Skin protective and regenerative effects of RM191A, a novel superoxide dismutase mimetic.

Superoxide dismutase (SOD) is known to be protective against oxidative stress-mediated skin dysfunction. Here we explore the potential therapeutic activities of RM191A, a novel SOD mimetic, on skin. RM191A is a water-soluble dimeric copper (Cu2+-Cu3+)-centred polyglycine coordination complex. It displays 10-fold higher superoxide quenching activity compared to SOD as well as significant antioxidant, anti-inflammatory and immunomodulatory activities through beneficial modulation of several significant inflammatory cytokines in vitro and in vivo. We tested the therapeutic potential of RM191A in a topical gel using a human skin explant model and observed that it significantly inhibits UV-induced DNA damage in the epidermis and dermis, including cyclobutane pyrimidine dimers (CPD), 8-oxo-guanine (8-oxoG) and 8-nitroguanine (8NGO). RM191A topical gel is found to be non-toxic, non-teratogenic and readily distributed in the body of mice. Moreover, it significantly accelerates excisional wound healing, reduces 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation and attenuates age-associated oxidative stress in skin, demonstrating both skin regenerative and geroprotective properties of RM191A.

Vapor Pressures and Thermodynamic Properties of Phenylpropanoid and Phenylbutanoid Attractants of Male Bactrocera, Dacus, and Zeugodacus Fruit Flies at Ambient Temperatures.

We report on the vapor pressures at ambient temperatures of seven attractants of Bactrocera, Dacus, and Zeugodacus fruit flies-raspberry ketone, cuelure, raspberry ketone trifluoroacetate, methyl eugenol, methyl isoeugenol, dihydroeugenol, and zingerone-by a vapor saturation method. Dry nitrogen was passed over each compound at well-controlled temperatures. Entrained vapor from the compounds was trapped on Tenax GR tubes and analyzed by thermal desorption-gas chromatography-mass spectrometry. The measured attractant amounts on the traps were converted to vapor pressures. Data were subsequently fitted by the Antoine equation. From the Antoine equation parameters, thermodynamic properties for each compound were calculated at 298 K. The calculated vapor pressures were used to compare the volatility of the fruit fly attractants and to infer implications for field applications. Using ambient temperature readings yields far better estimates of vapor pressure values at temperatures relevant for insect control than do Antoine equation parameters derived from high-temperature readings.

Comparing the chemical composition of dietary fibres prepared from sugarcane, psyllium husk and wheat dextrin.

A dietary fibre prepared from sugarcane stalk was compared with psyllium husk and wheat dextrin. In contrast to the other dietary fibres, sugarcane fibre was found to contain significant amounts of insoluble dietary fibre (73-86%), lignin (18.66-20.23%), and rare minerals such as chromium (0.67-2.54 mg/100 g) and manganese (1.07-2.34 mg/100 g). Analysis of the ethanol extract also detected compounds with antioxidant activity. Characterisation of five sugarcane fibres prepared from selected strains, harvest periods (growth or storage phase), and processing conditions showed these factors influenced the final composition. Furthermore, using in vitro digestion, we found that potassium, magnesium, chromium, and zinc in were bioaccessible in sugarcane samples. Also, sodium was shown to bind to the sugarcane fibre potentially indicating bile salt binding activity. Results from this study support the use of sugarcane as a source of dietary fibre in functional foods.

Spin-State Patterning in an Iron(II) Tripodal Spin-Crossover Complex.

A mononuclear iron(II) complex that displays a gradual two-step spin-crossover (SCO) transition is reported. The intermediate plateau (IP) occurs between HS0.40LS0.60 and HS0.30LS0.70 (HS = high spin; LS = low spin) ratios over the region of ca. 190-170 K. A phase change occurs at the IP, breaking the symmetry, resulting in six independent SCO sites compared to one at the 100% HS and LS plateau regions, respectively. Variable-temperature X-ray photoelectron spectroscopy shows that the SCO behavior is completely reversible among the HS, IP, and LS regions. The results both confirm and extend the related results for the above system described by Halcrow et al. (Kulmaczewski R.; Cespedes O.; Halcrow M. A.Gradual Thermal Spin-Crossover Mediated By a Reentrant Z' = 1 → Z' = 6 → Z' = 1 Phase Transition, Inorg. Chem. 2017, 56, 3144-3148) in a recent report.

Upconversion luminescence with tunable lifetime in NaYF4:Yb,Er nanocrystals: role of nanocrystal size.

Despite recent achievements to reduce surface quenching in NaYF(4):Yb,Er nanocrystals, a complete understanding of how the nanocrystal size affects the brightness of upconversion luminescence is still incomplete. Here we investigated upconversion luminescence of Yb,Er-doped nanocrystals in a broad range of sizes from 6 nm to 45 nm (cubic or hexagonal phases), displaying an increasing red-to-green luminescence intensity ratio and reduced luminescence lifetimes with decreasing size. By analyzing the upconversion process with a set of rate equations, we found that their asymptotic analytic solutions explain lower decay rates of red compared to green upconversion luminescence. Furthermore, we quantified the effect of the surface on luminescence lifetime in a model where nanocrystal emitters are divided between the near-surface and inside regions of each nanocrystal. We clarify the influence of the four nonradiative recombination mechanisms (intrinsic phonon modes, vibration energy of surface ligands, solvent-mediated quenching, and surface defects) on the decay rates for different-size nanocrystals, and find that the defect density dominates decay rates for small (below 15 nm) nanocrystals. Our results indicate that a defect-reduction strategy is a key step in producing small upconversion nanocrystals with increased brightness for a variety of bioimaging and biosensing applications.

Identification of compound classes in soil and peat fulvic acids as observed by electrospray ionization tandem mass spectrometry.

Soil and peat fulvic acids obtained from the International Humic Substances Society were fractionated by their solubility in methanol and analyzed by electrospray ionization tandem mass spectrometry. Precursor and product ion experiments produced mass spectra that indicated the presence of benzene, phenol, dihydroxy benzene, furan and thiophene carboxylic acids. Standards were used to substantiate the fragmentation patterns observed in the product ion spectra of the fulvic acid samples. This study makes significant progress into the direct identification of individual compounds in humic substances using a non-degradation technique.

Self-esterification of fulvic acid model compounds in methanolic solvents as observed by electrospray ionization mass spectrometry.

The self-esterification of two fulvic acid model compounds in methanolic solvents was studied by electrospray ionization mass spectrometry (ESI-MS). The strongly acidic tetrahydrofurantetracarboxylic acid rapidly self-esterified to form mono- and dimethyl esters when stored in methanol, even at reduced temperatures. The weakly acidic analogue, cyclopentanetetracarboxylic acid, reacted minimally under the same conditions. The use of 50:50 methanol/water as a solvent reduced self-esterification of the strong acid. However, the presence of water promoted the formation of multiply charged ions in the ESI mass spectra. The use of water and 50:50 acetonitrile/water as solvents eliminated self-esterification but the mass spectra still contained multiply charged ions. This study implies that the use of methanolic solvents with humic substances may compromise analytical data through the formation of methyl esters.