Free radical quenching activity and polyphenols in three species of Coleus

Coleus is an important aromatic herb of the family Lamiaceae which is routinely grown as a traditional medicinal herb in India. We examined the total content of polyphenols, tannins, flavones and flavonols, their antioxidant and lipid peroxidation inhibition properties in leaf and stem tissues of three species of Coleus (Coleus forskholii Briq., Coleus aromaticus Benth. and Coleus zeylanicus Benth.). Plant extracts of C. forskholii exhibited high amounts of polyphenols and higher antioxidant activity in the tissues compared to C. aromaticus and C. zeylanicus. The leaf extracts of C. forskholii showed significantly high amounts of total polyphenols (23.46 mg g-1 fw), flavones and flavonols (250.8 μg g-1 fw) and high antioxidant activity (12.29 mM g-1 fw). HPLC profiling of leaf and stem tissues showed the presence of standard antioxidative polyphenols and more potent antioxidative polyphenols. Our results demonstrate that C. forskholii could be used as an important source of phenolic compounds with significantly high antioxidant activity

The antioxidant and antiproliferative activities of methanolic extracts from Njavara rice bran

<p>Abstract</p> <p>Background</p> <p>Free radical-induced oxidative stress is the root cause for many human diseases. Naturally occurring antioxidant supplements from plants are vital to counter the oxidative damage in cells. The main objective of the present study was to characterize the antioxidant and antiproliferative potential of rice bran extracted from an important Indian rice variety, Njavara and to compare the same with two commercially available basmati rice varieties: Vasumathi, Yamini and a non medicinal variety, Jyothi.</p> <p>Methods</p> <p>Methanolic extracts of rice bran from four varieties; Vasumathi, Yamini, Jyothi and Njavara were used to study their total phenolic and flavonoid contents, <it>in vitro </it>antioxidant activities including total antioxidant activity, scavenging of nitric oxide and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical, reducing power and cytotoxic activity in C6 glioma cells. Correlation coefficient and regression analysis were done by using Sigmastat version 3.1 and Stata statistical package respectively.</p> <p>Results</p> <p>Rice bran methanolic extract from Njavara showed the highest antioxidant and cell cytotoxic properties compared to the other three rice varieties. IC₅₀values for scavenging DPPH and nitric oxide were in the range of 30.85-87.72 μg/ml and 52.25-107.18 μg/ml respectively. Total antioxidant activity and reducing power were increased with increasing amounts of the extract. Total phenolic and flavonoid contents were in the range of 3.2-12.4 mg gallic acid-equivalent (GAE)/g bran and 1.68-8.5 mg quercetin-equivalent (QEE)/g bran respectively. IC₅₀values of cytotoxic assay (MTT assay) were 17.53-57.78 μg/ml. Correlation coefficient and regression analysis of phenolic content with DPPH and NO scavenging, MTT (-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay, total antioxidant assay and reducing power showed a highly significant correlation coefficient values (96-99%) and regression values (91-98%).</p> <p>Conclusion</p> <p>The results of the present study show that the crude methanolic extract from Njavara rice bran contains significantly high polyphenolic compounds with superior antioxidant activity as evidenced by scavenging of free radicals including DPPH and NO. Njavara extracts also showed highest reducing power activity, anti-proliferative property in C6 glioma cells. In conclusion, it is conceivable that the Njavara rice variety could be exploited as one of the potential sources for plant - based pharmaceutical products.</p

Paclobutrazol treatment as a potential strategy for higher seed and oil yield in field-grown camelina sativa L. Crantz

<p>Abstract</p> <p>Background</p> <p><it>Camelina (Camelina sativa </it>L. Crantz) is a non-food oilseed crop which holds promise as an alternative biofuel energy resource. Its ability to grow in a variety of climatic and soil conditions and minimal requirements of agronomical inputs than other oilseed crops makes it economically viable for advanced biofuel production. We designed a study to investigate the effect of paclobutrazol [2RS, 3RS)-1-(4-Chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pentan-3-ol] (PBZ), a popular plant growth regulator, on the seed and oil yield of <it>Camelina sativa </it>(cv. Celine).</p> <p>Results</p> <p>A field-based micro-trial setup was established in a randomized block design and the study was performed twice within a span of five months (October 2010 to February 2011) and five different PBZ treatments (Control: T₀; 25 mg l^-1: T₁; 50 mg l^-1: T₂; 75 mg l^-1: T₃; 100 mg l^-1: T₄; 125 mg l^-1: T₅) were applied (soil application) at the time of initiation of flowering. PBZ at 100 mg l^-1concentration (T₄) resulted in highest seed and oil yield by 80% and 15%, respectively. The seed yield increment was mainly due to enhanced number of siliques per plant when compared to control. The PBZ - treated plants displayed better photosynthetic leaf gas exchange characteristics, higher chlorophyll contents and possessed dark green leaves which were photosynthetically active for a longer period and facilitated higher photoassimilation.</p> <p>Conclusion</p> <p>We report for the first time that application of optimized PBZ dose can be a potential strategy to achieve higher seed and oil yield from <it>Camelina sativa </it>that holds great promise as a biofuel crop in future.</p

