Effect of nitrate fertilization and saline stress on the contents of active constituents of Echinacea angustifolia DC

In this study, the effect of nitrogen form (nitrate and ammonium in the molar ratio of 1:1 or 1:0), supplied to the plant or NaCl salinity (up to a concentration of 50 mol m⁻³) of the feeding solution, on the content of selected caffeic acid derivatives and the activities of phenylalanine ammonia lyase (PAL; EC. 4.3.1.5) and shikimate dehydrogenase (SKDH; EC 1.1.1.25) were investigated in the leaves and the roots of Echinacea angustifolia DC, grown hydroponically. Two experiments were conducted under glasshouse conditions with seedlings transplanted in aerated stagnant nutrient solution (floating raft system) four weeks after emergence. The nitrate/ammonium ratio in the nutrient solution did not affect plant growth or dry matter partitioning, but it influenced the concentration of determined metabolites; in particular, the root concentrations of chlorogenic acid, echinacoside and caffeic acid were significantly higher in the plants grown with nitrate as sole source of nitrogen. NaCl salinity reduced plant growth, by reducing the biomass allocated to the inflorescences, and enhanced the accumulation of chlorogenic acid and cichoric acids, at least in the roots.     

Cytoprotective effects of geraniin against peroxynitrite- and peroxyl radical-induced cell death via free radical scavenging activity

The role of natural antioxidants in combating the deleterious effects of free radicals has received much attention. In the present study, the cytoprotective effects and the free radical scavenging activity of geraniin, a hydrolysable ellagitannin from Nephelium lappaceum rind, were evaluated by using various approaches. Addition of geraniin to the culture media resulted in a profound cytoprotective effect against damages induced by the peroxynitrite generator 3-morpholinosydnonimine (SIN-1), and the peroxyl radical generator 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH). Geraniin exhibits more potent cytoprotective activity than that of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox). Geraniin exhibited potent antioxidant activity against reactive species, such as nitric oxide, superoxide anion, and chemically synthesized peroxynitrite. Kinetic analysis of reactivity against peroxyl radicals generated by AAPH revealed that geraniin possesses potent reactivity against peroxyl radicals with higher stoichiometric number than Trolox. The cytoprotective effect of geraniin was only observed when geraniin and these toxic compounds were co-existing, suggesting that geraninn exhibits cytoprotective effects via free radical scavenging activity in the extracellular fluid.     

Total phenolic contents and antioxidant properties of commonly consumed vegetables grown in Colorado

A total of 38 commonly consumed vegetable samples, including 3 kale, 1 rhubarb, 3 spinach, 3 broccoli, 2 green bean, 5 carrot, 10 tomato, and 11 potato samples, were investigated for their total phenolic contents (TPC) and antioxidant properties. The measured antioxidant properties included free radical scavenging activities against DPPH, superoxide anion radical (O₂⁻), ABTS⁺ and peroxyl radical, and Fe²⁺ chelating capacity. The tested vegetables differed in their antioxidant properties and TPC, although all vegetables had significant antioxidant activities and contained significant levels of phenolics. The TPC and the measured antioxidant properties were correlated to each other. The Fe⁺² chelating capacity and the scavenging capacities against ABTS⁺, DPPH and O₂⁻ were reported for these commonly consumed vegetables for the first time. Results from this study suggest that kale, spinach, broccoli, and rhubarb are the better dietary sources of natural antioxidant activities and phenolic compounds. Furthermore, kale, broccoli and spinach produced in Colorado may have greater antioxidant contents than those grown at other locations.     

Modelling and optimization of ethyl butyrate production catalysed by Rhizopus oryzae lipase

Response surface methodology was used to model and optimise the production of ethyl butyrate, catalysed by Rhizopus oryzae lipase immobilised in a hydrophilic polyurethane foam. Experiments were carried out following a central composite rotatable design, as a function of reaction temperature (T: 22–38 °C) initial butyric acid concentration (A: 0.031–0.619 M) and initial molar ratio ethanol/acid (MR; 0.257–2.443). After 48 h reaction time, the production of ethyl butyrate could be fitted to a surface described by a second-order polynomial model. A maximum ethyl butyrate concentration of 0.106 M, corresponding to 47% conversion into ester and a productivity of 2.21 μmole/mL h, is expected at initial reaction conditions of T, A and MR of 33 °C, 0.225 M and 1.637, respectively. This maximum was experimentally confirmed.     

