Chemical composition,antioxidant and cytotoxicity activities of the essential oils of Myristica fragrans and Morinda citrifolia

BACKGROUND: In this study the chemical composition, antioxidant activities and cytotoxic effect of the essential oils of Myristica fragrans (nutmeg) and Morinda citrifolia (mengkudu) were determined. RESULTS: Thirty‐eight compounds in nutmeg oil and six compounds in mengkudu oil were identified by gas chromatography–mass spectrometry. The free radical scavenging activity of nutmeg oil was superior of that mengkudu oil. The MTT assay of nutmeg oil on human colorectal carcinoma (HCT‐116) and human breast carcinoma (MCF‐7) cell lines showed IC₅₀ values of 78.61 and 66.45 µg mL^?1, respectively. The mengkudu oil exhibited IC₅₀ values of 91.46 and 78.15 µg mL^?1 for HCT‐116 and MCF‐7, respectively. CONCLUSION: The results showed that nutmeg oil can be developed as potent anti‐cancer and antioxidant drugs. Copyright © 2011 Society of Chemical Industry     

In vitro antioxidant and antiproliferative activity of three rosemary (Rosmarinus officinalis L.) extract formulations

Antioxidant and antiproliferative activities of three rosemary extract formulations (VivOX 20, VivOX 40 and Inolens 50) with different contents of carnosic acid, carnosol and methylcarnosol were tested in vitro. Electron spin resonance measurements revealed that Inolens 50 extract that contained highest amount of carnosic acid was the most potent scavenger of hydroxyl (concentration of extract where 50% of its maximal scavenging activity is observed, that is, EC₅₀, 109.54 μg mL^?1), superoxide anion (EC₅₀ = 7.94 μg mL^?1) and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) (EC₅₀ = 27.4 μg mL^?1)‐free radicals. Comparison of the radar charts of standard antioxidants and rosemary extracts showed similarity between antioxidant characteristics of Inolens 50 and chlorogenic and caffeic acids. Tested rosemary extracts exhibited significant (P ≤ 0.01) antiproliferative effect in cervix epitheloid carcinoma (HeLa), breast adenocarcinoma (MCF7) and colon adenocarcinoma (HT‐29) cell lines. In both MCF7 and HeLa cell lines, the extracts yielded very low IC₅₀ values (concentration of extract needed to inhibit cell growth by 50%), the most pronounced being for Inolens 50 in MCF7 (IC₅₀ = 9.95 μg mL^?1) and VivOX 20 in HeLa cell line (IC₅₀ = 10.02 μg mL^?1). The obtained results may provide support for the use of tested rosemary extracts as nutraceuticals and phytopharmaceuticals.     

Effect of rosehip (Rosa canina L.) phytochemicals on stable free radicals and human cancer cells

BACKGROUND: The commercial development of plants as sources of antioxidants that can be used to enhance the properties of foods, for nutritional purposes and preservation as well as for prevention of oxidation‐related diseases, is currently of major interest. Rosehip (Rosa canina L.) is a rich source of vitamin C and polyphenols. RESULTS: Phytochemicals in rosehip tea were separated into three fractions: Fr1 (vitamin C, 39.17 mg kg^?1), Fr2 (flavonoids, 451.05 µg kg^?1) and Fr3 (phenolic acids, 504.69 µg kg^?1). Quercetin and ellagic acid were the most abundant polyphenolic compounds. Rosehip fractions, primarily rosehip flavonoids (EC₅₀ = 49 mg L^?1), showed high antioxidant activity towards 2,2‐diphenyl‐1‐picrylhydrazyl radicals (DPPH^?). Cell growth effects of rosehip fractions were assessed in HeLa, MCF7 and HT‐29 cell lines, with the lowest IC₅₀ values being determined for rosehip flavonoids, (80.63, 248.03 and 363.95 mg L^?1 respectively). However, the vitamin C fraction did not inhibit the growth of tested tumour cells. CONCLUSION: The results of this study confirm that vitamin C and flavonoids are responsible for the antioxidant activity of rosehip tea, while only polyphenols contribute to its antiproliferative activity. Copyright © 2011 Society of Chemical Industry     

