Analysis and metabolite profiling of glucosinolates,anthocyanins and free amino acids in inbred lines of green and red cabbage (Brassica oleracea L.)

We profiled and quantified glucosinolates (GSLs), anthocyanins and free amino acids in thirty-seven inbred lines green and red cabbage. Analysis of these distinct cabbages revealed the presence of 8 GSLs, 13 anthocyanins and 12 free amino acids. GSL contents were varied among the different lines of cabbage. The maximum levels of glucoraphanin (14.91 μmol/g DW) and glucobrassicin (12.37) were found in FX 1-28 and FX 1-32 lines, respectively. Total GSLs in red cabbage lines were 50% higher than those of green cabbage. Anthocyanin contents in red cabbage were ranged from 4.11 to 6.81 mg/g DW in FX 2-3 and FX 1-34 lines, respectively. Among the 13 anthocyanins, both cyanidin 3-(feruloyl) (sinapoyl)diglucoside-5-glucoside and cyanidin 3-(sinapoyl) (sinapoyl)diglucoside-5-glucoside levels were the highest amounts. The amounts of total free amino acids were ranged from 523.5 to 1308 mg/100 g fresh weight (FW) in green cabbage and 484.8 to 1271 in red cabbage, respectively. In red cabbage lines, 9.4% of the total free amino acids accounted essential amino acids such as valine, threonine, isoleucine, leucine and lysine. Thus, the amounts of GSLs, anthocyanins, and amino acids varied widely, and the variations in these compounds between the lines of cabbage were significant.     

Identification and quantitative determination of glucosinolates in seeds and edible parts of Korean Chinese cabbage

Glucosinolates (GSLs) have attracted major interest due to the chemopreventive properties of some of their transformation products. GSLs in the seeds and edible parts of Korean Chinese cabbage (Brassicacampestris L. ssp. pekinensis) were identified and quantified by LC–ESI–MS and LC–UV. As a result, nine GSLs were identified: progoitrin, glucoraphanin, glucoalyssin, gluconapin, 4-hydroxy-3-indolylmethyl, glucobrassicanapin, glucoerucin, glucobrassicin, and 4-methoxyglucobrassicin. The total GSL levels were 268–198 and 23.0–15.8 μmol/g dry weight (DW) for seeds and edible parts, respectively. Gluconapin (197 μmol/g DW) was the highest individual GSL in seeds, whereas 4-methoxyglucobrassicin (6.08–4.94 μmol/g DW) and glucobrassicanapin (8.18–3.09 μmol/g DW) were found in the edible parts. In addition, LC–MS profiles of the nine GSLs identified from Korean Chinese cabbage were subjected to principal components analysis (PCA) to evaluate differences among samples. The metabolome among the four cultivar seed or edible parts was clearly separated by PCA.     

Variation of glucosinolates in vegetable crops of Brassica rapa L. ssp. pekinensis

Glucosinolates of Chinese cabbage (Brassica rapa L. ssp. pekinensis) from Korea were characterised to determine the total glucosinolate content and the diversity amongst glucosinolates; 24 varieties were analysed. The profiles of 14 glucosinolates identified from the leaves were subjected to principal component analysis (PCA) to evaluate the differences among varieties. The Kori, Sandun and e-Norang varieties separated from the others based on glucosinolate concentration. Genetically modified Chinese cabbage containing the bar gene could not be separated from non-genetically modified varieties. Glucobrassicanapin, 4-methoxyglucobrassicin, gluconapin and glucobrassicin in Chinese cabbage were confirmed as the main glucosinolate compounds. The Kori, Sandun and e-Norang varieties appear to be good candidates for future breeding programmes since they have a high glucosinolate content. The presence of indolic glucosinolates in all varieties should be studied more extensively because they are the precursor of indole-3-carbinol, a potent cancer chemopreventive agent.     

Determination of antioxidant activities of various extracts and essential oil compositions of Thymus praecox subsp. skorpilii var. skorpilii

The aim of this work is to examine the chemical composition and antioxidant activity of separated essential oils and different solvent extracts of Thymus praecox subsp. skorpilii var. skorpilii (TPS). The ethanol, acetone, methanol, hexane, aqueous extracts and separated essential oils of TPS were assessed for their antioxidant activities. Antioxidant activities were evaluated by reduction of Mo(VI) to Mo(V), reducing power, superoxide scavenging activity, free radical-scavenging activity, metal chelating activity, linoleic acid peroxidation, hydrogen peroxide scavenging activity and peroxide scavenging activity. Essential oils were characterized in total to be 41 components, whereas 9 components were isolated by column chromatography for antioxidant activity. TPS essential oil was found to contain thymol (40.31%) and o-cymene (13.66%) as the major components. The ethanol, methanol and water extracts exerted significant free radical-scavenging activity. The methanol and water extracts displayed highest superoxide scavenging activity. The water extract has the highest total phenolics (6.211 mg gallic acid (GAE)/g DW) and flavonoids (0.809 mg quercetin/g DW).     

