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1.
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.  相似文献   

2.
Essential oils of the leaves and flowers of Anthemis cotula L. (family Asteraceae) grown in Jordan were extracted by hydro-distillation and then analyzed by GC–MS. Sesquiterpenes hydrocarbons (SH) were the dominant components in the oils extracted from leaves and flowers of A. cotula. γ-Muurolene and aromadendrene, were the major compounds that were obtained from the flowers oil, while γ-muurolene and trans-cadinene ether were detected as major ingredients in the leaves extract. LC-MS analysis was carried out to identify the significant compounds from each extract. Additionally, butanol (B), aqueous methanol (M) and water (W) extracts prepared from the flowers and the leaves of A. cotula were analysed by LC-MS/MS. Apigenin and chlorogenic acid were the main constituents detected in the flowers’ alcoholic extracts and leaves’ aqueous extract. Moreover, the essential oils and all prepared extracts were assayed for their total antioxidant activity using the DPPH, ABTS, and ferrous ion chelating effect (FIC) assay methods. All investigated oils and extracts showed interesting activity as compared to the positive controls employed (α-tocopherol and ascorbic acid).  相似文献   

3.
Our previous studies of action spectra for UV‐B‐induced anthocyanin accumulation in cultured carrot cells indicated that a reduced form of pterin, possibly tetrahydrobiopterin, contributes to UV‐B photoreception. In this report, we provide additional evidence for the involvement of pterin in UV‐B light sensing. UV‐B‐induced phenylalanine ammonia‐lyase (PAL) activity was considerably suppressed by N‐acetylserotonin (an inhibitor of tetrahydrobiopterin biosynthesis), and this suppression was partially recovered by adding biopterin or tetrahydrobiobiopterin. In addition, protein(s) specifically bound to biopterin were detected by radiolabeling experiments in N‐acetylserotonin‐treated cells. Furthermore, diphenyleneiodonium, a potent inhibitor of electron transfer, completely suppressed UV‐B‐induced PAL activity. These results suggest the occurrence of an unidentified UV‐B photoreceptor (other than UVR8, the tryptophan‐based UV‐B sensor originally identified in Arabidopsis) with reduced pterin in carrot cells. After reexamining published action spectra, we suggest that anthocyanin synthesis is coordinately regulated by these two UV‐B sensors.  相似文献   

4.
We have examined the kinetics and mechanism of dediazoniation of o‐, m‐ and p‐methylbenzenediazonium (ArN) tetrafluoroborate in the presence of ascorbic acid (H2A) at different pHs by combining spectophotometric (VIS‐UV), high performance liquid chromatography (HPLC), and polarographic measurements. Kinetic data show that, at low pH, observed rate constants increase linearly with increasing ascorbic acid concentration, but the saturation kinetics observed at higher pH suggest the formation of a transient diazo‐ether complex preceding the slow step of the reaction. Experimental evidence for the formation of such a complex was obtained from a competitive coupling reaction with the Na salt of `2‐naphthol‐6‐sulfonic acid' and by titration of ascorbic acid (H2A) with the arenediazonium ions (electrochemical measurements). HPLC Analysis of dediazoniation products indicates that, in the absence of H2A, only the heterolytic phenol derivative, ArOH, is formed quantitatively, in keeping with the predictions of the DN+AN mechanism. In the pH 2 – 4 range and in the presence of H2A, reduction products (ArH) are obtained in addition to heterolytic products (ArOH), corroborating that certain biological reducing agents like ascorbate (HA) are capable of inducing reductive fragmentation of ArN into aryl radicals. All evidence is consistent with two competitive reaction pathways, the thermal decomposition of ArN, and a rate‐limiting decomposition of the transient diazo ether `complex', formed during the reaction of ArN with HA in a rapid pre‐equilibrium step.  相似文献   

5.
Truxillines are alkaloids produced by Erythroxylum species and are thought to be derived from the UV‐driven dimerization of cinnamoylcocaines. This study was conducted to determine the effects of ambient UV radiation on the production of truxillines in Erythroxylum novogranatense var. novogranatense. Field plants were grown under shelters covered with plastic filters that were transparent to UV radiation, filtered UV‐B, or both filtered UV‐B and UV‐A radiation. The treatments had no significant effect on plant biomass or specific leaf weight. Absorption values in the UV‐C and UV‐A region of acidified‐methanol leaf extracts were higher for plants exposed to UV radiation compared to the no UV radiation treatment. There was a trend in decreasing levels of trans‐cinnamoylcocaine and a statistically significant decrease in levels of cis‐cinnamoylcocaine in the leaves of plants exposed to UV radiation compared to the no UV radiation treatment. Truxilline levels increased in leaves from plants exposed to UV radiation compared to the no UV radiation treatment. Most significantly, the ratio of truxillines to total cinnamoylcocaines in the leaves was affected by UV, increasing with increased UV exposure. The results support the hypothesis that UV radiation is involved in the formation of truxillines from cinnamoylcocaines.  相似文献   

