Saerheim Research Center

Klepp, Norway

Saerheim Research Center

Klepp, Norway
Time filter
Source Type

Braunlich M.,University of Oslo | Slimestad R.,Saerheim Research Center | Wangensteen H.,University of Oslo | Brede C.,University of Stavanger | And 2 more authors.
Nutrients | Year: 2013

Extracts, subfractions, isolated anthocyanins and isolated procyanidins B2, B5 and C1 from the berries and bark of Aronia melanocarpa were investigated for their antioxidant and enzyme inhibitory activities. Four different bioassays were used, namely scavenging of the diphenylpicrylhydrazyl (DPPH) radical, inhibition of 15-lipoxygenase (15-LO), inhibition of xanthine oxidase (XO) and inhibition of α-glucosidase. Among the anthocyanins, cyanidin 3-arabinoside possessed the strongest and cyanidin 3-xyloside the weakest radical scavenging and enzyme inhibitory activity. These effects seem to be influenced by the sugar units linked to the anthocyanidin. Subfractions enriched in procyanidins were found to be potent α-glucosidase inhibitors; they possessed high radical scavenging properties, strong inhibitory activity towards 15-LO and moderate inhibitory activity towards XO. Trimeric procyanidin C1 showed higher activity in the biological assays compared to the dimeric procyanidins B2 and B5. This study suggests that different polyphenolic compounds of A. melanocarpa can have beneficial effects in reducing blood glucose levels due to inhibition of α-glucosidase and may have a potential to alleviate oxidative stress. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Larbat R.,University of Lorraine | Olsen K.M.,University of Stavanger | Slimestad R.,Saerheim Research Center | Lovdal T.,University of Stavanger | And 6 more authors.
Phytochemistry | Year: 2012

High concentrations of phenolics have been shown to play a role in plant resistance to pathogens. One way to obtain increased phenolic concentrations in plant tissues is to limit mineral nitrogen (N) availability; however, over long periods, this treatment will have a negative effect on plant growth. The aim of our study was to determine the effect of repeated short-term N limitations on plant growth and phenolic metabolism in leaves. Tomato plants (Solanum lycopersicum, cv. Pixie) were subjected to two successive 10-day N-limitation periods (0.15 mM NO3 -, 0.01 mM NH4 +), followed by periods of full nutrient supply (15 mM NO 3 -, 1.2 mM NH4 +). Additionally, other plants were subjected to either of these two limitation periods, and a set of control plants was given a full nutrient supply during the entire period. The phenolic metabolism was monitored by measuring the leaf concentrations of chlorogenic acid, three flavonol glycosides (quercetin and kaempferol derivatives) and two major anthocyanins, together with the expression of eight structural genes and three transcription factors of the phenylpropanoid pathway. The relative growth rate of the plants decreased during the N-limitation periods but was restored as soon as N was resupplied. Each N-limitation period resulted in an up-regulation of the phenolic biosynthetic pathway, as demonstrated by an increase in the leaf phenolic concentration and an up-regulation of the related genes. The genes in the phenolic pathway were down-regulated immediately when N was resupplied; however, the leaf concentrations of several phenolics, particularly flavonol glycosides, were maintained at significantly higher levels than in the control plants for up to 17 days after the end of the first limitation. The amplitude of the increase in leaf phenolic concentration did not depend on the number of N-limitation periods to which the plant was subjected, which indicates that the plants did not acclimate to nitrogen limitation. Successive N-limitation periods resulted in additive increases in flavonol glycoside concentrations. © 2011 Elsevier Ltd. All rights reserved.

Braunlich M.,University of Oslo | Christensen H.,University of Oslo | Johannesen S.,University of Oslo | Slimestad R.,Saerheim Research Center | And 3 more authors.
Planta Medica | Year: 2013

Extracts, subfractions, isolated anthocyanins and procyanidins, and two phenolic acids from aronia [Aronia melanocarpa] were investigated for their CYP3A4 inhibitory effects, using midazolam as the probe substrate and recombinant insect cell microsomes expressing CYP3A4 as the enzyme source. Procyanidin B5 was a considerably stronger CYP3A4 inhibitor in vitro than the isomeric procyanidin B2 and comparable to bergamottin, a known CYP3A4 inhibitor from grapefruit juice. The inhibitory activity of proanthocyanidin-containing fractions was correlated to the degree of polymerization. Among the anthocyanins, cyanidin 3-arabinoside showed stronger CYP3A4 inhibition than cyanidin 3-galactoside and cyanidin 3-glucoside. Thus, the ability to inhibit CYP3A4 in vitro seems to be influenced by the sugar unit linked to the anthocyanidin. © Georg Thieme Verlag KG Stuttgart · New York.

