The influence of flavonoids on the binding of pantoprazole to bovine serum albumin by spectroscopic methods: With the viewpoint of food/drug interference

The interaction of pantoprazole to bovine serum albumin (BSA) has been investigated with and without four popular 5,7,3',4'-hydroxy-substituted flavonoids, quercetin, luteolin, taxifolin and (+)-catechin. The presence of flavonoids decreased binding constants of pantoprazole with BSA from 39.7% to 93.8%, which depended on flavonoid structures. Analysis of infrared spectroscopy (IR) and circular dichroism (CD) showed the binding of pantoprazole to BSA caused apparent change in secondary structure of BSA. The calculated values of spatial-distance indicated the existence of quercetin, luteolin and taxifolin may compete with pantoprazole binding to BSA, while the existence of (+)-catechin possibly formed ternary pantoprazole-BSA-(+)-catechin complex. However, all the fluorescence quenching was initiated by static quenching procedure irrespective of the absence or presence of flavonoids, while van der Waals force and hydrogen bonds played major roles for pantoprazole-BSA association. All above results may have relevant consequence in rationalising the interferences of common food to gastric ulcer treatments.     

Enhancing aspalathin stability in rooibos (Aspalathus linearis) ready-to-drink iced teas during storage: the role of nano-emulsification and beverage ingredients, citric and ascorbic acids

BACKGROUND: The effects of citric and ascorbic acids on the stability of aspalathin in rooibos (Aspalathus linearis) ready‐to‐drink (RTD) formulations containing fermented rooibos extract (FR), aspalathin‐enriched green rooibos extract (GR) and aspalathin‐enriched green rooibos extract ascorbic acid solubilisate (GR‐solubilisate) were investigated during storage (12 weeks at 25 °C). RESULTS: Storage of iced tea formulations containing FR and GR extracts reduced their flavonoid content. The aspalathin content of FR iced tea without citric or ascorbic acid was reduced to undetectable levels by week 8 of storage. Addition of citric acid resulted in improved stability of aspalathin, but ascorbic acid did not impart additional stability. Iso‐orientin and orientin were less affected than aspalathin, presumably owing to partial conversion of aspalathin to these flavones. Similar results were obtained for GR iced tea formulations. Improved stability of aspalathin was noted in iced tea containing GR‐solubilisate with or without citric acid. Lower pH was shown to favour stability, especially for fermented rooibos iced teas. CONCLUSION: Citric and ascorbic acids contribute to the stability of rooibos flavonoids during storage. Differences in stability between formulations are not due to pH differences but may be related to the matrix. Copyright © 2011 Society of Chemical Industry     

Flavonoids and Antioxidant Activity of Fresh Pepper (Capsicum annuum) Cultivars

Flavonoid, ascorbic acid and total phenolic content and antioxidant activity of “jalapeño” (Veracruz, Mitla, Tam Mild, Jaloro, Sweet Jalapeño), “yellow wax” [(Hungarian Yellow, Long Hot Yellow, Gold Spike (hybrid)], “Chile” (New Mexico-6, Green Chile), “ancho” (San Luis Ancho), and “serrano” (Hidalgo) peppers were investigated at green or yellow stages of maturity. Major pepper flavonoids were quercetin and luteolin which were present in conjugate forms. Total flavonoid content varied from none detectable to 800 mg/kg after hydrolysis. “Chile”, “yellow wax” and “ancho” peppers had greater flavonoid and ascorbic acid contents and antioxidant activities than “jalapeño” peppers. Sep-Pak C₁₈(tm) bound phenolic compounds, including flavonoids, correlated well with antioxidant activity (r²=0.86). Luteolin had highest antioxidant activity followed by capsaicin and quercetin on equimolar basis.     

APPLICATION OF THE OXIDATIVE STABILITY INDEX FOR ASSESSING THE ANTIOXIDANT PROPERTIES OF FLAVONOIDS1

The antioxidant activities of representative flavonoid classes (flavonols, flavones, flavanones, isoflavones and flavanols) relative to dl‐α‐tocopherol were evaluated using the Oxidative Stability Index (OSI) value. At 5 mM concentrations in tocopherol stripped corn oil (TSCO), antioxidant activity was determined as follows: (+) catechin > quercetin > (+,?) taxifolin > dl‐α‐tocopherol > THI (3′, 4′, 7‐trihydroxyisoflavone) > luteolin. Intra‐assay and inter‐assay coefficients of variation were 1.43% and 2.73%. Peroxide Induction (PI) values were utilizéd as a comparison method using compounds and conditions identical to those in OSI experiments. Relative values for OSI and PI of the flavonoids tested showed a 0.98 correlation. This method also revealed differences in antioxidant activity of catechins due to stereochemistry. The OSI offers a simple, reproducible method for the evaluation of flavonoid antioxidant activities in a lipid environment.     