Optimisation of hydrolysis of purple sea urchin (Strongylocentrotus nudus) gonad by response surface methodology and evaluation of in vitro antioxidant activity of the hydrolysate

BACKGROUND: Hydrolysates prepared from sea urchin (Strongylocentrotus nudus) gonad by enzymatic treatment showed strong 1,1‐diphenyl‐2‐picrylhydrazyl radical scavenging activity and reducing power. RESULTS: Hydrolysis of S. nudus gonad by the commercial protease papain was optimised for maximum degree of hydrolysis (DH) and trichloroacetic acid‐soluble peptide index (TCA‐SPI) using response surface methodology. Results showed that the optimal conditions were the following: temperature of 48.83 °C, pH of 6.92, enzyme‐to‐substrate ratio of 3143 U g^?1, and substrate concentration of 83.5 g L^?1. Under these conditions, a DH of 27.96 ± 0.54% and a TCA‐SPI of 57.32 ± 0.63% were obtained. The hydrolysate prepared in the optimal conditions was fractionated by an ultra‐filtration system and the resultant fraction below 10 kDa was found to effectively scavenge hydroxyl radical (EC₅₀ = 13.29 ± 0.33 mg mL^?1) and hydrogen peroxide (EC₅₀ = 16.40 ± 0.37 mg mL^?1), inhibit lipid peroxidation (EC₅₀ = 11.05 ± 0.62 mg mL^?1), chelate Fe²⁺ (EC₅₀ = 7.26 ± 0.44 mg mL^?1), and protect mice macrophages against death induced by tert‐butyl hydroperoxide. CONCLUSION: Hydrolysates prepared from S. nudus gonad have the potential to be applied as natural antioxidant agents. Copyright © 2012 Society of Chemical Industry     

Characteristics of the leaf parts of some traditional Korean salad plants used for food

BACKGROUND: Total phenolics content, antioxidant activity and cytotoxicity of the methanol extracts from leaf parts of 13 Korean traditional salad plants were investigated in order to determine their properties. RESULTS: The highest phenolics content (mg ferulic acid equivalents kg^?1 dry weight (d.w.), omit one) was found in methanol extracts from Polygonum aviculare, at 293.7 ± 6.0, followed by Euonymus alatus, at 250.7 ± 3.3, Saxifraga stolonifera, at 125.0 ± 8.1 and Ligularia fischeri, at 122.5 ± 5.9. The methanol plant extracts dose‐dependently increased free radical scavenging activity. Methanol extracts of Polygonum aviculare, Euonymus alatus and Saxifraga stolonifera, at 31 mg kg^?1, exhibited the highest 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity (%) by 90.8 ± 4.2, 85.7 ± 3.9 and 64.1 ± 3.2, respectively. According to 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay, the methanol extracts from Portulaca oleracea (IC₅₀ < 25.0 µg mL^?1) showed the highest cytotoxicity against Calu‐6, followed by Plantago asiatica (49.2 µg mL^?1) and Osmunda japonica (89.6 µg mL^?1). CONCLUSION: Total phenolics content of the tested plant extracts was correlated with the DPPH radical scavenging activity, suggesting the phenolics compounds are contributing to the antioxidant properties of Korean salad plants. The leaf parts of the 13 Korean traditional salad plants described here that are currently used as foods may also provide some benefit to human health, and research into their potential benefits as preventative and/or therapeutic agents is warranted. Copyright © 2008 Society of Chemical Industry     

Antioxidant and semicarbazide‐sensitive amine oxidase inhibitory activities of alginic acid hydroxamates