Antioxidant activity and phenolic content of 16 raisin grape (Vitis vinifera L.) cultivars and selections

Six raisin grape cultivars and 10 new raisin grape selections were analyzed for antioxidant activity (ABTS assay) and for total and individual phenolic compounds. Samples were freeze–dried and values are reported on a dry weight basis. Antioxidant activity across the 16 samples ranged from 7.7 to 60.9 μmol Trolox/g DW, with A95-27 exhibiting the greatest activity. Total phenolic content, determined in gallic acid equivalents using the Folin–Ciocalteau assay, ranged from 316.3 to 1141.3 mg gallic acid/100 g DW and was strongly correlated (r = 0.990) with antioxidant results. Concentrations of individual phenolics were determined by HPLC. trans-Caftaric acid was the predominant compound in all samples. A95-15 contained the lowest concentration (153.5 μg/g DW) of caftaric acid, while Fiesta contained the highest concentration (598.7 μg/g DW). Selections A56-66, A95-15, and A95-27 had much higher levels of catechin (86.5–209.1 μg/g DW) and epicatechin (126.5–365.7 μg/g DW) than the other samples.     

Phenolic acid analysis and antioxidant activity assessment of oil palm (E. guineensis) fruit extracts

Phenolic compounds in oil palm fruit (E. guineensis) were extracted in soluble free (SFP), insoluble-bound (ISBP) and esterified (EFP) forms. The total phenolic content (TPC) of the oil palm fruit extracts was determined using the Folin–Ciocalteu method and found to range from 5.03 to 9.04 g/L per g of dried weight (DW). The antioxidant activities of oil palm phenolic extracts were analysed using free radical scavenging assays and results showed that oil palm phenolic extracts contained antioxidant activities in the order of ISBP > EFP > SFP. Eight different phenolic acids were identified and quantified using a simple reversed-phase high performance liquid chromatography (HPLC) with a diode array detector (DAD) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). Ferulic, p-hydroxybenzoic and p-coumaric acid were the dominant phenolic acids found in oil palm fruit extracts and ranged from 55 to 376 μg/g of DW.     

Comparison of the antioxidant activity of two Spanish onion varieties

Phenol content and antioxidant activity of two Spanish onion varieties, namely white onion and Calçot de Valls, have been studied. White onions contained higher phenol content than Calçot onions, with values which ranged from 2.57 ± 0.51 to 6.53 ± 0.16 mg gallic acid equivalents/g dry weight (GAE/g DW) and 0.51 ± 0.22 to 2.58 ± 0.16 mg GAE/g DW, respectively, depending on the solvent used. Higher phenol content was associated with higher antioxidant capacity. White onion extracts had the highest antioxidant activity at 86.6 ± 2.97 and 29.9 ± 2.49 μmol Trolox/g DW for TEAC and FRAP assays, respectively, while the values for the Calçot variety were 17.5 ± 0.46 and 16.1 ± 0.10 μmol Trolox/g DW.     

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.     

Essential oil composition of Pistacia lentiscus L. and Myrtus communis L.: Evaluation of antioxidant capacity of methanolic extracts

The seasonal variation of the essential oil composition, the antioxidant activity (DPPH, FRAP assays) and the total phenolic content (Folin-Ciocalteu assay) of two aromatic wild plants, Pistacia lentiscus L. (Anacardiaceae) and Myrtus communis L. (Myrtaceae), grown in Zakynthos, a Greek island, was investigated. The essential oil was obtained by hydrodistillation and subsequently analysed by GC–MS.     

Antimicrobial and antioxidant properties of the essential oils and methanol extract from Mentha longifolia L. ssp. longifolia

This study was designed to evaluate antimicrobial and antioxidant activities of the essential oil and methanol extract from Mentha longifolia ssp. longifolia. The essential oil showed strong antimicrobial activity against all 30 microorganisms tested whereas the methanol extract almost remained inactive. In contrast, the extract showed much better activity than the essential oil in antioxidant activity assays employed, e.g. in the inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene/linoleic acid systems. In the former, the extract was able to reduce the stable free radical DPPH with an IC₅₀ of 57.4 μg/ml while that of the oils was 10 700 μg/ml. When compared to BHT, a synthetic antioxidant, both showed weaker antioxidative potential. Similarly, in β-carotene/linoleic acid assay, these samples were not effectively able to inhibit the linoleic acid oxidation; exhibiting only 24% and 36% inhibitions at 2 mg/ml, respectively; both were far below than that of BHT. Total phenolic constituent of the extract was 4.5 g/100 g as gallic acid equivalent. GC–MS analysis of the oil resulted in the identification of 45 constituents, cis-piperitone epoxide, pulegone and piperitenone oxide being the main components.     