Wangensteen H.,University of Oslo | Braunlich M.,University of Oslo | Nikolic V.,University of Oslo | Malterud K.E.,University of Oslo | And 2 more authors.
Journal of Functional Foods | Year: 2014

Aronia berries are known for their high content of anthocyanin and proanthocyanidin. Four different cultivars of aronia berries, Aronia melanocarpa 'Moskva', 'Hugin', 'Nero' and Aronia prunifolia, were studied with respect to their phenolic composition, antioxidant and enzyme inhibitory activities. Quantification of anthocyanins was determined by HPLC and separation was accomplished in less than 4. min. Cyanidin 3-galactoside was the major anthocyanin in all cultivars, with the highest content in A. prunifolia (497. ±. 20. mg/100. g FW). A. prunifolia was also found to have the highest content of polyphenols (2996. ±. 172. mg gallic acid equivalents/100. g FW) and proanthocyanidins (4.79. g procyanidin B2 equivalents/100. g FW). As antioxidants and enzyme inhibitors, the differences between extracts from the tested berries were minor. Berries from A. prunifolia constitute the richest source of polyphenols and might be the species of choice in order to attain berries with a high content of anthocyanin and proanthocyanidin. © 2014 Elsevier Ltd.

Lovdal T.,University of Stavanger | Lovdal T.,Nofima Norconserv AS | Olsen K.M.,University of Stavanger | Slimestad R.,Saerheim Research Center | And 2 more authors.
Phytochemistry | Year: 2010

Tomato plants (Solanum lycopersicum, cv. Suzanne) were subjected to complete nutrient solution or a solution without nitrogen (N), and placed at different temperatures and light conditions to test the effects of environment on flavonoids and caffeoyl derivatives and related gene expression. N depletion during 4-8 days resulted in enhanced levels of flavonoids and caffeoyl derivatives. Anthocyanins showed pronounced increased levels when lowering the growth temperature from 24 °C to 18 °C or 12 °C. Flavonol levels increased when the light intensity was increased from 100 μmol m-2 s-1 PAR to 200 μmol m-2 s-1 PAR. Synergistic effects of the various environmental factors were observed. The increase in content of quercetin derivatives in response to low temperatures was only found under conditions of N depletion, and especially at the higher light intensity. Expression of structural genes in the phenylpropanoid and flavonoid pathways, PAL (phenylalanine ammonia lyase), CHS (chalcone synthase), F3H (flavanone 3-hydroxylase), and FLS (flavonol synthase) increased in response to N depletion, in agreement with a corresponding increase in flavonoid and caffeoyl content. Expression of these structural genes generally also increased in response to lower temperatures. As indicated through expression studies and correlation analysis, effects of N depletion were apparently mediated through the overall regulators of the pathway the MYB transcription factor ANT1 (ANTHOCYANIN 1) and SlJAF13 (a bHLH transcription factor orthologue of petunia JAF13 and maize RED genes). A PAL gene (PAL6) was identified, and correlation analysis was compatible with PAL6 being an actively expressed gene with function in flavonoid synthesis. © 2009 Elsevier Ltd. All rights reserved.

Olsen K.M.,University of Stavanger | Hehn A.,University of Lorraine | Jugde H.,University of Lorraine | Slimestad R.,Saerheim Research Center | And 3 more authors.
BMC Plant Biology | Year: 2010

Background. Understanding the regulation of the flavonoid pathway is important for maximising the nutritional value of crop plants and possibly enhancing their resistance towards pathogens. The flavonoid 3'5'-hydroxylase (F3'5'H) enzyme functions at an important branch point between flavonol and anthocyanin synthesis, as is evident from studies in petunia (Petunia hybrida), and potato (Solanum tuberosum). The present work involves the identification and characterisation of a F3'5'H gene from tomato (Solanum lycopersicum), and the examination of its putative role in flavonoid metabolism. Results. The cloned and sequenced tomato F3'5'H gene was named CYP75A31. The gene was inserted into the pYeDP60 expression vector and the corresponding protein produced in yeast for functional characterisation. Several putative substrates for F3'5'H were tested in vitro using enzyme assays on microsome preparations. The results showed that two hydroxylation steps occurred. Expression of the CYP75A31 gene was also tested in vivo, in various parts of the vegetative tomato plant, along with other key genes of the flavonoid pathway using real-time PCR. A clear response to nitrogen depletion was shown for CYP75A31 and all other genes tested. The content of rutin and kaempferol-3-rutinoside was found to increase as a response to nitrogen depletion in most parts of the plant, however the growth conditions used in this study did not lead to accumulation of anthocyanins. Conclusions. CYP75A31 (NCBI accession number GQ904194), encodes a flavonoid 3'5'-hydroxylase, which accepts flavones, flavanones, dihydroflavonols and flavonols as substrates. The expression of the CYP75A31 gene was found to increase in response to nitrogen deprivation, in accordance with other genes in the phenylpropanoid pathway, as expected for a gene involved in flavonoid metabolism. © 2010 Olsen et al; licensee BioMed Central Ltd.

