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See detailMonitoring of anatabine release by methyl jasmonate elicited BY-2 cells using surface-enhanced Raman scattering
De Bleye, Charlotte ULg; Dumont, Elodie ULg; Dispas, Amandine ULg et al

in Talanta (2016), 160

A new application of surface-enhanced Raman scattering (SERS) in the field of plant material analysis is proposed in this study. The aim was to monitor the release of anatabine by methyl jasmonate (MeJa ... [more ▼]

A new application of surface-enhanced Raman scattering (SERS) in the field of plant material analysis is proposed in this study. The aim was to monitor the release of anatabine by methyl jasmonate (MeJa) elicited Bright Yellow-2 (BY-2) cells. Gold nanoparticles (AuNps) were used as SERS substrate. The first step was to study the SERS activity of anatabine in a complex matrix comprising the culture medium and BY-2 cells. The second step was the calibration. This one was successfully performed directly in the culture medium in order to take into account the matrix effect, by spiking the medium with different concentrations of anatabine, leading to solutions ranging from 250 to 5000 µg L-1. A univariate analysis was performed, the intensity of a band situated at 1028 cm-1, related to anatabine, was plotted against the anatabine concentration. A linear relationship was observed with a R2 of 0.9951. During the monitoring study, after the MeJa elicitation, samples were collected from the culture medium containing BY-2 cells at 0, 24h, 48h, 72h and 96h and were analyzed using SERS. Finally, the amount of anatabine released in the culture medium was determined using the response function, reaching a plateau after 72h of 82 µg of anatabine released / g of fresh weight (FW) MeJa elicited BY-2 cells. [less ▲]

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See detailEffect of Ribes nigrum leaf extracts on endothelium-dependent vasorelaxation
Tabart, Jessica; Shini-Kerth, Valérie; PINCEMAIL, Joël ULg et al

Poster (2016, April 22)

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See detailHigh anthocyanins content of commercial blackcurrant juices induced endothelium-dependent relaxation in isolated porcine coronary arteries
Kevers, Claire ULg; Shini-Kerth, Valérie; Tabart, Jessica et al

Poster (2016, April 22)

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See detailThe leaf extract of Ribes nigrum L. is a potent stimulator of the endothelial formation of NO in cultured endothelial cells and porcine coronary artery rings
Tabart, Jessica; Schini-Kerth, Valérie; PINCEMAIL, Joël ULg et al

in Journal of Berry Research (2016), 6

BACKGROUND: Endothelial dysfunction is a major hallmark of most types of cardiovascular diseases. Numerous plant extracts have been shown to cause endothelium-dependent relaxations by increasing the ... [more ▼]

BACKGROUND: Endothelial dysfunction is a major hallmark of most types of cardiovascular diseases. Numerous plant extracts have been shown to cause endothelium-dependent relaxations by increasing the endothelial formation of the potent vasoprotective factor, nitric oxide (NO). OBJECTIVE: The ability of different Ribes nigrum L. extracts (Grossulariaceae) to induce endothelium-dependent relaxation by stimulating the endothelial formation of NO was assesssed. METHODS: Ribes nigrum extracts were prepared from buds, berries and leaves by extraction (Acetone:H2O:Acetic Acid; 70/28/2 (v/v/v)) and lyophilized after acetone evaporation. The ability of the extracts to stimulate the endothelial formation of NO was assessed using cultured endothelial cells and isolated porcine coronary artery rings. RESULTS: The Ribes nigrum leaf extract increased to a greater extent than the bud and the berry extracts the formation of NO, and up-regulated eNOS mRNA expression in cultured endothelial cells (the stimulatory effects amounted to 197 ± 9 %, 134 ± 6 % and 118 ± 5 %, respectively). The leaf extract induced greater relaxations of isolated coronary arteries with endothelium than the bud and the berry extracts whereas no such effects were observed in rings without endothelium. Relaxations to the leaf extract were minimally affected by indomethacin and by inhibitors of endothelium-dependent hyperpolarization response, and markedly reduced by NG-nitro-L-arginine. CONCLUSIONS: The present findings indicate that the Ribes nigrum leaf extract is a more potent inducer of the endothelial formation of NO than the bud and the berry extracts. [less ▲]

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See detailEffects of planting methods and tuber weights on growth and yield of yam cultivars (Dioscorea rotundata Poir.) in Gabon
ONDO OVONO, Paul; Kevers, Claire ULg; Dommes, Jacques ULg

in International Research Journal of Agricultural Science and soil Science (2016), 6

