Evaluation of the antioxidant activity of Syzygium cumini leaves

The antioxidant activity of Syzygium cumini leaf extracts was investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging and ferric-reducing antioxidant power (FRAP) assays. The methanolic extract and its four water, ethyl acetate, chloroform, and n-hexane fractions were prepared and subjected to antioxidant evaluation. The results showed that the ethyl acetate fraction had stronger antioxidant activity than the other ones. HPLC data indicated that S. cumini leaf extracts contained phenolic compounds, such as ferulic acid and catechin, responsible for their antioxidant activity. A significant linear relationship between antioxidant potency, free radical-scavenging ability and the content of phenolic compounds of leaf extracts supported this observation.     

Antioxidant activity of phenolic and flavonoid compounds in some medicinal plants of India

In this study, total phenolics, flavonoids and vitamin C content vis-a-vis antioxidant activities were assayed in leaves and stem bark of Azadirachta indica, Butea monosperma, Cassia fistula, Mangifera indica, Syzygium cumini and Tamarindus indica using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging method. The DPPH radical scavenging activity positively correlated with the total phenolic content in both stem bark and leaf. Superoxide radical scavenging activity increased with increasing flavonoid contents. However, the vitamin C content could not be correlated with DPPH and superoxide radical scavenging capacity.     

Screening of allelopathic trees for their antifungal potential against Alternaria alternata strains isolated from dying-back Eucalyptus spp

Antifungal activity of methanolic extracts of leaves of three tree species, namely Azadirachta indica L., Syzygium cumini (L.) Skeels. and Melia azedarach L. was evaluated against two strains of Alternaria alternata, isolated from dying-back trees of two Eucalyptus spp., namely Eucalyptus citriodora and Eucalyptus globulus. All the concentrations (1,?2,?…?,?5% w/v) of the methanolic extracts of the three tree species significantly reduced the fungal biomass. There were reductions in the ranges 82-88%, 88-96% and 83-96% in the biomass of A. alternata strains due to different concentrations of the leaf extracts of S. cumini, A. indica and M. azedarach, respectively. Methanolic extract of M. azedarach was subjected to further fractionation using n-hexane, chloroform, ethyl acetate and n-butanol successively in the order of increasing polarity. Aqueous and n-butanol fractions gave promising results in the significant decrease in fungal biomass. This study concludes that aqueous and n-butanol fractions of methanolic leaf extract of M. azedarach can be used as biofungicides for the management of A. alternata.     

SPME determination of volatile aldehydes for evaluation of in-vitro antioxidant activity

The in-vitro antioxidant activity of natural (essential oils, vitamin E) or synthetic substances ( tert-butyl hydroxy anisole (BHA), Trolox) has been evaluated by monitoring volatile carbonyl compounds released in model lipid systems subjected to peroxidation. The procedure employed methodology previously developed for the determination of carbonyl compounds as their pentafluorophenylhydrazine derivatives which were quantified, with high sensitivity, by means of capillary gas chromatography with electron-capture detection. Linoleic acid and sunflower oil were used as model lipid systems. Lipid peroxidation was induced in linoleic acid by the Fe2+ ion (1 mmol L-1, 37 degrees C, 12 h) and in sunflower oil by heating in the presence of O2 (220 degrees C, 2 h). The change in hexanal (the main lipoxidation product) concentration found in the lipid matrix subjected to oxidation with and without the substance being tested was used to calculate the antioxidant protection effect. These procedures were employed to evaluate the antioxidant activity of the essential oils of cilantro ( Coriander sativum L.), fennel ( Foeniculum vulgare Mill.), rosemary ( Rosmarinus officinalis L.), "salvia negra" ( Lepechinia schiedeana), and oregano ( Origanum vulgare L.), and the well-known antioxidants BHA, vitamin E, and Trolox, its water-soluble analog. In the sunflower oil system, the essential oils had a stronger protective effect against lipid peroxidation than BHA, vitamin E, and Trolox within the range of concentrations examined (1-20 g L-1). The highest protecting effect, corresponding to a 90% drop in hexanal release, was observed for cilantro oil at 10 g L-1.     

