Physicochemical and Biochemical Characterization, Total Phenolic and Energy Value from Bulbs of Different Onion (Allium cepa L.) Varieties in Senegal

The purpose of this study is to investigate the physicochemical properties of some local varieties of onion (Allium cepa L.) and compare them with an imported variety, all collected in May 2021. Proteins, reducing sugars, lipids, and polyphenol content were estimated according to the AFNOR standardized methods. The determination of calcium, magnesium, iron, sodium, potassium and phosphorus was performed by atomic absorption spectrophotometer coupled with a CCD detector. The results highlighted an average acidity of 0.377% ± 0.002% lower than the value of the imported variety which is 0.520% ± 0.001%. Local varieties have a pH ranging from 6.35 ± 0.003 to 6.42 ± 0.004, while the variety has a pH of 6.36 ± 0.003. The ash and dry matter contents vary respectively from 4.788% ± 0.004% to 8.253% ± 0.003% and 7.945% ± 0.021% to 11.945% ± 0.007% for the local varieties. Moreover, the imported one has ash and dry matter contents of 5.175% ± 0.007% and 10.035% ± 0.021% respectively. The results show that the protein, reducing sugar and lipid contents in the local onion varieties vary respectively from 2.815 ± 0.000 to 15.634 ± 0.001 g·100 g-1;4.691 ± 0.001 to 12.596 ± 0.002 g·100 g-1 and 0.006 ± 0.001 to 0.050 ± 0.057 g·100 g-1. Furthermore, the imported variety has a protein, reducing sugar and lipid content of 5.649 ± 0.002;8.565 ± 0.002 g·100 g-1 and 0.011 ± 0.010 g·100 g-1 respectively. The maximum levels of total polyphenols are obtained in the imported variety, Bellani and Gandiol, respectively 9.973 ± 0.001, 4.535 ± 0.002, and 3.425 ± 0.006 mg EAG/g of dry matter. The local varieties have a significant calorific intake of between 35.451 ± 0.001 and 112.980 ± 0.003 kcal·100 g-1 compared to the imported one with an energy value of 56.953 ± 0.001 kcal·100 g-1 of dry matter. The bulbs of different onion varieties studied have a fairly high content of mineral elements. The potassium content of local varieties is between 502.16 ± 0.06 mg·100 g-1 and 582.77 ± 0.04 mg·100 g-1 while the imported variety has a content of 536.62 ± 1.30 mg·100 g-1. They note that the local varieties have a better calcium content (249.75 ± 0.07 to 434.20 ± 0.57 mg·100 g-1) and magnesium (142.15 ± 0.07 to 162.60 ± 0.42 mg·100 g-1) than the imported variety (229.58 ± 0.04 mg·100 g-1) except for the varieties White Grano (228.29 ± 0.01 mg·100 g-1) and Rouge Amposta (117.00 ± 0.42 mg·100 g-1) respectively. These results reveal that Gandiol, Dayo and Orient F1 are nutritionally found better due to their higher antioxidant property, proteins, carbohydrates, and reducing sugar and should be included in diets to supplement our daily allowance needed by the body.

Impact of Continuous Cropping on Soil Phenolic Acid Substances and Research Progress on Continuous Cropping Obstacle Reduction Techniques

At present,long-term continuous cropping in agricultural production has formed a relatively common development trend.With the increase of continuous cropping years,soil phenolic acids are also affected to varying degrees.This paper summarized the effects of continuous cropping on soil phenolic acids and the research progress of continuous cropping obstacle reduction techniques,aiming at providing theoretical basis and technical support for the research of continuous cropping obstacle reduction techniques and promoting the healthy and sustainable development of modern agriculture.

