红花桑寄生叶提取物的抗氧化活性及酚类物质分析

采用DPPH法、TEAC法、FRAP法对红花桑寄生叶不同溶剂提取物的抗氧化活性进行体外评价,并测定其总酚、总黄酮含量。结果表明,溶剂种类对红花桑寄生叶提取物的得率、总酚、总黄酮及抗氧化活性影响显著。在3种评价方法中,不同溶剂提取物的抗氧化活性均表现出不同程度的量效依赖关系。3种溶剂提取物的抗氧化活性强弱依次为丙酮提取物 >甲醇提取物 >水提取物,其中80%丙酮提取物(总酚含量最高,达276.83mg/g)抗氧化活性最强,清除DPPH自由基能力EC₅₀值为0.247,FRAP值(FeSO₄ mmol/100g)为115.81,浓度为1.0mg/ml时,TEAC值为2.04。     

苦碟子注射液抗氧化成分的分离与活性评价研究

苦碟子注射液经盐酸酸化,HPD大孔树脂柱分离,得到总酚酸部分,以抗坏血酸(Vc)做为阳性对照,利用清除二苯代苦味酰基(DPPH)自由基法和铁离子还原/抗氧化能力(FRAP)法对其进行抗氧化活性评价,研究结果表明,总酚酸部分具有较好的抗氧化能力。为此,我们利用大孔树脂柱色谱、MDS-5反相制备色谱对总酚酸进一步分离,共获得6个酚酸类成分。采用上述活性评价的方法对所获得的6个成分进行了抗氧化活性评价,发现除芹菜素-7-O-β-D葡萄糖醛酸苷外,其它5个酚酸类成分均具有很强的抗氧化活性,其清除DPPH自由基能力及总抗氧化能力好于或与阳性对照Vc相当。     

Evaluation of the copper(II) reduction assay using bathocuproinedisulfonic acid disodium salt for the total antioxidant capacity assessment: The CUPRAC-BCS assay

There is heightened interest in determining antioxidant status of individuals in experimental and clinical studies investigating progression of diseases or diverse aspects of oxidative stress, among others. The aim of this study was to evaluate the copper(II) reduction assay with bathocuproinedisulfonic acid disodium salt as chelating agent (the CUPRAC-BCS assay) for the total antioxidant capacity (TAC) assessment in human plasma and urine. Samples from 20 individuals were determined with four spectrophotometric assays—CUPRAC-BCS, ferric reducing ability of plasma (FRAP), trolox equivalent antioxidant capacity (TEAC), and 1,1-diphenyl-2-picrylhydrazyl assay (DPPH)—to compare these methods. CUPRAC-BCS was significantly correlated with FRAP and TEAC for plasma and urine samples (r > 0.5, P < 0.05 for all) and with DPPH for urine samples (r = 0.925, P < 0.001) but not with DPPH for plasma samples (r = 0.366, P = 0.112). However, the four methods do not agree given that lines of equality and regression were not matched up. The imprecision of the method is less than 6%, the detection limit is 41.8 μmol trolox equivalents/L, it is linear up to 2 mM trolox, and ethylenediaminetetraacetic acid dihydrate disodium salt (EDTA) binds to Cu(II), avoiding the formation of Cu(I)-BCS complex. This study shows that CUPRAC-BCS is a simple, fast, inexpensive, and suitable method for TAC assessment in human urine and heparinized plasma samples.     

Comparative <Emphasis Type="Italic">in vitro</Emphasis> Assessment of Antioxidant Activities of Low-Etherified Pectin from the Eelgrass <Emphasis Type="Italic">Zostera marina</Emphasis> and Antioxidative Medicines

A comparative study of antioxidant activities of low-etherified pectin extracted from the eelgrass Zostera marina and of two antioxidative medicines, mildronat and emoxipin, was carried out using two in vitro methods allowing us to estimate the reducing activities of the compounds (FRAP assay), and their ability to impede iron- and ascorbate-induced oxidation of Tween 80 to malondialdehyde. It was found that zosterin pectin manifested higher reducing activity compared to the medicines. The inhibitory capacity of zosterin was lower than that of mildronat.     