Water deficit as a regulatory switch for legume root responses

Plant roots perceive declining soil water potential as an initial signal which further triggers an array of physiological, morphological and molecular responses in the whole plant. Understanding the root responses with parallel insights on protein level changes has always been an area of interest for stress biologists. In a recent study, we reported drought stress-induced changes among certain structural and functional root proteins involved in reactive oxygen species (ROS) detoxification, primary and secondary metabolite biosynthetic pathways as well as proteins associated with cell signaling in an economically important legume crop Vigna radiata (L.) Wilczek. We also demonstrated photosynthetic gas exchange characteristics and root physiology under varying levels of water-deficit and recovery. In this report, we depict a closer analysis of the expression patterns of the identified proteins which were categorized into five major functional groups. These proteins represent a unique coherence and networking with each other as well as with the overall physiological and metabolic machinery in the plant cell

Effect of oxidative stress on <i>AdLEA</i> transgenic plants.

<p>(A and C) WT and transgenic seedlings after growth on MS medium supplemented with 5 and 10μM MV respectively. (B and D) Recovery of seedlings on MV free medium. (E) Chlorophyll content (μg mg^-1 FW) in the seedlings after growth on MV supplemented medium. (F) Phenotypic differences in the leaf discs from WT and transgenic plant lines floated in dose-dependent concentrations (5 and 10μM) of MV. (G) Chlorophyll content (μg mg^-1 FW) in the leaf discs after treatment with MV. (H) Lipid peroxidation expressed as TBARS content (μmol g^-1 FW) in leaf discs after treatment with MV. All the experiments were performed in triplicates and data represented as mean ± SD (n = 3; biological replicates). 11 seedlings per plate constitute one biological sample for seedling assay. 15 leaf discs from a single leaf constitute one biological sample for disc senescence assay. Statistical analysis was performed with two-way ANOVA (*P<0.05, **P<0.001).</p

Effect of salinity stress on <i>AdLEA</i> transgenic plants.

<p>(A and C) WT and transgenic seedlings after growth on MS medium supplemented with 200mM and 300mM NaCl respectively. (B and D) Individual seedlings morphology after growth on 200mM and 300mM NaCl respectively, depicting differences in root length between the seedlings. (E) Phenotypic differences in the leaf discs from WT and transgenic plant lines floated in dose-dependent concentrations (200mM and 300mM) of NaCl. (F) Graphical representation of root lengths in NaCl-treated seedlings after 15d and 9d growth on 200mM and 300mM NaCl respectively. (G) <b>C</b>hlorophyll content (μg mg^-1 FW) in the leaf discs after 72 h of treatment with NaCl. (H) Lipid peroxidation expressed as TBARS content (μmol g^-1 FW) in leaf discs after 72 h of treatment with NaCl. All the experiments were performed in triplicates and data represented as mean ± SD (n = 3; biological replicates). 11 seedlings per plate constitute one biological sample for seedling assay. 15 leaf discs from a single leaf constitute one biological sample for disc senescence assay. Statistical analysis was performed with two-way ANOVA (*P<0.05, **P<0.001).</p

ROS detection in leaf epidermal cells by confocal microscopy and quantification of ROS in leaves using NBT staining.

<p>(A) Fluorescence levels in WT and transgenic plants before and after treatment with PEG as shown in confocal microscopy. Bright field images of WT and transgenic plants are also displayed. Stomata with water treatment. (a and b) WT; (c and d) representative transgenic line 7. Stomata after treatment with PEG. (e and f) WT; (g and h) transgenic line 7; (i and j) transgenic line 2; (k and l) transgenic line 4. The figures are representative confocal images of stomatal guard cells (n < 1000) with three biological repetitions (Bar-100μm). (B) Quantification of ROS production in cells after H₂DCFDA staining using ImageJ software. (C) Unstressed (untreated), WT, and transgenic leaves treated with 100mM NaCl as visualized after NBT staining. (D) Graphical representation of formazan content (μg mg^-1 dry weight) in leaves of unstressed, WT, and transgenic leaves after treatment with 100mM NaCl. All the experiments were performed in triplicates and data represented as mean ± SD (n = 3; biological replicates). Single leaf from each plant constitute one biological sample. Statistical analysis was performed with one-way ANOVA (*P<0.05, **P<0.001).</p

Relative gene expression of <i>AdLEA</i> in <i>A</i>. <i>diogoi</i> in response to various abiotic stresses.

<p><i>A</i>. <i>diogoi</i> samples were treated with extreme temperatures (high and low), polyethylene glycol, sorbitol, sodium chloride and methyl viologen and <i>AdLEA</i> expression profile was analyzed by qRT-PCR. Data plotted are the mean values ± SD from three independent experiments (n = 3; biological replicates). RNA from two trifoliate leaves of <i>A</i>. <i>diogoi</i> represents one biological sample. Statistical analysis was performed with one-way ANOVA (*P<0.05, **P<0.001).</p