Fossdal C.G.,Norwegian Forest And Landscape Institute | Nagy N.E.,Norwegian Forest And Landscape Institute | Hietala A.M.,Norwegian Forest And Landscape Institute | Kvaalen H.,Norwegian Forest And Landscape Institute | And 3 more authors.
Tree Physiology | Year: 2012

Two mature clones of Norway spruce (Picea abies (L.) Karst.) that have previously been shown to have differential degrees of resistance towards the necrotrophic pathogen Heterobasidion parviporum (Niemelä & Korhonen) were compared with respect to the primed defense expression of transcripts related to biosynthesis of lignin, stilbenes and other phenolic compounds from one year to the next. The host's response to physical wounding and pathogen inoculation was examined in the initial year, whereas indications of heightened basal defense level or primed response, and responses to re-wounding, were examined the following year. The responses of the two clones to wounding and pathogen inoculation, examined in the initial year, differed; the increases in lignin and phenolics were more distinct in response to the pathogen than to wounding alone. The more resistant clone 589 had higher initial lignin concentrations in the cell walls when compared with clone 409, and these remained higher in clone 589 over both years and increased after the treatments. Both clones responded at the transcriptional and chemical levels to wounding; changes were evident both in the initial wounds and when re-wounded the following year. There were distinct differences in the basal transcript levels of the lignin pathway-related genes, phenolics and total lignin levels in healthy tissue from the initial year to the following year indicative of a primed host response or at least altered constitutive level of defense expression. © 2012 The Author.

Slimestad R.,Saerheim Research Center | Verheul M.,Norwegian Institute for Agricultural And Environmental Research Bioforsk
Journal of Agricultural and Food Chemistry | Year: 2011

Fresh cherry tomatoes cv. 'Susanne' contain more of the two flavonoids chalconaringenin (CN) and rutin than lycopene. Therefore some properties including antioxidant behavior of the flavonoids were studied. The two flavonoids were extracted from peel and isolated by use of different chromatographic methods. Molecular absorbtivities were found to be 26907 for CN and 20328 abs M-1 cm-1 for rutin. Both compounds exhibited properties as antioxidants through several assays, and rutin was found to be the strongest antioxidant except in one assay. None of the assays revealed pro-oxidative effects. As naringenin rather than CN is frequently reported as a tomato constituent, the stability of CN was investigated in order to detect potential ways of isomerization during sample preparation. CN isomerized slowly both under UVB radiation and in alkaline solutions. Thus, such factors do not explain the occurrence of naringenin in tomato samples. The deficiency in reports on CN may be explained by the similarity in chromatographic behaviors of CN and naringenin, and due to the fact that they have same molecular weights. © 2011 American Chemical Society.

Slimestad R.,Saerheim Research Center | Seljaasen R.,Norwegian Institute for Agricultural And Environmental Research Bioforsk | Meijer K.,Saerheim Research Center | Skar S.L.,Norwegian Institute for Agricultural And Environmental Research Bioforsk
Journal of the Science of Food and Agriculture | Year: 2010

Background: Two field trials growing Jerusalem artichoke (Helianthus tuberosus L.) are discussed. Twenty genetic variants were compared in order to find genotypes suitable for Norwegian production. A second trial investigated the above-ground part of early and late variants. Results: The highest yield (28.7 t ha-1) and highest amount of tubers per plant was obtained in early variants, e.g. the white Tysnes gave 1.72 kg tubers plant-1. Early variants had a markedly lower portion of smooth tubers. Late variants gave the most preferable tuber shape, but low yield. Only a weak correlation was found between dry matter content and total content of fructo-oligosaccharides (FOS) (r = 0.255) in the tubers. The mean content of FOS including sucrose through all variants was found to be 116 g kg-1 fresh weight (FW) or 550 g kg-1 dry weight (DW). The average chain length of FOS in the tubers was found to be DP3.9. There was no difference in tuber FOS content between early and late variants. The highest above-ground amount biomass was found for the late variants when harvested in September. The content of soluble carbohydrates was found to be highest in stalks in August (sucrose and FOS major compounds). Conclusion: Early variants give the highest tuber yield under Norwegian growing conditions. Late variants give highest above-ground biomass. © 2010 Society of Chemical Industry.

Vagen I.M.,Norwegian Institute for Agricultural And Environmental Research Bioforsk | Slimestad R.,Saerheim Research Center
Acta Horticulturae | Year: 2014

In Norway, onion (Allium cepa) production takes place at latitudes ranging from 58 to 64°N. Cultivars adapted to very long day conditions are necessary in order to succeed. Mild/sweet onions are most commonly grown at latitudes classified as short or intermediate day zones, and most available cultivars are developed for such areas. However, due to their popularity, mild onions would be interesting for production also in zones with very long days, provided that suitable cultivars could be found. Lately, there is also an increasing recognition of the very strong health benefits associated with onion consumption. In line with the high interest in functional foods, there should be a market for onion productions with documented high contents of beneficial substances, e.g., flavonoids or fructooligosaccharides (FOS). Through several years, we have conducted trials with onion cultivars in search of mild or high-flavonoid cultivars that work well under a very long day regime. This is a presentation of the overall results, suggesting some promising highflavonoid cultivars and mild cultivars suitable for production under very long day conditions.

Loading Saerheim Research Center collaborators
Loading Saerheim Research Center collaborators