Cold stress affects antioxidative response and accumulation of medicinally important withanolides in Withania somnifera (L.) Dunal

Withania somnifera (L.) Dunal (Indian ginseng) is a high value medicinal plant. It synthesizes a large array of biologically active withanolides. In this study, two month old seedlings of AGB002 (wild genotype) and AGB025 (cultivated genotype) of W. somnifera were subjected to cold stress (4 ◦C) under controlled envi-ronment. Plants were analyzed for three medicinally important secondary metabolites (withanolide A, withanone and withaferin A), lipid peroxidation (MDA), cell injury, superoxide radical (O2 •−) accumula-tion and anti-oxidative enzymes activities such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR). Increases in the titers of superoxide anion and MDA were observed from day 1 to day 7 in both genotypes, although the increase on the first day of exposure was significantly higher. Enzymatic activities of SOD, CAT, APX and GR also showed an increasing trend in both genotypes and reached a maximum on day 7 of the cold temperature exposure; however, this increase was higher in AGB002 than AGB025. Withanolide A (WS-1) in the roots of both genotypes sig-nificantly decreased on the first day of cold exposure and then showed a recovery until day 7. WS-1 was not detected in the leaves of either genotype. Withanone (WS-2) content in the leaves also decreased towards the end of the cold period in both genotypes. Cold stress also elicited the accumulation of WS-2 in AGB025, but was not detectable in control seedlings. At maturity, WS-2 was also detected in control plants. Furthermore, a significant increase in the leaf withaferin A (WS-3) content was recorded from day 1 to day 7 of the cold exposure in both the genotypes, suggesting the possible involvement of with-anolides in cold-protection. AGB002 showed comparatively higher accumulation of antioxidant enzymes and selected marker withanolides than AGB025, indicating that AGB002 is better adapted to cold than AGB025. It could be inferred from these observations that cold stress induces bioactive withanolide accu-mulation in W. somnifera as a mechanism for scavenging reactive oxygen species (ROS). These studies also provide an impetus for enhancing the withanolide accumulation in W. somnifera using controlled environment technology.CSIR-Indian Institute of Integrative Medicine (CSIR-IIIM).http://www.elsevier.com/locate/indcrop2016-11-30hb2016BiochemistryChemistryGenetic

Antioxidant and oxidative DNA damage protective properties of leaf, bark and fruit extracts of <em>Terminalia chebula</em>

127-134Terminalia chebula Retz., is an important herbal drug in Indian system of medicine. In the present study, methanol extract and fractions of leaf, bark and fruit of T. chebula were investigated for their antioxidant and DNA protective properties. The antioxidant activities of these extracts and fractions were evaluated by in vitro methods, including, DPPH radical scavenging assay, superoxide radical scavenging assay, hydroxyl radical scavenging assay, reducing power assay and metal chelating assay. DNA protective activity was also determined using hydroxyl radical induced DNA strand scission. Total phenolic content of the extracts and fractions was measured using Folin-Ciocalteu method. Among the different extracts and fractions, highest radical scavenging abilities were obtained in acetone fraction of fruit, including DPPH radical (EC50 value of 9.9 ± 0.70 μg/mL) superoxide anions (EC50 value of 27.0± 2.09 μg/mL), and hydroxyl radicals (EC50 value of 35.6 ± 1.97 μg/mL) scavenging activities. Similarly, reducing power (EC50 value of 71.4 ± 4.30 μg/mL) and percent Fe2+ chelating capacity (70.6 ± 4.84 at 500 μg/mL) was also highest in acetone fraction of fruit. Our results also revealed remarkable ability of the acetone fraction of fruit and bark in protecting the supercoiled pUC18 plasmid DNA against strand scission induced by hydroxyl radicals. In addition, our study showed significant (P <0.01) linear correlation between antioxidant activities and total phenolic content of extracts and fractions

Expression analysis of boiling-stable protein (BsCyp) in response to drought, salt and osmotic treatments in drought tolerant and susceptible cultivars of Triticum aestivum

The effect of osmotic, drought and salt stresses on the induction of boiling-stable proteins were studied in C-306 (drought tolerant) and HD-2004 (drought susceptible) cultivars of Triticum aestivum. Western blotting analysis, using polyclonal antibodies raised against a 20 kDa A. thaliana cyclophilin, revealed the induction of a cross-reacting band (40 kDa, BsCyp) in cv. 306. However no substantial expression was observed in drought sensitive cv. HD-2004, indicating its role in water stress adaptation. Thermostability studies of BsCyp in cv. 306 revealed that BsCyp was stable and can be detected even after 20 min of boiling treatment under all the stresses. Based upon these observations the possible role of BsCyp in water stress tolerance is discussed

Evaluation of nutritional and antioxidant status of Lepidium latifolium Linn.: a novel phytofood from Ladakh.