A study was conducted to investigate the influence of planting methods and tuber weight on growth and yield of local yam cultivars obtained by the minisett technique from white yam (D. rotundata) in Gabon ... [more ▼]

A study was conducted to investigate the influence of planting methods and tuber weight on growth and yield of local yam cultivars obtained by the minisett technique from white yam (D. rotundata) in Gabon. Trials were carried out in 2014 and 2015 at the experimental ground of the Higher National Institute of Agronomy and Biotechnology, under natural conditions of lightness, temperature and relative humidity. Twenty- four weeks old mini tubers obtained from local cultivar MVA of D. rotundata were harvested, weighed and categorized ( 40-80 g; 100-150 g; 200-300 g), and three planting methods (horizontal, oblique and vertical), arranged in ridges constituted the main factors. The experiment was laid out in Randomized Completely Block Design with eighteen treatments and two replications. Data pertaining to sprouting were recorded for 30, 60, 90 and 180 DAP, for tuber length (cm), tuber weight (Kg) and number of tubers per plant 270 DAP. Significant differences among tuber weight in all variables tested were observed. The larger tubers had better sprouting ability than the rest of the tuber weight. The methods of planting had no effects on yield and its components but they affect the depth and spread of tubers. Vertical planting produced deeper but more compactly arranged tubers while horizontal planting produced tubers which were shallower but more widespread. Slanting was intermediate for both depth and spread. The number and weight of tubers obtained from mini tubers planted out according to slanting method were significantly different (P< 0.05) from other planting methods. The production of seedlings from mini tuber is an improvement of traditional production of seed yam. Mini tubers must have at least 100-300 g and they should be planted slanting or vertically. [less ▲]

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See detailDetermination of total phenolic compounds content and antioxidant activity in cherry species and cultivars
Pissard, Audrey; Lateur, Marc; Baeten, V et al

in Journal of Berry Research (2016)

BACKGROUND: Several studies have shown that cherries, especially sour cultivars, contain substantial amounts of phenolic compounds. OBJECTIVE: This study aims to (i) analyze the total phenolic compound ... [more ▼]

BACKGROUND: Several studies have shown that cherries, especially sour cultivars, contain substantial amounts of phenolic compounds. OBJECTIVE: This study aims to (i) analyze the total phenolic compound (TPC) content and the antioxidant capacity (AC) of a large range of cultivars using the same methodology in one laboratory, and (ii) determine the possible relationship between agronomic characteristics and AC. METHODS: A total of 245 samples including sweet, sour and hybrid cultivars from our collections were harvested at their optimum maturity and characterized according to their TPC, DPPH and ORAC values. RESULTS: The TPC content and DPPH and ORAC values varied greatly among the cherries, with the sour cultivars presenting higher levels than the sweet ones. The PCA plot showed a slight grouping by species and confirmed the high TPC content level in sour cultivars. The bi-colored cultivars had lower TPC and antioxidant capacity (AC) values than dark-colored ones, indicating that coloration could give an indication of the AC of fruits. No significant relationship between the agronomic and chemical properties was highlighted. CONCLUSIONS: Cherry fruits, especially from sour cultivars, represent an important source of bioactive compounds and could attract new interest as a ‘functional food’. [less ▲]

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See detailAnthocyanin-rich blackcurrant juice induces a redox-sensitive caspase 3-related pro-apoptotic effect in leukemia Jurkat cells: role of delphinidin-3-O-glucoside and delphinidin-3-O-rutinoside
Leon-Gonzalez; Sharif, T; Kayali, A et al

in 7th International Conference on Polyphenols and Health (2015, October)

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See detailDelphinidin-3-O-glucoside and delphinidin-3-O-rutinoside mediate the redoxsensitive caspase 3-related pro-apoptotic effect of blackcurrant juice on leukaemia Jurkat cells
Leon-gonzalez, Antonio; Sharif, Tanveer; Kayali, Asaad et al

in Journal of Functional Foods (2015), 17

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See detailInduction of antioxidant capacity and hydroxymethylfurfural content variations by modifications of cooked fruit processing.
Kevers, Claire ULg; brack, François; PINCEMAIL, Joël ULg et al

in Journal of antioxidant activity (2015), 1(1), 42-54

Liège syrup is a Belgian traditional cooked fruit foodstuff, produced mainly from apples and pears. The process includes several hours of heating at high temperature during which complex chemical ... [more ▼]

