Identification and quantification of a major anti-oxidant and anti-inflammatory phenolic compound found in basil, lemon thyme, mint, oregano, rosemary, sage, and thyme

Major phenolic compounds from basil, lemon thyme, mint, oregano, rosemary, sage, and thyme were investigated using a high-performance liquid chromatography (HPLC) profiling technique in combination with DPPH-radical scavenging, xanthine oxidase and cyclooxygenase assays. For the present study, 15 plant-derived phenolic compounds (gallic, protocatechuic, vanillic, syringic, chlorogenic, rosmarinic, caffeic, ferulic, and sinapic acids, protocatechualdehyde, vanillin, N-coumaroyltyramine, N-caffeoyltyramine, N-feruloyltyramine, and N-sinapoyltyramine) were selected and their DPPH-radical scavenging activities were first determined. Then, a standard HPLC profiling of these phenolics was constructed using an HPLC method to isolate anti-oxidant and anti-inflammatory phenolic compounds from MeOH extracts of the plants. Rosmarinic acid was identified as a major anti-oxidant compound (0.22-0.97%) in all seven herbs, confirmed by nuclear magnetic resonance. Rosmarinic acid from the plants quenched superoxide radicals from xanthine oxidase and inhibited cyclooxygenase I and II enzymes. In this study, the rosmarinic acid content of perilla was also determined and compared with those of the seven herbs.     

Identification and quantification of a major anti-oxidant and anti-inflammatory phenolic compound found in basil,lemon thyme,mint, oregano,rosemary, sage,and thyme

Major phenolic compounds from basil, lemon thyme, mint, oregano, rosemary, sage, and thyme were investigated using a high-performance liquid chromatography (HPLC) profiling technique in combination with DPPH-radical scavenging, xanthine oxidase and cyclooxygenase assays. For the present study, 15 plant-derived phenolic compounds (gallic, protocatechuic, vanillic, syringic, chlorogenic, rosmarinic, caffeic, ferulic, and sinapic acids, protocatechualdehyde, vanillin, N-coumaroyltyramine, N-caffeoyltyramine, N-feruloyltyramine, and N-sinapoyltyramine) were selected and their DPPH-radical scavenging activities were first determined. Then, a standard HPLC profiling of these phenolics was constructed using an HPLC method to isolate anti-oxidant and anti-inflammatory phenolic compounds from MeOH extracts of the plants. Rosmarinic acid was identified as a major anti-oxidant compound (0.22–0.97%) in all seven herbs, confirmed by nuclear magnetic resonance. Rosmarinic acid from the plants quenched superoxide radicals from xanthine oxidase and inhibited cyclooxygenase I and II enzymes. In this study, the rosmarinic acid content of perilla was also determined and compared with those of the seven herbs.     

Protection capacity against low-density lipoprotein oxidation and antioxidant potential of some organic and non-organic wines

Current research suggests that phenolics from wine may play a positive role against oxidation of low-density lipoprotein (LDL), which is a key step in the development of atherosclerosis. Considering the effects of different wine-making techniques on phenols and the wine consumption preference influencing the benefical effects of the product, organically and non-organically produced wines were obtained from the grapes of Vitis vinifera origin var: Carignan, Cabernet Sauvignon, Merlot, Grenache, Columbard and Semillon. Levels of total phenols [mg/l gallic acid equivalents (GAE)], antioxidant activity (%) and inhibition of LDL oxidation [%, inhibition of diene and malondialdehyde (MDA) formation] were determined. Some phenolic acids (gallic acid, p-hydroxybenzoic acid, syringic acid, 2,3-dihydroxybenzoic acid, ferulic acid, p-coumaric acid and vanillic acid) were quantified by high-performance liquid chromatography equipped with an electrochemical detection carried at +0.65 V (versus Ag/AgCl, 0.5 microA full scale). The highest concentrations of gallic, syringic and ferulic acids were found in organic Cabernet Sauvignon; 2,3-dihydroxybenzoic acid in organic Carignan and p-coumaric and vanillic acids in non-organic Merlot wine. High levels of antioxidant activity (AOA), inhibition of LDL oxidation and total phenol levels were found in non-organic Merlot (101.950% AOA; 88.570% LDL-diene; 41.000% LDL-MDA; 4700.000 mg/l GAE total phenol) and non-organic Cabernet Sauvignon (92.420% AOA; 91.430% LDL-diene; 67.000% LDL-MDA; 3500.000 mg/l GAE total phenol) grape varieties. Concentrations of some individual phenolic constituents (ferulic, p-coumaric, vanillic) are correlated with high antioxidant activity and inhibition of LDL oxidation.The best r value for all examined characteristics was determined for gallic acid, followed by 2,3-dihydroxybenzoic, syringic, ferulic and p-coumaric acids. Negative correlation of vanillic with MDA and p-hydroxybenzoic acid with LDL were confirmed by principal component analysis (PCA) analyses. Red wines display a higher antioxidant activity (81.110% AOA) than white ones (19.512% AOA). The average level of LDL inhibition capacity in red wine was determined as 87.072% and for the white as 54.867%.     