Phenolic acid contents of kale (Brassica oleraceae L. var. acephala DC.) extracts and their antioxidant and antibacterial activities

Nine phenolic acids were identified and quantified by HPLC–MS in leaves and 10 in seeds of kale (black cabbage). The free, ester (methanol-soluble), glycoside and ester-bound (methanol-insoluble) phenolic acid contents of the leaves were 487, 532, 4989 and 6402 ng/g fresh weight, respectively. Ferulic and caffeic acids (total contents; 4269 and 4887 ng/g, respectively) were the most abundant. The seed contents of these fractions were 1993, 1477, 1231 and 4909 ng/g dry weight (DW), respectively, and sinapic acid was the most abundant (5037 ng/g DW). The fractions’ total phenolic contents, determined colorimetrically, were highly correlated with their DPPH scavenging capacity, and in antimicrobial activity assays, with nine test organisms representing a wide array of taxa, all of the fractions were effective against Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis and (most strongly) Moraxella catarrhalis. Antimicrobial and antioxidant activities of kale phenolics in free and conjugated forms are discussed.     

Effects of binary solvent extraction system,extraction time and extraction temperature on phenolic antioxidants and antioxidant capacity from mengkudu (Morinda citrifolia)

An investigation into the effects of ethanol concentration (0–100%, v/v), extraction time (20–120 min) and extraction temperature (25–65 °C) on the extraction of phenolic antioxidants from mengkudu (Morinda citrifolia) was performed using a single-factor experiment. Total phenolic content (TPC) and total flavonoid content (TFC) assays were used for determination of phenolic compounds. Antioxidant capacity was evaluated by measuring the scavenging effect on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radicals. Experimental results showed that extraction conditions had significant effect on extraction of phenolic compounds and antioxidant capacities. The optimised conditions were 40% ethanol for 80 min at 65 °C, with values of 919.95 mg GAE/100 g DW for TPC, 472.73 mg CE/100 g DW for TFC, 791.71 μmol TEAC/100 g DW for ABTS and 1928.5 μmol TEAC/100 g DW for DPPH. TPC was significantly correlated with DPPH under the effects of ethanol concentration (r = 0.932) and extraction time (r = −0.938).     

A comparative study of tocopherols composition and antioxidant properties of in vivo and in vitro ectomycorrhizal fungi

In aerobic organisms, the free radicals are constantly being produced during the normal cellular metabolism. The antioxidant properties of many organisms and particularly of wild mushrooms with their content in antioxidant compounds such as tocopherols, can detoxify potentially damaging forms of activated oxygen. Herein, a comparative study of tocopherols composition and antioxidant properties of in vivo (fruiting bodies) and in vitro (mycelia) ectomycorrhizal fungi: Paxillus involutus and Pisolithus arhizus. Tocopherols were determined by high performance liquid chromatography (HPLC) coupled to a fluorescence detector. The antioxidant properties were studied in terms of DPPH radical-scavenging activity, reducing power and inhibition of β-carotene bleaching. Fruiting bodies revealed the highest antioxidant properties, including scavenging effects on free radicals (EC₅₀ = 0.61 and 0.56 mg/ml) and inhibition of lipid peroxidation capacity (EC₅₀ = 0.40 and 0.24 mg/ml for P. involutus and P. arhizus, respectively), than mycelia produced in vitro cultures. Nevertheless, mycelia revealed higher levels of total tocopherols than fruiting bodies, and particularly P. arhizus mycelium proved to be a powerful source of γ-tocopherol (154.39 μg/g dry weight).     

The antioxidant activity and the bioactive compound content of Stevia rebaudiana water extracts

Stevia rebaudiana (SR), a chrysanthemum herb, has been used as a vegetable-based sweetening additive in health drinks and in other foods. This study was conducted to investigate the antioxidant activity and the bioactive compounds found in water extracts taken from SR leaves and calli. Analysis of vitamins in the leaves showed that folic acid (52.18 mg/100 g) was a major component, followed by vitamin C. The total phenolic and flavonoid contents were found to be 130.76 μg catechin and 15.64 μg quercetin for leaves and 43.99 μg catechin and 1.57 μg quercetin for cellus at mg of water extracts, respectively. Pyrogallol was the major material among the phenolic compounds in both leaf and callus extracts. Furthermore, our results showed that the leaf extracts contained higher amounts of free radicals, hydroxyl radicals and superoxide anion radical scavenging activities than those of the callus extracts.     