6.
In this study, high‐performance liquid chromatography coupled with amaZon SL high‐performance ion trap mass spectrometry was used to analyze the target components in white chrysanthemum flowers of Hangzhou. Twenty‐one components were detected and identified in both white chrysanthemum flowers of Hangzhou samples by using target compound analysis. Furthermore, seven new compounds in white chrysanthemum flowers of Hangzhou were found and identified by analyzing the fragment ion behavior in the mass spectra. The established method can be expedient for the global quality investigation of complex components in herbal medicines and food.  相似文献   

7.
Chrysanthemum morifolium cv. Fubaiju is rich in phenolic compounds with various benefits such as anti-inflammatory, antioxidant, and cardiovascular protection. In this study, 12 phenolic compounds, including five flavonoid glycosides and seven quinic acid derivatives, were successfully separated from the flowers of Chrysanthemum morifolium cv. Fubaiju by high-speed counter-current chromatography and preparative high-performance liquid chromatography. Ethyl acetate-n-butanol–acetonitrile–water–acetic acid (5:0.5:2.5:5:0.25, v/v/v/v/v) was selected as solvent system to separate six fractions from the flowers of Chrysanthemum morifolium cv. Fubaiju, and 20% aqueous acetonitrile (containing 0.1% formic acid) was chosen to be the elution solvent in preparative high-performance liquid chromatography for purifying the fractions above. Luteolin-7-O-β-D-glucoside ( 1 ), luteolin-7-O-β-D-glucuronide ( 2 ), apigenin-7-O-β-D-glucoside ( 3 ), luteolin-7-O-β-D-rutinoside ( 4 ), diosmetin-7-O-β-D-glucoside ( 5 ), chlorogenic acid ( 6 ), 1,5-dicaffeoylquinic acid ( 7 ), 1,4-dicaffeoylquinic acid ( 8 ), 3,4-dicaffeoylquinic acid ( 9 ), 3,4-dicaffeoyl-epi-quinic acid ( 10 ), 3,5-dicaffeoylquinic acid ( 11 ), and 4,5-dicaffeoylquinic acid ( 12 ) were isolated with purities all above 95%, respectively. In addition, all isolates were evaluated for their protective effects on H2O2-induced oxidative damage in adult retinal pigment epithelial cells.  相似文献   

8.
Physiological response of two cultivars of Matricaria chamomilla plants on UV irradiation was studied. The impact of used short‐time UV dose was evaluated in three time points; 2, 24 and 48 h after irradiation. Used UV irradiation immediately resulted in changes in plant oxidative status monitored as increased concentration of H2O2. Decrease in chlorophyll a and b indicated the impact on photosynthetic apparatus. For phenolic secondary metabolites, an increase in total soluble phenols and AlCl3‐reactive flavonols was observed. The activity of main phenolic enzyme, phenylalanine ammonia‐lyase, increased with time after irradiation. Significant changes, mainly decreasing trends, in the content of free coumarins and their glycosidic precursors were observed. Enhanced accumulation in chlorogenic and 1,5‐dicaffeoylquinic acid and in (Z)‐isoform of dicycloethers was detected. From these results, the redirecting precursors of coumarin biosynthesis to biosynthesis of substances with higher antioxidative potential can be assumed. Different reactions in diploid and tetraploid plants were recorded, too.  相似文献   

9.
Methanol-soluble constituents from the flowers, non-flowering aerial parts and roots of Chrysanthemum pacificum Nakai were analysed via high resolution UPLC-PDA-qTOF-MS followed by chemometrics. Forty-seven chromatographic peaks belonging to various metabolite classes were detected. Most metabolite classes showed qualitative and quantitative differences across parts, with luteolin conjugates being mostly enriched in flowers whereas non-flowering aerial parts contained mostly quercetin and methoxylated flavone conjugates. Root sample ranked the lowest for all flavones and dicaffeoylquinic acids. In contrast, 1,5-di-caffeoylquinic acid levels were found at high levels in flowers and aerial parts reaching 3145 and 1390 μg/g, respectively, suggesting that C. pacificum could serve as a natural resource of this well-recognised anti-hepatotoxic phenolic. Principal component analysis was further used for organs classification in an untargeted manner. This study provides the first map of secondary metabolites distribution in C. pacificum Nakai organs.  相似文献   