Phenolic acids,flavonols and anthocyanins in Corema album (L.) D. Don berries

Phenolic compounds of Corema album (Ericaceae) wild edible berries were determined by LC–DAD–MS/MS. Fifteen compounds were identified and quantified, including phenolic acids (2268.1 ± 229.2 mg/kg of dried weight, DW) such as chlorogenic and neochlorogenic acids, flavonols (638.3 ± 80.1 mg/kg DW) including quercetin 3-O-hexoside and rutin, and the anthocyanins (19. 6 ± 2.4 mg/kg DW) cyanidin 3-O-glucoside, cyanidin 3-O-pentoside and delphinidin 3-O-hexoside. Phenolic acids, the main phenolic compounds in this fruit, were fractionated into their free and bound forms, and analysed by GC–MS after hydrolysis. Eleven compounds (benzoic, salicylic, t-cinnamic, p-hydroxybenzoic, vanillic, gentisic, syringic, p-coumaric, gallic, ferulic and caffeic acids) were identified on the basis of GC retention times and simultaneously recorded mass spectra, namely caffeic, benzoic, ferulic and vanillic acids as the major phenolic acids in Corema album berries.     

Assessment of phenolic acid content and in vitro antiradical characteristics of hawthorn

The infusions and extracts obtained from leaves with flowers, fruit peel, and seed from hawthorn (Crataegus monogyna Jacq., Family Rosaceae) were subjected to evaluation as potential sources of antioxidant phytochemicals on the basis of their total content of phenolics, levels of phenolic acids, and in vitro antiradical activity. Total phenolic content of extracts was determined using the modified Folin-Ciocalteau method. Antioxidant activity was determined for phenolic extracts by a method involving the use of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Phenolic acids containing extracts and infusions from hawthorn leaves, fruit peel, and seeds were obtained using different polarity solvents and separated by reverse-phase high-performance liquid chromatography, which enabled improved separation by the use of a C(18) column, an acidic mobile phase, and gradient elusion. The highest total phenolic content (343.54?mg of gallic acid equivalents/g) and the highest DPPH radical scavenging activity as the inhibition percentage (60.36%) were obtained in ethyl acetate extract from hawthorn leaves with flower. Also, the highest phenolic acid content was measured in the extracts of hawthorn leaves with flowers: protocathechuic (108-128?mg/100?g), p-hydroxy benzoic (141-468?mg/100?g), caffeic (137-3,580?mg/100?g), chlorogenic (925-4,637?mg/100?g), ferulic (3,363-3,462?mg/100?g), vanillic (214?mg/100?g), and syringic (126?mg/100?g) acids. The results indicate that hawthorn is a promising plant because of its high antioxidant activity.     