Quantification of Total Phenols, Total Flavonoids, Total Anthocyanins and Evaluation of Antioxidant and Antiradical Activities of Detarium Senegalense Extracts from Chad

The aim of the present work is to assess the value of Detarium Senegalense by determining the content of total phenols, total flavonoids and total anthocyanins, and by evaluating the free radical scavenging activity of Detarium Senegalense extracts. For this purpose, sequential extraction using solvents of increasing polarity was essential. The various extracts obtained underwent phytochemical and biochemical analyses. Phytochemical screening revealed the presence of flavonoids, alkaloids, tannins, polyphenols, anthocyanins and steroids/terpenes. Quantitative analysis of total polyphenols, total flavonoids and total anthocyanins yielded the following results: total flavonoids (0.803 ± 0029 mg EQ/100g P for acetone extract of roots and 0.871 ± 0.401 mg EQ/100g P for methanol extract of leaves);total polyphenols (23.298 ± 12.68 mg EAG/100g P for acetone extract of roots and 24.69 ± 0.49 401 mg EAG/100g P for methanol extract of leaves);total monomeric anthocyanins (44.697 ± 0.939 mg EC3G/100g P and 16.699 ± 0.193 mg EC3G/100g P respectively for acetone and methanol extracts of stem bark). DPPH free radical scavenging activity was 1.674 ± 0.023 mg/mL for the acetone extract and 0.934 ± 0.24 mg/mL for the methanol extract of roots. .

Distribution of antioxidants and phenolic compounds in flour milling fractions from hard red winter wheat

Mature wheat kernels contain three main parts:endosperm,bran,and germ.Flour milling results in multiple streams that are chemically different;however,the distribution of antioxidants and phenolic compounds has not been well documented in terms of conventional milling by-product streams.In this study,multiple analytical methods were used to investigate antioxidant activity and phenolic compound compositions of hard red winter wheat(whole ground wheat),the parts of a wheat kernel(bran,flour,germ),and wheat by-product streams(mill feed,red dog,shorts)for the first time.For each mill stream,phenolic compounds(total,flavonoid,and anthocyanin contents)were determined and antioxidant activities were evaluated with 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical-scavenging activity,ferric reducing/antioxidant power(FRAP),and total antioxidant capacity assays.Significant differences(P<0.05)were observed in phenolic concentrations among fractions of bran,flour,and germ milled from the same kernels and noted that germ accounts for the majority of antioxidant properties,whereas bran contains a substantial portion of phenolic compounds and anthocyanins.Mill feed was high in phenolic content(5.29 mg FAE/g),total antioxidant capacity(866 mg/g),and antioxidant activity(up to 75% DPPH inhibition and 20.26μmol FeSO_(4)/g).The comprehensive information on distribution of antioxidants and phenolic compounds provides insights for future human consumption of commonly produced co-products from flour milling,and for selecting and using different milling fractions to make foods with improved nutritional properties.

Study on Optimization of Ethanol Reflux Extraction of Phenolic Acids from Salvia miltiorrhiza

The extraction technology of phenolic acid compounds from Salvia miltiorrhiza by ethanol reflux was studied. In this experiment, salvianolic acid B standard was used to make the standard curve. Single factor experiment and orthogonal experiment were used to study the extraction of different ethanol concentrations, reflux times and material-to-liquid ratios. The OD value of salvianolic acid compounds was measured with a spectrophotometer. The extraction rate of phenolic acid compounds under different extraction conditions was calculated through a regression equation, so as to obtain the optimal conditions for the ethanol reflux extraction process of Salvia miltiorrhiza. The experimental data can provide a reference for the ethanol reflux extraction process of salvianolic acids in the industry. According to the experiment, the extraction rate of phenolic acids in Salvia miltiorrhiza was the highest when the ethanol concentration was 60%, the reflux time was 1.5 hours, and the ratio of material-to-liquid was 1:10.

Establishment of an in vitro Tissue Culture and Rapid Propagation System using Lonicera hypoglauca and Content Assessment of Total Flavonoids and Chlorogenic Acid