Liège syrup is a Belgian traditional cooked fruit foodstuff, produced mainly from apples and pears. The process includes several hours of heating at high temperature during which complex chemical reactions occur, such as Maillard condensation between reducing sugars and amino acids. Aiming at understanding the modifications of the fruit juices during heating, different parameters were monitored throughout the process. It was shown that hydoxymethylfurfural was formed during the first step of concentration by heating. At the end of the process, hydroxymethylfurfural had totally disappeared and the deep brown color of the product suggested that this compound was transformed into melanoidins. A parallel increase in antioxidant capacity was also observed. To determine optimal conditions to reach high melanoidin content and high antioxidant capacity, different in vitro model systems were compared. It was shown that different combinations of an amino acid with glucose or fructose led to different levels of hydroxymethyfurfural, of melanoidins and antioxidant capacity. After heating of apple or pear puree, an increase of the antioxidant capacity and the hydroxymethylfurfural and melanoidin contents was observed when the heating time was doubled. An increase of the pH from 5 to 9 in apple marmalade’s also induced an increase in antioxidant capacity and in hydroxymethylfurfural and melanoidins. However it was not the case in pear marmalade where only the increase in antioxidant capacity was observed. These results suggest that some parameters of the processing could be modified to improve the health-promoting effect of this traditional food (antioxidant properties and composition in hydroxymethylfurfural and melanoidins). The main factors affecting the quality of the final product were the cooking times, the temperature, the pH, the addition of reducing sugars or amino acids. [less ▲]

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See detailThe Total Antioxidant Capacity of Foods: a reappraisal. Application to commercial orange juices
PINCEMAIL, Joël ULg; Tabart, Jessica; Defraigne, Jean-Olivier ULg et al

in journal of antioxidant activity (2015), 1

Since a few years, more and more attention has been specifically given to dietary antioxidants as agents promoting health and preventing the incidence of diseases. As part of these efforts, analytical ... [more ▼]

Since a few years, more and more attention has been specifically given to dietary antioxidants as agents promoting health and preventing the incidence of diseases. As part of these efforts, analytical methods and assays have been developed to measure the antioxidant content in food substances. In this paper, the antioxidant capacity of 17 orange juices is determined by various assays (DPPH, ORAC, heamolysis, xanthine/xanthine oxidase) as the content in ascorbic acid and total phenolics. The results evidence all the complexity to evaluate the in vitro antioxidant capacity of foods. In very general terms, in spite of the wide utilization in these tests (FRAP, TAC, ORAC TRAP and others), their significance remains obscure. The discrepancy of the results and the absence of good correlation between the assays clearly highlight all the importance of understanding the strengths and weakness of assays evaluating antioxidant potential of a food at the risk of giving erroneous information to the consumer. It is clear that the use of "total antioxidant capacity" assays for the in vitro assessment of antioxidant quality of food does not be employed by food industrials as a marketing argument or for the assessment of the "wholesomeness" of a food. [less ▲]

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See detailBilberry extract (Antho 50) selectively induces redox-sensitive caspase 3-related apoptosis in chronic lymphocytic leukemia cells by targeting the Bcl-2/Bad pathway
Alhosin, Mahmoud; León-González1, Antonio J.; Dandache et al

in Scientific Reports (2015), 5

Defect in apoptosis has been implicated as a major cause of resistance to chemotherapy observed in B cell chronic lymphocytic leukaemia (B CLL). This study evaluated the pro-apoptotic effect of an ... [more ▼]