Degradation kinetics of ascorbic acid in encapsulated spray-dried honey powder packaged in aluminium laminated polyethylene and high-density polyethylene

The present study evaluated the stability of nutritionally rich encapsulated spray-dried honey powders in terms of hygroscopicity, glass transition temperature, total phenolic content, antioxidant activity and ascorbic acid using maltodextrin, gum arabic, and whey protein concentrate as carriers during a storage period of 180 days using high-density polyethylene and aluminium laminated polyethylene as packaging materials at 25°C (room temperature) and 35°C (accelerated temperature). The results revealed that temperature caused a negative influence on the glass transition temperature and stability of ascorbic acid. The kinetics of ascorbic acid degradation followed a first-order reaction with a reaction rate constant dependent on temperature and packaging material. Honey powder developed with whey protein concentrate as carrier agent and stored in aluminium laminated polyethylene pouches at 35°C possessed the highest antioxidant activity and ascorbic acid due to the presence of phenolic compounds in honey, aonla (Emblica officinalis. Gaertn), and basil (Ocimum sanctum) extract. The honey powders stored in aluminium laminated polyethylene pouches showed comparatively better antioxidant properties (total phenolic content, ascorbic acid, and antioxidant activity) and minimum hygroscopicity than the powders stored in high-density polyethylene at both the storage temperatures.     

高效液相色谱法同时测定仙鹤草中6 种黄酮

目的：建立超声辅助萃取-高效液相色谱法分离仙鹤草中芦丁、花旗松素、香豆素、木犀草素、山奈酚和芹菜素6 种黄酮及其含量测定的方法。方法：采用Phenomenex C18色谱柱（150 mm×4.6 mm,5 μm）分离6 种成分;流动相为甲醇-0.1%醋酸溶液,梯度洗脱;流速0.8 mL/min,紫外检测波长320 nm,柱温35 ℃。结果：6 种成分在15 min内均达到基线分离,线性关系良好（r不低于0.999 1,n=6）,平均回收率均在97.78%～104.4%之间（相对标准偏差小于1.20%,n=3）。结论：本实验采用超声波法提取,方法简单、快速、经济、可靠,可用于仙鹤草的质量监控。     

贮藏温度对新鲜茎瘤芥品质和保鲜的影响

研究不同贮藏温度对新鲜茎瘤芥品质和保鲜效果的影响。茎瘤芥经预处理后,用聚乙烯袋(厚度0.03mm)包装,分别贮藏于相对湿度(RH)85%～95%的0、5、10℃和15℃恒温箱中,统计22d贮藏期内发芽率、腐烂率、商品率,每5d测定抗坏血酸、可溶性固形物、可溶性蛋白等指标。结果表明：0℃和5℃的低温贮藏与10℃和15℃的贮藏条件相比,显著提高了茎瘤芥的商品率,降低了茎瘤芥的发芽率、腐烂率、质量损失率,延缓了抗坏血酸、可溶性固形物和可溶性蛋白含量的下降,但不同温度间总酚和类黄酮变化规律性不强。其中0℃贮藏效果最好,商品率100%、腐烂率0%,贮藏期可达50d,且保持了茎瘤芥良好的品质,贮藏至第20天,其抗坏血酸分别比10、15℃贮藏的茎瘤芥高109%和208%,可溶性蛋白较5、10℃和15℃贮藏高16.7%、59.0%和89.6%。由此可知,10、15℃不利于茎瘤芥保鲜与贮藏,而0℃和5℃对茎瘤芥具较好保鲜效果,保持茎瘤芥良好的采后品质,但0℃总体上优于5℃,故0℃是茎瘤芥最适宜的贮藏温度。     

黄花菜中黄酮类物质抗氧化性的研究

采用浓度为95％的乙醇提取黄花菜中的总黄酮物质，分光光度法测定黄花菜中的总黄酮含量，提取率为6.85％。研究了黄花菜中黄酮类化合物对超氧自由基、羟基自由基的清除作用，结果表明：黄花菜中黄酮类化合物对清除自由基有明显的作用，黄酮类化合物的添加量在试验范围内与其抗氧化性呈正相关；同时还研究了提取物与Vc的协同抗氧化作用，证明有较好的增效作用。     

