Composition of native Australian herbs polyphenolic-rich fractions and in vitro inhibitory activities against key enzymes relevant to metabolic syndrome

Polyphenolic-rich fractions obtained from three native Australian herbs: Tasmannia pepper leaf, anise myrtle and lemon myrtle were characterised with regards to their composition, antioxidant capacities and inhibitory activities against α-glucosidase, pancreatic lipase and angiotensin I-converting enzyme, using in vitro models. Ellagic acid and derivatives were the dominant compounds of anise myrtle and lemon myrtle fractions, accompanied by flavonoids (catechin, myricetin, hesperetin, and quercetin). Tasmannia pepper leaf fraction comprised chlorogenic acid and quercetin derivatives, exhibited the highest oxygen radical absorbance capacity and effectively inhibited α-glucosidase (IC₅₀: 0.83 mg/ml) and pancreatic lipase (IC₅₀: 0.60 mg/ml). Anise myrtle and lemon myrtle fractions had pronounced α-glucosidase-inhibitory activities (IC₅₀: 0.30 and 0.13 mg/ml, respectively) and were less effective against lipase. Enzyme-inhibitory activities showed various levels of correlation with the levels of total phenolics and antioxidant capacities, indicating a specificity of individual phenolic compounds present in the isolated fractions to complex with proteins.     

Assessment of in vitro antioxidant capacity and polyphenolic composition of selected medicinal herbs from Leguminosae family in Peninsular Malaysia

Determination of total phenolic (TPC), flavonoid and anthocyanin contents, and various antioxidant activities (2,2-diphenyl-1-picrylhydrazyl radical scavenging, ferric reducing power, ferrous ion chelating and lipid peroxidation inhibition) of leaves and flowers of Bauhinia kockiana, Caesalpinia pulcherrima and Cassia surattensis were performed in this study. The B. kockiana flower was found to possess the highest TPC (8280 ± 498 mg GAE/100 g), free radical scavenging activity (ascorbic acid equivalents 14,600 ± 2360 mg AA/100 g) and reducing ability (72.4 ± 8.7 mg GAE/g). Rutin and chlorogenic acid were detected in the plants, where the C. pulcherrima leaf contained the highest amount of rutin (669 ± 26 mg/100 g), while minute amounts of chlorogenic acid were detected in C. surattensis leaf (9.13 ± 0.44 mg/100 g). The C. pulcherrima leaf displayed the highest ferrous ion chelating and lipid peroxidation inhibition activities. Positive correlation was observed between TPC and various antioxidant activities.     

Cytoprotective and pro-apoptotic activities of native Australian herbs polyphenolic-rich extracts

Three commercially grown native herbs unique to Australia, Tasmannia pepper leaf (Tasmannia lanceolata R. Br., Winteracea; TPL), anise myrtle (Syzygium anisatum Vickery, Craven & Biffen, Myrtaceae; AM) and lemon myrtle (Backhousia citriodora F. Muell, Myrtaceae; LM) as well as a reference sample bay leaf (Laurus nobilis L., Lauraceae; BL) were examined for potential cytoprotective properties. All native herbs exhibited greater cellular antioxidant activity as measured by the cellular antioxidant activity (CAA) assay than bay leaf and reduced the hydrogen peroxide (H₂O₂) induced death of hepatocellular carcinoma (HepG2) cells by 25–50%. All herb extracts reduced the proliferation of colon (HT-29; IC₅₀ = 0.75–1.39 mg/ml), stomach (AGS; IC₅₀ = 0.59–1.88 mg/ml), bladder (BL13; IC₅₀ = 0.56–1.12 mg/ml) and liver (HepG2; IC₅₀ = 0.38–1.36 mg/ml) cancer cells. No significant reduction of cell viability of non-transformed colon (CCD-18Co; IC₅₀ > 2.0 mg/ml) and mixed stomach and intestine (Hs 738.St/Int; IC₅₀ > 2.0 mg/ml) cells was observed. Flow cytometry analysis and the results of the cytokinesis block micronucleus cytome (CBMNCyt) assay conducted with respectively, promyelocytic leukaemia (HL-60) and colon adenocarcinoma (HT-29) cells suggest an increase in apoptosis following treatment with the herb extracts. The occurrence of apoptotic cells coincided with an increase in caspase-3 enzyme activity. The results of the CBMNCyt assay suggested no direct DNA damage in colon adenocarcinoma (HT-29) cells as a result of treatment with all extracts, applied at final concentrations of 0.5 and 1.0 mg/ml.     

