Ethylene Induction of Non-Enzymatic Metabolic Antioxidants in Matricaria chamomilla

Phytochemical investigations of Matricaria chamomilla L. (Asteraceae) stated the presence of several compounds with an established therapeutic and antioxidant potential. The chamomile non-enzymatic antioxidant system includes low molecular mass compounds, mainly polyphenols such as cinnamic, hydroxybenzoic and chlorogenic acids, flavonoids and coumarins. The objective of this work was to evaluate the role of the non-enzymatic antioxidant system after stimulation by ethylene in tetraploid chamomile plants. Seven days of ethylene treatment significantly increased the activity of phenylalanine ammonia-lyase, which influenced the biosynthesis of protective polyphenols in the first step of their biosynthetic pathway. Subsequently, considerable enhanced levels of phenolic metabolites with a substantial antioxidant effect (syringic, vanillic and caffeic acid, 1,5-dicaffeoylquinic acid, quercetin, luteolin, daphnin, and herniarin) were determined by HPLC-DAD-MS. The minimal information on the chlorogenic acids function in chamomile led to the isolation and identification of 5-O-feruloylquinic acid. It is accumulated during normal conditions, but after the excessive effect of abiotic stress, its level significantly decreases and levels of other caffeoylquinic acids enhance. Our results suggest that ethephon may act as a stimulant of the production of pharmaceutically important non-enzymatic antioxidants in chamomile leaves and thus, lead to an overall change in phytochemical content and therapeutic effects of chamomile plants, as well.     

Environmental UV‐A and UV‐B Threshold Doses for Apoptosis and Necrosis in Humans Fibroblasts¶

Apoptosis involves a highly organized and programmed series of events aimed at maintaining genomic stability by eliminating defective host cells. The purpose of this study was to determine the threshold doses and environmental UV‐A and UV‐B exposure times necessary to produce apoptosis and necrosis in the normal cells of a human fibroblast cell line. Enviromental UV‐A and UV‐B doses were measured over a 6 year period with a four‐channel UV radiometer. The fibroblasts were irradiated once using an Oriel UV Solar Simulator with six doses of environmentally‐based UV. Doses corresponded to 0,11,19,23 and 45 min of average environmental UV‐A and UV‐B radiation at solar noon in Puerto Rico. The Annexin‐V binding method was used to differentiate between normal fibroblasts and apoptotic or necrotic fibroblasts. The threshold dose from apoptosis to necrosis was found between 24–28 kJ/m², which corresponded to 19 and 23 min of environmental UV‐A and UV‐B exposure. This study provides the first data that specify the environmental threshold doses of UV‐A and UV‐B at which human fibroblasts undergo apoptosis and necrosis. These results may provide valuable dose‐response thresholds for apoptosis and necrosis for future mechanistic studies and baseline data for skin cancer prevention programs.     

Triplet–Triplet Energy Transfer from a UV‐A Absorber Butylmethoxydibenzoylmethane to UV‐B Absorbers

The phosphorescence decay of a UV‐A absorber, 4‐tert‐butyl‐4′‐methoxydibenzolymethane (BMDBM) has been observed following a 355 nm laser excitation in the absence and presence of UV‐B absorbers, 2‐ethylhexyl 4‐methoxycinnamate (octyl methoxycinnamate, OMC) and octocrylene (OCR) in ethanol at 77 K. The lifetime of the lowest excited triplet (T₁) state of BMDBM is significantly reduced in the presence of OMC and OCR. The observed quenching of BMDBM triplet by OMC and OCR suggests that the intermolecular triplet–triplet energy transfer occurs from BMDBM to OMC and OCR. The T₁ state of OCR is nonphosphorescent or very weakly phosphorescent. However, we have shown that the energy level of the T₁ state of OCR is lower than that of the enol form of BMDBM. Our methodology of energy‐donor phosphorescence decay measurements can be applied to the study of the triplet–triplet energy transfer between UV absorbers even if the energy acceptor is nonphosphorescent. In addition, the delayed fluorescence of BMDBM due to triplet–triplet annihilation was observed in the BMDBM–OMC and BMDBM–OCR mixtures in ethanol at 77 K. Delayed fluorescence is one of the deactivation processes of the excited states of BMDBM under our experimental conditions.     