The commercial polysaccharides of alginic acid (medium (3500 cps, 2% solution) and low (250 cps, 2% solution) viscosities) were esterified with acidic methanol (1 mmol L^?1 HCl) at 4 °C with gentle stirring for 5 days to obtain methyl esters of medium‐viscosity alginic acid (ME‐MVA) and low‐viscosity alginic acid (ME‐LVA). These ME‐MVA and ME‐LVA were reacted with alkaline hydroxylamine to obtain medium‐viscosity alginic acid hydroxamates (MVA‐NHOH) and LVA‐NHOH. The percentages of hydroxamic acid content in MVA‐NHOH and LVA‐NHOH were calculated as 25% and 20%, respectively. The hydroxamate derivatives of alginic acid were used to test the antioxidant and semicarbazide‐sensitive amine oxidase (SSAO) inhibitory activities in comparison with original materials (MVA and LVA). The half‐inhibition concentrations, IC₅₀, of scavenging activity against 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) were 24.5 and 29.8 µg mL^?1 for MVA‐NHOH and LVA‐NHOH, respectively. However, few scavenging activities of the MVA and LVA were found at the same concentrations. The IC₅₀ of the positive control of butylated hydroxytoluene was 5 µg mL^?1. The scavenging activity of DPPH radical was pH‐dependent, and the optimal pH for both of MVA‐NHOH and LVA‐NHOH was the Tris‐HCl buffer (pH 7.9). Using electron spin resonance (ESR) to detect the activity of scavenging hydroxyl radicals, both alginic acid hydroxamates showed dose‐dependent scavenging activities, and the IC₅₀ was 90 and 92 µg mL^?1, respectively, for MVA‐NHOH and LVA‐NHOH. Both alginic acid hydroxamates also exhibited protection against hydroxyl radical‐mediated DNA damage. Both MVA‐NHOH and LVA‐NHOH showed dose‐dependent inhibitory activities against bovine SSAO (2.53 units); the IC₅₀ was 0.16 and 0.09 µg mL^?1, respectively, for MVA‐NHOH and LVA‐NHOH, compared with 3.81 µg mL^?1 of semicarbazide (positive controls). Amine oxidase activity staining also revealed that both MVA‐NHOH and LVA‐NHOH exhibited SSAO inhibitory activities. Both MVA‐NHOH and LVA‐NHOH showed mixed non‐competitive inhibition against bovine SSAO. It was found that the V′_max value was reduced and the K′_m value was either increased (added MVA‐NHOH, 0.05 µg mL^?1) or reduced (added LVA‐NHOH, 0.11 µg mL^?1) in the presence of alginic acid hydroxamate. Copyright © 2006 Society of Chemical Industry     

Antioxidant and Antihemolytic Activities of Ethanolic Extract of Flowers,Leaves, and Stems of Hyssopus officinalis L. Var. angustifolius

In this study, antioxidant and antihemolytic activities of ethanolic extract of flowers, leaves, and stems of Hyssopus officinalis L. Var. angustifolius were investigated employing different in vitro assay systems. Extracts showed good antioxidant activity. IC₅₀ for 1,1-diphenyl-2-picryl hydrazyl radical-scavenging activity were 148.8 ± 4.31 μg mL^?1 for flowers, 79.9 ± 2.63 μg mL^?1 for stems, and 208.2 ± 6.45 μg mL^?1 for leaves. All extracts showed moderate iron (II) chelating ability. Extracts exhibited good antioxidant activity in the hemoglobin-induced linoleic acid model and also they were capable of scavenging hydrogen peroxide in a concentration dependent manner. Extracts showed good antihemolytic activity againts hydrogen peroxide-induced hemolysis (IC₅₀ were 48.51 ± 2.27 μg mL^?1 for flowers, 19.47 ± 0.73 μg mL^?1 for leaves, and 63.1 ± 2.65 μg mL^?1 for stems). The total amount of phenolic compounds in the extracts was determined as gallic acid equivalents and total flavonoid content was calculated as quercetin equivalents from a calibration curve.     

Mechanochemical‐assisted extraction and antioxidant activity of polysaccharides from Ganoderma lucidum spores

Mechanochemical‐assisted extraction (MCAE) method was developed to an effective method for polysaccharides extraction from Ganoderma lucidum spores. The MCAE parameters and the antioxidant activity of polysaccharides were investigated. Through response surface methodology design experiments, the processing conditions were optimised as follows: material/solid reagent (Na₂CO₃) 5 g·g^?1, milling time 20 min, solution/material ratio twenty (mL·g^?1) and extraction time 130 min. Under these conditions, the yield of polysaccharides was (5.92 ± 0.13)%, which was in close agreement with the predicted value. Compared with the heat‐reflux extraction method, the MCAE method had higher extraction yield, shorter extraction time and lower extraction temperature. In addition, the polysaccharides obtained from MCAE exhibit significant antioxidant activity.     