Evolution of benzoate derivatives and their hydroxycinnamate analogues during ageing of white wines in oak barrels

Two white wines produced industrially, originating from the V. vinifera cultivars Asyrtiko and Chardonnay, were monitored with regard to the evolution of selected phenolic acids, during “on lees” ageing in oak casks for a period of 197 days. Four benzoic acid derivatives, namely p-hydroxybenzoic acid, protocatechuic acid, vanillic acid and syringic acid, and their corresponding hydroxycinnamate analogues p-coumaric acid, caffeic acid, ferulic acid and sinapic acid, were considered. The most abundant benzoate and hydroxycinnamate derivatives were protocatechuic acid and caffeic acid, with concentrations varying from 0.31 to 0.42 μg mL⁻¹ and 1.71 to 2.47 μg mL⁻¹, respectively, while the profile of both phenolic categories was essentially the same in both wines. The evolution pattern of benzoates showed that maximum concentration of protocatechuic acid was achieved after approximately 100 days (0.45–0.48 μg mL⁻¹) of ageing for both samples, whereas all other compounds exhibited an increasing trend towards the end of the examination period. The concentration of all hydroxycinnamates increased at the end of ageing, from 49.4% (caffeic acid) to 123% (p-coumaric acid), to the exception of sinapic acid which underwent practically no changes.     

Composition and distribution of phenolic acids in Ponkan (Citrus poonensis Hort. ex Tanaka) and Huyou (Citrus paradisi Macf. Changshanhuyou) during maturity

Composition and distribution of phenolic acids in Ponkan (Citrus poonensis Hort. ex Tanaka) and Huyou (Citrus paradisi Macf. Changshanhuyou) during maturity was investigated comprehensively in this study. High-performance liquid chromatography (HPLC) coupled with photodiode array (PDA) detector method was developed to separate and quantify protocatechuic, p-hydroxybenzoic, vanillic, caffeic, p-coumaric, ferulic, sinapic, and chlorogenic. For all of the phenolic acids, detection limits were about 0.01 μg/mL. Repeatability was 0.57–2.99% (relative standard deviation, RSD) for intraday and recovery ranged from 80.23% to 114.53%. In this study, phenolic acids were divided into four fractions: free, ester, glycoside and ester-bound. Generally, in each fraction, Ponkan had higher content of phenolic acids than Huyou, and with maturity there was a sharp decrease of them in both varieties, also peel contained more of them than flesh. Furthermore, chlorogenic acid and ferulic acid were the highest among the eight quantified phenolic acids, and content of caffeic acid was rather high at unripe stage, and hydroxycinnamic acids accounted for a larger portion compared with hydroxybenzoic acids especially for Ponkan. The total content of phenolic acids ranged from 180 μg/g DW (flesh of Huyou at ripe stage) to 5060 μg/g DW (peel of Ponkan at unripe stage). The data obtained here can be potentially used for discriminating the adulteration of citrus juices and may be useful for consumers and food technologists.     

Protection capacity against low-density lipoprotein oxidation and antioxidant potential of some organic and non-organic wines

Current research suggests that phenolics from wine may play a positive role against oxidation of low-density lipoprotein (LDL), which is a key step in the development of atherosclerosis. Considering the effects of different wine-making techniques on phenols and the wine consumption preference influencing the benefical effects of the product, organically and non-organically produced wines were obtained from the grapes of Vitis vinifera origin var: Carignan, Cabernet Sauvignon, Merlot, Grenache, Columbard and Semillon. Levels of total phenols [mg/l gallic acid equivalents (GAE)], antioxidant activity (%) and inhibition of LDL oxidation [%, inhibition of diene and malondialdehyde (MDA) formation] were determined. Some phenolic acids (gallic acid, p-hydroxybenzoic acid, syringic acid, 2,3-dihydroxybenzoic acid, ferulic acid, p-coumaric acid and vanillic acid) were quantified by high-performance liquid chromatography equipped with an electrochemical detection carried at +0.65 V (versus Ag/AgCl, 0.5 μA full scale).