Lonicera hypoglauca is a traditional Chinese medicinal plant.In this study,the tender young leaves of L.hypoglauca were used for the first time as the explants to establish a rapid in vitro propagation and regeneration system.The results revealed that the optimal time for disinfection of the explants was 8 min and the optimal medium for callus induction was MS+2,4-D 4.0 mg·L^(-1)+sucrose 30 g·L^(-1),with an average callus induction rate of 86.67%.The optimal medium to induce differentiation of callus to bud was MS+6-BA 1.0 mg·L^(-1)+NAA 0.10 mg·L^(-1)+sucrose 30 g·L^(-1),with an average germination rate of 83.33%.The optimal medium to induce multiplication was MS+6-BA 1.5 mg·L^(-1)+NAA 0.05 mg·L^(-1)+sucrose 30 g·L^(-1),with a multiplication coefficient of 5.42.The optimal medium for root induction was 1/2 MS+NAA 0.15 mg·L^(-1)+activated carbon 0.3 g·L^(-1)+sucrose 15 g·L^(-1),with an average rooting rate of 91.11%.The survival rate of tissue-cultured seedlings in nutrient soil cultivation medium was as high as 100%.The total flavonoid content and chlorogenic acid content in the explant,callus tissue and regenerated plant were 1.83%,2.27%,1.33%and 2.77%,1.83%,1.74%respectively.This study provides novel insights into the rapid propagation and mass production of L.hypoglauca seedlings at an industrial scale and that it exhibits important application value and future prospects.

Evaluation of Phytochemical Analysis and Total Phenol Content of Proso Millet and Barnyard Millet

Whole grains of proso and barnyard millets were sequentially extracted using different solvents(hexane,chloroform,ethyl acetate,and methanol).Phytochemical analysis was performed qualitatively,and the total phenolic content in the extracts of proso and barnyard millets was quantified.Alkaloids and cardiac glycosides were identified in all solvent extracts of both millets.Anthraquinone and glycosides yielded negative results in all solvent extracts of both millets.Among all the solvent extracts,methanol extracts of proso and barnyard millets showed the presence of major compounds such as flavonoids,terpenoids,amino acids,tannins,and phenolics compounds.The maximum amount of phenols was found in methanolic extracts of proso and barnyard millets(0.669±0.003 and 0.625±0.003),followed by the chloroform extract of proso and barnyard millets(0.284±0.002 and 0.257±0.003).The minimum amount of phenolics was found in the acetone extract of proso and barnyard millets.The methanol extract of both millets showed the presence of major compounds with high phenolic content.

Temperature and Acidified Solvent Effect on Total Anthocyanins and RP-HPLC Phenolic Acids Determination in Selected Spices

Total anthocyanins of spices (Syzygium aromaticum L., Coriadrum sativum L., Cuminum cyminum L., Zingiber officinale Rosc., Elettaria cardamomum, Curcuma longa, Rhus coriaria L., Cinnamomum zeylanicum Blume, Foeniculum vulgare Mill and Laurus nobilis L.) were determined using acidified (1% HCl) solvents (methanol, ethanol and acetone) at three temperatures (20℃, 40℃ and 60℃). Also phenolic acids were separated and identified by RP-HPLC. Results showed that sumac and cinnamon had the highest levels of anthocyanins, while for the acetone the cinnamon indicated the highest amount of anthocyanins when methanol and ethanol were used as extracting solvents at 20℃. At 40℃ using ethanol, sumac showed the highest level of anthocyanins whereas acetone solvent yielded the highest anthocyanin contents for cinnamon. At 60℃, cinnamon showed the highest level of anthocyanins when methanol and acetone were the solvents, while sumac had the highest anthocyanins level using ethanol as solvent. HPLC results showed ten phenolic acids found in those spices and varied in their concentrations. Gallic acid had the highest level (1642.3 mg/100g) (cloves). Gentisic acid had the lowest level (1.2 mg/100g) in ginger. Also sumac showed the highest level of chlorogenic acid (1528.7 mg/100g). Some acids were not found in some spices, for instance, benzoic acid was not found in coriander, cumin, ginger, green cardamom, cinnamon and sweet laurel.

Edible Ectomycorrhizal Mushrooms Russula spp. of Côte d’Ivoire: Total Phenolic Content, HPLC-Profiles of Phenolic Compounds and Organic Acids, Antioxidant Activities

