In vivo and in vitro testing for selenium and selenium compounds bioavailability assessment in foodstuff

The assessment of selenium and selenium species bioavailability in foodstuff is of special concern on the context of human nutrition. In vivo (human and animal), and in vitro tests are important approaches for estimating the bioavailability of toxic and essential compounds to humans. An overview on in vivo and in vitro bioavailability assays for releasing selenium and selenium species in foodstuffs is summarized. Se and Se species content in a foodstuff critically influence Se bioavailability and bioactivity to humans and animals. Se bioavailability is affected by foodstuff-matrix major composition and minor components. Foodstuffs processing and/or treatments could enhancement or decrease Se bioavailability. Experimental conditions such as the selection of healthy status of examined people (in in vivo humans approaches), the selection of animal model (in vivo animals approaches), or the selection of GI conditions (in in vitro tests) could determines the results. Thus, international standardized protocol for in vivo and in vitro approaches assessment is mandatory.     

Determination of sun protection factors. Correlation between in vivo human studies and an in vitro skin cast method

Sun protection factors were determined by both an in vitro method which used resin casts taken from replicas of human skin and by an in vivo SPF method. Thirty-eight product development samples were tested for the level of sun protection using both methods and the results were compared. The values obtained showed a positive relationship which was closely approximated by a log-linear regression of in vivo data on in vitro data (regression coefficient, r² = 0.86).
It is concluded that the cast technique is quick, convenient, inexpensive and in its present form useful for screening sunscreen products prior to in vivo SPF testing.     

天然调味香料月桂精油化学成分的研究

采用水蒸气蒸馏法提取了调味香料月桂的精油,并利用气相色谱/质谱(GC/MS)联用技术和保留指数比较法分析了该精油的化学成分.从月桂的精油中鉴定了44种化合物,占精油总量的99.97％.主要成分为α-乙酸松油酯(19.52％)、肉桂醛(8.00％)、β-按叶油醇(6.18％)、β-石竹烯(5.72％)和丁香酚甲醚(5.25％).     

Exploitation of essential oil extracted from Tunisian Laurus nobilis for the development of PET antibacterial sutures

The main purpose of this study is the use of a Tunisian bio resource for the improvement of mechanical and physical properties of braided polyethylene terephthalate (PET) sutures. In this study, antibacterial PET sutures were developed using Tunisian essential oil of Laurus nobilis. A new lubrication process was proposed for this fact. The essential oil of L. nobilis was selected because of its antibacterial properties as well as analgesic, antiseptic, antiviral, and anti-infectious proprieties. Optimized extraction process of essential oil was also determined. Characteristics and cytotoxicity of extracted essential oil were also investigated. In order to study the impact of lubrication conditions on PET suture performances, mechanical properties and antibacterial effects of braided sutures were studied. The obtained results prove that sutures lubrication improves suture knot efficiency and leads to smoother surface. Developed sutures show also obvious antibacterial effect against Staphylococcus aureus ATCC 6538 G (+) colonies.     

In vitro skin permeation evaluation: the only realistic option

Increasing requirements for cruelty-free risk assessment in the cosmetic industry have led to the development of several alternative experimental evaluation strategies. Quantification of the potential dermal absorption of ingredients of cosmetic and other formulations by determination of human skin permeation rates in vitro is particularly relevant. Using modifications of standard in vitro protocols the human skin permeation rates of several cosmetic ingredients and potential contaminants have been determined under conditions designed to mimic consumer use. Skin penetration and permeation of octyl salicylate (a sunscreen), nonylphenol ethoxylates (surfactants) and three nitrosamines (potential contaminants) is discussed. The data demonstrate the usefulness of this technique as a tool in the overall risk assessment of cosmetic formulations.     