ATMOSPHERIC OXIDATION OF VITAMIN C AND E IN THE SURFACTANT SYSTEM

The association of ascorbic acid (H₂A, AA) with α-tocopherol (α-T) enhances the antioxidant capability of the two vitamins in a microemulsion formed by water, pentanol and sodium dodecyl sulphate. The comparison of vitamin C oxidation kinetics in the presence and absence of α-T in the system shows that there are no tangible differences in the time of the ascorbic acid decomposition. The main effect is the enhancement of the H₂A oxidation with increased pentanol concentration in the system. Ascorbic anion interacts with surfactant association structures, changing W/O microemulsion towards O/W system. The polar part of H₂A is exposed to aqueous solution and subjected to oxidation.

For the vitamin C to vitamin E weight ratio equal 0.13, ascorbic acid stimulates α-T decomposition as long, as it does in the non-oxidised form. When not all amounts of both vitamins are decomposed their activity is similar to each other in the anionic surfactant system. It means they are both good antioxidants in W/O microemulsions. After some time, when vitamin C is completely decomposed, all these micellar systems become more stable with regard to vitamin E. Vitamin E occurs to be a better antioxidant in O/W microemulsion.     

Fucoidan and Alginate from the Brown Algae Colpomenia sinuosa and Their Combination with Vitamin C Trigger Apoptosis in Colon Cancer

Brown seaweeds are producers of bioactive molecules which are known to inhibit oncogenic growth. Here, we investigated the antioxidant, cytotoxic, and apoptotic effects of two polysaccharides from the brown algae Colpomenia sinuosa, namely fucoidan and alginate, in a panel of cancer cell lines and evaluated their effects when combined with vitamin C. Fucoidan and alginate were isolated from brown algae and characterized by HPLC, FTIR, and NMR spectroscopy. The results indicated that highly sulfated fucoidans had higher antioxidant and cytotoxic effects than alginate. Human colon cancer cells were the most sensitive to the algal treatments, with fucoidan having an IC₅₀ value (618.9 µg/mL⁻¹) lower than that of alginate (690 µg/mL⁻¹). The production of reactive oxygen species was increased upon treatment of HCT-116 cells with fucoidan and alginate, which suggest that these compounds may trigger cell death via oxidative damage. The combination of fucoidan with vitamin C showed enhanced effects compared to treatment with fucoidan alone, as evidenced by the significant inhibitory effects on HCT-116 colon cancer cell viability. The combination of the algal polysaccharides with vitamin C caused enhanced degeneration in the nuclei of cells, as evidenced by DAPI staining and increased the subG1 population, suggesting the induction of cell death. Together, these results suggest that fucoidan and alginate from the brown algae C. sinuosa are promising anticancer compounds, particularly when used in combination with vitamin C.     

Beating cancer in multiple ways using nanogold

Gold nanoparticles possess a unique combination of properties which allow them to act as highly multifunctional anti-cancer agents (X. H. Huang, P. K. Jain, I. H. El-Sayed and M. A. El-Sayed, Nanomedicine, 2007, 2, 681-693; P. Ghosh, G. Han, M. De, C. K. Kim and V. M. Rotello, Adv. Drug Delivery Rev., 2008, 60, 1307-1315; S. Lal, S. E. Clare and N. J. Halas, Acc. Chem. Res., 2008, 41, 1842-1851; D. A. Giljohann, D. S. Seferos, W. L. Daniel, M. D. Massich, P. C. Patel and C. A. Mirkin, Angew. Chem., Int. Ed., 2010, 49, 3280-3294). Not only can they be used as targeted contrast agents for photothermal cancer therapy, they can serve as scaffolds for increasingly potent cancer drug delivery, as transfection agents for selective gene therapy, and as intrinsic antineoplastic agents. This tutorial review will highlight some of the many forms and recent applications of these gold nanoparticle conjugates by our lab and others, as well as their rational design and physiologic interactions.     

