scholarly journals The Function of Flavonoids in the Diurnal Rhythm under Rapidly Changing UV Conditions—A Model Study on Okra

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2268
Author(s):  
Susanne Neugart ◽  
Mark A. Tobler ◽  
Paul W. Barnes
Keyword(s):  
Antioxidant Activity ◽  
Uv Radiation ◽  
Diurnal Rhythm ◽  
Uv Absorption ◽  
Flavonoid Glycosides ◽  
Plant Responses ◽  
Adaptation Period ◽  
Model Study ◽  
Associated Functions ◽  
Considerable Impact

Flavonoids are favored compounds in plant responses to UV exposure and act in UV absorption and antioxidant activity. Here, it was investigated, with okra as a model species, how fast plants can react to changing UV conditions and to what extent these reactions take place. Okra (Abelmoschus esculentus) plants were exposed to either full or nearly no UV radiation. The diurnal rhythm of the plants was driven by the UV radiation and showed up to a 50% increase of the flavonoid content (measured optically in the +UV plants). This was reflected only in the trends in UV-absorption and antioxidant activity of the extracts but not in the soluble flavonoid glycosides and hydroxycinnamic acid derivatives. In a second experiment, a transfer from a −UV to a +UV condition at 9:00 CDT showed the immediate start of the diurnal rhythm, while this did not occur if the transfer occurred later in the day; these plants only started a diurnal rhythm the following day. After an adaptation period of seven days, clear differences between the +UV and -UV plants could be found in all parameters, whereas plants transferred to the opposite UV condition settle between the +UV and -UV plants in all parameters. Broadly, it can be seen that the flavonoid contents and associated functions in the plant are subject to considerable changes within one day and within several days due to the UV conditions and that this can have a considerable impact on the quality of plant foods.

In Situ and Ex Situ Ellipsometric Characterization of Oxygen Plasma and UV Radiation Effects on Spacecraft Materials

1997 ◽  
Vol 502 ◽  
Author(s):  
C. L. Bungay ◽  
T. E. Tiwald ◽  
M. J. DeVries ◽  
B. J. Dworak ◽  
John A. Woollam
Keyword(s):  
Uv Radiation ◽  
Oxygen Plasma ◽  
Index Of Refraction ◽  
Uv Absorption ◽  
Ex Situ ◽  
Absorption Bands ◽  
Space Applications ◽  
Growth Trends ◽  
Ellipsometry Data

ABSTRACTAtomic Oxygen (AO) and ultraviolet (UV) radiation contribute (including synergistically) to degradation of spacecraft materials in Low Earth Orbit (LEO). NASA is, therefore, interested in determining what effects the harsh LEO environment has on materials exposed to it, as well as develop materials that are more AO and UV resistant. The present work involves the study of AO and UV effects on polyarylene ether benzimidazole (PAEBI) with in situ and ex situ spectroscopic ellipsometry. PAEBI is a polymer proposed for space applications due to its reported ability to form a protective phosphorous oxide on the surface when exposed to AO. In our experiments PAEBI was exposed to UV radiation from a xenon lamp while in situ ellipsometry data were acquired. The effects of UV radiation were modeled as an exponentially graded layer on the surface of bulk PAEBI. The change in UV absorption spectra, depth profile of the index of refraction, and growth trends of the UV irradiated PAEBI were all studied in these experiments. In addition, PAEBI was exposed to an oxygen plasma to simulate the synergistic effects of AO and UV. Ellipsometry data were acquired in-line with both a UV-Visible ellipsometer and an infrared ellipsometer. The change in UV absorption bands and index of refraction due to synergistic AO/UV, as well as the growth trends of the oxide layer were studied.

scholarly journals Seychelles Lagoon Provides Corals with a Refuge from Bleaching

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
David Iluz ◽  
Razi Vago ◽  
Nanette E. Chadwick ◽  
Razi Hoffman ◽  
Zvy Dubinsky
Keyword(s):  
Ultraviolet Radiation ◽  
Uv Radiation ◽  
Seawater Temperature ◽  
Uv Absorption ◽  
Bleaching Event ◽  
Laboratory Examination ◽  
Shallow Lagoon

