Phytonutrients affecting hydrophilic and lipophilic antioxidant activities in fruits,vegetables and legumes

The antioxidant activities of fruits (n = 21), vegetables (n = 67) and legumes (n = 7) commonly consumed in Korea were determined by both the lipophilic antioxidant performance assay (LAP) and the hydrophilic oxygen radical absorbance capacity assay (ORAC). The LAP assay used the lipophilic radical initiator MeO‐AMVN [2,2′‐azobis(4‐methoxy‐2,4‐dimethylvaleronitrile)] and the lipophilic probe BODIPY 581/591 [4,4‐difluoro‐5‐(4‐phenyl‐1,3‐butadienyl)‐4‐bora‐3a, 4a‐diaza‐s‐indacene‐3‐undecanoic acid]. The ORAC assay used the hydrophilic radical initiator AAPH [2,2′‐azobis(2‐amidinopropane) dihydrochloride] and the hydrophilic probe fluorescein. In addition, the lipid‐soluble phytonutrients, carotenoids and tocopherols were determined by a reverse‐phase HPLC system using a C30 column with a UV detector. The water‐soluble phytonutrient, ascorbic acid, was analyzed using an HPLC system with an electrochemical detector. Total phenols were determined by UV spectrophotometry. Tocopherols (r = 0.774, p < 0.0001) and carotenoids (r = 0.569, p < 0.0001) were significantly correlated with LAP in total samples (n = 95). ORAC was significantly correlated with total phenols (r = 0.893, p < 0.0001), but not with ascorbic acid (r = 0.009, p = 0.929) in total samples (n = 95). These data indicate that carotenoids and tocopherols and total phenols are the major contributors to the lipophilic and hydrophilic antioxidant capacities, respectively. Therefore, the contribution of both the hydrophilic and lipophilic components of fruits and vegetables should be considered when determining the actual ‘total’ antioxidant activity of fruits and vegetables. Copyright © 2007 Society of Chemical Industry     

基于HepG2细胞模型的褐赭色羊肚菌多酚抗氧化及抗增殖活性研究

本实验研究了褐赭色羊肚菌游离酚和结合酚体内抗氧化能力以及对HepG2细胞的毒性和抗增殖作用。采用HPLC对褐赭色羊肚菌多酚组分进行鉴定,测定多酚抗氧化能力指数(ORAC);以人肝癌细胞HepG2为模型,测定多酚细胞抗氧化活性(CAA值)及抗增殖活性(EC50值)。结果显示:褐赭色羊肚菌游离酚和结合酚含量分别为(4.27±0.07)、(0.14±0.01)mg GAE/g DW;其ORAC值分别为(4624.52±400)、(429.41±60)μmol TE/100 g DW;CAA值分别为(15.33±0.60)、(0.37±0.01)μmol QE/100 g DW(PBS清洗)和(51.84±0.83)、(1.27±0.04)μmol QE/100 g DW(不经PBS清洗)。游离酚和结合酚浓度为125μg/m L和70μg/m L时,对HepG2细胞增殖抑制率分别为77.28%、66.31%,且试验浓度范围内,羊肚菌多酚对HepG2基本无细胞毒性。褐赭色羊肚菌多酚具有一定的细胞抗氧化及抗增殖活性,可将褐赭色羊肚菌作为开发此类功能营养食品的原料,为羊肚菌的进一步综合利用提供理论依据。     

茶籽油防晒功效的研究与应用

利用朗伯-比尔定律,从波长200~500 nm测定各溶液的紫外吸光度,确定最大吸收波长证明茶籽油等在250~360 nm处有很好的紫外吸收能力。把天然茶籽油、生物活性物质D按一定比例调配成最佳配方,从240~400 nm测定产品紫外吸光度,绘制、分析紫外吸收图谱。将天然茶籽油、生物活性物质D与具有物理防晒的TiO2为紫外吸收剂相结合,制成具有良好的紫外吸收效果的O/w型防晒霜,天然绿色,成本低廉,具有很大的市场开发潜力。     

Monitoring Insulin Aggregation via Capillary Electrophoresis

Early stages of insulin aggregation, which involve the transient formation of oligomeric aggregates, are an important aspect in the progression of Type II diabetes and in the quality control of pharmaceutical insulin production. This study is the first to utilize capillary electrophoresis (CE) with ultraviolet (UV) detection to monitor insulin oligomer formation at pH 8.0 and physiological ionic strength. The lag time to formation of the first detected species in the aggregation process was evaluated by UV-CE and thioflavin T (ThT) binding for salt concentrations from 100 mM to 250 mM. UV-CE had a significantly shorter (5-8 h) lag time than ThT binding (15-19 h). In addition, the lag time to detection of the first aggregated species via UV-CE was unaffected by salt concentration, while a trend toward an increased lag time with increased salt concentration was observed with ThT binding. This result indicates that solution ionic strength impacts early stages of aggregation and β-sheet aggregate formation differently. To observe whether CE may be applied for the analysis of biological samples containing low insulin concentrations, the limit of detection using UV and laser induced fluorescence (LIF) detection modes was determined. The limit of detection using LIF-CE, 48.4 pM, was lower than the physiological insulin concentration, verifying the utility of this technique for monitoring biological samples. LIF-CE was subsequently used to analyze the time course for fluorescein isothiocyanate (FITC)-labeled insulin oligomer formation. This study is the first to report that the FITC label prevented incorporation of insulin into oligomers, cautioning against the use of this fluorescent label as a tag for following early stages of insulin aggregation.     