The highest concentrations of gallic, syringic and ferulic acids were found in organic Cabernet Sauvignon; 2,3-dihydroxybenzoic acid in organic Carignan and p-coumaric and vanillic acids in non-organic Merlot wine. High levels of antioxidant activity (AOA), inhibition of LDL oxidation and total phenol levels were found in non-organic Merlot (101.950% AOA; 88.570% LDL-diene; 41.000% LDL-MDA; 4700.000 mg/l GAE total phenol) and non-organic Cabernet Sauvignon (92.420% AOA; 91.430% LDL-diene; 67.000% LDL-MDA; 3500.000 mg/l GAE total phenol) grape varieties. Concentrations of some individual phenolic constituents (ferulic, p-coumaric, vanillic) are correlated with high antioxidant activity and inhibition of LDL oxidation.The best r value for all examined characteristics was determined for gallic acid, followed by 2,3-dihydroxybenzoic, syringic, ferulic and p-coumaric acids. Negative correlation of vanillic with MDA and p-hydroxybenzoic acid with LDL were confirmed by principal component analysis (PCA) analyses. Red wines display a higher antioxidant activity (81.110% AOA) than white ones (19.512% AOA). The avarage level of LDL inhibition capacity in red wine was determined as 87.072% and for the white as 54.867%.     

酚酸对亚硝基吗啉（NMOR）体外形成的影响

研究了在体外模拟胃液条件下,酚酸在不同浓度和pH时对亚硝基吗啉(NMOR)合成的影响,并分析了酚酸化合物阻断作用与分子结构之间的关系。结果表明NMOR的合成量与酚酸的浓度成负相关,其阻断能力以咖啡酸、单宁酸、没食子酸、阿魏酸、芥子酸较好,绿原酸、龙胆酸、丁香酸次之;pH对酚酸的阻断作用影响很大,总的来说pH2～3范围内酚酸的阻断作用较强;在pH1～4范围内两类酚酸化合物(苯甲酸类和肉桂酸类)对NMOR合成的阻断作用影响趋势是一致的,而在pH4～5范围内相反,即在pH4～5内随着pH升高,肉桂酸类化合物的阻断作用升高,而苯甲酸类化合物阻断作用降低。酚酸的阻断作用与其分子结构关系很密切。     

Avenanthramides and phenolic acids from oats are bioavailable and act synergistically with vitamin C to enhance hamster and human LDL resistance to oxidation

The intake of phenolic acids and related polyphenolic compounds has been inversely associated with the risk of heart disease, but limited information is available about their bioavailability or mechanisms of action. Polyphenolics, principally avenanthramides, and simple phenolic acids in oat bran phenol-rich powder were dissolved in HCl:H(2)O:methanol (1:19:80) and characterized by HPLC with electrochemical detection. The bioavailability of these oat phenolics was examined in BioF1B hamsters. Hamsters were gavaged with saline containing 0.25 g oat bran phenol-rich powder (40 micromol phenolics), and blood was collected between 20 and 120 min. Peak plasma concentrations of avenanthramides A and B, p-coumaric, p-hydroxybenzoic, vanillic, ferulic, sinapic, and syringic acids appeared at 40 min. Although absorbed oat phenolics did not enhance ex vivo resistance of LDL to Cu(2+)-induced oxidation, in vitro addition of ascorbic acid synergistically extended the lag time of the 60-min sample from 137 to 216 min (P < or = 0.05), unmasking the bioactivity of the oat phenolics from the oral dose. The antioxidant capability of oat phenolics to protect human LDL against oxidation induced by 10 micromol/L Cu(2+) was also determined in vitro. Oat phenolics from 0.52 to 1.95 micromol/L increased the lag time to LDL oxidation in a dose-dependent manner (P < or = 0.0001). Combining the oat phenolics with 5 micromol/L ascorbic acid extended the lag time in a synergistic fashion (P < or = 0.005). Thus, oat phenolics, including avenanthramides, are bioavailable in hamsters and interact synergistically with vitamin C to protect LDL during oxidation.     

