Enlarged extracellular space of aquaporin-4–deficient mice does not enhance diffusion of Alexa Fluor 488 or dextran polymers

Aquaporin-4 (AQP4) water channels expressed on glia have been implicated in maintaining the volume of extracellular space (ECS). A previous diffusion study employing small cation tetramethylammonium and a real-time iontophoretic (RTI) method demonstrated an increase of about 25% in the ECS volume fraction (α) in the neocortex of AQP4^−/− mice compared to AQP4^+/+ mice but no change in the hindrance imposed to diffusing molecules (tortuosity λ). In contrast, other diffusion studies employing large molecules (dextran polymers) and a fluorescence recovery after photobleaching (FRAP) method measured a decrease of about 10%–20% in λ in the neocortex of AQP4^−/− mice. These conflicting findings on λ would imply that large molecules diffuse more readily in the enlarged ECS of AQP4^−/− mice than in wild type but small molecules do not. To test this hypothesis, we used integrative optical imaging (IOI) to measure tortuosity with a small Alexa Fluor 488 (molecular weight [MW] 547, λ_AF) and two large dextran polymers (MW 3000, λ_dex3 and MW 75,000, λ_dex75) in the in vitro neocortex of AQP4^+/+ and AQP4^−/− mice. We found that λ_AF=1.59, λ_dex3=1.76 and λ_dex75=2.30 obtained in AQP4^−/− mice were not significantly different from λ_AF=1.61, λ_dex3=1.76, and λ_dex75=2.33 in AQP4^+/+ mice. These IOI results demonstrate that λ measured with small and large molecules each remain unchanged in the enlarged ECS of AQP4^−/− mice compared to values in AQP4^+/+ mice. Further analysis suggests that the FRAP method yields diffusion parameters not directly comparable with those obtained by IOI or RTI methods. Our findings have implications for the role of glial AQP4 in maintaining the ECS structure.     

Characterization of phenolics,betacyanins and antioxidant activities of the seed,leaf, sprout,flower and stalk extracts of three Amaranthus species

Hydrophilic extracts from different parts including leaves, stalks, seeds, flowers and sprouts of 3 Amaranthus species (Amaranthus hypochondriacus, Amaranthus caudatus and Amaranthus cruentus) were characterized for their phytochemical profiles including the phenolics and betacyanins by UHPLC and LC–ESI–MS, and their antioxidant activities by FRAP and ORAC assays. The main betacyanins in Amaranthus samples were identified to be amaranthine and isoamaranthine. Eleven phenolic compounds (gallic acid, protocatechuic acid, chlorogenic acid, gentistic acid, 2,4-dihydroxybenzoic acid, ferulic acid, salicylic acid, rutin, ellagic acid, kaempferol-3-rutinoside and quercetin) were identified in the extracts of different parts of Amaranthus. The total phenolic content (TPC) ranged from 1.04 to 14.94 mg GAE/g DW; the total flavonoid content (TFC) ranged from 0.27 to 11.40 mg CAE/g DW; while the total betalain content (TBC) ranged from 0.07 to 20.93 mg/100 g DW. FRAP values ranged from 0.63 to 62.21 μmol AAE/g DW and ORAC ranged from 30.67 to 451.37 μmol TE/g DW. The leaves of Amaranthus showed the highest TPC, TFC, TBC, FRAP and ORAC values; while the seeds and stalks the lowest. There was a strong correlation between TPC, TBC, TFC and the antioxidant activity. The result suggests that all parts of the Amaranthus plant can be a good source of antioxidants.     