Synthesis of a novel sulfur-bearing secondary antioxidant with a high molecular weight and its comparative study on antioxidant behavior in polypropylene with two commercial sulfur-bearing secondary antioxidants having relatively low molecular weight

A novel sulfur-bearing secondary antioxidant with a high molecular weight of 2252 (OS-POSS), successfully synthesized via photoinitiated thiol-ene click reaction, was compared with two commercial sulfur-bearing secondary antioxidants on the stabilization of polypropylene (PP). The results of their oxidation induction time (OIT) via differential scanning calorimeter measurement (DSC) showed that the higher the molecular weight of secondary antioxidant is, the longer the OIT value, whether such sulfur-bearing antioxidant is used singly or in combination with primary antioxidant. The study of their long-term accelerated thermal aging in the air oven at 150 °C displayed that the molecular structure of sulfur-bearing secondary antioxidant, besides molecular weight, is another highly important factor determining the antioxidant efficiency, i.e., physical loss of antioxidants with the relatively low molecular weight may determine antioxidant efficiency, whereas thioether groups having neighboring ester carbonyl moieties may decompose more hydroperoxides with quicker rate.     

An electrophoretic study of vitamin E status and expression of heat shock proteins in alveolar type II and liver cells

Vitamin E is the most important lipophilic antioxidant. Oxidative injuries are prevented or minimized by vitamin E supplementation. Various physiological and pathological situations are accompanied by vitamin E deficiency. However, it is not clear whether alimentary vitamin E deficiency in itself constitutes oxidant stress that induces appropriate responses, which, in turn, can be avoided by adequate vitamin E supplies, or whether the remaining cellular antioxidants compensate a temporary vitamin E deficiency. We studied effects of the dietary vitamin E status on cellular vitamin E levels and on the expression of heat shock proteins (HSPs) in alveolar type II cells and liver. The expression of HSPs, representing an early and very sensitive marker of cellular stress, was compared with the activity of antioxidative enzymes. Vitamin E depletion caused a substantial increase in HSP32 in alveolar type II cells, whereas in liver there was a marked increase in HSP70. The activity of the antioxidant enzymes, however, did not change significantly. A reversal of HSP expression to almost normal levels was seen after vitamin E resupplementation. These results indicate that, under normal conditions, a suboptimal supply of vitamin E to rats exposes the alveolar type II cells and the liver to reversible cellular stress.     

Ultrasound as a Promising Tool for the Green Extraction of Specialized Metabolites from Some Culinary Spices

Spices are a popular food of plant origin, rich in various phytochemicals and recognized for their numerous properties. The aim of the study was to evaluate the antioxidant and antimicrobial activity, as well as the content of specialized metabolites, of aqueous extracts of three spice species––garlic (Allium sativum L.), ginger (Zingiber officinalle L.) and turmeric (Curcuma longa L.)––prepared by green extraction methods. Ultrasound treatment increased the chromaticity parameter b value of turmeric and ginger extracts, thus indicating a higher yellow color predominantly due to curcuminoids characteristic of these species. Ultrasound-assisted extraction significantly increased the content of total soluble solids, phenolic compounds, total carotenoids and vitamin C. The temperature of the system was also an important factor, with the highest (70 °C) conditions in ultrasound-assisted extraction having a positive effect on thermolabile compounds (vitamin C, phenolics, total carotenoids). For example, turmeric extract treated with ultrasound at 70 °C had up to a 67% higher vitamin C content and a 69.4% higher total carotenoid content compared to samples treated conventionally at the same temperature, while ginger extracts had up to 40% higher total phenols. All different concentrations of spice extracts were not sufficient for complete inhibition of pathogenic bacterial strains of Salmonella, L. monocytogenes and S. aureus; however, only garlic extracts had an effect on slowing down the growth and number of L. monocytogenes colonies. Spice extracts obtained by ultrasonic treatment contained a significantly higher level of bioactive compounds and antioxidant capacity, suggesting that the extracts obtained have significant nutritional potential and thus a significant possibility for phytotherapeutic uses.     