The aim of this study was to investigate the phenolic compounds content, HPLC-profiles of phenolic compounds and organic acids, and also antioxidant activities via the ability to scavenge DPPH radical of three wild edible mushrooms belonging to Russula genus and being collected in center of Côte d’Ivoire. Total phenolic compounds, flavonoids and tannins contents of methanolic extracts were assessed by colorimetric assays. So, the obtained values of these chemical parameters ranged from 394.05 to 513.50 mg/100 g DW, 94.50 to 139.95 mg/100 g DW and from 124.20 to 165 ± 0.54 mg/100 g DW, respectively. Otherwise, HPLC-profiles of the methanolic extracts revealed that quercetin, salicylic acid and tannin ol were the main phenolic compounds in R. delica whereas R. lepida contained gallic acid, catechin and protocatechuic acid as main phenolic compounds. Besides, it showed that the phenolic compounds such as salicylic acid, tannin ol and catechin were observed in R. mustelina. As for HPLC-profiles of organic acid, the fumaric and malic acid were recorded as the main organic acids in the three species of wild edible mushrooms. However, citric acid content was found to be highest in R. lepida. The methanolic extracts of the three mushrooms exhibited high DPPH radical scavenging activities ranging from 74.92% to 58.92%. These wild edible mushrooms could be considered a potential supply source of adequate natural antioxidant for local population.

A change of phenolic acids content in poplar leaves induced by methyl sali-cylate and methyl jasmonate

The contents of seven different phenolic acids such as gallic acid, catechinic acid, pyrocatechol, caffeic acid, coumaric acid, ferulic acid and benzoic acid in the poplar leaves （Populus Simonii×Populus Pyramibalis c.v and Populus deltoids） suffocated by Methyl jasmonate （MeJA） and Methyl salicylate （MeSA） were monitored for analyzing their functions in interplant communications by using high-pressure liquid chromatography （HPLC）.The results showed that the contents of phenolic acids had obviously difference in leaves exposed to either MeSA or MeJA.When P.deltoides leaves exposed to MeJA or MeSA, the level of gallic acid, coumaric acid, caffeic acid, ferulic acid and benzoic acid was increased, gallic acid in leaves treated with MeJA comes to a peak at 24 h while to a peak at 12-d having leaves treated with MeSA.When P.Simonii ×P.Pyramibalis c.v leaves were exposed to MeJA or MeSA, the level of gallic acid, pyrocatechol and ferulic acid was increased; The catechinic acid and benzoic acid had a little drop; The caffeic acid and coumaric acid were undetected in both suffocated and control leaves.This changed pattern indicated that MeJA and MeSA can act as airborne signals to induce defense response of plants.

Two New Phenolic Carboxylic Acid Esters from Opuntia vulgaris

Two new phenolic carboxylic acid esters n-butyl eucomate(1) and methyl eucomate (2) and six known compounds eucomic acid(3), 3-β-acetyl-taraxerol (4), friedelin(5),lupenone(6),methyl linoleate(7) and methyl oleate(8) were isolated from the stems of Opuntia vulgaris Mill(Cactaceae). Their structures were determined on the basis of spectral methods. Compounds 3,4,6,7,8 were isolated for the first time from this plant.

Efficacy and safety of intravenous tranexamic acid in total shoulder arthroplasty:A meta-analysis

BACKGROUND Total shoulder arthroplasty(TSA)results in a large amount of perioperative blood loss due to severe trauma.AIM To investigate the safety and efficacy of intravenous tranexamic acid(TXA)in TSA.METHODS We searched the PubMed,Cochrane Library,Embase and Web of Science databases for randomized controlled trials(RCTs)on the use of TXA in TSA.And all the results were checked and assessed by Reference Citation Analysis(https://www.referencecitationanalysis.com/).A meta-analysis was performed with Review Manager 5.3 to calculate the odds ratio(OR)or weighted mean difference(WMD)of related outcome indicators.RESULTS A total of 5 RCTs with level 1 evidence were included.There were 369 cases,with 186 in the TXA group and 183 in the placebo group.The meta-analysis showed that TXA can significantly reduce total blood loss during the perioperative period[WMD=-249.56,95%confidence interval(CI):-347.6 to-151.52,P<0.0001],and the incidence of adverse reactions was low(OR=0.36,95%CI:0.16-0.83,P=0.02).Compared with the placebo group,the TXA group had significantly less total haemoglobin loss(WMD=-34.39,95%CI:-50.56 to-18.22),less haemoglobin fluctuation before and after the operation(WMD=-0.6,95%CI:-0.93 to-0.27)and less 24-h drain output(WMD=-136.87,95%CI:-165.87 to-106.49).There were no significant differences in the operation time(P=0.11)or hospital length of stay(P=0.30)between the two groups.CONCLUSION The application of intravenous TXA in the perioperative period of TSA can significantly reduce the total volume of perioperative blood loss and reduce the incidence of adverse reactions,so TXA is worthy of widespread clinical use.