Antioxidants in Fruits and Vegetables: a Study of Cellular Availability and Direct Effects on Human DNA

The effects of several types of whole fruits and vegetables on human lymphocytic DNA were investigated by using two versions of the comet assay. The total antioxidative capacity, as the FRAP value, and ascorbic acid (AA) content were also measured to explore the relationship between the effect and antioxidant content.     

Demethyloleuropein and beta-glucosidase activity in olive fruits

Demethyloleuropein plays a major role in the defense mechanism of olive fruits. To understand how this molecule is metabolized during different stages of maturation of olive fruits, a biomolecular approach to identify the demethyloleuropein chemistry was employed. The beta-glucosidase activity in crude extracts was assayed spectrophotometrically using the chromogenic substrate p-nitrophenyl-beta-D-glucopyranoside. Demethyloleuropein was extracted and identified by HPLC-MS from both infected and uninfected olive fruits at different physiological stages. The release of more functionally relevant dialdehydes in uninfected fruits was investigated using ESIMS/ MS. In fruits harvested in October, the activity of beta-glucosidase was significantly enhanced in uninfected fruits when compared to the infected fruits. Quantitative differences in the demethyloleuropein content from uninfected fruits showed the highest values (5.09 mg/g) in October, whereas lower levels (4.44 mg/g) were found in infected fruits. The results demonstrated that demethyloleuropein derivatives could be influenced by beta-glucosidase activity to improve the quality of the olive products with the best dialdehyde nutraceutical content.     

10种黄酮类抗氧化剂活性差异的理论阐释

借助理论方法,包括结构－活性关系（ＳＡＲ）和最子化学计算阐释了１０种黄酮类抗氧化剂清除自由基活性的痉异。发现ＳＡＲ可以定性地解释抗氧化剂的活性差异。而半经验量子化学方法ＡＭＩ计算的理论参数△ＨＯＦ（抗氧化剂与其抽氢反应产生的自由基的和成热之差）可以对此给出进一步的解释。△ＨＯＦ与抗氧化清除自由基速率常数的对数还有一定相关性,相关系数为－０．７５２３。因此理论方法在解释抗氧化剂的活性差异方面是有效的     

Reassessment of antioxidant activity of arbutin: Multifaceted evaluation using five antioxidant assay systems

Abstract

Arbutin, a practically used skin-lightening agent, has been reported to possess a weak antioxidant activity compared to that of its precursor, hydroquinone. However, its antioxidant activity has not been systematically evaluated. Hence, this study reassessed its activity using five assay systems. Assays were first performed using model radicals, DPPH radical and ABTS^?+. Arbutin showed weak DPPH radical-scavenging activity compared to that of hydroquinone, but showed strong ABTS^?+-scavenging activity. Its activity by ORAC assay was then evaluated using a physiologically relevant peroxyl radical. Arbutin exerted weak but long-lasting radical-scavenging activity and showed totally the same antioxidant activity as that of hydroquinone. Finally, it was shown that, in two cell-based antioxidant assays using erythrocytes and skin fibroblasts, arbutin exerted strong antioxidant activity comparable or even superior to that of hydroquinone. These findings indicate that the antioxidant activity of arbutin may have been under-estimated and suggest that it acts as a potent antioxidant in the skin.     

黑尾蜡嘴雀冬季对树木果实的取食作用

2009年11月至2011年2月,在江苏省南京市观察到黑尾蜡嘴雀冬季取食12种树木的果实及种子。该鸟通常咬破果皮或种皮,取食种子的胚和胚乳等营养物质,为种子捕食者。由于其他一些食果鸟类也同期取食有关树木的果实,并传播其种子,黑尾蜡嘴雀的取食对这些树木的种子传播的影响是有限的。在初冬季节,黑尾蜡嘴雀常在树冠层取食果实,而在深冬季节,则主要在地表取食落果。黑尾蜡嘴雀能够咬碎枫杨等坚果的坚硬果皮,可为一起在地表觅食的麻雀取食种子碎屑物提供便利条件。黑尾蜡嘴雀与麻雀之间的偏利取食关系属于首次报道。文中对于城市环境管理中合理利用树木落果,为黑尾蜡嘴雀等鸟类提供越冬食物等方面提出了相关建议。     