10.
Stratospheric ozone depletion has caused an increase in the amount of ultraviolet‐B (UV‐B) radiation reaching the earth's surface. Numerous investigations have demonstrated that the effect of UV‐B enhancements on plants includes reduction in grain yield, alteration in species competition, susceptibility to disease and changes in plant structure and pigmentation. Many experiments examining UV‐B radiation effects on plants have been conducted in growth chambers or greenhouses. It has been questioned whether the effect of UV‐B radiation on plants can be extrapolated to field responses from indoor studies because of the unnaturally high ratios of UV‐B/ ultraviolet‐A radiation (320–400 nm) and UV‐B/photosynthetically active radiation (PAR) in many indoor studies. Field studies on UV‐B radiation effect on plants have been recommended to use the UV and PAR irradiance provided by natural light. This study reports the growth and yield responses of a maize crop exposed to enhanced UV‐B radiation and the UV‐B effects on aize seed qualities under field conditions. Enhanced UV‐B radiation caused a significant reduction in the dry matter accumulation and the maize yield in turn was affected. With increased UV‐B radiation the flavonoid accumulation in maize leaves increased and the contents of chlorophyll a, b and (a+b) of maize leaves were reduced. The levels of protein, sugar and starch of maize seed decreased with enhanced UV‐B radiation, whereas the level of lysine increased with enhanced UV‐B radiation.  相似文献   

11.
A chain based on the Keggin polyoxoanions, (H2bipy)2(Hbipy) [AsW11CoO39]·H2O (bipy = 4,4′-bipyridine) (1) has been hydrothermally synthesized and characterized by elemental analysis, IR, UV, TG, and single-crystal X-ray diffraction. In 1, substituted cobalt atoms share half occupancy sites with two W atoms on two asymmetric positions of opposite W3O13 trimers forming mono-substituted Keggin arsenotungstate. The Keggin clusters of two different arrays are alternately connected to generate unique wave-like chains in –A–B–A–B– ways via Co–O–W bridge. Compound 1 exhibits bifunctional electrocatalytic behavior for oxidation of ascorbic acid (AA) and reduction of hydrogen peroxide (H2O2), and good degradation ability for three typical dyes under UV light.  相似文献   

12.
Both ocean acidification (OA) and solar ultraviolet (UV) radiation can bring about changes in macroalgal physiological performance. However, macroalgal responses to UV radiation when acclimatized to OA under different time scales are rare. Here, we investigate the response of Ulva linza, a green tide alga, to UV radiation in the form of photosynthetically active radiation (PAR) or PAB (PAR+UVA+UVB) radiation. Radiation exposures were assessed following long‐term (from spore to adult stage, 1 month) and short‐term (adult stage, 1 week) OA treatments. Results showed that increased CO2 decreased the damage rate (k) and repair rate (r) of thalli grown under short‐term OA conditions with PAB treatment, the ratio of r:k was not altered. Following long‐term OA conditions, r was not affected, although k was increased in thalli following PAB treatment, resulting in a reduced ratio of r:k. The relative level of UV inhibition increased and UV‐absorbing compounds decreased when algae were cultured under long‐term OA conditions. The recovery rate of thalli was enhanced when grown under long‐term OA after UV radiation treatment. These results show that blooming algae may be more sensitive to UV radiation in marine environments, but it can develop effective mechanisms to offset the negative effects, reflecting acclimation to long‐term OA conditions.  相似文献   

13.
The degradation of the pharmaceutical compound ibuprofen (IBP) in aqueous solution induced by direct photolysis (UV‐A and UV‐C radiation) and photocatalysis (TiO2/UV‐A and TiO2/UV‐C systems) was evaluated. Initially, we observed that whereas photocatalysis (both systems) and direct photolysis with UV‐C radiation were able to cause an almost complete removal of IBP, the mineralization rates achieved for all the photodegradation processes were much smaller (the highest value being obtained for the TiO2/UV‐C system: 37.7%), even after an exposure time as long as 120 min. Chemical structures for the by‐products formed under these oxidative conditions (11 of them were detected) were proposed based on the data from liquid chromatography coupled to high‐resolution mass spectrometry (LC‐HRMS) analyses. Taking into account these results, an unprecedented route for the photodegradation of IBP could thus be proposed. Moreover, a fortunate result was achieved herein: tests against Artemia salina showed that the degradation products had no higher ecotoxicities than IBP, which possibly indicates that the photocatalytic (TiO2/UV‐A and TiO2/UV‐C systems) and photolytic (UV‐C radiation) processes can be conveniently employed to deplete IBP in aqueous media. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

