Enhanced growth and antioxidant efficiency of Vigna radiata seedlings in the presence of titanium dioxide nanoparticles synthesized via the sonochemical method

Nanosized titanium dioxide (nTiO2) is one of the most diverse nanomaterials available today but inconclusive studies on the effects of nTiO2 on plants are withholding its successful application in agriculture. In the present work, an attempt has been made to evaluate the interaction of nTiO2 with Vigna radiata (L.) Wilczek from the seed germination stage until the plants were 14 days old. TEM analysis revealed that nTiO2 was synthesized in the size range of 1–10 nm and X-ray diffraction (XRD) analysis confirmed the crystal structure. The plants were raised hydroponically in nutrient solution spiked with two different concentrations of nTiO2 (10 and 100 mg L−1). Inductively coupled plasma mass spectrometry (ICP-MS) results established the accumulation of nTiO2 in leaves. In response to the presence of nTiO2, V. radiata plants performed better as indicated by their increased seed germination, root and shoot length, higher fresh and dry weight and elevated chlorophyll and flavonoid contents. Germination percentage of V. radiata seeds increased by about 22% at 10 mg L−1 and 14% at 100 mg L−1 nTiO2 concentration. Maximum stimulation of total chlorophyll, flavonoids and phenolic contents was observed at 100 mg L−1 nTiO2 concentration in 7-day old plants, where an astonishing 8 fold increase in chlorophyll, 3 fold increase in flavonoids and 2 fold increase in phenolics was observed. However, a decrease in carbohydrate and protein contents and an increase in lipid peroxidation also marked the presence of mild oxidative stress that was neutralized by increased activity of antioxdant enzymes namely catalase, glutathione reductase and glutathione-s-transferase. The activity of superoxide dismutase was more or less stable while glutathione peroxidase activity reduced compared to the control plants. The higher ABTS and DPPH free radical scavenging activities of the nTiO2 treated plants also supported effective neutralization of free radicals.

Nutrient Composition, Antioxidant and Antibacterial Activities of Ulva prolifera O. F. Müller

Seaweeds are marine organisms capable of producing diverse kinds of chemical compounds with promising pharmacological use. The study evaluated the proximate and elemental composition and the potential antioxidant (using CUPRAC, ABTS+, and DPPH assays) and antibacterial activities (using microtiter plate dilution assay) of Ulva prolifera O. F. Müller. The seaweed has a total phenolic content of 829 ± 2.00 mg GAE/g. Antioxidant efficiency of U. prolifera exerted high ability of reducing copper ions, potent ABTS+ and DPPH scavenging activities in a concentration-dependent manner with IC50 value of 24.7 mg GAE/mL, 43.52 mg GAE/mL, and 54.1 mg GAE/mL, respectively, more effective than ascorbic acid. In vitro antibacterial activity assay showed that U. prolifera exhibited inhibitory activity against bacterial pathogens such as Methicillin-resistant Staphylococcus aureus (MIC = 125 mg/mL), S. epidermidis (MIC = 125 mg/mL), and Pseudomonas fluorescens (MIC = 500 mg/mL). This investigation is the first documented report regarding antibacterial activity of U. prolifera against P. fluorescens. In addition, results showed elemental composition to be in decreasing order of Ca K Mg Na Mn Fe Zn Cu Pb Cd Cr. Proximate composition of U. prolifera showed high carbohydrate and protein content with a percentage composition of 36.20 ± 0.27% and 23.72 ± 0.31% (dry weight), respectively. This study is the first report in the Philippines that shows the potential of U. prolifera as an excellent candidate organism as source of chemical compounds with relevant application to the pharmacological industry.