天山茶茎黄酮苷元提取工艺优化及其生物活性

为了优化天山茶藨茎5种黄酮苷元（木犀草素、槲皮素、山奈酚、异鼠李素、芹菜素）的酸水解提取工艺,评价其体外抗氧化和α-葡萄糖苷酶抑制活性,本文利用UPLC-MS/MS法测定天山茶藨茎5种黄酮苷元的提取率,通过单因素实验和正交试验优化天山茶藨茎黄酮苷元酸水解提取工艺。利用DPPH、ABTS自由基清除实验测定天山茶藨茎提取物及5种黄酮苷元的抗氧化活性,并测定了其α-葡萄糖苷酶抑制活性。结果表明,5种黄酮苷元的检出限、定量限分别在0.8~1.6、2.9~5.4 μg/L,在3.2~207.0 μg/L范围内具有良好的线性关系（R2≥ 0.9962）,方法的稳定性、精密度和重复性良好（RSD≤4.4%）。确定最佳酸水解提取工艺为:90%甲醇溶液（含5%盐酸）、提取温度:70℃、提取时间:100 min,该条件下,总黄酮苷元提取率为4.06 mg/g,RSD<5%,表明正交试验优化的提取条件稳定可行。天山茶藨茎提取物及5种黄酮苷元均具有一定的α-葡萄糖苷酶抑制活性和抗氧化活性,其中甲醇盐酸提取物与5种黄酮苷元的α-葡萄糖苷酶抑制活性均高于阳性对照阿卡波糖（IC₅₀:53.84±2.41 mg/L）,槲皮素对DPPH自由基的清除活性最好（IC₅₀:（2.94±0.18） mg/L）,木犀草素、山奈酚对ABTS自由基清除活性较好（IC₅₀分别为（5.34±0.10）、（5.55±0.17） mg/L）,它们的抗氧化活性高于阳性对照V_C。本研究建立的UPLC-MS/MS方法灵敏、精确、高效,可以对天山茶藨茎5种黄酮苷元化合物同时进行定量分析。优化的酸水解提取工艺能有效提高天山茶藨茎黄酮苷元的提取率。     

LC-DAD-ESI/MS analysis of flavonoids and abscisic acid with chemometric approach for the classification of Slovenian honey

The flavonoid profiles of seven types of Slovenian honey were analysed. The flavonoids are phenolic compounds that have health-related properties, and their presence in honey is attributed to the plants visited by the bees. The flavonoids were extracted from honey samples by solid-phase extraction and analysed by liquid chromatography, with diode array detection and electrospray ionisation mass spectrometry (LC-DAD-ESI/MS). The honey samples had similar, but quantitatively different, flavonoid profiles. The flavonoids myricetin, luteolin, quercetin, naringenin, apigenin, kaempferol, pinocembrin, chrysin and galangin were identified using reference standards, while pinobanksin was tentatively identified through its retention time, m/z, UV spectrum and MS/MS data. Two non-phenolic compounds were also identified; cis–trans-abscisic acid and, tentatively, trans–trans-abscisic acid. The analysis did not show any specific compounds to use as markers for determination of the botanical origins of these different types of Slovenian honey. Further analyses of more honey samples with additional standards are needed to identify such potential markers, although linear discriminant analysis correctly classified 85% of these honey samples according to their botanical origins.     

Degradation Kinetics and Storage Stability of Vacuum Spray-Dried Micro Wet-Milled Orange Juice (<Emphasis Type="Italic">Citrus unshiu</Emphasis>) Powder

The aim of this work was to evaluate the degradation kinetics and stability of micro wet milled orange juice powders obtained by vacuum spray drying, using maltodextrin as a carrier agent. Powders were produced with four combinations of orange juice solids/maltodextrin solids 60:40, 50:50, 40:60, and 30:70 by weight. Ascorbic acid degradation, color, and antioxidant activity of powders were evaluated throughout 90 days. Powders were stored at 10, 25, and 35 °C and relative humidity of 33%. Temperature and storage time negatively influenced the stability of ascorbic acid and color, whereas antioxidant activity increased at the beginning of storage at a higher temperature then decreased slightly after 60 days. For stability study, powders were stored at different water activities (0.11 to 0.84) in order to determine the plasticizing effects of water on glass transition temperature. Both water activity and glass transition temperature were used to predict the critical conditions for storage. Vacuum spray dried powder produced with a ratio of 30:70 (orange juice solids/maltodextrin solids) was considered as the most stable, since it showed highest critical water activity (a_w?=?0.61) and lowest moisture content (0.11 g water/g of dry solid) among the four powders. Vacuum spray drying using superheated steam as the heating medium was proven to be an effective way of producing orange juice powders with minimum loss of nutrients.     

