Sophia Jun Xue

Purification and identification of antioxidant peptides from grass carp muscle hydrolysates by consecutive chromatography and electrospray ionization-mass spectrometry

Grass carp muscles were hydrolyzed with various proteases (papain, bovine pancreatin 6.0, bromelain, neutrase 1.5MG and alcalase 2.4L) to extract antioxidant peptides. The hydrolysates were assessed using methods of hydroxyl radical scavenging ability and lipid peroxidation inhibition activity. Hydrolysate prepared with alcalase 2.4L was found to have the highest antioxidant activity. It was purified using ultrafiltration and consecutive chromatographic methods including ion-exchange chromatography, multilayer coil high-speed counter-current chromatography, and gel filtration chromatography. The purified peptide, as a potent antioxidant, was identified as Pro-Ser-Lys-Tyr-Glu-Pro-Phe-Val (966.3Da) using RP-HPLC connected on-line to an electrospray ionization mass spectrometry. As well, it was found that basic peptides had greater capacity to scavenge hydroxyl radical than acidic or neutral peptides and that hydrophobic peptides contributed more to the antioxidant activities of hydrolysates than the hydrophilic peptides. In addition, the amino acid sequence of the peptide might play an important role on its antioxidant activity.

Enhanced antioxidant and antityrosinase activities of longan fruit pericarp by ultra-high-pressure-assisted extraction.

The health benefits of fruits acting against chronic diseases are ascribed to their antioxidant activities which are mainly responsible due to the presence of phenolic compounds. The use of ultra-high-pressure-assisted extraction (UHPE) has shown great advantages for the extraction of these phenolic compounds from longan fruit pericarp (LFP). Studies were carried out to investigate the effects of UHPE at pressures of 200, 300, 400 and 500 MPa on total phenolic contents, extraction yield, antioxidant and antityrosinase activities from LFP. The antioxidant activities of these extracts were analyzed, using various antioxidant models like 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, total antioxidant capacity and superoxide anion radical scavenging activity. Extract from ultra-high-pressure-assisted extraction at 500MPa (UHPE-500) showed the highest antioxidant activities of all the tested models. In addition, it also showed moderate tyrosinase inhibitory activity. Three phenolic acids, namely gallic acid, ellagic acid, and corilagin were identified and quantified by HPLC. Corilagin content was the highest compared to other phenolic acids identified. UHPE-500 obtained the higher phenolic acid contents compared to other high pressure processing and conventional extractions (CE). Compared with CE, UHPE-500 exhibited good extraction effectiveness in terms of higher extraction yields with high phenolic contents and also with higher antioxidant and antityrosinase activities.

Inhibition effects and induction of apoptosis of flavonoids on the prostate cancer cell line PC-3 in vitro.

Myricetin and myricitrin are naturally occurring flavonoids have been suggested to play a role in inhibition of proliferation and transformation of carcinogenic cell. However, the underlying molecular mechanisms of their activity have not yet to be revealed. The aim of the present study was to clarify the molecular mechanisms of apoptosis cell on the prostate cancer induced by myricetin, myricitrin, quercetin and quercitrin. The MTT assay confirmed that myricetin had the strongest inhibitory effect on human prostate cancer cell line PC-3, myricitrin was second, and quercitrin was the weakest. A noticeable synergistic effect was observed with the inhibition of cell proliferation when myricetin was used in combination with myricitrin. In the concentration range of 37.5-300 μmol/L, the inhibitory effects of these flavonoids were enhanced with increasing dose and treatment time. The acridine orange analysis and annexin V-FITC/PI double-staining results confirmed that myricetin and myricitrin were effective in inducing PC-3 cell apoptosis. The results showed that myricetin was more effective than myricitrin in inducing cell apoptosis. The apoptosis rate increased with increasing flavonoid concentration in a dose dependent manner. A synergistic effect was observed on the apoptosis rate when myricetin was used in combination with myricitrin.