Antioxidant activity of three edible seaweeds from two areas in South East Asia

Total phenolic content (TPC) and antioxidant activity (AOA) of 50% aqueous methanol extracts of the marine algae, Padina antillarum, Caulerpa racemosa and Kappaphycus alvarezzi were studied. TPC was measured using Folin-Ciocalteu method while 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), ferrous ion chelating (FIC) assay and beta carotene bleaching (BCB) assay were used to study their AOA. P. antillarum was found to have the highest TPC, 2430±208 mg gallic acid equivalents (GAE) per 100 g dried sample and ascorbic acid equivalent antioxidant capacity (AEAC), 1140±85 mg AA/100 g. C. racemosa and K. alvarezzi displayed lower TPC and AEAC. C. racemosa had 144±22 mg GAE/100 g dried sample of TPC and 14.3±2.0 mg AA/100 g of AEAC, while K. alvarezzi had 115±35 mg/100 g dried sample of TPC and 37.8±16.8 mg AA/100 g of AEAC. In addition, P. antillarum displayed the highest reducing power, 15.7±2.6 mg GAE/g and highest chelating ability. C. racemosa and K. alvarezzi exhibited lower reducing power, 0.737±0.423 mg GAE/g and 0.561±0.269 mg GAE/g, and lower chelating ability. However, the AOA of these three seaweeds as assessed by BCB assay were equally high.     

Antioxidant capacity and vasodilatory properties of Mediterranean food: The case of Cannonau wine,myrtle berries liqueur and strawberry-tree honey

The aim of this work was to use different assays to evaluate the antioxidant and vasodilatory properties of three typical food products from the Mediterranean area and to correlate these activities with their phenolic content. For this purpose, red wines Cannonau, liqueurs obtained by cold maceration of myrtle (Myrtus communis L.) berries and bitter honeys obtained from strawberry-tree flowers (Arbutus unedo L.) were analysed. The total phenolic (TP) content was measured spectrophotometrically with a modified Folin–Ciocalteau method and phenolic compounds were identified and dosed by HPLC-DAD and LC-MS/MS. Antioxidant activities were evaluated with DPPH, FRAP and ABTS assays and the in vitro vasodilatory effects were assessed using norepinephrine precontracted rat aortic rings. Cannonau wines and myrtle liqueurs showed high levels of TP (1978 ± 279 and 1741 ± 150 mg GAE/L, respectively), linearly correlated to the results of FRAP, ABTS, and DPPH assays. Their maximal vasodilatory activity was 61.7 ± 4.1% and 53.0 ± 3.0%, respectively. Although strawberry-tree honey contained relatively high levels of phenolic compounds (922 ± 38 mg GAE/kg), it did not induce vasodilation, even at the highest dose tested (0.206 g/L). These results indicate that foods with high levels of phenolic compounds should be studied using several different biological assays before being recommended to the general public as functional foods.     