Lepidium latifolium Linn. (perennial pepperweed) is one of the preferred phytofoods among cold arid region of Ladakh, India and its leaves contribute significantly to people's diet. This study was conducted to determine its nutritive value and antioxidant activity. Plant samples from three different locations were selected in the present study. Results showed that this plant is an excellent source of glucosinolates, notably sinigrin that is present in very high amount (∼70-90%). Its value ranged from 149 to 199 µg per g fresh weight. Fatty acid composition analysis showed that its leaves were abundant in unsaturated fatty acids, specifically linolenic acid (18∶3) whose percentage is about 50%. Higher glucose and crude protein along with higher nitrogen to sulfur ratio, supplements the nutritive value of this plant. Based on total phenol, flavanoids, free radical scavenging activity and DNA protective activity showed that this ecotype of perennial pepperweed contains high antioxidant properties. The percentage inhibition for O2(-) scavenging activity ranged from 41.3% to 83.9%. Higher content of phenols (26.89 to 50.51 mg gallic acid equivalents per g dry weight) and flavanoids (38.66 to 76.00 mg quercetin equivalents per g dry weight) in leaves could be responsible for the free radical scavenging activity of this plant. Depending upon the location of the plants, variations were observed in different activities. Based on the systematic evaluation in this study, preparations of Lepidium latifolium from Ladakh can be promoted as substitute to dietary requirements

Purification and Characterization of a Novel Redox-Regulated Isoform of Myrosinase (β-Thioglucoside Glucohydrolase) from Lepidium latifolium L.

Myrosinase (ExPASy entry EC 3.2.1.147) is involved in the hydrolysis of glucosinolates to isothiocyanates, nitriles, and thiocyanates that are responsible for various ecological and health benefits. Myrosinase was purified from the leaves of Lepidium latifolium, a high-altitude plant, to homogeneity in a three-step purification process. Purified enzyme exists as dimer in native form (∼160 kDa) with a subunit size of ∼70 kDa. The enzyme exhibited maximum activity at pH 6.0 and 50 °C. With sinigrin as substrate, the enzyme showed <i>K</i>_m and <i>V</i>_max values of 171 ± 23 μM and 0.302 μmol min^–1 mg^–1, respectively. The enzyme was found to be redox-regulated, with an increase in <i>V</i>_max and <i>K</i>_cat in the presence of GSH. Reduced forms of the enzyme were found to be more active. This thiol-regulated kinetic behavior of myrosinase signifies enzyme’s strategy to fine-tune its activity in different redox environments, thus regulating its biological effects

Testosterone acts within the medial amygdala of rats to reduce innate fear to predator odor akin to the effects of Toxoplasma gondii infection

Rats infected with the protozoan Toxoplasma gondii exhibit a reduced aversion to cat odor. This behavioral change is thought to increase trophic transmission of the parasite. Infected male rats also show a greater testicular synthesis of testosterone and epigenetic change in arginine vasopressin within the medial amygdala. Here, we show that exogenous supply of testosterone within MeA of uninfected castrates recapitulates reduction in innate fear akin to behavioral change attributed to the parasite. We also show that castration post establishment of chronic infection precludes changes in fear and medial amygdala arginine vasopressin in the infected male rats. These observations support the role of gonadal hormones and pursuant neuroendocrine changes in mediating the loss of fear in the infected rats. This work also demonstrates that testosterone acting specifically within the medial amygdala sufficiently explains reduced defensive behaviors often observed during the appetitive component of reproductive behaviors.Published versio

Enhancement in Inulinase Production by Mutagenesis in Penicillium purpurogenum

270-274Extracellular inulinase producing strain of Penicillium purpurogenum was isolated from rhizosphere soil of chicory. Conidia of this selected strain were subjected to mutagenesis with UV and NTG (3-nitro, 5-methyl guanidine). After mutagenesis, of various colonies screened, few were selected to carry out the inulinase study. The study revealed 2.5-fold higher inulinase activity with 8 to 21-fold I/S ratio in all the selected colonies, indicating the enhancement in inulinase production after both mutagenic treatments in all the selected mutants

Percentage (%) fatty acid composition of <i>Lepidium latifolium</i> from different locations of Ladakh.

<p>C12:0, lauric acid; C14:0, myristic acid; C15:0, pentadecanoic acid; C16:0, palmitic acid; C16:1 n-7, palmitoleic acid; C18:0, stearic acid; C18:1 n-9, oleic acid; C18:2 n-6, linoleic acid; C18:3 n-3, linolenic acid; SFA, saturated fatty acid; MUFA, monounsaturated fatty acids; PUFA, polyunsaturated fatty acids; Cox: calculated oxidizability value. Each value is a mean of a duplicate analysis performed on different samples.</p

Representation of the major glucosinolates in native plant species of <i>Lepidium latifolium</i> in Ladakh.

<p>Values represent the average of all the three locations.</p