Risk assessment of population exposure to toxic trace elements via consumption of vegetables and fruits grown in some mining areas of Armenia

Consumption of unsafe food is one of the most important public health concerns. Trace elements’ contamination caused by direct or indirect activities of mining industries is of importance in this respect. The present study was conducted to assess the chronic dietary exposure and related health risks of trace elements through the intake of selected vegetables and fruits grown under the impact of mining industry in Syunik region (Armenia). Consumption data were obtained via food frequency questionnaire and the concentrations of Cu, Mo, Ni, Cr, Pb, Zn, Hg, and Cd in different fruits and vegetables were determined. Moreover, by combining concentration data with consumption data, estimated daily intake, and target hazard quotient were assessed for each element. The results obtained showed that mean concentrations for Pb and Hg in some vegetables exceeded maximum acceptable levels set by international organizations. Hazard indexes > 1 have been obtained in some cases indicating that for some vegetables (particularly for potato, carrot, maize, onion leaf, grape, bean, beet, sweet pepper, eggplant, and tomato) habitual consumption has a potential to pose adverse health effect to the local population.     

Synthesis,anti-inflammatory,analgesic and antioxidant activities of some tetrasubstituted thiophenes

Sets of tetrasubstituted thiophene esters 4a-4g, 5a-5f and 6a-6e were synthesized by reaction of 1-(α-Carbomethoxy-β-aminothiocrotonoyl)-aryl/aroyl amines (3) with 3-(bromoacetyl)coumarin, 1,4-dibromodiacetyl and chloroacetone respectively. The compound 3 were synthesized by nucleophilic addition of aryl/aroylisothiocyanate and enamine (2). The synthesized targeted compounds (4a-4g, 5a-5f and 6a-6e) were evaluated for their in vivo anti-inflammatory activity in carrageenin-induced rat hind paw oedema model at three graded doses employed at 10, 20 and 40 mg/kg body weight using mefanamic acid, ibuprofen and in vivo analgesic activity in acetic acid induced writhing response model at 10 mg/kg dose using ibuprofen as standard drug. The compounds 4a-4f, 5c, 5f, 6c and 6e were evaluated for their in vitro antioxidant nitric oxide radical scavenging assay at the concentrations of 5, 10, 15, 20, 25, 30 and 35 μg/mL using ascorbic acid as standard drug. Among all the targeted compounds 4c showed maximum anti-inflammatory activity of 71% protection at 10 mg/kg and 77% protection at 20 mg/kg to inflamed paw and analgesic activity of 56% inhibition and also maximum in vitro nitric oxide radical scavenging activity having IC₅₀ value 31.59 μg/mL.     

Phenolic Profiling,Antioxidant, and Antibacterial Activities of Selected Medicinal Plants from Tunisia

Phytochemical screening of aqueous extract from six medicinal wild plants grown in South-eastern of Tunisia: Atriplex halimus, Teucrium polium, Moricandia arvensis, Deverra tortuoa, Haplophyllum tuberculatum and Polygonum equisetiforme were evaluated. Both decoction and ultrasound assisted extraction were used. Antioxidant, antibacterial proprieties, and phenolic profiling, using LC-ESI-MS method, were assessed. Total polyphenols, flavonoids, and condensed tannins contents ranged from 7.47±0.19 to 22.25±0.49 mg GAE/g Dw, 5.47±0.06 to 7.55±0.07 mg RE/g Dw, and 0.33±0.02 to 19.43±0.64 mg TAE/g Dw, respectively. Moreover, the reducing power and DPPH tests showed that P. equisetiforme (EC₅₀: 12.50±0.50 μg/ml; DPPH⋅⁺: 213.49±4.24 mg TEAC/g DW), T. polium (EC₅₀: 25.00±1.00 μg/ml; DPPH⋅⁺: 181.39±9.47 mg TEAC/g DW) as well as H. tuberculatum (EC₅₀: 56.25±0.25 μg/ml; DPPH⋅⁺: 177.83±5.85 mg TEAC/g DW) extracts were the most effective natural antioxidants. For anti-bacterial activity, the ultrasonic extract of H. tuberculatum showed the highest activity against both P. aeruginosa (13.50±0.71 mm) and S. aureus (13.00±0.00 mm) at 10 mg/ml. Furthermore 24 phenolic compounds were identified, with predominance of quinic acid, gallic acid, protocatechuic acid, syringic acid, p-coumaric acid, trans-ferulic acid, catechin (+), trans-cinnamic and silymarin. These results were further consolidated by to heatmap clustering with P. equisetiforme, H. tuberculatum, T. polium as the main antioxidant and antibacterial sources which supports their domestication and industrial use.     

