 1, 1-diphenyl-2-picryl-hudrazyl radical (DPPH^•), 2, 2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS^•), hydrogen peroxide (H₂O₂), hydroxyl radical (HO^•), nitric oxide (NO) and nitrite (NO₂) scavenging effects. The <i>ex vivo</i> anti-oxidant activity of basil oil was determined through measuring NADH oxidase (NOX) and inducible nitric oxide synthase (iNOS) mRNA expression in lipopolysaccharide-stimulated murine macrophages using real-time polymerase chain reaction (RT-PCR). GC-MS analysis indicated that the main components in the basil oil were methylchavicol (47%), geranial (19%) and neral (15%). Basil oil had effective DPPH^•, ABTS^•, H₂O₂, HO^•, NO and NO₂ scavenging effects. Basil oil significantly reduced NOX and iNOS mRNA expression in lipopolysaccharide-stimulated murine macrophages at concentrations of 1-10 μg/mL. Basil oil had radical scavenging and anti-oxidant activities and could potentially be used as a safe and effective source of natural anti-oxidants in therapy against oxidative damage and stress associated with some inflammatory conditions.</p

Effects of NO and nitrogen sources on NR activity.

<p>Wheat seedlings (cvs Spitfire and Westonia) were grown in glasshouse for two weeks. Then, plants were irrigated with nitrogen-free nutrient solution for a week. Plants treated with different concentrations (left = 4mM and right = 40 mM) and different chemical forms of nitrogen (A = NHCl, B = KNO₃ and C = NH₄NO₃) with 0 (as a control), 20 or 100 μM of SNP for 3 days. Leaf tissues were harvested 24 hours after nitrogen treatments. NR activity was measured on three biological repeats. Different letters mean significantly different at 5% levels as calculated by Duncan multiple test.</p

How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels

<div><p>Nitrogen (N) is one of the most important nutrients for plants and nitric oxide (NO) as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE). This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP) as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH₄NO₃) treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in <i>Triticum aestivum</i> plants.</p></div

Effects of NO and nitrogen sources on GS activity.

<p>Wheat seedlings (cvs Spitfire and Westonia) were grown in glasshouse for two weeks. Then, plants were irrigated with nitrogen-free nutrient solution for a week. Plants treated with different concentrations (left = 4mM and right = 40 mM) and different chemical forms of nitrogen (A = NHCl, B = KNO₃ and C = NH₄NO₃) with 0 (as a control), 20 or 100 μM of SNP for 3 days. Leaf tissues were harvested 24 hours after nitrogen treatments. GS activity was measured on three biological repeats. Different letters meaning significantly different at 5% levels as calculated by Duncan multiple test.</p

List of primers.

<p>List of primers.</p

Effects of NO and nitrogen sources on NO content.

<p>Wheat seedlings (cvs Spitfire and Westonia) were grown in glasshouse for two weeks. Then, plants were irrigated with nitrogen-free nutrient solution for a week. Plants treated with different concentrations (left = 4mM and right = 40 mM) and different chemical forms of nitrogen (A = NHCl, B = KNO₃ and C = NH₄NO₃) with 0 (as a control), 20 or 100 μM of SNP for 3 days. Leaf tissues were harvested 24 hours after nitrogen treatments. NO content was measured on three biological repeats. Different letters meaning significantly different at 5% levels as calculated by Duncan multiple test.</p

Effects of high nitrogen (40 mM) on mRNA expression.

<p>Effects of high nitrogen (40 mM) on mRNA expression.</p