Major flavonoids of Argentinean honeys. Optimisation of the extraction method and analysis of their content in relationship to the geographical source of honeys

In the present research we optimised an extraction procedure for the flavonoid aglycones: myricetin, quercetin and luteolin from honeys (as natural biological matrices), based on Amberlite XAD-4 resin followed by HPLC quantification. In addition, honeys from three geographical regions of Argentina were analysed with regard to the contents of these flavonoids. The extraction procedure was optimised for XAD-4 resin considering: resin/honey ratio, elution volume to desorb flavonoids and colour intensity of honeys. Differences in flavonoid recoveries were observed depending on the colour intensity. The flavonoid aglycones contents, in accordance with differences in geochemical characteristics and typical vegetation, varied with the geographical origin of honeys. The results obtained allowed us to consider these three flavonoids as chemical markers for the phytogeographical origin of honeys. In the case of monofloral honeys, the contribution of each one of the flavonoids was associated with the presence of a dominant pollen kind in these samples.     

Effect of moisture content, storage temperature and storage period on colour, ascorbic acid, lycopene and total flavonoids of dried tomato halves

Dried tomato halves with three storage moisture contents [18%, 24% and 30%, wet basis (wb)], packed in glass jar, plastic container and polyethylene bag were stored in room and cool-chamber environments for 5 months. During storage period average room and cool-chamber temperatures were 20 ± 4 and 5 ± 1 °C respectively. Changes of colour, ascorbic acid, lycopene, total flavonoids and moisture contents were monitored 1-month interval. Significantly higher losses of colour, ascorbic acid, lycopene and total flavonoids were found for room environment than those of cool chamber. A set of regression equations had been developed for colour, ascorbic acid, lycopene and total flavonoids as a function of storage time. No visible microorganisms were detected in the samples during the storage period. Dried tomato with ≤24% (wb) moisture content may be recommended to store in cool chamber (5 °C) and ≤18% (wb) to store in room environment (20 °C) both to be packed in glass jar.     

Evaluation of Aluminium Complexation Reaction for Flavonoid Content Assay

Two widely applied spectrophotometric assays based on aluminium complex formation used for determination of total flavonoid content in food or medicinal plant samples were examined for several compounds from different classes of flavonoid family. The method which involves the measurement at 410–430 nm after addition of AlCl₃ solution is selective only for flavonols and flavones luteolin. The procedure in the presence of NaNO₂ in alkaline medium seems to be specific for rutin, luteolin and catechins, but also phenolic acids exhibit considerable absorbance at 510 nm. Application of both procedures to natural samples gave different order in terms of their flavonoid content. Thus, the expression “total flavonoid” content is not adequate as the results of both methods are dependent on the structure of the individual flavonoids present.     

不同切割方式对菠萝抗氧化活性的影响

研究不同切割方式对菠萝贮藏期间抗氧化活性的影响。将菠萝分别切成1,2和3 cm正方体块状,置于4℃贮藏24 h。结果表明,贮藏期间不同切割方式的处理导致菠萝的过氧化物酶(CAT)活性、过氧化氢酶(POD)活性、多酚氧化酶(PPO)活性、类黄酮物质均呈上升趋势,不同切割方式处理却使抗坏血酸(ASA)含量下降,并且3 cm正方体块状菠萝ASA含量下降最多,CAT活性和POD活性在切割处理3 cm正方体块状的菠萝中最好,24 h时PPO活性、类黄酮物质在切割处理2 cm正方体块状菠萝中影响最好。贮藏期间,适当切割有利于菠萝提高其抗氧化能力。     

EFFECTS of SEMPERFRESH and JONFRESH FRUIT COATINGS ON POSTSTORAGE QUALITY of "SATSUMA" MANDARINS

Mandarins were coated with Semperfresh^TM and Jonfresh^TM edible coatings. the weight gain of mandarins after application of Jonfresh and Semperfresh coatings was 0.8% and 0.6% respectively. Weight loss, respiration rate, ascorbic acid, soluble solids (brix) and acidity changes of coated mandarins were compared with uncoated mandarins during storage at 20C and 40% RH for 4 weeks. Semperfresh^TM and Jonfresh^TM coatings delayed the ripening of mandarins. Both of the coatings were effective to reduce the change of ascorbic acid, soluble solids, titratable acidity and respiration rate. But Jonfresh^TM was determined to be most efficient coating for reduction of weight loss.     