Effect of high-intensity ultrasound on the physicochemical properties and nanostructure of citrus pectin

BACKGROUND Modified pectin has been found to have various biological activities. The preparation of modified pectin is generally accomplished by either chemical or enzymatic depolymerisation processes, but both methods have several disadvantages. Ultrasound treatment is simple and requires shorter times and lower temperatures than conventional techniques used for processing plant materials. In recent years the application of ultrasound to modify polysaccharides has received increasing attention. The objective of this study was to use ultrasound to modify citrus pectin. RESULTS The average molecular weight of citrus pectin decreased under different ultrasonic conditions. The average molecular weight decreased from 464 to 296 kDa after 30 min of sonication. The degree of methylation of citrus pectin changed slightly and its monosaccharide component remained unchanged when high-intensity ultrasound was applied. The reduced (Gal+Ara)/Rha ratio after ultrasonication suggested degradation in the neutral sugar side chains of citrus pectin. Atomic force microscopy results confirmed the degradation of citrus pectin chains by ultrasound at nanolevel. CONCLUSION Ultrasound is an effective way to pretreat or modify pectin. The degradation of citrus pectin is due to the cavitational effects of ultrasound. Thus ultrasound may be useful in establishing environmentally friendly extraction and modification technologies for pectin.

Effect of the Complex of Zinc(II) and Cerium(IV) with Chitosan on the Preservation Quality and Degradation of Organophosphorus Pesticides in Chinese Jujube (Zizyphus jujuba Mill. cv. Dongzao)

The effects of a novel complex of zinc(II) and cerium(IV) with chitosan film-forming material on the preservation quality of Chinese jujube fruits (Zizyphus jujuba Mill. cv. Dongzao) and degradation of organophosphorus pesticides in the fruits during the room temperature storage were investigated. The results showed that after 18 days of storage, the weight loss, respiratory intensity, and polyphenol oxidase (PPO) activity of fruits treated with the complex were 11.72, 31.51, and 7.07% lower than the control. Furthermore, total soluble solids, ascorbic acid, and polyphenol contents were 15.45, 14.55, and 13.93% higher than the control. The degradation rates of chlorpyrifos and parathion were increased to 97.31 and 92.70% for the complex treatment, which were 30.18 and 17.02% higher than the control, respectively. Therefore, the complex can be applied for preserving Chinese jujube fruits to expand their shelf life and decrease residues of organophosphorus pesticides on the fruits.

Wound-healing Properties of the Oils of Vitis vinifera and Vaccinium macrocarpon

Vitis vinifera (grape) and Vaccinium macrocarpon (cranberry) are well known medicinal plants; most of the pharmacologically active phytochemicals have been isolated from the skin, fruit juice, fermented extract and alcohol fractions of the plants above. Here, the pharmacological properties of the phytochemical constituents present in oils of cranberry and grape were investigated. The oil of grape and cranberry has been evaluated for their wound healing activity by using an excision wound model in rats. The animals were divided into four groups of six each (n = 6). The experimental group 1 and 2 animals were treated topically with the grape and cranberry oil (100 mg/kg body weight), respectively. The controls were treated with petroleum jelly. The standard group of animals were treated with mupirocin ointment (100 mg/kg body weight). The healing was assessed by the rate of wound contraction and hydroxyproline content. On day 13, animals treated with cranberry oil exhibited a (88.1%) reduction in the wound area compared with grape‐oil treated (84.6%), controls (74.1%) and standard group animals (78.4%) (p < 0.001). The hydroxyproline content of the granulation tissue was significantly higher in the animals treated with cranberry and the grape‐oil (p < 0.000). Comparative investigation of the curative properties of the oils of V. vinifera and V. macrocarpon revealed a significant result which suggests their wound‐healing potential. Copyright

Production, Quality, and Biological Effects of Oolong Tea (Camellia sinensis)