Phenolic compounds and antioxidant activity of Spanish commercial grape juices

Evaluation of the antioxidant activity of components of the diet is important in order to establish healthy consumption patterns. Data are reported here on the antioxidant activity (FRAP and ABTS), of 20 commercial grape juices and 10 typical Spanish wines and on their content of total phenolic compounds, anthocyanins, flavonoids and 10 individual phenolic compounds (flavanols, benzoic acids and cinnamic acids, measured by HPLC-UV). Red grape juices had a significantly higher (p < 0.05) concentration of total phenols (1177 vs. 744 mg gallic acid/L), flavonoids (98 vs. 63 mg catechin/L) and a higher antioxidant activity (9.16 vs. 2.83 meq Trolox/L) in comparison to white grape juices. In comparison to the white wines, white grape juices contained more total phenols (744 vs. 286 mg gallic acid/L) and flavonoids (63 vs. 29 mg catechin/L) and evidenced higher antioxidant activity (p < 0.05). In comparison to the red wines, a lower content of total phenols (286 vs. 2358 mg gallic acid/L) and flavonoids (228 vs. 29 mg catechin/L) and an absence of anthocyanins were observed in the white wines, which are therefore less antioxidant. Although a two-fold higher concentration of antioxidant compounds was found in red wines than in red grape juices, the latter may be a good option for all age groups because of the absence of alcohol and the potentially beneficial health effects of their phenolic composition and elevated antioxidant activity.     

野牡丹提取液的抗氧化活性研究

目的 研究野牡丹提取液的抗氧化活性。方法 采用二苯代苦味肼基自由基（DPPH•）和铁离子还原/抗氧化能力（FRAP）测定法,测定其抗氧化活性,并将其与芦丁和维生素C（Vc）的抗氧化能力进行比较研究。结果 野牡丹提取液具有较强的抗氧化能力,对DPPH自由基有较好的清除率,半数清除浓度（IC₅₀）为23 μg/mL;对Fe³⁺也具有较好的还原能力,0.5 mol/L FeSO₄当量对应野牡丹提取液质量浓度为55 μg/mL。结论 野牡丹的抗氧化能力与芦丁相近,低于Vc。野牡丹的抗氧化活性在一定浓度范围内与黄酮的含量有较好的相关性。     

Therapeutic Potentials of Oroxylum indicum Bark Extracts

AIM:Diverse therapeutic potentials of methanolic and aqueous extracts of Oroxylum indicum(L.)Vent.bark,includ- ing antioxidant property,cytotoxicity and protection against oxidative DNA damage were investigated in this study.METHODS:Total phenolics in the extracts were determined by spectrophotometric method.Ferric reducing antioxidant property(FRAP),free radical (DPPH·and ·OH)scavenging activities,as well as inhibitory effect on lipid peroxidation have been investigated.Cytotoxicity of the extracts was inv...     

何首乌炮制前后及其主要成分体外抗氧化活性研究

目的：研究何首乌生品、炮制品及其主要成分的体外抗氧化活性,探讨何首乌的炮制机理及其抗氧化作用物质基础。方法：采用2,2-二苯基-1-苦肼基（DPPH）自由基清除实验及铁离子还原（FRAP）法抗氧化能力检测方法评价何首乌炮制前后及其主要化学成分的体外抗氧化活性。结果：DPPH自由基清除实验中,何首乌生品（S）,随着乙醇浓度的增加,对DPPH自由基的清除率也增加,制品（Q/H/Z）中,以90%乙醇提取所得样品的平均清除率为最高,其次是水、70%乙醇和50%乙醇提取物;FRAP法检测结果显示何首乌生品（S）、黑豆汁制品（H）、清蒸制品（Q）及市售制品（Z）的FRAP值范围分别为2.23~9.27 mmol·L^-1,5.94~9.66 mmol·L^-1,5.74~10.49 mmol·L^-1,3.99~10.40 mmol·L^-1 FeSO₄,不同溶剂提取物的FRAP值由大到小为70%醇 > 50%醇 > 水 > 90%醇;何首乌的组成成分中虎杖苷、白藜芦醇、槲皮苷、槲皮素、芦丁、儿茶素、金丝桃苷、二苯乙烯苷和没食子酸有明显的清除DPPH自由基的作用,没食子酸、槲皮素、槲皮苷、儿茶素、芦丁和白藜芦醇的FRAP值较高,具有较强的抗氧化作用。结论：何首乌炮制前后均有较强的抗氧化作用,虎杖苷、白藜芦醇、槲皮苷、槲皮素、芦丁、儿茶素、金丝桃苷、二苯乙烯苷和没食子酸对何首乌的抗氧化活性有一定的贡献作用。     

Effects of cranberry powder on serum lipid profiles and biomarkers of oxidative stress in rats fed an atherogenic diet