An extensive bleaching event in the summer of the year 1997-1998 affected most reefs along East Africa's shores. In the aftermath of that episode, the reefs of Île Alphonse in the Seychelles were examined and it was found that reefs along the seaward slopes of the island lost >95% of their branching coral colonies, with considerably higher survival of massive species. Île Alphonse features a nearly circular shallow lagoon, with steep seaward slopes. Contrary to our expectations, mortality in the warmer lagoon was far lower than of coral colonies on the surrounding slopes, bathed in deeper and cooler waters. We suggest that corals in the lagoon were protected from UV radiation by leachate stemming from seagrass leaves steeped in the lagoon. Our measurements in the lagoon showed a strong attenuation of ultraviolet radiation, not observed in the waters outside the lagoon, and laboratory examination confirmed that the strong UV absorption of substances leached into seawater from decomposing leaves of the seagrassThalassodendron (=Cymodocea) testudinaceum. Our findings demonstrate the synergism between elevated seawater temperature and UV radiation in triggering bleaching on shallow reefs.

Chemical characterization and in vivo antioxidant activity of parsley (Petroselinum crispum) aqueous extract

2020 ◽  
Vol 11 (6) ◽  
pp. 5346-5356
Author(s):  
Neide Mara de Menezes Epifanio ◽  
Lynn Rykiel Iglesias Cavalcanti ◽  
Karine Falcão dos Santos ◽  
Priscila Soares Coutinho Duarte ◽  
Piotr Kachlicki ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Aqueous Extract ◽  
Chemical Characterization ◽  
Flavonoid Glycosides ◽  
Petroselinum Crispum

Twenty-nine flavonoid glycosides were identified in the aqueous extract (PC) of Petroselinum crispum var. crispum leaves and apiin, the major compound, was isolated thereof.

scholarly journals Evaluation of Antioxidant Capacity ofSolanum sessiliflorum(Cubiu) Extract: AnIn VitroAssay

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Diego Rocha de Lucena Herrera Mascato ◽  
Janice B. Monteiro ◽  
Michele M. Passarinho ◽  
Denise Morais Lopes Galeno ◽  
Rubén J. Cruz ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Capacity ◽  
Antioxidant Activities ◽  
Flavonoid Glycosides ◽  
Specific Staining ◽  
Native Populations ◽  
Chemical Groups ◽  
Solanaceae Family ◽  
Hydroethanolic Extract

Cubiu is a vegetable of Solanaceae family, native to the Amazon, which is widely distributed through Brazil, Peru, and Colombia. It is used in food, medicine, and cosmetics by native populations. Research has shown that cubiu extracts have antioxidant activities with great biological relevance. We performed a phytochemical screening to identify the main chemical groups that could confer antioxidant activity to this extract. Several tests and qualitative precipitation specific staining for major classes of secondary metabolites were used. Antioxidant capacityin vitrotests (DPPH and ABTS) were also used to assess the extract’s ability to sequester free radicals of 70% hydroethanolic and aqueous extracts of cubiu flour. Alkaloids, organic acids, phenols, flavonoid glycosides, and coumarins were found in the hydroethanolic extract while the aqueous extract presented anthocyanins, gums, tannins and mucilage, amino groups, and volatile and fixed acids. Forin vitrotests, theIC50value obtained in the DPPH assay was 606.3 ± 3.5 μg/mL while that for the ABTS assay was 290.3 ± 10.7 µg/mL. Although cubiu extracts present chemical compounds directly related to antioxidant activity, our results show that it has a low antioxidant activity. Additional studies will be needed to isolate and characterize specific compounds to further assess antioxidant activity.

scholarly journals Identification of phenolic secondary metabolites from Schotia brachypetala Sond. (Fabaceae) and demonstration of their antioxidant activities in Caenorhabditis elegans

2016 ◽  
Author(s):  
Mansour Sobeh ◽  
Esraa A ElHawary ◽  
Herbenya Peixoto ◽  
Rola M Labib ◽  
Heba Handoussa ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Caenorhabditis Elegans ◽  
Nuclear Translocation ◽  
Antioxidant Activities ◽  
In Vitro Assays ◽  
Flavonoid Glycosides ◽  
Alcoholic Extract ◽  
C Elegans