Evaluation of a gas in vitro system for predicting methane production in vivo

Methane production from ruminant livestock varies with the diet as a result of factors such as dry matter intake, diet composition, and digestibility. To estimate the effect of dietary composition and feed additives, CH₄ production can be measured in vitro as a first step because large numbers of samples can be incubated and analyzed at the same time. This study evaluated a recently developed in vitro method for prediction of in vivo CH₄ production by examining the relationship between predicted and observed CH₄ production values. A total of 49 different diets (observations), used in previous 13 in vivo studies, were selected to include diets varying in nutrient composition. Methane production was measured in all in vivo studies by respiration chambers or the GreenFeed system (C-Lock Inc., Rapid City, SD). Overall, the in vitro system predicted CH₄ production well (R² = 0.96), but the values obtained were slightly underestimated compared with observed in vivo values (mean 399 L/d compared with 418 L/d: root mean square prediction error = 51.6 L/d or 12.3% of observed mean). Further analysis of the effect on residuals showed no significant relationship between CH₄ production and most factors known to affect CH₄ production such as dry matter intake, digestibility, and dietary concentrations of fat and starch. However, some factors included in the model were not well predicted by the system, with residuals negatively related to neutral detergent fiber concentration and positively related to concentrate proportion. The in vitro system can thus be useful for screening diets and evaluation of feed additives as a first step that can be best interpreted when feeding cows at maintenance level.     

中华圆田螺肉抗氧化肽的分离纯化及小鼠体内外活性研究

采用超滤、大孔树脂、凝胶过滤色谱和半制备液相色谱对中华圆田螺肉的酶解液进行分离纯化,以DPPH自由基清除率、ABTS自由基清除率、铁离子还原能力(FRAP)、氧自由基吸收能力(ORAC)为指标,制备抗氧化肽,并通过小鼠体内抗氧化酶活性及MDA生成量进行测定试验。结果表明:分子质量1kDa部位的抗氧化活性最强,分离出的混合物抗氧化肽纯度达到90%。体外抗氧化活性显示,该抗氧化肽的DPPH自由基清除率、ABTS自由基清除率、ORAC均为最高,且ORAC与谷胱甘肽相比效果无显著差异(P0.05),通过小鼠体内抗氧化酶及MDA增加值的测定显示,除GSH-PX外,试验组与谷胱甘肽阳性对照组无显著差异(P0.05),说明试验所获得的抗氧化肽具有和谷胱甘肽相当的抗氧化活性,具有深层的开发利用价值。     

In vitro gas and methane production of silages from whole-plant corn harvested at 4 different stages of maturity and a comparison with in vivo methane production

The current study investigated the relationship between in vitro and in vivo CH₄ production by cows fed corn silage (CS)-based rations. In vivo CH₄ production was measured in climate respiration chambers using 8 rumen-cannulated Holstein-Friesian cows. In vitro CH₄ production was measured using rumen fluid from the 8 cows that were fully adapted to their respective experimental rations. The animals were grouped in 2 blocks, and randomly assigned to 1 of the 4 total mixed rations (TMR) that consisted of 75% experimental CS, 20% concentrate, and 5% wheat straw [dry matter (DM) basis]. The experimental CS were prepared from whole-plant corn that was harvested at either a very early (25% DM), early (28% DM), medium (32% DM), or late (40% DM) stage of maturity. The 4 experimental TMR and the corresponding CS served as substrate in 2 separate in vitro runs (each run representing 1 block of 4 animals) using rumen fluid from cows fed the TMR in question. No relationship was found between in vivo CH₄ production and in vitro CH₄ production measured at various time points between 2 and 48 h. None of the in vitro gas production (GP) and CH₄ production parameters was influenced by an interaction between substrate and origin of rumen fluid. In vitro measured 48-h GP was not affected by the maturity of whole-plant corn, irrespective whether CS alone or as part of TMR was incubated in adapted rumen inoculum. Incubation of the experimental TMR did not affect the kinetics parameters associated with gas or CH₄ production, but when CS alone was incubated the asymptote of GP of the soluble fraction was slightly decreased with increasing maturity of CS at harvest. In vitro CH₄ production expressed as a percent of total gas was not affected by the maturity of whole-plant corn at harvest. Several in vitro parameters were significantly affected (GP) or tended to be affected (CH₄) by diet fed to donor cows. It was concluded that the current in vitro technique is not suitable to predict in vivo CH₄ production from CS-based rations.     