Antioxidant capacity and hydrophilic phytochemicals in commercially grown native Australian fruits

Hydrophilic phytochemicals and antioxidant capacities of eight commercially grown native Australian fruits were determined. Kakadu plum (Terminalia ferdinandiana) contained a 6-fold higher level of total phenolic compounds and quandong (Santalum acuminatum) a 1.9-fold higher level of total phenolic compounds (TP, Folin–Ciocalteu assay) than blueberry (Vaccinum sp., cv. Biloxi). Both fruits displayed superior oxygen radical-scavenging capacity (ORAC-H assay) that was, respectively 4.1-fold and 6.5-fold of that of blueberry. The total reducing capacity (TRC; ferric reducing antioxidant power (FRAP) assay) of Kakadu plum and quandong exceeded the TRC of blueberry, respectively, 13.1- and 2.3-times. The primary sources of antioxidant capacities in the evaluated fruits were phenolic acids (benzoic and cinnamic) and flavonoids (flavonols, flavanones and anthocyanins) tentatively detected by liquid chromatography–mass spectrometry (LC–PDA–MS/MS). A high level of vitamin C was recorded for Kakadu plum and Australian citrus fruits. The major organic acids detected were citric and malic acid.     

Antioxidant and free radical-scavenging activities of seeds and agri-wastes of some varieties of soybean (Glycine max)

In order to find antioxidant potential, seeds of 30 varieties of Glycine max were studied for their total phenolic contents (TPC), flavonoids and antioxidant activity (AOA). The seed extracts showed wide variation of TPC from 6.4 to 81.7 mg GAE/g, flavonoids 3.5 to 44.6 mg QE/g and AOA 7.5% to 74.7%. Free radical-scavenging activity (FRSA), assayed by DPPH in terms of IC₅₀ (inhibitory concentration), ranged from 0.14 to 0.80 mg/ml, EC₅₀ (efficiency concentration) from 6.1 to 34.8 mg/mg DPPH, ARP (anti-radical power) 2.9 to 16.4 and reducing power from 1.9 to 4.7 ASE/ml. Variety Kalitur showed highest the FRSA followed by Alankar and Hara soya, as evident from their low IC₅₀, EC₅₀ and high ARP values. Alankar, Kalitur NRC-37, PK-472, VLS-47, Hara soya varieties were with comparatively higher TPC (52.7–81.7 mg GAE/g), AOA (50.5–74.7%) and showed better inhibition of peroxide formation assayed through ammonium thiocyanate and egg yolk, non-site-specific and site-specific inhibition of hydroxyl radical induced deoxyribose degradation and ferrous ion-chelating capacity than did the other varieties. Seed extracts of these varieties and leaves of Kalitur showed significant protection against DNA damage caused by free radicals. The agri-wastes of some promising varieties, e.g. Alankar, Kalitur, NRC-37 and PK-472, showed TPC ranging from 27.4 to 167 mg GAE/g, total flavanoids from 10.4 to 63.8 mg QE/g and AOA from 26.5% to 84.7% and their values were highest in the leaves, followed by pod pericarp and twigs. Out of all the varieties studied, leaves of Alankar and Kalitur varieties were more potent free radical-scavengers than were seeds, pod pericarp or twigs. The specific phenolic compositions and their quantifications were performed by HPLC and MS/MS, which showed that the seeds of Kalitur were higher in genistin (127 μg/g), seeds and leaves of Alankar in diadzin (113 μg/g) and gallic acid (87.2 μg/g), respectively. The present studies may be of importance in varietal improvement, nutraceuticals, bio-pharmaceuticals and utilization of agri-wastes as possible cost-effective natural antioxidants.     

Phenolic content, antioxidant, anti-inflammatory and anticancer activities of the edible halophyte Suaeda fruticosa Forssk

Suaeda fruticosa is an edible and medicinal halophyte known for its hypoglycaemic and hypolipidaemic activities. In this study, novel biological activities of the shoot extracts related to their phenolics were investigated. Results showed an appreciable total phenolic (31.8 mg GAE/g DW) in shoot extracts. The estimation of antioxidant capacities using oxygen radical absorbance capacity (ORAC method) and a cell based-assay (WS1) of four extracts (hexane, dichloromethane, methanol and water) showed that shoot methanol extract exhibit the highest antioxidant activities. The same extract displayed the utmost anti-inflammatory activity, inhibiting nitric oxide (NO) release, by 66.4% at 160 μg/ml in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Besides, the dichloromethane extract showed the highest anticancer activity against human lung carcinoma (A-549) and colon adenocarcinoma cell lines (DLD-1, Caco-2 and HT-29) with specificity against DLD-1 (IC₅₀ = 10 ± 1 μg/ml). These findings demonstrate the remarkable potentiality of this edible halophyte as valuable source of antioxidants which exhibit original and interesting anti-inflammatory and anticancer capacities.     