A review of the antioxidant potential of medicinal plant species

Some researchers suggest that two-thirds of the world's plant species have medicinal value; in particular, many medicinal plants have great antioxidant potential. Antioxidants reduce the oxidative stress in cells and are therefore useful in the treatment of many human diseases, including cancer, cardiovascular diseases and inflammatory diseases. This paper reviews the antioxidant potential of extracts from the stems, roots, bark, leaves, fruits and seeds of several important medicinal species. Synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxylanisole (BHA) are currently used as food additives, and many plant species have similar antioxidant potentials as these synthetics. These species include Diospyros abyssinica, Pistacia lentiscus, Geranium sanguineum L., Sargentodoxa cuneata Rehd. Et Wils, Polyalthia cerasoides (Roxb.) Bedd, Crataeva nurvala Buch-Ham., Acacia auriculiformis A. Cunn, Teucrium polium L., Dracocephalum moldavica L., Urtica dioica L., Ficus microcarpa L. fil., Bidens pilosa Linn. Radiata, Leea indica, the Lamiaceae species, Uncaria tomentosa (Willd.) DC, Salvia officinalis L., Momordica Charantia L., Rheum ribes L., and Pelargonium endlicherianum. The literature reveals that these natural antioxidants represent a potentially side effect-free alternative to synthetic antioxidants in the food processing industry and for use in preventive medicine.     

二氧化氯-碘-丙二酸-硫酸化学振荡体系的探讨

对ClO2-I2-CH2（COOH）2-H2SO4化学振荡封闭体系,改变体系中各反应物的初始浓度,在350 nm处检测I3-的吸光度随反应时间的变化,结果发现丙二酸、碘及硫酸的初始浓度越高,二氧化氯的浓度越低,振荡的振幅越大,波数越少;当反应组分浓度较高时反应物一经混合振荡立即出现,没有诱导期,但当反应组分浓度较低时存在诱导期。     

p型透明导电氧化物CuCrl-xMgxO2的制备及光电性能研究

采用溶胶-凝胶法制备了CuCr1-xMgO2粉末,压制烧结形成了CuCr1-xMgxO2陶瓷样品,研究了Mg2+掺杂量和压制压强对CuCrO2粉末和陶瓷的相组成、显微结构及光电性能的影响.结果表明:随着Mg2+掺杂量从0.01增加到0.07,所制CuCr1-xMgxO2粉末对紫外-可见光的吸收度增加,光学带隙宽度由3.25eV逐渐减小到2.86eV.随着Mg2+掺杂量或压制压强的增加,其相应陶瓷样品的电导率均先增大后减小.当Mg掺杂量x为0.03,压制压强为550 MPa时,制备的CuCr0.97Mg0.03O2陶瓷样品的电导率达到最大值,为19.8S/cm.     

磁场处理对水分子结构和CaCO3成核影响实验及分析

采用紫外可见分光光度法研究了CaCl2溶液在是否施加交变磁场及不同温度、浓度下吸光度的变化情况,证明了磁处理对水分子间结构状态的影响.通过对CaCO3溶液的电导率与加磁反应时间之间的实验分析,进一步验证了磁处理对CaCO3晶核生成的促进作用.     

常见服装面料的太赫兹光谱研究

利用自建的太赫兹时域光谱系统对生活中主要的常见服装面料进行了实验研究,实验中首先对棉、毛、麻、丝、涤纶、氨纶、混纺等这7 种典型面料分别进行测试,可以获得各自的太赫兹时域光谱,然后利用快速傅里叶变换关系分别对每个时域脉冲进行相关计算,最终获得这些面料的太赫兹频域光谱信息,尤其是样品的折射率和吸收系数等。研究表明,这些在可见光波段不透明的服装面料,在太赫兹频段几乎完全可透视,且没有特征吸收峰,该研究对于进一步开展隐藏危险物的识别和成像具有非常重要的意义。     

Metabolic profile and biological activities of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco: Studies on the essential oil and polar extracts

We investigated the metabolic profile and biological activities of the essential oil and polar extracts of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco collected in south Portugal. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that oxygen-containing monoterpenes was the principal group of compounds identified in the essential oil. Camphor (40.6%) and fenchone (38.0%) were found as the major constituents. High-performance liquid chromatography with diode array detection (HPLC–DAD) analysis allowed the identification of hydroxycinnamic acids (3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and rosmarinic acids) and flavones (luteolin and apigenin) in the polar extracts, with rosmarinic acid being the main compound in most of them. The bioactive compounds from L. pedunculata polar extracts were the most efficient free-radical scavengers, Fe²⁺ chelators and inhibitors of malondialdehyde production, while the essential oil was the most active against acetylcholinesterase. Our results reveal that the subspecies of L. pedunculata studied is a potential source of active metabolites with a positive effect on human health.