Defect in apoptosis has been implicated as a major cause of resistance to chemotherapy observed in B cell chronic lymphocytic leukaemia (B CLL). This study evaluated the pro-apoptotic effect of an anthocyanin-rich dietary bilberry extract (Antho 50) on B CLL cells from 30 patients and on peripheral blood mononuclear cells (PBMCs) from healthy subjects, and determined the underlying mechanism. Antho 50 induced concentration- and time-dependent pro-apoptotic effects in B CLL cells isolated from patients but little or no effect in PBMCs. Among the main phenolic compounds present in this bilberry extract, delphinidin-3-O-glucoside and delphinidin-3-O-rutinoside showed the highest apoptotic effect on B CLL cells, suggesting that anthocyanins play a main role in the cytotoxic activity. Antho 50-induced apoptosis is associated with activation of caspase 3 and down-regulation of the anti-apoptotic protein UHRF1. Antho 50 induced also rapid dephosphorylation of Akt and Bad, and down-regulation of Bcl-2 resulting in reduced cell viability. Antho 50 significantly induced PEG-catalase-sensitive formation of reactive oxygen species in B CLL cells. PEG-catalase prevented the Antho 50-induced reduced cell viability, induction of apoptosis, up-regulation of caspase 3, down-regulation of UHRF1 and Bcl-2, and dephosphorylation of Bad. The present findings indicate that Antho 50 exhibits strong pro-apoptotic activity through redox-sensitive caspase 3 activation-related mechanism in B CLL cells involving dysregulation of Bad/Bcl-2 pathway. This activity is due, at least in part, to a composition rich on glucoside and rutinoside derivatives of delphinidin. They further suggest that Antho 50 has chemotherapeutic potential by targeting selectively B CLL cells. [less ▲]

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See detailBehavior of various types of seeds of two species of yams tuber (Dioscorea cayenensis Lam. and Dioscorea rotundata Poir.) in Gabon
Ondo Ovono, Paul; Kevers, Claire ULg; Dommes, Jacques ULg

in International Research Journal of Agricultural Science and Soil Science (2015), 5

Low multiplication ratio of yam and scarcity of planting materials are major constraints militating against sustainable yam production. In order to evaluate the behavior of the four various types of seeds ... [more ▼]

Low multiplication ratio of yam and scarcity of planting materials are major constraints militating against sustainable yam production. In order to evaluate the behavior of the four various types of seeds of two species of yams Dioscorea cayenensis and Dioscorea rotundata, cultivated on the experimental ground of the Higher National Institute of Agronomy and Biotechnology (INSAB), a test was realized in a randomized complete block design with six replications. The samples were cut and three levels of each tuber were used :proximal, medial and distal parts of the tuber. The fragments of tuber and the whole tuber represent the various types of seed used in this work. The results showed significant (P<0.05) differences in number of plants emerged and time of emergence in a mixture of 40% soil and 60% sand three months and half after planting. For all species, the proximal parts sprouted earlier than the medium parts and then the distal parts. The fragmentation of tubers in 3 parts can show the existence of a gradient alone the tuber in its potential for sprouting and growth. There was a highly significant (P<0.05) difference between yield performances after 9 months of culture. This technique improves the production of tubers in both species. [less ▲]

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See detailAdventitious organogenesis induced in sweet orange (Citrus sinensis L.) var. "half-blood" maltese: morphogenetic and histological study
Benmahmoud, Kaouther; Jedidi, Zmna; Najar, Asma et al

in International Journal of Agronomy and Agricultural Research (2015), 6(2), 1-7

Tunisian citrus crops are faced to several abiotic and biotic constraints among which virus and virus-like diseases are incurable. The production of virus-free plants systematically needs the use of in ... [more ▼]

Tunisian citrus crops are faced to several abiotic and biotic constraints among which virus and virus-like diseases are incurable. The production of virus-free plants systematically needs the use of in vitro techniques. In this context, somatic embryogenesis and further plantlet regeneration of the Tunisian “half-blood” Maltese orange were obtained using explants consisting in style/stigma collected from unopened flowers. Somatic embryos were induced on Murashige and Skoog medium containing 13.3 µM 6-benzylaminopurine and 500 mg.l-1 malt extract, but their germination was obtained on hormone free-medium. Somatic embryogenesis was induced indirectly from intermediate friable callus initiated at the basal part of the style. Somatic embryos exhibited central procambial cells and were surrounded by a protoderm isolating them from the callus. These embryos had bipolar structure confirmed by the presence of shoot and root apices at cotyledonary stage. The use of cotyledon excised from those embryos failed to regenerate somatic embryos, but gave rise to direct organogenesis in two forms, true buds and protuberances both evolved in shoots after transfer in hormone-free medium. According to histological observations, protuberances are induced from epidermal and subepidermal cells of the cotyledon explant and remain closely attached to their mother tissue even at the shoot stage. [less ▲]