Solid-state fermentation of apple pomace using Phanerocheate chrysosporium – Liberation and extraction of phenolic antioxidants

Apple pomace is a by-product from the apple processing industry and can be used for the production of value-added phenolic compounds. A study was carried out to understand the changes and liberation of phenolic compounds and improvement in antioxidant activity during solid-state fermentation of apple pomace using Phanerocheate chrysosporium. The solid-state fermentation of apple pomace using P. chrysosporium mobilised the polyphenolic compounds and improved the nutraceutical properties. The polyphenol content in acetone extract increased and the results were statistically significant (P < 0.05) from 4.6 to 16.12 mg GAE/g dry weight during solid-state fermentation. The effect of various solvents, temperature, time and detergents were also investigated for the extraction of polyphenolics by ultrasonication and microwave-assisted extraction methods. The polyphenol content of the extracts was found to be in the range of 5.78–16.12 mg GAE/g DW of samples, depending on the solvent, extraction time and temperature. Antioxidant activities of polyphenol extracts were tested using the 2,2-diphenyl-1-picryhydrazyl (DPPH) radical methods, where the IC₅₀ ranged from 12.24 to 23.42 μg DW sample, depending on the extraction conditions and the antioxidant activities correlated well with the polyphenol concentrations.     

Antioxidant activity of white and black sesame seeds and their hull fractions

The total phenolic content (TPC), total antioxidant status (TAS), free radical scavenging capacity, inhibition of low density lipoprotein (LDL) cholesterol and metal chelating capacity of extracts of whole black and whole white sesame seeds and their hull fractions in 80% aqueous ethanol were investigated. The TPC of whole black sesame seeds and hull extracts were 29.9 ± 0.6 and 146.6 ± 0.6 mg catechin equivalents/g crude ethanolic extract, respectively. The corresponding values for white sesame were 10.6 ± 1.6 and 29.7 ± 0.9 mg catechin equivalents/g crude ethanolic extract. The TAS as determined by Trolox equivalent antioxidant capacity assay and expressed as Trolox equivalents was highest for black sesame hulls (65.9 ± 1.7) while white seeds showed the lowest (4.4 ± 0.6). Free radical scavenging capacity of sesame extracts (5–40 μg/mL) was measured using 2,2-diphenyl-1-picrylhydrazyl radical. The highest scavenging capacity was obtained at 40 μg/mL and was 94.9 ± 0.8, 25.1 ± 0.4, 14.4 ± 0.9 and 2.5 ± 0.4 for black sesame hulls, black sesame seeds, white sesame hulls and white sesame seeds, respectively. Inhibition of LDL oxidation at 100 ppm level was highest for black sesame hulls (96.7%) followed by those for white sesame hulls (84.6%), black sesame (78.4%) and white sesame seeds (57.3%). Sesame products displayed good ferrous ion chelating capacities, which ranged from 12% to 46% and 17% to 62% at 50 and 100 ppm levels, respectively. Results demonstrated considerable antioxidant activity of sesame products tested especially black sesame hulls.     