Preservation of saffron floral bio-residues by hot air convection

Large amounts of floral bio-residues are wasted in saffron spice production, which need to be stabilized because of how quickly they deteriorate. These bio-residues are rich in phenolic compounds, and the aim of this study was to evaluate the effect of drying temperatures and air flows on their color and phenolic composition. Anthocyanins and flavonols were degraded at 110 and 125 °C. The best drying temperatures were 70 and 90 °C for maintaining their physicochemical quality. The duration at 70 °C was double than that of 90 °C. Anthocyanins and flavonols were stable at 70 and 90 °C with 2, 4, 6 and 8 m s⁻¹. Dehydrations at 90 °C with 2, 4 and 6 m s⁻¹ were the most appropriate, due to a better color and greater similarity to control samples for their flavonols and anthocyanins.     

Inhibitory effect of Chardonnay and black raspberry seed extracts on lipid oxidation in fish oil and their radical scavenging and antimicrobial properties

Ethanol extracts of Chardonnay grape and black raspberry seed flours were evaluated for their capacity to suppress lipid oxidation, preserve important fatty acids, and inhibit microbial growth. They were also tested for radical scavenging activity against DPPH and peroxyl radicals as reflected in oxygen radical absorbance capacity (ORAC), and total phenolic content (TPC). Both tested seed flour extracts suppressed lipid oxidation and rancidity development in fish oil. Black raspberry seed flour extract significantly reduced the degradation of biologically important n − 3 PUFA under accelerated oxidative conditions. Black raspberry and Chardonnay seed flour extracts at 165 and 160 μg seed flour equivalents/mL, respectively exhibited bacteriocidal activity against Escherichia coli and growth inhibition of Listeria monocytogenes under experimental conditions. Both seed flour extracts exhibited DPPH radical quenching activity and Chardonnay had the stronger ORAC of 663 μmol Trolox equivalents per gram seed flour and the higher TPC of 99 mg gallic acid equivalents/g flour. The data from this study suggest the potential for developing natural food preservatives from these seed flours for improving food stability, quality, safety, and consumer acceptance.     

Relationship between antioxidant capacity and total phenolic content of red,rosé and white wines

Phenolic compounds are one of the most important quality parameters of wines, since they contribute to wine organoleptic characteristics such as colour, astringency, and bitterness. Furthermore, several studies have pointed out that many show biological properties of interest, related to their antioxidant capacity. This antioxidant activity has been thoroughly studied and a wide variety of methods have been developed to evaluate it.     

Radical scavenging and reducing properties of extracts of cashew shoots (Anacardium occidentale)

The total phenolic content and antioxidant activities of methanol, hexane and ethyl acetate extracts of the shoots of Anacardium occidentale were measured. Total phenolic content was assessed by the Folin–Ciocalteau assay whereas antioxidant activities were assessed by measuring the ability of the extracts to scavenge the ABTS^·+ and DPPH^· radicals, superoxide anion radicals and nitric oxide radicals as well as their ability to reduce ferric ions. Results indicated that the methanol extract of A. occidentale was the most potent reducing agent and radical-scavengers compared to the other two extracts. The ethyl acetate extract exhibited some antioxidant activities whereas the hexane extract is the least reactive. The order of the antioxidant potency of the plant extract is methanol > ethyl acetate > hexane. The methanol extract contained more than 7 fold of total phenolic content compared to the hexane and ethyl acetate extracts indicating the likely possibility that the observed antioxidant activities were partly contributed by the phenolics. The results suggest that the shoots of A. occidentale are a source of natural antioxidants.