Sugars and acid invertase mediate the physiological response of Schenkia spicata root cultures to salt stress

A heterotrophic model system was established in our studies in order to differentiate the effect of high salt concentrations in external medium on growth and sugar metabolism in roots from the effect of reduced sugar availability resulting from decreased photosynthesis under salinity. Soluble sugar content and the activity of acid invertase in root cultures of salt-tolerant (ST) and salt-sensitive (SS) Schenkia spicata (L.) Mansion genotypes were investigated during exposure to different NaCI concentrations (0-200 mM). Their response to severe salinity was characterized by a metabolic adjustment that led to the accumulation of sucrose (Suc) in root tissues. There was clear evidence that cell wall invertase (CW-Inv) is, the major contributor to the Suc/hexose ratio in roots during exposure to elevated salinity. The results of CW-Inv activity and immunodetection assays in our study suggest that the regulation of CW-Inv expression is most likely achieved in a salt stress dependent manner. Also, NaCI modulated soluble acid invertase (SA-Inv) expression differentially in SS and ST genotypes of S. spicata. Regardless of the salt treatment, genotype, or the amount of enzyme, SA-Inv activity was generally low, indicating regulation at the posttranslational level. The results suggest no direct role of SA-Inv in the regulation of the root tissue carbohydrate pool and therefore in the control of the availability of glucose and fructose for the primary metabolism and/or osmotic adjustment in the present heterotrophic model system, 2012 Elsevier GmbH. All rights reserved

Comparative phytochemical analysis of Gentiana cruciata L. roots and aerial parts, and their biological activities

The purpose of this study was to evaluate the antioxidant potential of methanol extracts of Gentiana crudata L. aerial parts and roots, as well as the stability of the phenolic compounds and antioxidant capacity of extracts during heating, at different pHs and after an in vitro digestion procedure. Also, their genotoxicity and antigenotoxicity against carbon tetrachloride in the liver of albino Wistar rats using the comet assay were evaluated. Three secoiridoid glycosides (swertiamarin, gentiopicrin, and sweroside) and four phenolic compounds (orientin, vitexin and two isovitexin-glucosides) were identified as the major constituents in aerial parts and roots of G. cruciata, using UHPLC-DAD/+/- HESI-MS/MS analysis. The results of antioxidant assays showed that aerial parts displayed higher antioxidant activity compared to the roots, which could be related to higher phenolics content, especially flavonoids. In general, extracts showed pH and thermal stability, while duodenal condition had more influence on total phenolic condition and antioxidant activity of extracts. Both extracts showed a protective effect against CCl4 in comet assays. The roots extract showed no genotoxic activity, while aerial parts extract showed slight genotoxicity at concentrations of 400 mg/kg b.w. (C) 2015 Elsevier B.V. All rights reserved.Ministry of Education, Science and Technological Development of the Republic of Serbia {[}III 43004, III 41010, OI 173024