羟基红花黄色素A体外消化特性与体内代谢规律研究

目的 研究羟基红花黄色素A (hydroxysafflor yellow A, HSYA)体外模拟胃肠道系统中的稳定性,口服后小鼠组织中的分布,以及HSYA跨小肠上皮细胞膜运输能力。方法 体外模拟胃肠道消化实验采用紫外分光光度法检测体外模拟胃肠道消化分别为1和2h后的HSYA的全光谱特性以及高效液相色谱法(high performance liquid chromatography,HPLC)测定HSYA的含量,动物实验包括3种不同摄入方式:腹腔注射、灌胃及长期饲喂。腹腔注射和灌胃给药方式分别有两个时间点:1和2 h,剂量为0.01 mL/g;长期饲喂方式为含有2.5%红花小花饲喂10周,采集小鼠组织,样品处理采用6%高氯酸和甲醇沉淀蛋白法,利用HPLC测定样本中HSYA的含量。HSYA与小肠上皮细胞共培养不同时间后,吸取培养液,把细胞裂解后,通过HPLC测定培养液和裂解后的HSYA含量。结果 体外消化实验结果表明,胃、肠道消化后的HSYA结构未被破坏, HSYA在胃肠道的稳定性较好;腹腔注射红花水提物后HSYA在小鼠血清、肝脏、肾、肺中的含量随着时间延长而下降,只有肌肉中HSYA的含...     

石榴籽油的体内抗氧化性评价

利用水酶法提取石榴籽油,以5、10、15 mL/(kg.bw.d)3种剂量的石榴籽油分别给低剂量组(5 mL/(kg.bw.d))、中剂量组(10 mL/(kg.bw.d))和高剂量组(15 mL/(kg.bw.d))的昆明小鼠经口灌胃,空白对照组以蒸馏水灌胃,30 d后全部小鼠颈椎脱臼处死,快速取出肝、脑组织并测定其中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)的活性和丙二醛(MDA)的含量。结果显示:低剂量石榴籽油试验组小鼠肝、脑组织中SOD、GSH-PX等抗氧化酶活性明显高于正常对照组(p0.05),而脑中的MDA含量明显低于正常对照组(p0.05)。表明适当剂量石榴籽油可以增强机体的抗氧化机能,从而延缓衰老的发生。     

Short‐term in vivo digestibility assessment of a highly oxidized and polymerized sunflower oil

The aim of this study was to test the in vivo digestibility of a highly polymerized sunflower oil. The true digestibility of both the unheated oil and of an oil heated at frying temperature (180 °C) for 50 h in the presence of air was determined by using a 4 h in vivo test after applying the oil by an oesophageal probe to Wistar rats followed by high‐performance exclusion chromatography analysis of the luminal remaining fat. The true digestibility coefficient of the heated oil did not change significantly with respect to the unheated oil, although it tended to decrease (p < 0.1; 38%). The true digestibility of polymers, dimers, and total oligomers was 30%, 59%, and 38% respectively, whereas those of the unheated oil was much higher (95%, 90%, and 91% respectively). True digestibility did not change for the triacylglycerol monomers. The plasma concentration of triacylglycerol tended to decrease (9.7%; p > 0.05) in the rats receiving the heated oil, suggesting some delay in the absorption mechanism. Data show that thermoxidized compounds from abused oil are poorly but actively hydrolysed and absorbed in vivo. Copyright © 2003 Society of Chemical Industry     

In vitro and in vivo determinations of sun protection factors of sunscreen lotions with octylmethoxycinnamate

The aim of this work was to evaluate the correlation between in vitro and in vivo determinations of sun protection factors (SPF) of sunscreen lotions containing the synthetic sunscreen octyl methoxycinnamate. Three sunscreen lotions containing either 2, 4.5 or 7.5% octyl methoxycinnamate were prepared. The in vitro SPFs of these sunscreen lotions were determined according to the spectrophotometric method of Mansur et al. The in vivo SPF values were determined according to the Food and Drug Administration (FDA) method. The results indicate that there was a good correlation between the in vitro and in vivo determinations for the sunscreen lotions examined.     