Isolation of a free radical‐scavenging antioxidant from water spinach (Ipomoea aquatica Forsk)

Ipomoea aquatica Forsk, a green leafy vegetable that is a rich source of vitamins and amino acids with many health benefits, has been explored for the isolation and identification of its bioactive compounds. Activity‐guided repeated fractionation of a methanol extract on a silica gel column followed by an XAD column yielded a compound that exhibited antioxidant activity with an EC₅₀ value of 83 ± 1.02 µg ml^?1 reaction mixture. It also showed very strong lipid peroxidation‐inhibitory activity in a liposome model system with an EC₅₀ value of 72.2 ± 0.9 µg ml^?1. However, it showed negligible metal‐chelating activity. Based on UV, 2D nuclear magnetic resonance and gas chromatography/mass spectrometry studies, the compound was tentatively identified to be 7‐O‐β‐D ‐glucopyranosyl‐dihydroquercetin‐3‐O‐α‐D ‐glucopyranoside. This is the first report on the antioxidant properties of I aquatica leaf extracts. Copyright © 2005 Society of Chemical Industry     

Chemical composition and in vitro antioxidant studies on Syzygium cumini fruit

Syzygium cumini, widely known as Jamun, is a tropical tree that yields purple ovoid fleshy fruit. Its seed has traditionally been used in India for the treatment of diabetes. Based on the available ethno‐pharmacological knowledge, further studies were extended to understand the chemical composition and antioxidant activities of three anatomically distinct parts of fruit: the pulp, kernel and seed coat. Fruit parts, their corresponding ethanol extracts and residues were evaluated for chemical composition. The alcoholic extract was evaluated for its antioxidant potential against DPPH^?, OH^?, O₂^?? and lipid peroxidation. The whole fruit consisted of 666.0 ± 111.0 g kg^?1 pulp, 290.0 ± 40.0 g kg^?1 kernel and 50.0 ± 15.0 g kg^?1 seed coat. Fresh pulp was rich in carbohydrates, protein and minerals. Total fatty matter was not significant in all three parts of fruit. Detailed mineral analysis showed calcium was abundant in all fruit parts and extracts. Total phenolics, anthocyanins and flavonoid contents of pulp were 3.9 ± 0.5, 1.34 ± 0.2 and 0.07 ± 0.04 g kg^?1, respectively. Kernel and seed coat contained 9.0 ± 0.7 and 8.1 ± 0.8 g kg^?1 total phenolics respectively. Jamun pulp ethanol extract (PEE), kernel ethanol extract (KEE) and seed coat ethanol extract (SCEE) showed a high degree of phenolic enrichment. DPPH radical scavenging activity of the samples and standards in descending order was: gallic acid > quercetin > Trolox > KEE > BHT > SCEE > PEE. Superoxide radical scavenging activity (IC₅₀) of KEE was six times higher (85.0 ± 5.0 µg mL^?1) compared to Trolox (540.0 ± 5.0 µg mL^?1) and three times compared to catechin (296.0 ± 11.0 µg mL^?1). Hydroxyl radical scavenging activity (IC₅₀) of KEE was 151.0 ± 5.0 µg mL^?1 which was comparable with catechin (188.0 ± 6.0 µg mL^?1). Inhibition of lipid peroxidation of the extracts was also studied and their activity against peroxide radicals were lower than that of standard compounds (BHT, 79.0 ± 4.0 µg mL^?1; quercetin, 166.0 ± 13.0 µg mL^?1; Trolox, 175.0 ± 4.0 µg mL^?1; PEE, 342.0 ± 17.0 µg mL^?1; KEE, 202.0 ± 13.0 µg mL^?1 and SCEE, 268.0 ± 13.0 µg mL^?1. Copyright © 2007 Society of Chemical Industry     

GC/MS analysis and antimicrobial and antioxidant activities of essential oil of Eucalyptus radiata