Phenolic Acid and Fatty Acid Composition in the Fruits ofLaurocerasus officinalisRoem. and Its Cultivars

The phenolic acids and fatty acids present in some cherry laurel cultivars (Oxygemmis, Globigemmis, and Angustifolia) and the wild from (Laurocerasus officinalisRoem.) have been studied. The phenolic acids analyzed by gas chromatography-mass spectrometry were vanillic, protocatechuic,p-hydroxybenzoic acids (benzoics), and caffeic andp-coumaric acids (cinnamics). The fatty acids analyzed in the same manner were palmitic (16:0), stearic (18:0), oleic (18:1), and linoleic (18:2) acids. Vanillic acid was predominant and present in all cultivars and the wild form. Linoleic acid was the predominant fatty acid in all cultivars and the wild form. Quantities of all phenolic and fatty acids varied significantly in these fruits.     

Sugar,Non-volatile and Phenolic Acids Composition of Strawberry Tree (Arbutus unedo L. var.ellipsoidea ) Fruits

Using GC-MS, phenolic and non-volatile acids and soluble sugars were identified and quantified in strawberry tree (Arbutus unedo L.) fruits. The phenolic acids quantified were gallic (10.7 mg/g dry weight), gentisic (1.9 mg/g), protocatechuic (0.6 mg/g), p -hydroxybenzoic (0.3 mg/g), vanillic (0.12 mg/g) and m -anisic (0.05 mg/g). From the group of non-volatile acids, fumaric (1.94 mg/g dry weight), lactic (0.84 mg/g), malic (0.84 mg/g), suberic (0.23 mg/g) and citric acids were found. Fructose, glucose, sucrose and maltose were the soluble sugars identified and quantified in the amount of 27.8, 21.5, 1.8 and 1.11% dry weight, respectively. Fructose and glucose among the sugars, fumaric and malic acids among the non-volatile acids and gallic acid among the phenolic acids were found to be major compounds contributing the taste of the fruits.     

Bioprocessing of wheat bran in whole wheat bread increases the bioavailability of phenolic acids in men and exerts antiinflammatory effects ex vivo

Whole grain consumption has been linked to a lower risk of metabolic syndrome, which is normally associated with a low-grade chronic inflammation. The benefits of whole grain are in part related to the inclusion of the bran, rich in phenolic acids and fiber. However, the phenols are poorly bioaccessible from the cereal matrix. The aim of the present study was to investigate the effect of bioprocessing of the bran in whole wheat bread on the bioavailability of phenolic acids, the postprandial plasma antioxidant capacity, and ex vivo antiinflammatory properties. After consumption of a low phenolic acid diet for 3 d and overnight fasting, 8 healthy men consumed 300 g of whole wheat bread containing native bran (control bread) or bioprocessed bran (bioprocessed bread) in a cross-over design. Urine and blood samples were collected for 24 h to analyze the phenolic acids and metabolites. Trolox equivalent antioxidant capacity was measured in plasma. Cytokines were measured in blood after ex vivo stimulation with LPS. The bioavailabilities of ferulic acid, vanillic acid, sinapic acid, and 3,4-dimethoxybenzoic acid from the bioprocessed bread were 2- to 3-fold those from the control bread. Phenylpropionic acid and 3-hydroxyphenylpropionic acid were the main colonic metabolites of the nonbioaccessible phenols. The ratios of pro-:antiinflammatory cytokines were significantly lower in LPS-stimulated blood after the consumption of the bioprocessed bread. In conclusion, bioprocessing can remarkably increase the bioavailability of phenolic acids and their circulating metabolites, compounds which have immunomodulatory effects ex vivo.     