The Reversibility of UV‐B Induced Alterations in Optical Properties of the Rabbit Cornea Depends on Dose of UV Irradiation

Solar UVB radiation evokes photokeratitis, accompanied by increased corneal hydration and changes in corneal transparency, resulting in increased light absorption. Corneal optical properties are disturbed and visual acuity decreased. The aim of this study was to investigate the reversibility of these UVB‐induced changes. Rabbit corneas were irradiated with UVB doses of 0.5 J cm^?2 or 1.01 J cm^?2 during 4 days. Some rabbits were sacrificed after the last irradiation and some 2 months later. Corneas were investigated spectrophotometrically for light absorption, and corneal hydration was evaluated by central corneal thickness with an ultrasonic pachymeter. Corneal impression cytologies were examined immunohistochemically for proinflammatory cytokines and malondialdehyde. The increased corneal light absorption, hydration and the staining of immunohistochemical markers found in corneas after irradiation returned to normal values during 2 months in corneas irradiated with the lower UVB dose. In contrast, in corneas irradiated with the higher UVB dose, a moderate but statistically significant increase in corneal light absorption, hydration and positive immunohistochemical stainings remained as residual changes. This was in contrast to normal corneas, where the staining of proinflammatory cytokines as well as malondialdehyde was negative. In conclusion, the reversibility of UVB‐induced disturbances was dependent on UVB dose.     

Effects of UV‐B Irradiation on a Marine Microecosystem¶

Purpose of this work was to study the effect of UV irradiation on a microecosystem consisting of several interacting species. The system chosen was of a hypersaline type, where all the species present live at high salt concentration; it comprises different bacteria; a producer, the photosynthetic green alga Dunaliella salina; and a consumer, the ciliated protozoan Fabrea salina, which form a complete food chain. We were able to establish the initial conditions that give rise to a selfsustaining microecosystem, stable for at least 3 weeks. We then determined the effect of UV irradiation on this microecosystem under laboratory‐controlled conditions, in particular by measuring the critical UV exposure for the two main components of the microecosystem (algae and protozoa) under UV‐B irradiances comparable to those of solar irradiation. In our experiments, we varied irradiance, total dose and spectral composition of the actinic light. The critical doses at irradiances of the order of 56 kJ/m² (typical average daily irradiance in a sunny summer day in Pisa), measured for each main component of the microecosystem (algae and ciliates), turned out to be around 70 kJ/m² for ciliates and 50 kJ/m² for D. salina. By exposing microecosystems to daily UV‐B irradiances of the order of 8 kJ/m² (typical average daily irradiance in a sunny winter day in Pisa), we found no effect at total doses of the order of the critical doses at high irradiances, showing that the reciprocity law does not hold. We have also measured a preliminary spectral‐sensitive curve of the UV effects, which shows an exponential decay with wavelength.     

Intra‐strain Variability in the Effects of Temperature on UV‐B Sensitivity of Cyanobacteria

Stratospheric ozone depletion is mostly marked over the Antarctic and to a lesser extent over the Arctic, though recent reports have revealed that this also occurs at lower latitudes. Continued depletion of ozone in the lower stratosphere allows more UVR to reach the Earth's surface. Furthermore, it is projected that surface water temperatures will increase by between 0.2 and 2.0°C by the year 2060 and this will directly or indirectly influence algal growth. The interactions between environmental factors are complicated by the existence of different strains (ecotypes) of the same species that may respond differently. To understand the interactive effects of temperature and UV‐B on two strains of Anabaena circinalis, we investigated the damaging effects of UV‐B on cell numbers and photosynthetic characteristics and also examined the effect of temperature on the capacity of cells to recover from such stress. Both strains of A. circinalis responded differently in terms of survival, photosynthetic characteristics and recovery with interactions between temperature and UV‐B. This could be due to the variations in strain‐specific photoreactive mechanisms. This needs to be explored further including more strains and species before definitive conclusions can be reached about effects of global change on cyanobacteria generally.     