BACKGROUND: The essential oil from Eucalyptus radiata leaves collected in Tunisia was extracted by steam distillation and analysed by gas chromatography/flame ionisation detection and gas chromatography/mass spectrometry. Its antioxidant and antiradical properties were evaluated by the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) assays. The antimicrobial activity of the oil was examined in vitro against two plant‐pathogenic bacteria (four strains each of Agrobacterium tumefaciens and Pseudomonas savastanoi pv. savastanoi) and two plant‐pathogenic fungi (Fusarium solani and Rhizoctonia solani). RESULTS: Thirty‐five compounds were identified and quantified in the essential oil, the major ones being 1,8‐cineole (69.53%), α‐pinene (11.94%) and trans‐pinocarveol (4.81%). Medium antioxidant activity was found in the ABTS assay (IC₅₀ = 484.3 ± 17.3 mg L^?1), whereas no significant free radical‐scavenging activity was detected in the DPPH assay (IC₅₀ > 10 000 mg L^?1). The antimicrobial assays showed that the oil exhibited a high level of activity against A. tumefaciens and R. solani, with minimum inhibitory concentrations ranging between 750 and 1000 µL L^?1. However, it was less efficient against P. savastanoi pv. savastanoi and F. solani. CONCLUSION: The results indicate that the essential oil of E. radiata, with a high content of terpenic compounds, exhibits significant antimicrobial activity against strains of A. tumefaciens and the fungus R. solani and may therefore be useful for their control. Copyright © 2009 Society of Chemical Industry     

Assessment of in vitro antioxidant, antibacterial and immune activation potentials of aqueous and ethanol extracts of Phyllanthus niruri

BACKGROUND: Recently much attention has been paid to biologically active plants because of their low production cost and fewer adverse effects compared with chemical drugs. In the present investigation the bioactivity of Phyllanthus niruri ethanol and aqueous extracts was evaluated in vitro. RESULTS: The ethanol extract of P. niruri showed a high level of flavonoid content (123.9 ± 0.002 mg g^?1), while the aqueous extract showed the highest 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH; IC₅₀6.85 ± 1.80 µmol L^?1) and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS; 46.44 ± 0.53 µmol L^?1) free radical scavenging activities with high phenol content (376 ± 0.02 mg g^?1) and elevated levels of ferric reducing antioxidant power (FRAP; 23 883 ± 0.019 mmol g^?1) with excellent antibacterial activity against Staphylococcus aureus (20 mm inhibition zone) and Streptococcus agalactiae (12 mm inhibition zone), respectively, in addition to the best immune activation potential of human peripheral blood mononuclear cells (450.5%). CONCLUSIONS: It is clear from our results that both extracts of P. niruri has excellent bioactivity roles via elevated levels of antibacterial, antioxidant and percentage of peripheral blood mononuclear cell proliferation, which could lead to the development of medications for clinical use. Copyright © 2012 Society of Chemical Industry     

Browning,polyphenol oxidase activity and headspace gas composition during storage of minimally processed pears using modified atmosphere packaging

Modified atmosphere packaging was used to prevent browning of minimally processed Conference pears, thus extending their shelf‐life. Colour changes as well as PPO activity were strongly influenced by the package headspace gas composition, which was determined by the packaging conditions. The initial colour of minimally processed pears was preserved for several weeks under cold storage in plastic pouches of very low O₂ permeability and an initial atmosphere of 100% N₂. A fractional conversion kinetic model fitted the experimental browning data with high accuracy. Colour degradation (ΔE*) of minimally processed pears occurred exponentially (k_ΔE = 0.019–0.077 day^?1) owing to changes in lightness (k_L = 0.021–0.07 day^?1). In contrast, PPO exhibited a linear increase in activity which could be related to the availability of O₂ in the package headspace. © 2002 Society of Chemical Industry     

Biological activities of the essential oil and methanolic extract of Micromeria fruticosa (L) Druce ssp serpyllifolia (Bieb) PH Davis plants from the eastern Anatolia region of Turkey