Effects of Surfactant Volume Fraction on the Antioxidant Efficiency and on The Interfacial Concentrations of Octyl and Tetradecyl p-Coumarates in Corn Oil-in-Water Emulsions

Surfactants have been used for decades in the food industry for the preparation of lipid-based emulsified food stuffs. They play two main roles in the emulsification processes: first they decrease the interfacial tension between the oil and water, facilitating droplet deformation and rupture; second, they reduce droplet coalescence by forming steric barriers. However, addition of surfactants to binary oil-water mixtures also brings up the formation of three-dimensional interfacial layers, surrounding each emulsion droplet, that significantly alter chemical reactivity. This is the case, for instance, in the inhibition reaction between antioxidants and the lipid radicals formed in the course of the spontaneous oxidation reaction of unsaturated lipids, which are commonly employed in the preparation of food-grade emulsions. The rate of the inhibition reaction depends on the effective concentrations of antioxidants, which are mostly controlled by the amount of surfactant employed in the preparation of the emulsion. In this work, we analyze the effects of the surfactant Tween 20 on the oxidative stability and on the effective concentrations of two model antioxidants derived from cinnamic acid, determining their interfacial concentrations in the intact emulsions to avoid disrupting the existing equilibria and biasing results. For this purpose, a recently developed methodology was employed, and experimental results were interpreted on the grounds of a pseudophase kinetic model.

Chemical Composition, Antioxidant and Inhibitory Effect of Cupressus sempervirens Essential Oils and Methanolic Extract on Beta-lactamase producing Isolates

The Jordanian endemic medicinal plant, Cupressus sempervirens was obtained from Dhana Natural Reserve, Al-Tafilah, Jordan to investigate its antibacterial and antioxidant activities. The procuring of essential oil was made by processing of dry leaves of C. sempervirens using steam-distillation method giving 0.26% (w/w) yield. The analysis of obtained EO for its chemical constituents, was achieved by GC-MS. The equivalent of 94.02% of the entire EO has been extracted and consists of twenty-two compounds. The characterization of EO was made by their presence of three groups of chemical compounds namely Sesquiterpene hydrocarbons (71.0%), Oxygenated sesquiterpenes (11.5%) and Monoterpenes hydrocarbons (10.6%). The major constituent was germacrene-D (14.2%) along with the d-cadinene (11.0%), ß-pinene (10.0%) and isocedrol (9.8%). This conferring a chemotaxonomic value as well as a higher degree of polymorphism in the occurrence of these compounds in C. sempervirens as compared with the same species in different location worldwide. The efficiency of methanol extract and essential oil as antibacterial was evaluated against nine bacteria, using disc diffusion and MIC methods. Results showed that the methanol extract at 2000µg/disc of C. sempervirens caused the growth inhibition of Bacillus subtilis, Micrococcus luteus, Staphylococcus epidermidis and Staphylococcus aureus and producing inhibition zone ranges between 12-15mm. The MIC values recorded by essential oils of C. sempervirens were as follow: S. epidermidis and S. aureus (370µg/mL), Escherichia coli and Enterobacter aerogenes (1000µg/mL), Pseudomonas aeruginosa (2000µg/mL) and M. luteus, Klebsiella pneumonia and Salmonella typhi (3000µg/mL). In the present study, C. sempervirens extract exerted antioxidant efficiency with an IC50 value of 27.31µg/mL.

Systematic Evaluation of Antioxidant Efficiency and Antibacterial Mechanism of Bitter Gourd Extract Stabilized Silver Nanoparticles

In this study, we accentuate the facile and green synthesis of ecologically viable silver nanoparticles (AgNPs) using aqueous (A-BGE) and ethanolic (E-BGE) dried bitter gourd (Momordica charantia) fruit extract as reducing and capping agents. Although AgNPs synthesized using BGEs have been reported earlier in fundamental antimicrobial studies, the possible antioxidant activity, antibacterial efficacy against superbugs, and a potential antimicrobial mechanism are still lacking. The characterization of as-prepared AgNPs was studied through UV-vis, TEM, Zeta-potential, FT-IR, XRD, and XPS analysis. The antioxidant ability of BG-AgNPs was extensively evaluated through DPPH and FRAP assays, which showed that A-BG-AgNPs possessed higher scavenging ability and superior reducing power due to the high phenolic content present in the BG extract. Furthermore, A-BG-AgNPs were highly stable in various physiological media and displayed excellent antibacterial activity against drug-resistant bacterial strains (i.e., MIC value of 4 µg/mL). The generation of reactive oxygen species evidenced that the possible antimicrobial mechanism was induced by BG-AgNPs, resulting in bacterial cell damage. Within the minimal hemolysis, the BG-mediated AgNPs possessed synergistic antioxidant and antibacterial agents and open another avenue for the inhibition of the growth of pathogens.