Differential anti-inflammatory effects of phenolic compounds from extra virgin olive oil identified in human whole blood cultures

OBJECTIVE: The olive oil-rich Mediterranean diet protects against cardiovascular disease, which involves inflammatory processes. This study investigated the effects of phenolic compounds found in extra virgin olive oil on inflammatory mediator production by human mononuclear cells. METHODS: Diluted human blood cultures were stimulated with lipopolysaccharide in the presence of phenolics (vanillic, p-coumaric, syringic, homovanillic and caffeic acids, kaempferol, oleuropein glycoside, and tyrosol) at concentrations of 10(-7) to 10(-4) M. Concentrations of the inflammatory cytokines tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 and of the inflammatory eicosanoid prostaglandin E2 were measured by enzyme-linked immunosorbent assay. RESULTS: Oleuropein glycoside and caffeic acid decreased the concentration of interleukin-1beta. At a concentration of 10(-4) M, oleuropein glycoside inhibited interleukin-1beta production by 80%, whereas caffeic acid inhibited production by 40%. Kaempferol decreased the concentration of prostaglandin E2. At a concentration of 10(-4) M, kaempferol inhibited prostaglandin E2 production by 95%. No effects were seen on concentrations of interleukin-6 or tumor necrosis factor-alpha and there were no effects of the other phenolic compounds. CONCLUSIONS: Some, but not all, phenolic compounds derived from extra virgin olive oil decrease inflammatory mediator production by human whole blood cultures. This may contribute to the antiatherogenic properties ascribed to extra virgin olive oil.     

Absorption and metabolism of caffeic acid and chlorogenic acid in the small intestine of rats

The absorption and metabolism in the small intestine of chlorogenic acid (5-O-caffeoylquinic acid), the main phenolic acid in the human diet, and of caffeic acid were studied in rats in order to determine whether chlorogenic acid is directly absorbed or hydrolysed in the small intestine. Chlorogenic and caffeic acids were perfused into a segment of ileum plus jejunum during 45 min (50 microm, 0.75 ml/min) using an in situ intestinal perfusion rat model with cannulation of the biliary duct, and were quantified together with their metabolites in perfusion effluent, bile and plasma. The net absorption (influent flux minus effluent flux of phenolic acids and their metabolites) accounted for 19.5 % and 8 % of the perfused caffeic and chlorogenic acids, respectively. A minor fraction of the perfused caffeic acid was metabolized in the intestinal wall and secreted back into the gut lumen in the form of ferulic acid (0.5 % of the perfused flux). Part of the chlorogenic acid (1.2 % of the perfused flux) was recovered in the gut effluent as caffeic acid, showing the presence of trace esterase activity in the gut mucosa. No chlorogenic acid was detected in either plasma or bile, and only low amounts of phenolic acids (less than 0.4 %) were secreted in the bile. The present results show that chlorogenic acid is absorbed and hydrolysed in the small intestine. In contrast to numerous flavonoids, absorbed phenolic acids are poorly excreted in the bile or gut lumen. Their bioavailability therefore appears to be governed largely by their uptake into the gut mucosa.     

Antioxidant activity of extracts from the leaves of Smallanthus sonchifolius

Summary. Background & Aims: Yacon (Smallanthus sonchifolius, Asteraceae) is a native Andean plant, cultivated for its tubers throughout South America. The leaves are used in folk medicine as a medicinal tea for hypoglycemia. This paper describes the antioxidant activity of various extracts from S. sonchifolius leaves for their content of phenolic components. Methods: The dried leaves were extracted in several ways. Two fractions were selected for their high content of phenolic compounds and analyzed by RP-HPLC. The antioxidant activity of these fractions was tested in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and xanthine/XOD superoxide radical scavenging assays, as inhibition of lipoperoxidation of subcellular membranes and as protective activity against oxidative injury of rat hepatocytes in primary cultures. Results and conclusions: The presence of protocatechuic (2.5 and 0.12 mg/g), chlorogenic (9.9 and 1.7 mg/g), caffeic (14.7 and 0.09 mg/g) and ferulic (traces) acids were determined in the two fractions. Both fractions showed potent antioxidant activity in DPPH (IC₅₀ = 16.1 ± 3.4 and 24.3 ± 2.7 mg/ml) and xanthine/XOD superoxide radical scavenging (42.0 ± 20.3 and 34.3 ± 11.4 SOD equivalents (U/mg)) tests, they inhibited the lipoperoxidation of rat liver subcellular membranes and they protected rat hepatocytes against oxidative injury. Our results may predetermine the use of S. sonchifolius leaves in human diet as a potential remedy in the prevention of chronic diseases caused by radicals, e. g., arteriosclerosis. Received: 10 July 2002, Accepted: 25 November 2002 Correspondence to: K. Valentova     