14.
A simple, rapid and sensitive column liquid chromatographic method was developed and validated to measure simultaneously the amount of ascorbic acid and phenolic acids at single wavelength (240 nm) in order to assess drug release profiles and drug-excipients compatibility studies for a new sustained release tablet formulation and its subsequent stability studies. A combined isocratic and linear gradient reversed-phase LC method was carried out at 240 nm. Quantification was achieved with reference to the external standards. The linearity for concentrations between 0.042 and 0.150 mg mL?1 for ascorbic acid, 0.084–0.250 mg mL?1 for chlorogenic acid, 0.053–0.360 mg mL?1 for caffeic acid, and 0.016–0.250 mg mL?1 for ferulic acid (r > 0.99 for all analytes) were established. The recovery of the active ingredients from the samples was at the range of 92.3–102.9%. Intra- and inter-day precisions were less than 2.5%. The limits of detection and quantification were 8 and 24 μg mL?1 for ascorbic acid, 18 and 54 μg mL?1 for chlorogenic acid, 37 and 112 μg mL?1 for caffeic acid, and 11 and 34 μg mL?1 for ferulic acid. The determination of the four active ingredients was not interfered by the excipients of the products. Samples were stable in the release mediums (37 °C) at least for 12 h.  相似文献   

15.
The endemic Antarctic brown macroalga Desmarestia anceps is strongly shade‐adapted, but shows also a high capacity to cope with different environmental stressors, e.g. UV radiation and temperature. Therefore, this species colonizes wide depth gradients, which are characterized by changing environmental conditions. In this study, we examine whether the different physiological abilities allowing D. anceps to grow across a wide depth range is determined by high levels of phlorotannins. Photosynthesis, measured by PAM‐fluorometry, the contents of soluble phlorotannins, antioxidant capacities of field grown were analyzed in response to different conditions of radiation (PAR and PAR + UV) and temperature (2, 7 and 12°C). The results show that maximal quantum of fluorescence (Fv/Fm) decreased with increasing doses of UV radiation, but remained unaffected by temperature. High levels of soluble phlorotannins were detected and confirmed by microscopic observation revealing the abundance of large physodes. Exposure to UV radiation and elevated temperature showed that phlorotannins were not inducible by UV but increased at 12°C. ROS scavenging capacity was positively correlated with the contents of phlorotannins. In general, highest contents of phlorotannins were correlated with the lowest inhibition of Fv/Fm in all experimental treatments, highlighting the UV‐protective role of these compounds in D. anceps.  相似文献   

16.
Current scenarios under global climate change envisage a considerable increase in ultraviolet B (UV‐B) radiation in near future which may affect the productivity and yield quality of major agricultural crops. Present investigation was conducted to examine various defense strategies adopted against elevated UV‐B (ambient + 7.2 kJ mˉ2 dayˉ1) and their impact on seed nutrients, content and quality of oil including fatty acid profile of two soybean cultivars (JS‐335 and PS‐1042). Elevated UV‐B (eUV‐B) exposure leads toward higher unsaturation of fatty acids and changes in other oil quality parameters (acid, iodine and saponification value) indicated that eUV‐B favored the synthesis of long‐chain fatty acids with fewer carboxylic acid groups, making the oil rancid, with undesirable flavor and low nutritional value. The effect was more severe in JS‐335 as compared to PS‐1042. Negative effects were also seen on nutrients of soybean seeds. Adverse effects resulted due to insufficient quenching of ROS (superoxide radical and hydrogen peroxide) by the defense system and thus unable to overcome the imposed oxidative stress. Credit of better performance by PS‐1042 against eUV‐B may be given to the adoption of efficient defense strategies like higher wax deposition, increase in lignin and flavonoids (quercetin and kaempferol) contents.  相似文献   

17.
The aim of this study was to analyze the photostability and phototoxicity mechanism of anthracene (ANT) in a human skin epidermal cell line (HaCaT) at ambient environmental intensities of sunlight/UV‐R (UV‐A and UV‐B). Photomodification of ANT under sunlight/UV‐R exposure produced two photoproducts, anthrone and 9,10 anthracenedione. Generation of 1O2, O2?? and ?OH was measured under UV‐R/sunlight exposure. Involvement of reactive oxygen species (ROS) was further substantiated by their quenching with free radical quenchers. Photodegradation of 2‐deoxyguanosine and linoleic acid peroxidation showed that ROS were mainly responsible for ANT phototoxicity. ANT generates significant amount of intracellular ROS in cell line. Maximum cell viability (85%) was reduced under sunlight exposure (30 min). Results of MTT assay accord NRU assay. ANT (0.01 μg mL?1) induced cell‐cycle arrest at G1 phase. RT‐PCR demonstrated constitutive inducible mRNA expression of CYP 1A1 and 1B1 genes. Photosensitive ANT upregulates CYP 1A1 (2.2‐folds) and 1B1 (4.1‐folds) genes. Thus, the study suggests that ROS and DNA damage were mainly responsible for ANT phototoxicity. ANT exposure may be deleterious to human health at ambient environmental intensities reaching the earth’s surface through sunlight.  相似文献   