In vitro total phenolics,flavonoids contents and antioxidant activity of essential oil,various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah

Objective:To detect the in vitro total phenolics,flavonoids contents and antioxidant activity of essential oil,various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah.Methods:The dry powder leaves of Tetrastigma were extracted with different organic solvent such as hexane.ethyl acetate,chloroform,butanol and aqueous methanol.The total phenolic and total flavonoids contents of the essential oil and various organic extracts such as hexane,ethyl acetate,chloroform,butanol and aqueous ethanol were determined by Folin-Ciocalteu method and the assayed antioxidant activity was determined in vitro models such as antioxidant capacity by radical scavenging activity usingα,α-diphenyl-β-picrylhydrazyl (DPPH) method.Results:The total phenolic contents of the essential oil and different extracts as gallic acid equivalents were found to be highest in methanol extract(386.22 mg/g) followed by ethyl acetate(190.89 mg/g).chloroform(175.89 mg/g).hexane(173.44 mg/g).and Imtanol extract (131.72 mg/g) and the phenolic contents not detected in essential oil.The antioxidant capacity of the essential oil and different extracts as ascorbic acid standard was in the order of methanol extract】ethyl acetate extract】chloroform】butanol】hexane extract also the antioxidant activity was not detected in essential oil.Conclusions:The findings show that the extent of antioxidant activity of the essential oil and all extracts are in accordance with the amount of phenolics present in that extract.Leaves of Tetrastigma being rich in phenolics may provide a good source of antioxidant.

Total phenolic, flavonoid content, and antioxidant activity of flour, noodles, and steamed bread made from different colored wheat grains by three milling methods

The objective of this study was to evaluate the effects of wheat variety, food processing, and milling method on antioxidant properties. Black wheat variety Heibaoshi 1 had the highest total phenolic content(659.8 μg gallic acid equivalents g-1), total flavonoid content(319.3 μg rutin equivalents g-1), and antioxidant activity, whereas light purple wheat variety Shandongzimai 1 had the lowest total flavonoid content(236.2 μg rutin equivalents g-1) and antioxidant activity. Whole wheat flour and partially debranned grain flour had significantly higher total phenolic contents, total flavonoid contents, and antioxidant activity than refined flour(P < 0.05). Compared with flour, total phenolic contents, total flavonoid contents and antioxidant activity decreased in noodles and steamed bread, whereas noodles had slightly higher total phenolic and flavonoid content than steamed bread. Antioxidant activities(by ferric reducing ability of plasma assay) of steamed bread made from whole wheat flour, partially debranned grain flour, and refined flour were 23.5%, 21.1%, and 31.6% lower, respectively, than the corresponding values of flour. These results suggested that black whole wheat flour and partially debranned grain flour are beneficial to human health.

Correlation Between Antioxidation and the Content of Total Phenolics and Anthocyanin in Black Soybean Accessions

The objective of this study was to investigate the correlations between antioxidations and the contents of the total phenolics and anthocyanin in 127 accessions of black soybean. A T-test, a fast clustering procedure, and a correlation coefficient analysis were used for experimentation. The variation ranges of the total antioxidant capacity （TAC）, the total phenolics, and anthocyanin contents in 127 black soybean accessions were 0.44-3.56, 7.05-74.82, and 0.22-1.87 mg g-l, respectively, displaying significant genotype differences. The major differences in TAC, the total phenolics, and the anthocyanin contents existed among various types of accessions from geographical regions. The differences between the accessions from black and yellow soybeans, spring and autumn, summer and autumn, Dongbeichun and Nanfangchun, Dongbeichun and Nanfangxia, Beifangchun and Nanfangchun, and Beifangchun and Nanfangxia were significant at 0.01 or 0.05 levels, respectively. The general tendency was that the TAC, the total phenolics, and the anthocyanin contents of Beifangchun accessions were higher than that of Dongbeichun ones, while that of Nanfangchun accessions were the worst. 127 black soybean accessions could be clustered into 6 clusters, which consisted of 3, 24, 20, 31, 37, and 12 accessions, respectively. The most significant （P 〈 0.01） correlations existed respectively between the TAC and the total showed that the total substances phenolics content, and the TAC and the anthocyanin content of black soybean. The results phenolics and anthocyanin in black soybean seed coat were the important antioxidation