Determination of antioxidant activity,rutin, quercetin,phenolic acids and trace elements in tea infusions: Influence of citric acid addition on extraction of metals

Antioxidant activity of tea, content of bioactive compounds (rutin, quercetin, phenolic acids including: gallic, chlorogenic, protocatechuic, p-coumaric, caffeic, ferrulic, syringic and sinapic as well as other selected organic acids) and trace elements (Mn, selected as a metal playing a role in oxidative metabolism; Al; Cd; and Pb – the so-called heavy or noxious metals) were studied as these parameters greatly influence the quality of tea infusions. A number of different samples were tested including white, green, black and lemon-flavored teas, as well as the Red Lapacho tea. Antioxidant activity was measured using DPPH and ABTS tests, and a strong correlation between obtained results was observed. Infusions made from lemon teas packed in bags showed increased levels of rutin, quercetin and phenolic acids. Nevertheless, the positive effect of the increased level of phenolic compounds extracted is also connected with higher level of extracted noxious elements. Citric acid added to tea and herbal Red Lapacho infusions significantly increased Al, Cd, and Pb trace elements concentrations. Nevertheless, the infusions prepared from the lemon tea bags contained even the 10–70-fold higher content of these elements. On the other hand, addition of citric acid to tea infusions increased amount of extracted Mn only in black teas and Red Lapacho.     

Analysis of 17 polyphenolic compounds in organic and conventional legumes by high-performance liquid chromatography-diode array detection (HPLC-DAD) and evaluation of their antioxidant activity

Consumption of legumes has become popular among health-conscious consumers due to the high levels of nutrients such as proteins, dietary fibres, minerals, vitamins and micronutrients like polyphenols. Ten legumes cultivars organically and conventionally grown were compared regarding their chemical profiles in terms of total phenolic content (TPC), total anthocyanin content (TAC), total flavonoid content (TFC) and their antioxidant capacity. The chemical profiles (i.e. free phenolics and anthocyanins) were determined with aid of new high-performance liquid chromatography-diode array detection (HPLC-DAD) method able to identify two individual anthocyanins and 15 polyphenols. Results showed that phenolic acids, namely gallic acid, caffeic acid, syringic acid and ferulic acid, are mainly significantly higher in the organic samples with respect to the conventional ones. All organic legumes showed a higher antioxidant capacity with respect to conventional samples with the exception of red and yellow dehulled lentils.     

Determination of free and bound phenolics using HPLC-DAD,antioxidant activity and in vitro digestibility of Eragrostis tef

White and brown Eragrostis tef were assessed for total flavonoid and phenolic content, HPLC profile of the most common phenolics and antioxidant activity including both free and bound phenolics. Antioxidant activity was evaluated in correlation with free and bound phenolics and in vitro digestibility was determined. Content of flavonoids (0.52–1.02 mg RE/g) and phenolics (0.90–1.42 mg GAE/g) as well as antioxidant activity (1.70–4.37 μmol TEAC/g using ABTS method) was higher in free phenolic fraction. Correlation showed that bound flavonoids were not significant contributors to antioxidant activity (R² = 0.4513 and 0.4893, respectively). The main free phenolics in brown teff were trans-p-coumaric, protocatechuic, ferulic and gallic acids, while the major free phenolics in white teff were rutin, protocatechuic and ferulic acids. The main bound phenolics in brown teff were ferulic and gallic acids, quercetin and catechin, in white teff ferulic acid, rutin, catechin and quercetin. Cooked teff showed very high level of in vitro organic matter digestibility (80.5–85.1%), whereas brown teff was significantly more digestible than white teff (P < 0.05).