Comparative study of polyphenols and caffeine in different coffee varieties affected by the degree of roasting

The bioactive composition of coffee, as one of the most popular beverages in the world, has attracted interest as a potential source of beneficial bioactive compounds, especially polyphenols and caffeine. Since the content of these compounds is affected by the processing conditions, the objective of this study was to determine the content of polyphenolic compounds and caffeine in four different coffee varieties: Minas and Cioccolatato (Coffea arabica), and Cherry and Vietnam (Coffea canephora syn. Coffea robusta), roasted by three varying degrees (light, medium and dark). The content of the polyphenolic compounds and the antioxidant capacity of coffees were determined using UV/Vis spectrophotometric methods, while the content of chlorogenic acid derivatives was determined using HPLC analysis. The caffeine content was determined by means of two spectrophotometric methods, as well as HPLC analysis. Additionally, raw caffeine was also obtained by an isolation procedure with chloroform. Cherry coffee, a variety of C. canephora exhibited the highest overall content of total phenols (42.37 mg GAE/g), followed by Minas coffee, while Cioccolatato contained the lowest TPC (33.12 mg GAE/g). Cherry coffee also exhibited the highest content of individual classes of polyphenols (flavan-3-ols, procyanidins and tannins), while the highest content of chlorogenic acid (CQA) derivatives was determined in Minas and Cioccolatato coffees (C. arabica). The highest content of total and individual polyphenolic compounds was determined in coffees roasted in both light and medium roasting conditions, which was also observed for the content of CQA derivatives and antioxidant capacity of roasted coffees. The highest caffeine content in the coffee samples was determined by employing the HPLC analysis (0.06–2.55%). Light roasted Cherry coffee contained the highest overall content of caffeine among all coffees, which exhibited a decrease with intensified roasting.     

Chemical and biological variability of hot pepper fruits (Capsicum annuum var. acuminatum L.) in relation to maturity stage

The aim of the present work was to evaluate the chemical composition and the radical-scavenging and antioxidant activities of hot pepper fruits (Capsicum annuum L. var. acuminatum) at three maturity stages (small green, green and red). GC–MS analysis of n-hexane and chloroform fractions showed a different composition between the three stages of ripening. The first stage of maturation (small green) showed the highest radical-scavenging activity (IC₅₀ of 129 μg/ml). Using the bovine brain peroxidation assay, the methanolic extract of green pepper showed significant antioxidant activity (IC₅₀ of 522 μg/ml). Addition of methanolic extract of red and green pepper inhibited oxidation of linoleic acid. Methanolic extract of red pepper showed greater antioxidative potency than the others (IC₅₀ of 3 μg/ml). The different composition of lipophilic compounds and the various amount of phenolics, showed in the three stage of ripening of C. annuum var. acuminatum fruits, modifies the antioxidant activity.     

Antioxidant capacity of medicinal plants from the Province of Córdoba (Argentina) and their in vitro testing in a model food system

The total phenols content (Folin–Ciocalteau assay) and antioxidant capacity (ferric reducing/antioxidant power – FRAP) of 41 plants from Córdoba (Argentina) were analyzed. Phenol content ranged from 8.2 to 100.2 mg GAE/g. FRAP ranged from 85.2 to 1862.0 μmol of Fe(II)/g. Capparis atamisguea had the lowest values of total phenols content and antioxidant capacity (8.2 mg GAE/g and 85.2 μmol of Fe(II)/g, respectively), while Ligaria cuneifolia exhibited the highest values (100.2 mg GAE/g and 1862.0 μmol of Fe(II)/g, respectively). A significant linear correlation (p < 0.05) was found (0.9125) between phenols content and antioxidant capacity. Results support the idea that these plants may be a good source of natural antioxidants for food applications. Plants from the Asteraceae family (the most representative of the Córdoba flora) were further tested for their DPPH radical scavenging activity. Some plant extracts were tested in a simple food system to investigate to their potential use in foods.     

Rhus verniciflua Stokes flavonoid extracts have anti-oxidant,anti-microbial and α-glucosidase inhibitory effect

We isolated four compounds, fustin, gallic acid, 3′,4′,7-trihydroxyflavone, and fisetin from Rhus verniciflua. These compounds showed electron donation ability (87–94%) that was stronger than butylated hydroxyanisole (52%). Gallic acid (OD₇₀₀ = 1.98) showed the highest reducing power, and the other isolated compounds (OD₇₀₀ = 0.66–1.31) showed stronger activity than α-tocopherol (OD₇₀₀ = 0.21). The ethyl-acetate fraction had the highest phenolic content (723 mg GAE/g), followed by the 80% ethanolic extract (597 mg GAE/g). For Gram-negative bacteria, fisetin had the most potent anti-bacterial activity (MIC = 8 μg/ml) against Escherichia coli. 3′,4′,7-Trihydroxyflavone (106%), the 80% ethanolic extract (101%), and ethyl-acetate (98%) had the most powerful α-glucosidase inhibitory effect at 50 μg/ml. R. verniciflua extracts have potential as functional food additives.     