Secondary Metabolites from the Leaves of Litsea lii var. nunkao‐tahangensis

Investigation of the leaves extract of Litsea lii var. nunkao‐tahangensis led to the isolation of five new butanolides, litsealiicolide A ( 1 ), isolitsealiicolide A ( 2 ), litsealiicolide B ( 3 ), isolitsealiicolide B ( 4 ), and isolitsealiicolide C ( 5 ), along with 17 known compounds. Their structures were determined through in‐depth spectroscopic and mass‐spectrometric analyses. Among the isolates, compounds 1 and 2 were cytotoxic against MCF‐7, NCI‐H460, and SF‐268 cell lines in vitro. Compound 5 and isolinderanolide B ( 6 ) showed marginal cytotoxic activity against these three cell lines in vitro.     

Cutaneous Photoprotective Activity of a Short‐term Ingestion of High‐Flavanol Cocoa: A Nutritional Intervention Study

In vivo and in vitro studies have shown that prolonged oral administration of flavanol‐rich cocoas extracts have photoprotective effects. The aim of the present study was to assess the photoprotective activity of short‐time administration of a new variety of naturally selected cocoa extract rich in bioactive compounds. We selected a cocoa powder particularly rich in polyphenols, flavanols, caffeine, theobromine and theophylline. We then investigated, in 10 healthy subjects, the photoprotective effects of one week of daily oral administration of two doses of such powder. Phototesting with solar simulated radiation was performed at baseline and after cocoa supplementation. Visual assessment of the minimal erythema dose and spectrophotometric measurement of the “a” parameter were done after 24 h from the irradiation. Oral daily supplementation of 1 g of high‐flavanol cocoa was not effective but a one‐week administration of 4–6 g of cocoa induced a statistically significant increase in the visual erythema threshold and a significant reduction in the “a” parameter. We demonstrated that a new variety of naturally selected cocoa extract, even when administered for a short time, retains a dose‐dependent photoprotective effect. These results are also indicative of the fact that topical sunscreens could be supplemented by a specific diet.     

Short‐term dynamics of isotopic composition of leaf‐respired CO2 upon darkening: measurements and implications

Recent advances in understanding the metabolic origin and the temporal dynamics in δ¹³C of dark‐respired CO₂ (δ¹³C_res) have led to an increasing awareness of the importance of plant isotopic fractionation in respiratory processes. Pronounced dynamics in δ¹³C_res have been observed in a number of species and three main hypotheses have been proposed: first, diurnal changes in δ¹³C of respiratory substrates; second, post‐photosynthetic discrimination in respiratory pathways; and third, dynamic decarboxylation of enriched carbon pools during the post‐illumination respiration period. Since different functional groups exhibit distinct diurnal patterns in δ¹³C_res (ranging from 0 to 10‰ diurnal increase), we explored these hypotheses for different ecotypes and environmental (i.e. growth light) conditions. Mass balance calculations revealed that the effect of respiratory substrates on diurnal changes in δ¹³C_res was negligible in all investigated species. Further, rapid post‐illumination changes in δ¹³C_res (30 min), which increased from 2.6‰ to 5‰ over the course of the day, were examined by positional ¹³C‐labelling to quantify changes in pyruvate dehydrogenase (PDH) and Krebs cycle (KC) activity. We investigated the origin of these dynamics with Rayleigh mass balance calculations based on theoretical assumptions on fractionation processes. Neither the estimated changes of PDH and KC, nor decarboxylation of a malate pool entirely explained the observed pattern in δ¹³C_res. However, a Rayleigh fractionation of ¹²C‐discriminating enzymes and/or a rapid decline in the decarboxylation rate of an enriched substrate pool may explain the post‐illumination peak in δ¹³C_res. These results are highly relevant since δ¹³C_res is used in large‐scale carbon cycle studies. Copyright © 2009 John Wiley & Sons, Ltd.     

Inactivation of Bacteriophage Infecting Bacteroides Strain GB124 Using UV‐B Radiation

Ultraviolet‐B radiation (280–320 nm) has long been associated with the inactivation of microorganisms in the natural environment. Determination of the environmental inactivation kinetics of specific indicator organisms [used as tools in the field of microbial source tracking (MST)] is fundamental to their successful deployment, particularly in geographic regions subject to high levels of solar radiation. Phage infecting Bacteroides fragilis host strain GB124 (B124 phage) have been demonstrated to be highly specific indicators of human fecal contamination, but to date, little is known about their susceptibility to UV‐B radiation. Therefore, B124 phage (n = 7) isolated from municipal wastewater effluent, were irradiated in a controlled laboratory environment using UV‐B collimated beam experiments. All B124 phage suspensions possessed highly similar first order log‐linear inactivation profiles and the mean fluence required to inactivate phage by 4 ? log¹⁰ was 320 mJ cm^?2. These findings suggest that phage infecting GB124 are likely to be inactivated when exposed to the levels of UV‐B solar radiation experienced in a variety of environmental settings. As such, this may limit the utility of such methods for determining more remote inputs of fecal contamination in areas subject to high levels of solar radiation.     