夏枯草总黄酮的提取分离与自由基清除活性研究

分析超声波辅助提取对夏枯草总黄酮得率的影响,采用正交设计试验优化总黄酮提取工艺,筛选适合于分离总黄酮的大孔吸附树脂,最后研究其自由基清除活性。结果发现：超声波辅助提取不能提高夏枯草总黄酮得率,最佳提取条件为乙醇体积分数50%、料液比1:30(g/mL)、时间3h、温度80℃,得率可达5.05%;大孔吸附树脂AB-8 适合于分离夏枯草总黄酮;紫外- 可见光谱分析其可能为黄烷酮和双氢黄酮醇类;随质量浓度增加,夏枯草总黄酮的DPPH 自由基和羟自由基清除活性越接近VC,当质量浓度分别大于82μg/mL 和0.83mg/mL 时,两者的清除率都大于90%,显著高于叔丁基羟基茴香醚。     

Effects of anticaking agents and storage conditions on the moisture sorption,caking, and flowability of deliquescent ingredients

Deliquescent highly soluble crystalline ingredients are prone to caking and dissolution when they are stored above a certain relative humidity (RH) but exhibit minimal moisture adsorption below this RH. Anticaking agents are added to improve the flowability of powders and to prevent or reduce caking. The objective of this study was to determine the effects of anticaking agents on the moisture sorption behavior, flowability, and caking characteristics of deliquescent ingredients and blends thereof. Single deliquescent food ingredients (sodium chloride, sucrose, fructose, and citric acid) and binary systems (sodium chloride blended with sucrose, fructose, or citric acid) were used as the host powders, and silicon dioxide, calcium silicate, and calcium stearate were the three anticaking agents studied. Moisture sorption isotherms were generated to investigate the water–solid interactions of the anticaking and host powders. Following controlled RH storage treatments, caking was assessed by the sieve test and flowability by avalanche power and avalanche angle measurements. Formulation had variable effects on deliquescence behavior and moisture sorption, while formulation, storage RH, length of storage, and RH cycling all significantly affected the physical stability of the powder blends. Calcium stearate was the most effective anticaking agent at reducing moisture sorption and delaying the onset of deliquescence, as well as maintaining the flowability properties of all powders tested. In particular, calcium stearate was able to substantially alter the moisture sorption behavior of blends of deliquescent ingredients, which are inherently more susceptible to the deleterious effects of moisture due to deliquescence lowering. The results are of great significance because they show that the effectiveness of an anticaking agent in preventing moisture-induced caking depends on the complexity of the host powders as well as on the interaction with environmental moisture. Thus, the type of anticaking agent added to a deliquescent ingredient must be tailored to the host powder to enhance product quality and stability.     

Free radical scavenging and antioxidant activity of 5,7,3′,4′-hydroxy-substituted flavonoids

The antioxidant efficiencies of 5,7,3′,4′-hydroxy-substituted flavonoids were examined. The tested compounds (quercetin, luteolin, taxifolin, (+)-catechin and eriodictyol) were selected with a view to their C-ring differentiated pattern. Each one was added in cottonseed oil at equimolar amounts and the retardation of lipid peroxidation was estimated by means of peroxide value. Furthermore, their ability to scavenge DPPH radical was studied in two solvents (methanol and ethyl acetate) and the DPPH method proved a satisfactory prediction test for the antioxidant action of flavonoids in oils when methanol was used as the reaction media. Furthermore, the comparison of the C-ring structural element contribution to the antioxidant action revealed the full substitution to be the most important followed by the 3-OH and 2,3-double bond in the presence of the 4-carbonyl. Concerning the monosubstituted flavonoids, the 4-carbonyl group induced minor activity, whereas the 3-OH increased significantly the antiradical and antioxidant action.     

Composition of flavonoids in fresh herbs and calculation of flavonoid intake by use of herbs in traditional Danish dishes

Many herbs are known as excellent sources of natural antioxidants, and consumption of fresh herbs in the diet may therefore contribute to the daily antioxidant intake. The present study was performed in order to quantify flavonoids in commonly eaten fresh herbs. Fifteen fresh herbs (basil, chives, coriander, cress, dill, lemon balm, lovage, oregano, parsley, rosemary, sage, spearmint, tarragon, thyme, and watercress) were analysed by HPLC and mass spectrometry. Five major flavonoid aglycones were detected and quantified by HPLC after acid hydrolysis: apigenin, isorhamnetin, kaempferol, luteolin, and quercetin. The highest levels of flavonoids were found in parsley (510–630 mg apigenin /100 g), lovage (170 mg quercetin/100g), mint (18–100 mg apigenin/100 g), and dill (48–110 mg quercetin/100 g). Mass spectrometric detection, using atmospheric pressure chemical ionisation (APCI), was used to verify the presence of flavonoids in the hydrolysed extracts of herbs. Some traditional Danish dishes contain herbs, particularly parsley, dill, cress and chives, and the contribution to the flavonoid intake by consumption of these dishes was calculated.