Effect of damaged starch on acrylamide formation in whole wheat flour based Indian traditional staples, chapattis and pooris

Variation in acrylamide content of two Indian traditional products, chapatti and poori was observed with respect to the damaged starch content in whole wheat flour of different wheat varieties from which these products were prepared. Wheat cultivar ‘lokwan’ was milled by altering mill aperture, feed rate and moisture content to obtain whole wheat flour with damaged starch contents ranging from 6.23% to 28.12%. Acrylamide content of the chapatti and pooris prepared from such flours ranged from 12.5 to 65.5 μg/kg in chapatti, and 25.5 to 130.5 μg/kg in pooris. Impact of several additives showed 10 μmol/g flour citric acid, and 100 μmol/g flour calcium chloride to reduce acrylamide in pooris by approximately 54% and 72%, respectively, without altering the sensory analysis of the products.     

Antioxidant activity of Mammea longifolia bud extracts

Mammea longifolia buds (nagkesar) are extensively used in India as a minor spice. The antioxidant activity of its methanol (NM) and aqueous-ethanol (NW) extracts were evaluated by several in vitro experiments, e.g., DPPH, hydroxyl, superoxide radicals and H₂O₂-scavenging assays as well as inhibition of Fe(II)-induced lipid peroxidation of rat liver mitochondria. The extracts were found to possess impressive antioxidant activity in all the tests, the activity of NW being higher than that of NM in most of the assays. The differential activities of NW and NM could be correlated with their respective total phenolic, flavonoid and proanthocyanidin contents.     

Antioxidant properties of dried product of ‘haba-nori’, an edible brown alga, Petalonia binghamiae (J. Agaradh) Vinogradova

Dried ‘haba-nori’ Petalonia binghamiae, a brown alga, is a traditional food in the fisheries towns in Japan. To determine the antioxidant properties of the dried P. binghamiae, assays for antioxidant activities, including ferrous-reducing power, ferrous ion chelating, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and scavenging of a superoxide anion radical-generated by non-enzymatic system were tested in this study. A water extract solution contained total phenols at about 75 μmol phloroglucinol equivalents/g dry sample and showed strong antioxidant activities in the reducing power, DPPH radical and superoxide anion radical scavenging assays. The antioxidant activities were detected in high-molecular (>100 kDa), 10–30 kDa, and low-molecular (<5 kDa) fractions and were correlated with, not only phenolic compounds, but also brown compounds. The radical- scavenging activities were increased by heat treatment at 121 °C for 1 h. These results suggest that P. binghamiae is both a useful seafood and a healthy food with antioxidant activity.     

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.     

In vitro determination of antioxidant activity of proteins from jellyfish Rhopilema esculentum

In this study, the antioxidant activity of proteins isolated from jellyfish, Rhopilema esculentum Kishinouye (R. esculentum), was determined by various antioxidant assays, including superoxide anion radical-scavenging, hydroxyl radical-scavenging, total antioxidant activity, reducing power and metal chelating activity. Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol, vitamin C and mannitol were used as standards in those various antioxidant activities. The crude protein (CP) and the protein fractions isolated by Sephadex chromatography, first peak (FP) and second peak (SP), had very low reductive power and metal chelating abilities compared to EDTA, but they showed strong scavenging effects on the superoxide anion radical, hydroxyl radical and varying total antioxidant activity. FP and SP exhibited stronger scavenging effects on the superoxide anion radical than BHA, BHT or α-tocopherol. The EC₅₀ values of FP and SP were 6.12 and 0.88 μg/ml, respectively, while values EC₅₀ of BHA, BHT and α-tocopherol were 31, 61 and 88 μg/ml, respectively. CP, FP and SP showed far higher hydroxyl radical-scavenging activities than did vitamin C or mannitol. The EC₅₀ values of CP, FP and SP were 48.76, 45.42 and 1.52 μg/ml, but EC₅₀ values of vitamin C and mannitol were 1907 and 4536 μg/ml, respectively. In a β-carotene–linoleate system, SP and CP showed antioxidant activity, but lower than BHA. Of the three samples, SP had the strongest antioxidant activity. So, SP may have a use as a possible supplement in the food and pharmaceutical industries.