Background: Schotia brachypetala Sond. (Fabaceae) is an endemic tree of Southern Africa whose phytochemistry and pharmacology were slightly studied.The present work aimed at profiling the major phenolics compounds present in the hydro-alcoholic extract from S. brachypetala leaves (SBE) using LC/HRESI/MS/MS and NMR and prove their antioxidant capabilities using novel methods. Methods: In vitro assays; DPPH, TEAC persulfate decolorizing kinetic and FRAP assays, and in vivo assays: Caenorhabditis elegans strains maintenance, Intracellular ROS in C. elegans, Survival assay, GFP expression and Subcellular DAF-16 localization were employed to evaluate the antioxidant activity. Results: More than forty polyphenols ,including flavonoid glycosides, galloylated flavonoid glycosides, isoflavones, dihydrochalcones, procyanidins, anthocyanins, hydroxybenzoic acid derivatives, hydrolysable tannins, and traces of methylated and acetylated flavonoid derivatives were identified. Three compounds were isolated and identified from the genus Schotia for the first time, namely gallic acid, myricetin-3-O-α-L-1C4-rhamnoside and quercetin-3-O-L-1C4-rhamnoside.The tested extract was able to protect the worms against juglone induced oxidative stress and attenuate the reactive oxygen species (ROS) accumulation. SBE was also able to attenuate the levels of heat shock protein (HSP) expression. Discussion: A pronounced antioxidant activity in vivo, which can be attributed to its ability to promote the nuclear translocation of DAF-16/FOXO, the main transcription factor regulating the expression of stress response genes. The remarkable antioxidant activity in vitro and in vivo correlates to SBE rich phenolic profile.

Effects of different UV radiation on photoprotective pigments and antioxidant activity of the hot‐spring cyanobacterium Leptolyngbya cf. fragilis

2019 ◽  
Vol 67 (3) ◽  
pp. 215-220 ◽  
Author(s):  
Maryam Kokabi ◽  
Morteza Yousefzadi ◽  
Maryam Soltani ◽  
Mitra Arman
Keyword(s):  
Antioxidant Activity ◽  
Uv Radiation ◽  
Hot Spring

scholarly journals Flavonoid Glycosides from Siparuna gigantotepala Leaves and Their Antioxidant Activity

2016 ◽  
Vol 64 (5) ◽  
pp. 502-506 ◽  
Author(s):  
Harlen Gerardo Torres Castañeda ◽  
Ana Julia Colmenares Dulcey ◽  
José Hipólito Isaza Martínez
Keyword(s):  
Antioxidant Activity ◽  
Flavonoid Glycosides

Plant Responses to UV Radiation and Links to Pathogen Resistance

2006 ◽  
pp. 1-40 ◽  
Author(s):  
Bernard A. Kunz ◽  
David M. Cahill ◽  
Peter G. Mohr ◽  
Megan J. Osmond ◽  
Edward J. Vonarx
Keyword(s):  
Uv Radiation ◽  
Pathogen Resistance ◽  
Plant Responses

UV Radiation Dependent Flavonoid Accumulation of Cistus laurifolius L

1991 ◽  
Vol 46 (1-2) ◽  
pp. 37-42 ◽  
Author(s):  
Thomas Vogt ◽  
Paul-Gerhard Gülz ◽  
Hans Reznik
Keyword(s):  
Uv Radiation ◽  
Flavonoid Glycoside ◽  
Flavonoid Glycosides ◽  
Field Exposure ◽  
Flavonoid Aglycones ◽  
Flavonoid Accumulation

Abstract Epicuticular and in tracellular flavonoids of Cistus laurifolius grown with and without UV radiation in a phytotron as well as under natural garden conditions in the field were studied. The amount of intracellular flavonoid glycosides of leaves receiving UV -A radiation was two fold higher than that measured in the absence of UV -A radiation , whether grown in the phyto­tron or in the field. Exposure of previously protected leaves to UV -A radiation increased the intracellular flavonoid glycoside content to that of unprotected leaves. The qualitative com­position of intracellular flavonoid glycosides showed a reduced amount of quercetin-3-galactoside to the myricetin monosides when the leaves were grown without UV-A radiation in the field and in the phytotron . Epicuticular flavonoid aglycones were not influenced by UV radiation significantly.

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