Oolong tea is a semi-fermented Chinese traditional tea that dates back centuries and now its unique characteristics are attracting more and more consumers worldwide. The formation of Oolong teas special quality is attributed to the proper processing of the fresh tea leaf. The quality of Oolong tea can be evaluated by aroma, flavor, color, and appearance with aroma and flavor being the two most important quality indices. The formation of the distinct aroma of Oolong tea depends largely on the decomposition of lipids and carotenoids. However, other compounds that can be hydrolyzed and/or oxidized also contribute to Oolong teas special aroma. During the processing of Oolong tea, some major flavor compounds are formed by the oxidation of catechins, amino acids, and sugars. The flavor of Oolong tea is complex due to the interaction of many different flavor compounds. Oolong tea exhibits antioxidant, anticancer, antiobesity, prevention of atherosclerosis and heart disease, antidiabetes, and antiallergic effects. Management of environmental factors, selection of tea cultivars and improvements in tea production needs to be emphasized to ensure the high quality of Oolong tea. The exact mechanisms responsible for the beneficial health effects of Oolong tea are not known.

Biological properties and characterization of lectin from red kidney bean (Phaseolus vulgaris).

Red kidney beans (Phaseolus vulgaris) contain significant amounts of lectins which have both beneficial and detrimental biological properties. Lectins are carbohydrate-binding glycoproteins that can react specifically with human blood cells, preferentially agglutinate malignant cells, and undergo mitogenic stimulation of lymphocytes. Some lectins are resistant to heat and proteolytic enzymes and can enter the circulatory system intact. Phytohaemagglutinin (PHA)—a lectin isolated from the red kidney bean—consists of four subunits with a molecular weight of 125 kDa. This bioactive compound has been partially purified by affinity chromatography using Affi-gel Blue. PHA has been shown to inhibit the viral enzymes, immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT), and α- and β-glucosidases. This paper will review the chemical properties, biological activity, distribution, isolation, and heath benefits of red kidney bean lectin.

Solubility of Carotenoids in Supercritical CO2

Carotenoids have been shown to provide a range of health benefits and to decrease the risk of disease. Although carotenoids are naturally present in plants advanced extraction technologies to remove carotenoids from plant materials are needed to prepare concentrated materials. Because carotenoids are sensitive to heat, oxygen, and light, large-scale supercritical fluid extraction (SFE) has drawn attention as a separation technology. SFE with solvents such as CO2 offers an organic-chemical-free process that yields quality end food products, compared to traditional extraction methods that organic solvents. In the SFE process for plant materials, an important step is to measure and predict the solubility of target components in the supercritical fluid at various pressure and temperature conditions to optimize the extraction process. The solubility of targeted carotenoids in supercritical fluids is related to its physical and chemical properties such as polarity, molecular structure, and nature of the material particles, and it is also related to the operating conditions such as temperature, pressure, density of solvent and co-solvents, and solvent flow rate in the supercritical region. The solubility of β-carotene, α-carotene, and other carotenoids under different extraction conditions has been reviewed. It would be interesting and useful for researchers and food industries to compare the data of the solubility of carotenoids to develop optimum extraction process and to get maximum yields.

Wound-healing activity of the skin of the common grape (Vitis Vinifera) variant, Cabernet Sauvignon.

The common Grape L. (Vitaceae) is regarded as an important medicinal plant. European healers have suggested the use of grapevine sap, juice, and whole grape in the treatment of pain, allergic reactions, inflammation, and to promote wound healing. We evaluated grape‐skin powder for its wound‐healing activity using an excision wound model in rats. Animals were randomly divided into three groups of six (n = 6) each. The test group animals were treated topically with the grape‐skin powder (100 mg/kg/day). The controls and standard group animals were treated with petroleum jelly and mupirocin ointment respectively. Healing was assessed by the rate of wound contraction, period of epithelialization, and hydroxyproline content. On day 13, treatment of the wounds with grape‐skin powder enhanced significantly the rate of wound contraction (100 %). Treated animals showed significant decrease in the epithelialization period (p < 0.000) and increase in the hydroxyproline content (p < 0.05) when compared to control and the standard. Histological analysis was also consistent with the proposal that grape‐skin powder exhibits significant wound‐healing potential. Increased rate of wound contraction, hydroxyproline content, and decrease in epithelialization time in the treated animals support the use of grape‐skin powder in the management of wound healing. Copyright