Trophic shifts in predatory catfishes following the introduction of Nile perch into Lake Victoria

This study looked for evidence of trophic shifts in the diet of two predatory catfishes ( Bagrus docmac and Schilbe intermedius ) following the establishment of introduced Nile perch ( Lates niloticus ) into lakes of the Lake Victoria basin. Bagrus docmac exhibited a shift from a primarily piscivorous diet dominated by haplochromine cichlids to a broader diet that included a significant proportion of invertebrates and the cyprinid fish, Rastrineobola argentea , which became abundant following depletion of the haplochromines. Schilbe intermedius exhibited a trophic shift from a piscivorous diet dominated by haplochromines to an insectivorous diet. The flexibility in diet exhibited by these two catfishes may have permitted these species to persist, albeit in reduced numbers, subsequent to the introduction of Nile perch and may facilitate resurgence as fishing pressure reduces numbers of large Nile perch.     

Yeasts associated with fresh and frozen pulps of Brazilian tropical fruits

The occurrence of yeasts on ripe fruits and frozen pulps of pitanga (Eugenia uniflora L), mangaba (Hancornia speciosa Gom.), umbu (Spondias tuberosa Avr. Cam.), and acerola (Malpighia glaba L) was verified. The incidence of proteolytic, pectinolytic, and mycocinogenic yeasts on these communities was also determined. A total of 480 colonies was isolated and grouped in 405 different strains. These corresponded to 42 ascomycetous and 28 basidiomycetous species. Candida sorbosivorans, Pseudozyma antarctica, C. spandovensis-like, C. spandovensis, Kloeckera apis, C. parapsilosis, Rhodotorula graminis, Kluyveromyces marxianus, Cryptococcus laurentii, Metchnikowia sp (isolated only from pitanga ripe fruits), Issatchenkia occidentalis and C. krusei (isolated only from mangaba frozen pulps), were the most frequent species. The yeast communities from pitanga ripe fruits exhibited the highest frequency of species, followed by communities from acerola ripe fruits and mangaba frozen pulps. Yeast communities from frozen pulp and ripe fruits of umbu had the lowest number of species. Except the yeasts from pitanga, yeast communities from frozen pulp exhibited higher number of yeasts than ripe fruit communities. Mycocinogenic yeasts were found in all of the substrates studied except in communities from umbu ripe fruits and pitanga frozen pulps. Most of the yeasts found to produce mycocins were basidiomycetes and included P. antarctica, Cryptococcus albidus, C. bhutanensis-like, R. graminis and R. mucilaginosa-like from pitanga ripe fruits as well as black yeasts from pitanga and acerola ripe fruits. The umbu frozen pulps community had the highest frequency of proteolytic species. Yeasts able to hydrolyse casein at pH 5.0 represented 38.5% of the species isolated. Thirty-seven percent of yeast isolates were able to hydrolyse casein at pH 7.0. Pectinolytic yeasts were found in all of the communities studied, excepted for those of umbu frozen pulps. The highest frequency of pectinolytic activity was found in mangaba frozen pulp communities. Around 30% of all isolates produced pectinases. The ability to split arbutin was observed in all communities ranging from 8% in yeasts from pitanga frozen pulps to 40.6% in acerola ripe fruit communities. Among 432 species tested, 125 were active for beta-glucosidase production, and Kloeckera apis, P. antarctica, C. sorbosivorans, and C. spandovensis-like were the most active species.     