Antioxidant and Antibacterial Properties of Norway Spruce (Picea abies H. Karst.) and Eastern Hemlock (Tsuga canadensis (L.) Carrière) Cone Extracts

According to recent studies, Norway spruce cones and eastern hemlock cones possess exceptionally high antioxidant capacities; however, the antioxidant efficiency of extractives and their bioactive effects have yet to be investigated in detail. The present article utilizes state-of-the art analytical chemical methodology and chemometric evaluation to reveal cone extractives with the highest antioxidant potential, accounting for possible bioactive effects. Antioxidant properties were determined by the Ferric reducing antioxidant power (FRAP) assay and the Folin–Ciocalteu’s total phenol content (TPC) assay. Structure and relative polyphenol concentrations were determined using liquid chromatography/diode array detection/tandem mass spectrometry. The antibacterial testing was conducted using Staphylococcus aureus and Escherichia coli strains. Using correlation analysis and factor analysis, a scoring evaluation was implemented to determine and compare the antioxidant efficiency of extractives. In Norway spruce, piceatannol-O-hexoside and coumaric acid derivatives were found to be the most powerful antioxidants, while in eastern hemlock, kaempferol glycosides were the most powerful. The antibacterial test did not show any promising antimicrobial activity against E. coli, although a visible inhibitory effect on S. aureus strain was observed.

Comparison between In Vitro Chemical and Ex Vivo Biological Assays to Evaluate Antioxidant Capacity of Botanical Extracts

The anti-oxidative activity of plant-derived extracts is well-known and confers health-promoting effects on functional foods and food supplements. Aim of this work is to evaluate the capability of two different assays to predict the real biological antioxidant efficiency. At this purpose, extracts from five different plant-derived matrices and commercial purified phytochemicals were analyzed for their anti-oxidative properties by using well-standardized in vitro chemical method (TEAC) and an ex vivo biological assay. The biological assay, a cellular membrane system obtained from erythrocytes of healthy volunteers, is based on the capability of phytochemicals treatment to prevent membrane lipid peroxidation under oxidative stress by UV-B radiation. Plant extracts naturally rich in phenols with different structure and purified phytochemicals showed different in vitro and ex vivo antioxidant capacities. A high correlation between phenolic contents of the plant-derived extracts and their ability to prevent oxidative injuries in a biological system was found, thus underlying the relevance of this class of metabolites in preventing oxidative stress. On the other hand, a low correlation between the antioxidant capacities was shown between in vitro and ex vivo antioxidant assay. Moreover, data presented in this work show how food complex matrices are more effective in preventing oxidative damages at biological level than pure phytochemicals, even if for these latter, the antioxidant activity was generally higher than that observed for food complex matrices.

Effects of the Reactive Moiety of Phenolipids on Their Antioxidant Efficiency in Model Emulsified Systems

Our previous research was focused on the effects of hydrophobicity on the antioxidant (AO) efficiency of series of homologous antioxidants with the same reactive moieties. In this work we evaluate the antioxidant efficiency of hydrophobic phenolipids in 4:6 olive oil-in-water emulsions, with different phenolic moieties (derived from caffeic, 4-hydroxycinnamic, dihydrocaffeic acids, tyrosol and hydroxytyrosol), with alkyl chains of 8 and 16 carbons, and compare the antioxidant efficiency with that of the parent compounds. All catecholic phenolipids, in particular the C8 derivatives, have proven to be better antioxidants for the oxidative protection of emulsions than their parental compounds with octyl dihydrocafffeate being the most efficient (16-fold increase in relation to the control). To understand the importance of some factors on the antioxidant efficiency of compounds in emulsions, Pearson’s correlation analysis was carried out between antioxidant activity and the first anodic potential (Epa), reducing capacity (FRAP value), DPPH radical scavenging activity (EC50) and the concentration of antioxidants in each region of the emulsified system. Results confirm the importance of the effective concentration of AOs in the interfacial region (AOI) (ρ = 0.820) and of the Epa (ρ = −0.677) in predicting their antioxidant efficiency in olive oil-in-water emulsions.