Enhanced UV‐B Radiation Increases Glyphosate Resistance in Velvetleaf (Abutilon theophrasti)

Depletion of the ozone layer leads to increasing UV‐B radiation on the earth's surface, which may affect weeds and their responses to herbicides. However, the effect of increased UV‐B radiation on weeds and the interaction of weeds and herbicides are still obscure. The objective of this study was to compare glyphosate efficacy on velvetleaf that was grown under with and without increased UV‐B radiation. Leaf area, dry weight and net photosynthesis of velvetleaf seedlings were adversely affected by increased UV‐B radiation. Leaf cuticle wax significantly increased by 28% under increased UV‐B radiation. Glyphosate efficacy on velvetleaf, evaluated by shoot dry weight, was significantly decreased by increased UV‐B radiation. Exposure to increased UV‐B radiation significantly decreased ¹⁴C‐glyphosate absorption from 49% to 43%, and also resulted in less ¹⁴C‐glyphosate translocation out of treated leaves and less glyphosate accumulation in newly expanded leaves. The decrease in glyphosate efficacy was due to changes in absorption and distribution, which were attributed to increased cuticle wax and decreased photosynthesis caused by increased UV‐B radiation. These results suggest that the responses of weeds to herbicides may be affected by increased UV‐B radiation, to the extent that higher rates may be required to achieve the desired effects.     

An experimental study of the effects of Matricaria chamomilla extract on cutaneous burn wound healing in albino rats

Previous studies conducted on the anti-inflammatory, antimicrobial and antioxidant effects of Matricaria chamomilla (chamomile) extract led us to study the effect of topical chamomile extract on burn wound healing in albino rats. Thirty male albino rats (250-300 g) were randomly divided into three groups, as control, vehicle, and treatment. Second-degree burning was induced in 20% of whole surface area of animal body by placing the back of animal into boiling water for 8s. Animals of control group received no treatment. Animals of vehicle and treatment groups were treated topically by olive oil and extract dissolved in olive oil twice a day respectively from the first day of burn induction to complete wound healing. The percentage of wound healing was calculated weekly. The results showed that there was significant difference (p < 0.05) between vehicle and treatment groups. So we concluded that the chamomile extract in the form of rubbing oil had a good potential for acceleration of burn wound healing in rats.     

Strong Short‐Range Cooperativity in Hydrogen‐Bond Chains

Chains of hydrogen bonds such as those found in water and proteins are often presumed to be more stable than the sum of the individual H bonds. However, the energetics of cooperativity are complicated by solvent effects and the dynamics of intermolecular interactions, meaning that information on cooperativity typically is derived from theory or indirect structural data. Herein, we present direct measurements of energetic cooperativity in an experimental system in which the geometry and the number of H bonds in a chain were systematically controlled. Strikingly, we found that adding a second H‐bond donor to form a chain can almost double the strength of the terminal H bond, while further extensions have little effect. The experimental observations add weight to computations which have suggested that strong, but short‐range cooperative effects may occur in H‐bond chains.     

Effects of Enhanced UV‐B Radiation on Biochemical Traits in Postharvest Flowers of Medicinal Chrysanthemum