The in vitro antimicrobial and antioxidant activities of the essential oil and methanolic extract of Micromeria fruticosa ssp serpyllifolia as well as the composition of the essential oil were examined. The essential oil exhibited activity against 14 bacteria, three fungi and a yeast, with minimal inhibitory concentration (MIC) values ranging from 31.25 to 125 µl ml^?1, whilst the methanolic extract was inactive. Antioxidant activity was measured by two methods, namely scavenging of the free radical DPPH and inhibition of linoleic acid oxidation. The methanolic extract exhibited significant antioxidant activity in both assays, providing 50% inhibition at 70.9 ± 0.5 µg ml^?1 concentration in the DPPH assay and inhibiting linoleic acid oxidation to 59% at 2 mg ml^?1 concentration, whilst the essential oil showed activity only at higher concentrations. The gallic acid equivalent total phenolic content of the methanolic extract was found to be 55.2 ± 2.00 µg mg^?1 dry weight extract (5.5% w/w). The chemical composition of the hydrodistilled essential oil was analysed by means of GC/MS. Twenty‐nine constituents were identified, the main ones being piperitenone (50.61%) and pulegone (29.19%). Copyright © 2004 Society of Chemical Industry     

Emissions of volatile organic compounds originating from UK livestock agriculture

In this paper we estimate the quantity of non‐methane volatile organic compounds (NMVOCs) emitted from UK livestock. The final estimate is derived from published values and from direct measurements of NMVOC emissions from dairy cattle slurry and laying hen manure. Emission rates of NMVOCs were determined for fresh dairy cattle slurry and laying hen manure using a 40 m³ emissions chamber. Dimethyl sulphides dominated emissions from laying hen manure at 753 ± 263 g m^?3 day^?1. Emissions from dairy cattle slurry were dominated by volatile fatty acids (C₂? C₅, 6.3 ± 3.1 g m^?3 day^?1) and phenols (2.4 ± 1.2 g m^?3 day^?1). Many of these NMVOCs are decomposition products from protein sources from which ammonia is also a by‐product. There is a close association between ammonia and NMVOC production from manure, and on this basis we estimated the annual NMVOC emissions from UK livestock as 165 ± 56 kt for 2002. These emissions compare to those from the larger industrial and transport sectors and exceed the 50–100 kt C year^?1 currently determined as originating from biogenic sources including agriculture. These findings have implications for air quality, and these NMVOCs may affect the cleansing capacity of the troposphere. Copyright © 2004 Society of Chemical Industry     

A two‐step inoculation of Candida etchellsii to enhance soy sauce flavour and quality

Effects of novel two‐step inoculation to enhance soy sauce special flavour in Candida etchellsii were investigated at the cell growth phase. The first‐stage consists of a 5% culture inoculum of log phase cells at 30‐day. Subsequently, a 20% culture inoculum of stationary phase cells was added at 60‐day. The resulting amino nitrogen and soluble salt‐free solid yield reached 9.15 ± 0.12 and 269.60 ± 3.15 mg L^?1 in 30 °C incubator experiments, increased by 23.1% and 17.6%, respectively, as compared to the control without culture inoculation. Maximal free amino acid yield of 58.21 ± 1.77 g L^?1 was achieved, and 39 types of volatile flavour compounds content was 17.81 ± 0.45 g L^?1, which were 1.76% and 178.7% higher than the control. A novel two‐step inoculation using the C. etchellsii yeast was developed and optimised. It was proven to be a feasible reproducible process for industrial application for the improvement of the flavour and quality of soy sauce production.     

Carboxymethylation of corn bran polysaccharide and its bioactive property

Corn bran polysaccharides were extracted using an ultrasonic‐assisted method with a yield of 33.50% and then carboxymethylated. The occurrence of modification was confirmed using Fourier transform infrared spectral analysis. The surface of polysaccharide particles became loosened following the carboxymethylation. The effect of sodium hydroxide concentration, reaction temperature, and the reaction time on the degree of substitution was investigated, and the relationship among the substitution degree, total phenolic content and antioxidant activity were studied. With sodium hydroxide concentration of 6.0 mol L^?1, keeping the reaction temperature of 60 °C and reaction time of 5.0 h, the modified polysaccharides possessed the highest degree of substitution and antioxidant activity. Cell culture model indicated that the carboxymethylated polysaccharide significantly inhibited the proliferation of A549 and HepG‐2 cells, and these antitumour characteristics may be associated with the elevated expression of CASP3, CASP8, CASP9, and p53, as well as the significantly decreased expression of Bcl‐2 and iNOS genes. The excellent antioxidant capacity and strong antitumour activity of these polysaccharides might provide a potential application as a naturally functional ingredient.     