Nutritional and in vitro antioxidant properties of edible wild greens in Iberian Peninsula traditional diet

Wild greens are nutritionally well-balanced vegetables. Herein, nutritional and in vitro antioxidant properties of the sprouts of three commonly used species were determined. Wild asparagus revealed the highest levels of moisture (84.6 g/100 g fw), ash (12.3 g/100 g dw), proteins (22.4 g/100 g dw), total sugars (9.24 g/100 g dw), including sucrose (4.27 g/100 g dw), and of the essential n-6 fatty acid linoleic acid (44.5%); white bryony gave the highest contents of reducing sugars, including glucose (2.97 g/100 g dw), essential n-3 fatty acid α-linolenic acid (70.3%), and the best ratios of PUFA/SFA, and n-6/n-3 fatty acids (3.59 and 0.0907, respectively); black bryony showed the highest concentrations of carbohydrates (69.3 g/100 g dw), fructose and trehalose (3.83 and 1.34 g/100 g dw, respectively). Besides their culinary characteristics, their high content in vitamins (asparagus, 135 and 142 mg/100 g dw of total tocopherols and ascorbic acid, respectively), chlorophylls (white bryony, 50.9 mg/100 g dw), carotenoids (23.3 mg/100 g dw) and phenolics (black bryony, 759 mg GAE/g extract), together with the antioxidant properties (EC₅₀ values lower than 640 μg/ml) and potential health benefits increase their importance in traditional as well as in contemporary diets.     

Identification and quantification of phenols, carotenoids, and vitamin C from papaya (Carica papaya L., cv. Maradol) fruit determined by HPLC-DAD-MS/MS-ESI

Recent studies have demonstrated that vitamin C, phenols, and carotenoids are bioactive compounds that protect the body from oxidative stress, reducing the risk of cardiovascular diseases and some types of cancer. Qualitative and quantitative analysis of the major phytochemicals found in papaya fruit flesh and skin (Carica papaya L., cv Maradol) was conducted in four stages of ripeness, using high-performance liquid chromatography mass spectrometry. Phenolic compounds identified in the fruit skin tended to decrease with ripening. The compounds identified were ferulic acid (277.49 to 186.63 mg/100 gDW), p-coumaric acid (229.59 to 135.64 mg/100 gDW), and caffeic acid (175.51 to 112.89 mg/100 gDW). The following carotenoids, along with vitamin C, increased in flesh with ripening; lycopene (0.36 to 3.40 mg/100 gDW), ??-criptoxanthin (0.28 to 1.06 mg/100 gDW), ??-carotene (0.23 to 0.50 mg/100 gDW), and vitamin C (25.07 to 58.59 mg/100 gDW). These results indicate that stage of ripeness significantly influences the contents of bioactive compounds in papaya fruit.     

Chemical and antioxidant properties of pomegranate cultivars grown in the Mediterranean region of Turkey

Arils from six pomegranate (Punica granatum L.) cultivars obtained from various sites from the Mediterranean region of Turkey were evaluated for their chemical and antioxidant properties. These properties included total phenolics (TP), total monomeric anthocyanins (TMA), soluble solids (TSS), titratable acidity (TA), individual sugars and organic acids. Antioxidant capacities of arils were determined by both the ferric reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. The antioxidant capacities averaged 5.60 and 7.35 mmol TE/l by the TEAC and FRAP methods. Variability among cultivars was greatest for TMA content (CV 132%); individuals ranged from 6.1 to 219 mg cy3-Gluc l⁻¹. TP means averaged 1507 mg GAE/l. Levels of FRAP, TEAC, TP, and TMA were strongly correlated (r = 0.82–0.96). The major sugars were fructose (6.4 g/100 ml) and glucose (6.8 g/100 ml), the major acids were citric (1.78 g/100 ml) and malic (0.12 g/100 ml).     