This article reported UV‐B radiation effects on biochemical traits in postharvest flowers of chrysanthemum. The experiment included six levels of UV‐B radiation (UV0, 0 μW cm^?2; UV50, 50 μW cm^?2; UV200, 200 μW cm^?2; UV400, 400 μW cm^?2; UV600, 600 μW cm^?2 and UV800, 800 μW cm^?2). Enhanced UV‐B radiation significantly increased hydrogen peroxide content (except for UV50), but did not evidently affect malondialdehyde content in flowers. Chlorophyll b and total chlorophyll content were significantly increased by UV600 and UV800. UV400 and UV600 significantly increased anthocyanins, carotenoids and UV‐B absorbing compounds content, and the activities of phenylalanine ammonia lyase (PAL) and cinnamic acid‐4‐hydroxylase (C4H) over the control. 4‐coumarate CoA ligase (4CL) activity was significantly decreased by enhanced UV‐B radiation (except for UV50). The relationships between UV‐B radiation intensities and the activities of secondary metabolism enzymes were best described by a second‐order polynomial. The R² values for UV‐B radiation intensities and the activities of PAL, C4H and 4CL were 0.8361, 0.5437 and 0.8025, respectively. The results indicated that enhanced UV‐B radiation could promote secondary metabolism processes in postharvest flowers, which might be beneficial for the accumulation of medically active ingredients in medicinal plants. The optimal UV‐B radiation intensities in the study were between UV400‐UV600.     

Growth under Visible Light Increases Conidia and Mucilage Production and Tolerance to UV‐B Radiation in the Plant Pathogenic Fungus Colletotrichum acutatum

Light conditions can influence fungal development. Some spectral wavebands can induce conidial production, whereas others can kill the conidia, reducing the population size and limiting dispersal. The plant pathogenic fungus Colletotrichum acutatum causes anthracnose in several crops. During the asexual stage on the host plant, Colletototrichum produces acervuli with abundant mucilage‐embedded conidia. These conidia are responsible for fungal dispersal and host infection. This study examined the effect of visible light during C. acutatum growth on the production of conidia and mucilage and also on the UV tolerance of these conidia. Conidial tolerance to an environmentally realistic UV irradiance was determined both in conidia surrounded by mucilage on sporulating colonies and in conidial suspension. Exposures to visible light during fungal growth increased production of conidia and mucilage as well as conidial tolerance to UV. Colonies exposed to light produced 1.7 times more conidia than colonies grown in continuous darkness. The UV tolerances of conidia produced under light were at least two times higher than conidia produced in the dark. Conidia embedded in the mucilage on sporulating colonies were more tolerant of UV than conidia in suspension that were washed free of mucilage. Conidial tolerance to UV radiation varied among five selected isolates.     

Potential‐Controlled Chromatography of Short‐Chain Carboxylic Acids

A chromatographic column was constructed which could be operated with an electrically conductive stationary phase of graphite particles. This column allowed chromatographic experiments at variable electric potentials of the column material. The chromatographic behavior of selected carboxylic acids was significantly influenced at positive column potentials. An equimolar mixture of three different carboxylic acids were separated at a potential of +600 mV (versus. Ag/AgCl). Surprisingly, the stereoisomers maleic and fumaric acid, which are identical in molecular mass and charge, could also be separated. Further improvements to the chromatographic performance were achieved by applying potential drops and linear potential gradients.     

UV‐Light‐Induced Hydrogen Transfer in Guanosine–Guanosine Aggregates

Aggregates of a lipophilic guanine (G) derivative have been studied in n‐hexane by femtosecond‐to‐microsecond UV‐visible broadband transient absorption, stationary infrared and UV‐visible spectroscopy and by quantum chemical calculations. We report the first time‐resolved spectroscopic detection of hydrogen transfer in GG aggregates, which leads to (G?H) ^. radicals by means of G⁺G^? charge transfer followed by proton transfer. These radicals show a characteristic electronic spectrum in the range 300–550 nm. The calculated superimposed spectrum of the species that result from NH???N proton transfer agrees best with the experimental spectrum.     

Synthesis and characterization of UV‐curable ladder‐like polysilsesquioxane

Various ladder‐like structured poly(phenyl‐co‐methacryl silsesquioxane)s (LPMSQ)s with high molecular weight (M_w = 10,000 ～ 40,000) were synthesized by direct hydrolysis and polymerization in the presence of base catalyst at 25 °C. Synthesized LPMSQs mainly showed ladder‐like structure and photo‐cure reaction by 100 mW/cm² (360 nm) for 10 s without any photo‐cure initiators. Chemical composition and structural analysis of the obtained LPMSQs were characterized using ¹H NMR, ²⁹Si NMR, Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and X‐ray diffraction (XRD). Physical properties of LPMSQs before and after photcuring were analyzed by Nanoindentation. Surface modulus increased to 8GPa and hardness of thin films increased from 100 to 400 MPa. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011