18.
The mass spectrometric (MS) analysis of flavone di‐C‐glycosides has been a difficult task due to pure standards being unavailable commercially and to that the reported relative intensities of some diagnostic ions varied with MS instruments. In this study, five flavone di‐C‐glycoside standards from Viola yedoensis have been systematically studied by high performance liquid chromatography‐electrospray ionization‐tandem ion trap mass spectrometry (HPLC‐ESI‐IT‐MSn) in the negative ion mode to analyze their fragmentation patterns. A new MS2 and MS3 hierarchical fragmentation for the identification of the sugar nature (hexoses or pentoses) at C‐6 and C‐8 is presented based on previously established rules of fragmentation. Here, for the first time, we report that the MS2 and MS3 structure‐diagnostic fragments about the glycosylation types and positions are highly dependent on the configuration of the sugars at C‐6 and C‐8. The base peak (0,2X10,2X2? ion) in MS3 spectra of di‐C‐glycosides could be used as a diagnostic ion for flavone aglycones. These newly proposed fragmentation behaviors have been successfully applied to the characterization of flavone di‐C‐glycosides found in V. yedoensis. A total of 35 flavonoid glycosides, including 1 flavone mono‐C‐hexoside, 2 flavone 6,8‐di‐C‐hexosides, 11 flavone 6,8‐di‐C‐pentosides, 13 flavone 6,8‐C‐hexosyl‐C‐pentosides, 5 acetylated flavone C‐glycosides and 3 flavonol O‐glycosides, were identified or tentatively identified on the base of their UV profiles, MS and MSn (n = 5) data, or by comparing with reference substances. Among these, the acetylated flavone C‐glycosides were reported from V. yedoensis for the first time. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

19.
Coreopsis tinctoria, also called “snow chrysanthemum” in China, is a flower tea material that has been reported to possess excellent pharmacological properties such as antioxidant and antidiabetic activities. The chemical characteristics of different parts (flowers, buds, seeds, stems, and leaves) of C. tinctoria were investigated based on microwave‐assisted extraction and the simultaneous determination of 13 major active compounds by high‐performance liquid chromatography, including taxifolin‐7‐O‐glucoside, chlorogenic acid, (R/S)‐flavanomarein, isocoreopsin, quercetagetin‐7‐O‐glucoside, isookanin, 5,7,3′,5′‐tetrahydroxyflavanone‐7‐O‐glucoside, marein, 3,5‐dicaffeoylquinic acid, coreopsin, okanin, 5,7,3′,5′‐tetrahydroxyflavanone, and N1,N5,N10,N14‐tetra‐p‐coumaroylspermine. Chemometric analysis based on the contents of investigated compounds from 13 samples showed that C. tinctoria and the related flower tea materials, Chrysanthemum morifolium cv “Hangju” and “Gongju,” were in different clusters, and different parts (flowers, buds, seeds, stems, and leaves) of C. tinctoria were obviously different. This study is helpful for the quality control and pharmacological evaluation of different parts from C. tinctoria and its related products.  相似文献   

20.
Helicrysum melaleucum is a medicinal plant traditionally used in the islands of the Macaronesia region for the treatment of respiratory diseases. In this work, the phenolic compounds of Helicrysum melaleucum plants collected in different geographical locations of Madeira Island and their morphological parts (total aerial parts, leaves, flowers and stems) were extracted and analyzed separately by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC‐DAD/ESI‐MSn). A total of 68 compounds were characterized based mainly on their UV and mass spectra. These included derivatives of O‐glycosylated flavonoids (flavonol and flavones type), quinic acid, caffeic acid, lignans and polyphenols. The flowers were found to be the morphological part with higher variety of phenolic compounds. The large differences in the phenolic composition of plants collected from different geographical locations allowed the identification of a few components, such as pinoresinol and methoxylated flavone derivatives, likely to be useful as geographical markers. Also, these results promote further comparison of the bioactivities of the different samples analyzed. This paper marks the first report on the chemical analysis of Helichrysum melaleucum species. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

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