Phenolic composition,antioxidant and acetylcholinesterase inhibitory activities of Sclerocarya birrea and Harpephyllum caffrum (Anacardiaceae) extracts

Total phenolic content, proanthocyanidins, gallotannins, flavonoids, and antioxidant activities of Sclerocarya birrea and Harpephyllum caffrum methanolic extracts were evaluated using in vitro assays. S. birrea young stem extract contained the highest levels of total phenolic content (14.15 ± 0.03 mg GAE/g), flavonoids (1.21 ± 0.01 mg CE/g) and gallotannins (0.24 ± 0.00 mg GAE/g). H. caffrum stem bark extract had the highest content of proanthocyanidins (1.47%). The EC₅₀ values of the extracts in the DPPH free radical scavenging assay ranged from 4.26 to 6.92 μg/ml, compared to 6.86 μg/ml for ascorbic acid. A dose-dependent linear curve was obtained for all extracts in the ferric-reducing power assay. Dichloromethane and methanol extracts exhibited dose-dependent acetylcholinesterase inhibitory activity. Similarly, all extracts exhibited high antioxidant activity comparable to butylated hydroxytoluene based on the rate of β-carotene bleaching (84.1–93.9%). The two Anacardiaceae species provide a source of natural antioxidants and acetylcholinesterase inhibitors, and may be beneficial to the health of consumers.     

Chemical,biochemical and electrochemical assays to evaluate phytochemicals and antioxidant activity of wild plants

Plants are a source of compounds that may be used as pharmacologically active products. Cytisus multiflorus, Filipendula ulmaria and Sambucus nigra have been used as important medicinal plants in the Iberian Peninsula for many years, and are claimed to have various health benefits. Herein, the phytochemical composition and antioxidant activity of the mentioned wild medicinal plants were evaluated in vitro, based on chemical, biochemical and electrochemical methods. F. ulmaria was found to be richest in antioxidant phytochemicals, such as phenolics (228 mg GAE/g DW), flavonoids (62 mg CE/g DW), ascorbic acid (2700 μg/g DW) and tocopherols (497 μg/g DW). The antioxidant activity was found to vary in the order: F. ulmaria > S. nigra > C. multiflorus, irrespective of the analysis method. Electrochemical methods have proven to be rapid and inexpensive techniques to characterise the antioxidant activity of plant extracts.     

Fluctuations in the phenolic content and antioxidant capacity of dark fruit juices in refrigerated storage

The changes in total phenol content and antioxidant capacity were monitored in six industrial dark fruit juices during 29-day refrigerated storage. The initial total phenol values ranged from 1302.1 mg/L GAE (strawberry) to 1919.8 mg/L GAE (black currant) with a mean of 1573.3 mg/L GAE. All juices exhibited fluctuations in TP values with a marked increase after 48 hours in refrigerated storage, and a greater overall TP content in 5/6 studied juices after 29 days. Antioxidant capacity was evaluated using the DPPH radical scavenging assay and cyclic voltammetry (CV) and expressed as Trolox equivalent antioxidant capacity (TEAC). Black currant juice exhibited the highest TEAC values according to both CV (2.42 mM Trolox) and the DPPH assay (5.68 mM Trolox), while cranberry juice antioxidants exhibited the greatest storage stability and the smallest antioxidant capacity decrease on day 29, 20% (CV) and 15% (DPPH assay). At the end of 29-day storage 5/6 juices exhibited a significant loss in antiradical activity and all 6 juices exhibited a significant loss in TEAC derived from CV measurements. Significant linear correlation was observed between the results of CV measurements and the DPPH antiradical activity (r² = 0.62).