Synthesis and evaluation of in vitro antioxidant capacities of some benzimidazole derivatives

New, except 1d, melatonin analogue benzimidazole derivatives were synthesized and characterized in the present study. The potential role of melatonin as an antioxidant by scavenging and detoxifying ROS raised the possibility that compounds that are analogous to melatonin can also be used for their antioxidant properties. Therefore the antioxidant effects of the newly synthesized compounds were investigated in vitro by means of their inhibitory effect on hydrogen peroxide-induced erythrocyte membrane lipid peroxidation (EMLP) and on various erythrocyte antioxidant enzymes viz. superoxide dismutase (SOD), catalase (CAT) and glucose-6-phosphate dehydrogenase (G6PD). The synthesized benzimidazole derivatives showed remarkable antioxidant activity in vitro in the H₂O₂-induced EMLP system. Furthermore their effects on various antioxidant enzymes are discussed and evaluated from the perspective of structure- activity relationships.     

Mushroom Species Stereum hirsutum as Natural Source of Phenolics and Fatty Acids as Antioxidants and Acetylcholinesterase Inhibitors

Many lignicolous mushroom species are used as a food supplement and may represent an alternative treatment of Alzheimer's disease (AD). This study aimed to evaluate acetylcholinesterase inhibition (AChEI) of Stereum hirsutum together with antioxidant activity (AO) and cytotoxic activity against HepG2 cells. Different extracts (water, ethanol, methanol, polysaccharide) were analyzed, with respect to their mineral composition and chemical content. Ethanol extract was the most potent in AChEI (98.44 %) and demonstrated cytotoxic activity (91.96 % at 900.00 μg/mL), while the highest AO was demonstrated for polar extracts (methanol and water) as well. These activities may be attributed to determined phenolics (hydroxybenzoic and quinic acid) and fatty acids (FA), while biflavonoid amentoflavone may be responsible for cytotoxic activity. The most prevalent FA was linoleic (40.00 %) and the domination of unsaturated FA (UFA) (71.91 %) over saturated (26.96 %) was observed. This is the first report of AChEI of S. hirsutum extracts and first detection of amentoflavone. Due to high amount of UFA and well-expressed AChEI, this species can be considered as a potent food supplement in the palliative therapy of AD.     

Occurrence of UDPG: Sterol glucosyltransferase activity in some lower plants

A study was made of the sterol glucosylating ability of cell-free homogenates obtained from 16 species of photosynthesizing and nonphotosynthesizing lower plants (2 species of Chlorophyceae, 2 species of Cyanophyceae, 1 species of Phycomycetes, 3 species of Ascomycetes, 3 species of Basidomycetes, 1 species of Myxomycetes, 3 species of Musci and 1 species of Sphenopsida). Except for the blue-green and green algae, all the remaining species showed distinct in vitro synthesis of steryl monoglucosides from UDPG and cholesterol or sitosterol. Preliminary studies on the specificity of the relevant enzymes pointed to a correlation between the sterol composition of the plant and the specificity of its glucosylating enzyme. The enzyme from Ascomycetes and Basidomycetes utilized ergosterol better than cholesterol or sitosterol. Enzymic preparations from mosses utilized sitosterol the best.     

Predation pressure in Ugandan cotton fields measured by a sentinel prey method

Pest suppression by natural enemies is an important ecosystem service, which is a valuable resource to poor smallholders in developing countries. Diverse natural enemy assemblages of arthropod predators and parasitoids are documented in various regions in Africa, but our knowledge of their impact on herbivores in agroecosystems remains limited. We conducted experiments in cotton, Gossypium hirsutum L. (Malvaceae), under typical local agronomic practices in Uganda to assess levels of predation pressure ascribed to natural enemies. We measured predation rates on artificial caterpillars made of plasticine glued to cotton plants. Predation pressure on cotton fields varied between 1.96 and 4.1% per day, but was not significantly influenced by cotton treatments (insecticide/no insecticide, monocropping/intercropping with Phaseolus spp.). Predation pressure in non‐crop habitats adjacent to cotton fields was up to 12× higher than in the fields. Marks left on the artificial caterpillars revealed that arthropods and birds were largely accountable for predation in cotton fields, whereas arthropods and small mammals were dominant in non‐cultivated habitats.