Isolation and identification of an antioxidant flavonoid compound from citrus-processing by-product

BACKGROUND: Large amounts of citrus by‐products are released from juice‐processing plants every year. Most bioactive compounds are found in the peel and inner white pulp. Flavonoids are a widely distributed group of bioactive compounds. The methanolic extract of citrus peel powder has been shown to possess strong antioxidant activity. Therefore the aim of this study was to isolate the major antioxidant flavonoid compound from Citrus unshiu (satsuma) peel as citrus by‐product and evaluate its antioxidant activity. RESULTS: The major flavonoid isolated from C. unshiu peel was identified as quercetagetin. The structure of the compound was determined by tandem mass spectrometry and ultraviolet spectroscopy. Its antioxidant activity was assessed by assays of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical, hydroxyl radical and intracellular reactive oxygen species (ROS) scavenging and DNA damage inhibition. Quercetagetin showed strong DPPH radical‐scavenging activity (IC₅₀7.89 µmol L^?1) but much lower hydroxyl radical‐scavenging activity (IC₅₀203.82 µmol L^?1). Furthermore, it significantly reduced ROS in Vero cells and showed a strong protective effect against hydrogen peroxide‐induced DNA damage. CONCLUSION: The results of this study suggest that quercetagetin could be used in the functional food, cosmetic and pharmaceutical industries. Copyright © 2011 Society of Chemical Industry     

Physicochemical, functional and angiotensin converting enzyme inhibitory properties of amaranth (Amaranthus hypochondriacus) 7S globulin

BACKGROUND: Amaranth 7S globulin is a minor globulin component and its impact on the properties of an amaranth protein ingredient depends on its proportion in the variety of amaranth being considered. Some physicochemical, functional and angiotesin I‐converting enzyme (ACE) inhibitory properties of amaranth vicilin were studied in this work and compared with the 11S globulin. RESULTS: Fluorescence spectroscopy results indicated that 7S globulin tryptophans were more exposed to the solvent and, by calorimetry, the 7S globulin denaturation temperature (T_d) was found lower than the 11S globulin T_d, suggesting a more flexible structure. The 7S globulin surface hydrophobicity was higher than that of the 11S globulin, which is in agreement with the better emulsifying properties of the 7S globulin. The solubility in neutral buffer of the 7S globulin (851 ± 25 g kg^?1) was also higher than that of the 11S globulin (195 ± 6 g kg^?1). Bioinformatic analyses showed the presence of ACE inhibitory peptides encrypted in 7S tryptic sequences and peptides released after in vitro gastrointestinal digestion showed a high ACE‐inhibitory capacity (IC₅₀ = 0.17 g L^?1), similar to that of 11S globulin peptides. CONCLUSION: Compared with the 11S globulin, the 7S globulin presents similar ACE inhibitory activity and some functional advantages, better solubility and emulsifying activity, which suits some food requirements. The functional behavior has been related with the structural properties. Copyright © 2011 Society of Chemical Industry     

Extraction of saponin from Camellia oleifera cake and evaluation of its antioxidant activity

Response surface methodology was employed to optimise extraction conditions of saponins from Camellia oleifera cake. Optimal conditions were extraction at 82.2 °C for 3.3 h with an 8.6:1 ratio (mL g^?1) of solvent to solid. The saponin extract was further extracted with n‐butanol, and nine saponins were found as the main components. The identification of these saponins was carried out by HPLC–ESI–MS, and their possible structures were given. Antioxidant activities of the saponins were evaluated in vitro by 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH), 1, 2, 3‐phentriol self‐oxidation and metal chelating activity assays. IC₅₀ value of each assay was 3866 ± 3, 4744 ± 2 and 2389 ± 2 μg mL^?1, respectively. The effects of environmental factors on antioxidant activity of saponins from C. oleifera cake were studied for the first time. The antioxidant activity is pH dependent with 9.0 as the optimal pH and is also temperature independent.