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See detailEffects of 2,4-dichlorophenoxyacetic acid combined to 6-Benzylaminopurine on callus induction, total phenolic and ascorbic acid production, and antioxidant activities in leaf tissue cultures of Crataegus azarolus L. var. aronia
Chaabani, Ghaya; Tabart, Jessica; Kevers, Claire ULg et al

in Acta Physiologiae Plantarum (2015), 37

The present research work describes the effects of 2,4-dichlorophenoxyacetic acid (2,4-D)/6-Benzylamino-purine (BAP) ratio on callus induction, total phenols and ascorbic acid production and antioxidant ... [more ▼]

The present research work describes the effects of 2,4-dichlorophenoxyacetic acid (2,4-D)/6-Benzylamino-purine (BAP) ratio on callus induction, total phenols and ascorbic acid production and antioxidant activities in leaf-derived calli of Crataegus azarolus (hawthorn). The supplementation of 1.0 mg/L 2,4-D and 1.0 mg/L BAP to MS medium was found to be the most efficient for callus induction (as percentage and fresh weigh). The results of biochemical analysis showed that the highest total phenols contents were obtained in callus cultured on MS medium supplemented with 2.0 mg/L 2,4-D and 1.0 mg/L BAP (52 ± 0.56 mg GAE/g DM) and were significantly lower than those of intact leaves (76 ± 1.72 mg GAE/g DM). However, the highest ascorbic acid contents were found in callus cultured on MS supplemented with 1.0 mg/L 2,4-D and 0.5 mg/L BAP (0.96 ± 0.13 mg AAE/g DM) and these amounts were statistically similar to those found in leaves tissues (0.74 ± 0.07 mg AAE/g DM). Antioxidant activities of callus extracts were determined using two TEAC assays and results showed that extract of callus cultured on MS medium supplemented with 2.0 mg/L 2,4-D and 1.0 mg/L BAP have the greatest antiradical activities against DPPH (124 ± 2.92 mg TE/g DM) and ABTS (0.19 ± 0.02 mg TE/g DM) compared to the leaves of field-grown plant. Thus, the use of high level of 2,4-D over BAP can be suitable to enhance the quality more than the quantity of bioactive compounds in leaf callus culture of hawthorn. [less ▲]

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See detailAntioxidant capacity and phenolic composition of red wines from various grape varieties : specificity of pinot noir.
degives, Julien; Kevers, Claire ULg; DEFRAIGNE, Jean ULg et al

in Giuseppe Viali (Ed.) 3rd international conference on cellular environmental stressors in biology and medicine : focus on redox reactions (2014, June 25)

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See detailAntioxidant fractions and phenolic constituents from leaves of Pluchea carolinensis and Pluchea rosea
Perera Cordoba, Wilmer Hervet; Wauters, Jean-Noël ULg; Kevers, Claire ULg et al

in Free Radicals and Antioxidants (2014), 4(2), 1-7

Abstract: Objective: To evaluated the antioxidant potential of several polar fractions of P. carolinensis and P. rosea as well as pure chemicals, some of them quantified in both species by HPLC. Methods ... [more ▼]

Abstract: Objective: To evaluated the antioxidant potential of several polar fractions of P. carolinensis and P. rosea as well as pure chemicals, some of them quantified in both species by HPLC. Methods: The antioxidant potential of polar fractions and pure chemicals were assayed by 2,2-diphenyl-1-picrylhydrazyl and oxygen radical potential methods. The phenolic content was performed by using Folin–Ciocalteu’s reagent. Specific phenolic acids and flavonoids were quantified by DAD-RP-HPLC. Results: The highest DPPH antioxidant potential expressed in mg TE/gDE were frequently measured in fractions from n-butyl alcohol i.e 2 (192.1 ± 0.3); 6 (181.0 ± 0.1) of P. carolinensis and in fraction 7 (188.1 ± 5.5) of P. rosea while for ORAC (mg TE/gDE) assay fraction 2 (543.0 ± 64.6) and 4 (501.4 ± 49.7) of P. carolinensis and 3 (401.3 ± 16.1) and 6 (401.3 ± 16.1) of P. rosea showed the best results. Some flavonoids and phenolic acids were also assayed; all of them showed highest Oxygen radical absorbance capacity values. Conclusion: We report the antioxidant potential of polar fractions, as well as of some pure phenolics responsible of the antioxidant potential. Some phenolics were identified and quantified for the first time in both species. Apparently, caffeoylquinic acid derivatives contribute more significant to the total antioxidant potential of the extracts. [less ▲]

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