This study investigated that the antioxidative effect of freeze-dried cranberry powder against protein and lipid oxidation and ameliorative effect of serum lipid profile in rat fed atherogenic diet. Six weeks old male Sprague-Dawley rats were divided into the following four groups: normal diet group with 5% corn oil (control), atherogenic diet group with 5% corn oil, 10% lard, 1% cholesterol, and 0.5% sodium cholate (HFC), atherogenic plus 2% cranberry powder diet group (HFC + C2), and atherogenic plus 5% cranberry powder diet group (HFC + C5), and respective diet and water were fed daily for 6 weeks. After the experimental period, the serum lipid profile, such as total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride, ferric reducing ability of plasma (FRAP), plasma phenolics content, superoxide dismutase (SOD) activity, serum protein carbonyl and thiobarbituric acid reactive substances (TBARS) levels were examined. Total phenolic compound and total flavonoid levels in freeze-dried cranberry powder were 9.94 mg/g and 8.12 mg/g, respectively. Serum total cholesterol and LDL-cholesterol levels were not significantly different for cranberry powder treatment, but serum HDL-cholesterol level was significantly increased in HFC + C5 group compared with HFC group. Plasma FRAP value tended to be increased by cranberry powder treatment though there was no significant difference. Plasma total phenol concentrations and SOD activities were not significantly different among all groups. Serum protein carbonyl and TBARS levels were significantly decreased in HFC + C5 group compared with HFC group. Overall results suggested that freeze-dried cranberry powder might have the serum lipid improving effect, as well as antioxidative effect demonstrated by its protective effect against protein and lipid oxidation.     

Phytochemical Studies and Antioxidant Properties of Four Medicinal Plants Used in Cameroon

Four plants (Amphimas pterocaroides, Harungana madagascariensis, Myrianthus arboreus, and Cussonia barteri) that are commonly used in Cameroon for the management or reversal of anaemia were screened for their phytochemical content and antioxidant potential. Four extracts (methanolic, hydro-ethanolic, aqueous, and hydrolysed) from each of the plants were prepared and analysed. Qualitative phytochemical tests were used to detect the presence of alkaloids, tannins, saponins, flavonoids, glycosides and phenols, while three quantitative methods; Folin, Ferric Reducing Antioxidant Power (FRAP) and diphenyl -1, 2-picryl hydrazyl (DPPH) were used to determine the antioxidant potential of these extracts. With the exception of the extracts of Cussonia barteri (negative for triterpenes and phenols) and the aqueous extract of Harungana madagascariensis (negative result for cardiac glycosides and glycosides), all other extracts contained the phytochemicals tested. The highest antioxidant activities were observed in the hydrolysed extracts of each plant, while the aqueous extract showed the least activity irrespective of the method used. The presence of active phytochemical substances with antioxidant activities may provide substantial basis for the use of these plants in ethnomedicine.     

Diffusion measurements in epidermal tissues with fluorescent recovery after photobleaching

Background/purpose: Pressure ulcers are areas of soft tissue breakdown, resulting from sustained mechanical loading of the skin and underlying tissues. Measuring biochemical markers that are released upon mechanical loading by the epidermis seems a promising method for objective risk assessment of the development of pressure ulcers. This risk assessment method will better determine the risk of a patient to develop pressure ulcers than the risk score lists currently used. So far, experimental studies have been performed that measure the tissue response in the culture supernatant. To elucidate the transport of the biochemical markers within the epidermis, the diffusion coefficient needs to be established. Methods: In the current study, fluorescent recovery after photobleaching (FRAP) is used to determine the diffusion coefficient of fluorescent‐labeled dextran molecules in human epidermis, porcine epidermis and engineered epidermal equivalents. These dextran molecules have a similar weight to the biochemical markers. Results: Similar diffusion coefficients were found for human and porcine epidermal samples (6.2 × 10⁻⁵±1.2 × 10⁻⁵ and 5.9 × 10⁻⁵±6.1 × 10⁻⁶ mm²/s, respectively), whereas the diffusion coefficient of the engineered epidermal equivalent was significantly lower (2.3 × 10⁻⁵±1.0 × 10⁻⁵ mm²/s). Conclusion: The diffusion could be measured in epidermal tissues using FRAP. In the future, the diffusion coefficients obtained in the current study will be used to study the difference between the transport in EpiDerm cultures and in human epidermis.