Estimation of total phenolic content,in-vitro antioxidant and anti-inflammatory activity of flowers of Moringa oleifera

Objective:To evaluate and compare the antioxidant potential and anti-inflammatory activity of ethanolic extract of flowers of Moringa oleifera(M.oleifera)grown in Oman.Methods:Flowers of M.oleiferawere collected in the month of December 2012 and identified by a botanist.Alcoholic extract of the dry pulverized flowers ofM.oleiferawere obtained by cold maceration method.The ethanolic flower extract was subjected to preliminary phytochemical screening as the reported methods.Folin-Ciocalteu reagent was used to estimate total phenolic content.DPPH was used to determinein-vitroantioxidant activity and anti-inflammatory activity of flowers was investigated by protein denaturation method.Results:Phytochemical analysis of extract showed presence of major classes of phytochemicals such as tannins,alkaloids,flavonoids,cardiac glycosidesetc.M.oleiferaflowers were found to contain 19.31 mg/g of gallic acid equivalent of total phenolics in dry extract but exhibited moderate antioxidant activity.The anti-inflammatory activity of plant extract was significant and comparable with the standard drug diclofenac sodium.Conclusions:The results of our study suggest that flowers ofM.oleiferapossess potent anti-inflammatory activity and are also a good source of natural antioxidants.Further study is needed to identify the chemical compounds responsible for their anti-inflammatory activity.

Induced Effects of Exogenous Phenolic Acids on Allelopathy of a Wild Rice Accession(Oryza longistaminata,S37)

Four exogenous phenolic acids, including salicylic acid, fumalic acid, p-coumaric acid and p-hydroxybenzonic acid, were used to investigate the regulatory effects on allelopathy of a wild rice accession of S37 （Oryza Iongistaminata）, which is a known allelopathic rice. The four exogenous phenolic acids induced the enhancement of the allelopathic potential of wild rice S37 in target weeds though the weed-suppressive activities were low, and the inducible effects were dependent on the specific phenolic acid, concentration and treatment time. After foliar application of exogenous phenolic acids, the inhibition rates for plant height, root length and fresh weight of barnyard grass （Echinochioa crus-galli） were significantly higher than those of the control. Especially at the concentration of 100 mg/L, the inhibition rates for plant height and fresh weight of barnyard grass by fumalic acid were 38.12% and 26.31% higher than those of the control, showing that fumalic acid was more effective compared with other phenolic acids in inhibiting monocotyledon weed growth. Furthermore, the weedsuppressive activity of aqueous extract from the leaves of wild rice S37 treated with exogenous phenolic acids was increased, and it peaked at 48 h after the treatment with the aqueous extract, and then gradually declined.

Total Phenolic Content and Antioxidant Activity of Red and Yellow Quinoa (<i>Chenopodium quinoa</i>Willd.) Seeds as Affected by Baking and Cooking Conditions

Seeds with colored testa (seed coat) contain high concentrations of polyphenolic compounds that exhibit high levels of antioxidant activity. Common processing procedures, such as cooking and baking, decrease the levels of these bioactive compounds and consequently, overall antioxidant activity. Here, the effects of baking and cooking processes were examined on total phenolic content (TPC), total flavonoid content (TFC) and ferric-reducing ability of plasma antioxidant activity (FRAP AA) of red and yellow quinoa seeds. Our results indicate that red quinoa seed contains significantly higher levels of TPC, TFC and FRAP AA than yellow quinoa seeds. In addition, cooked and baked quinoa seeds retain most of their TPC, TFC and FRAP AA in the final product. Thus, red quinoa seeds processed by these two methods might be considered a functional food, in addition to its traditional role of providing dietary proteins. Due to their high antioxidant activity, red quinoa seeds might also contribute significantly to the management and/or prevention of degenerative diseases associated with free radical damage.