In vitro cultured human skin cells as alternatives to animals for skin irritancy screening

In the last few years a lot of attention has been paid to the development of the in vitro models which would substitute for animals in cutaneous irritancy studies. These models explore either organ or explant cultures using freshly excised skin or serial cultures of isolated skin cells (epidermal keratinocytes or dermal fibroblasts). The organ or explant models are suitable only for short exposures of skin samples to the compounds tested and the use of it will always be restricted by the limited availability of fresh human skin. The model that uses submerged cultures of keratinocytes or fibroblasts permits the production of a large number of cells, and permits large scale toxicity screening tests with many substances, that can be applied in a broad concentration range. Since the stratum corneum is absent in conventional (submerged) keratinocyte culture systems, this model is mainly suited for testing of water soluble compounds and it is less suitable for poorly soluble compounds and for topical products consisting of complex formulations which are made of active ingredients and their vehicles. This shortcoming can be overcome by using ‘organotypic cultures’in which keratinocytes are grown at the air-liquid interface on a suitable dermal substrate. Under these conditions, the culture forms a multilayered epidermis showing an overall structure which resembles that of a native epidermis. The presence of a coherent stratum corneum layer in these cultures permits the application of potential irritants at concentrations and in formulations as applied in vivo. For the evaluation of toxicity a number of tests have already been developed: assessment of cell viability, changes in cell morphology, modulation of cell proliferation and differentiation, monitoring of membrane damage, the measurements of the uptake or incorporation of radioactive precursors, establishment of the modulation of cell metabolism, determination of the release of inflammatory mediators, etc. All these in vitro techniques are still in a state of validation as far as their predictive value for in vivo skin irritancy is concerned.     

沙棘籽渣酶解产物的体内外抑菌作用

以沙棘籽渣为原料,采用水提法提取沙棘籽渣蛋白,再用ProteAX复合蛋白酶和胃蛋白酶两种酶酶解,利用膜过滤对其分离纯化,得到具有抑菌活性的沙棘籽渣蛋白酶解物。体外实验结果表明：ProteAX复合蛋白酶水解多肽对金黄色葡萄球菌、沙门氏菌、绿脓杆菌均有抑制作用,胃蛋白酶水解多肽对大肠杆菌、金黄色葡萄球菌、沙门氏菌有抑制作用。动物实验表明：胃蛋白酶水解多肽灌胃的小鼠粪便中,沙门氏菌的菌落总数与阳性对照组相比显著减少（P＜0.05）;而灌胃ProteAX复合蛋白酶水解多肽的小鼠粪便中,金黄色葡萄球菌的菌落总数比阳性对照组显著降低（P＜0.05）。     

芦苇叶黄酮类提取物体内体外抗氧化性研究

研究醇提芦苇叶黄酮类提取物的体内体外抗氧化性。通过测定芦苇叶黄酮类提取物对体外大鼠肝组织匀浆、肝线粒体丙二醛（malondialdehyde,MDA）生成量及大鼠红细胞溶血的影响。结果表明：芦苇叶黄酮类提取物在0.5～10 mg/mL范围内能抑制大鼠肝组织匀浆及肝线粒体MDA的生成,抑制大鼠红细胞溶血,具有量效关系,表明芦苇叶黄酮类提取物具有体外抗氧化效果。随着剂量的增加,芦苇叶黄酮类提取物可提高S180荷瘤小鼠血清中谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）和超氧化物歧化酶（superoxide dismutase,SOD）活性,降低MDA含量,从而提高其体内抗氧化活性,当剂量达到300 mg/（kg·d）时,芦苇叶黄酮类提取物与10 mL/（kg·d）的氟尿嘧啶均可促进荷瘤小鼠体内抗氧化能力的提高,且二者间没有显著性差异。     

芹菜籽精油的抑菌与抗氧化作用研究

目的:测定芹菜籽精油(Celery seed essential oil)对几种常见食品污染微生物的抑菌活性以及抗氧化作用。方法:采用琼脂扩散法及肉汤稀释法测定精油的抑菌作用、采用DPPH(对二苯代苦味肼基)法、ABTS(2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐)法、清除超氧离子法和抗亚油酸脂质过氧化法测定芹菜籽精油的清除自由基、抗氧化作用。结果:芹菜籽精油对于多种病原性微生物有良好的抑制作用,尤其对于革兰氏阳性菌,抑制效果尤为明显。并且,芹菜籽精油具有良好的清除自由基、抗氧化的作用,其作用要强于丁基羟基苯甲醚(BHA)和二丁基羟基甲苯(BHT)。