Measurement of total phenolic content and antioxidant activity of aerial parts of medicinal plant Coronopus didymus

Objective: To evaluate the total phenolic content and compare the antioxidant activity of various solvent extracts and fractions from the aerial parts of Coronopus didymus through various assays. Methods: Total phenolic content was determined using the Folin-Ciocalteu assay and the in vitro antioxidant activity of a number of different extracts was investigated in a dose-dependent manner with three different methods: the 2,2-diphenyl-1-picrylhydrazyl(DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt(ABTS) and ferric reducing antioxidant power(FRAP) assays. A flavone was isolated from the most active ethanolic extract with high antioxidant activity using size exclusion chromatography. IC_(50) values were calculated for the DPPH and ABTS methods. The FRAP activity was assessed in terms of μM Fe(II) equivalent. Results: The phenolic content was found to be highest in the ethanol extract(CDA Et; 47.8 mM GAE) and the lowest in the dichloromethane extract(CDA DCM; 3.13 mM GAE). The ethanol extract showed high radical scavenging activity towards DPPH and ABTS radicals with IC_(50) values of(7.80 × 10~2) and(4.32 × 10~2) μg/m L, respectively. The most active ethanol extract had a FRAP value of 1 921.7 μM Fe(Ⅱ) equivalent. The isolated flavone F10C(5,7,4'-trihydroxy-3'-methoxy flavone) was far more effective for scavenging free radicals in the DPPH and ABTS assays with IC_(50) of 43.8 and 0.08 μg/m L, than the standard trolox, with IC_(50) values of 97.5 and 21.1 μg/m L, respectively. In addition, the flavone F10C and the standard ascorbic acid had FRAP values of 1 621.7 and 16 038.0 μM Fe(Ⅱ) equivalents, respectively. Conclusions: The total phenolic content of extracts in decreasing order is ethanol extract(CDA Et)> acetone extract(CDA ACE)> phenolic extract(CDA MW)> n-hexane extract(CDA nHX)> chloroform extract(CDA CHL)> dichloromethane extract(CDA DCM). The ordering of extracts in terms of antioxidant activity from highest to lowest is CDA Et> CDA MW> CDA DCM> CDA CHL> CDA ACE> CDA nHX in DPPH, ABTS and FRAP assays. A significant relationship is found between antioxidant potential and total phenolic content, suggesting that phenolic compounds are the major contributors to the antioxidant activity of Coronopus didymus.

The effects of phenolic acid on nitrogen metabolism in Populus 3 euramericana ‘Neva’

The declines in soil fertility and productivity in continuously cropped poplar plantations axe related to phenolic acid accumulation in the soil. Nitrogen is a vital life element for poplar and whether the accumulation of phenolic acid could influence nitrogen metabolism in poplar and thereby hinder continuous cropping is not clear. In this study, poplar cuttings of Populus × euramericana ‘Neva＇ were potted in vermiculite, and phenolic acids at three concentrations （032, 0.5X and 1.0X） were added according to the actual content （1.0X） in the soil of a second-generation poplar plantation. Each treatment had eight replicates. We measured gas exchange parameters and the activities of key enzymes related to nitrogen metabolism in the leaves. Leaf photosynthetic parameters varied with the concentration of phenolic acids. The net photosynthetic rate （PN） significantly decreased with increasing phenolic acid concentration, and non-stomatal factors might have been the primary limitation for PN- The activities of nitrate reductase （NR）, glutamine synthetase （GS） and glutamate synthase （GOGAT）, as well as the contents of nitrate nitrogen, ammonium nitrogen, and total nitrogen in the leaves decreased with increasing phenolic acid concentration. This was significantly and positively related to PN （P 〈 0.05）. The low concentration of phe- nolic acids mainly affected the transformation process of NO3- to NO2-, while the high concentration of phenolic acids affected both processes, where NO3- was transferred to NO2- and NH4＋ was transferred to glutamine （Gln）. Overall, phenolic acid had significant inhibitory effects on the photosynthetic productivity of Populus x euramericana ＇Neva＇. This was probably due to its influence on the activities of nitrogen assimilation enzymes, which reduced the amount of amino acids that were translated into protein and enzymes. Improving the absorption and utilization of nitrogen by plants could help to overcome the problems caused by continuous cropping.