Antiviral activity of some Tunisian medicinal plants against Herpes simplex virus type 1

Fifteen species of Tunisian traditional medicinal plants, belonging to 10 families, were selected for this study. They were Inula viscosa (L.) Ait and Reichardia tingitana (L.) Roth ssp. discolor (Pom.) Batt. (Asteraceae), Mesembryanthemum cristallinum L. and M. nodiflorum L. (Aizoaceae), Arthrocnemum indicum (Willd.) Moq., Atriplex inflata Muell., A. parvifolia Lowe var. ifiniensis (Caball) Maire, and Salicornia fruticosa L. (Chenopodiaceae), Cistus monspeliensis L. (Cistaceae), Juniperus phoenicea L. (Cupressaceae), Erica multiflora L. (Ericaceae), Frankenia pulverulenta L. (Frankeniaceae), Hypericum crispum L. (Hypericaceae), Plantago coronopus L. ssp. eu-coronopus Pilger var. vulgaris G.G. (Plantaginaceae) and Zygophyllum album L. (Zygophyllaceae). Fifty extracts prepared from those plants were screened in order to assay their antiviral activity against Herpes simplex virus type 1 (HSV-1), using neutral red incorporation. Extracts from eight plants among these 15 showed some degree of antiviral activity, while the methanolic extract of E. multiflora was highly active with EC(50) of 132.6 microg mL(-1). These results corroborate that medicinal plants from Tunisia can be a rich source of potential antiviral compounds.     

Inhibiting the photosensitized oxidation of anthracene and tryptophan by means of natural antioxidants

It is shown that model reactions of photosensitized oxidation of anthracene and tryptophan can be used for evaluation and comparison of antioxidant activity of various classes of compounds. Inhibition of the oxidation of substrates in the presence of the familiar antioxidants tocopherol (vitamin E), ascorbic acid (vitamin C), and mixtures of these vitamins with methionine, and in the presence of reputed antioxidants dihydroquercetin and taurine, are considered. It is concluded that all of the above compounds except for taurine have antioxidant properties; i.e., they reduce the rate constants of the photosensitized oxidation of anthracene and tryptophan. It is found that the inhibition of oxidation is associated with the interaction between antioxidants and singlet oxygen. Analysis of the kinetic dependences of the photosensitized oxidation of substrates in the presence of antioxidants reveals that a mixture of vitamins inhibits the process most efficiently, and inhibition occurs at the initial stages due to more active interaction between singlet oxygen and vitamin C     

Hypolipidemic and hepatoprotective synergistic effects of selenium nanoparticles and vitamin. E against acrylamide-induced hepatic alterations in male albino mice

The potential benefit of selenium nanoparticles (SeNPs) and vitamin E (Vit.E) that they are potent antioxidants , they were used as antioxidants against acrylamide (ACR) hepatotoxicity, ACR is found in the starchy foods that had been heated for long periods in high degrees above 120°C. So the aim of the current study was to elucidate the antihyperlipidemic and hepatoprotective effects of either SeNPs and/or Vit.E against ACR toxicity, SeNPs were characterized by SEM, EDX, TEM and they proved their spherical nanostructure. Zeta potential value was –22.9 mv with particle size with a diameter range (48.75-67.24 nm) which proved the high stability of the used SeNPs. Seven groups of male mice were used: group I was control,group II ACR,group III was treated with SeNPs, IV group was received Vit.E and groups V,VI received ACR plus SeNPs and ACR plus Vit.E, group VII was given combination of SeNPs and Vit.E plus ACR,So,The effect of SeNPs and/or Vit.E were monitored against ACR hepatotoxicity and hyperlipidemia. ACR administration afforded significant elevation in the hepatic enzymes with severe alterations in the lipid metabolism. These findings clarified the efficacy of SeNPs and Vit.E by declining the high hepatic enzymes activities induced by ACR along with improving the lipid profile, elevation of the antioxidant enzymes (SOD,CAT and GRx), reduction of MDA level, improving histological and ultrastructutral hepatic tissues and restoration of most normal structures that were damaged in ACR group. So, SeNPs and/or Vit.E were proved to enhance the hepatic antioxidant capacities.     

Investigation of photoinduced electron transfer in model system of vitamin E-duroquinone by time-dependent density functional theory

Photoinduced electron transfer of the model system composed of vitamin E and duroquinone has been investigated using time-dependent density functional theory. Calculations for the excited states tell that the photoexcitation of the model system can directly yield the charge transfer states in which the vitamin E moiety is positively charged but the duroquinone moiety is negatively charged. Our theoretical investigations indicate that the second charge transfer state of the model system can also be produced through the decay of higher locally excited state S(4). Since S(4) state in the model system corresponds to S(1) state of the isolated duroquinone used as a model for peroxyl radical, and S(2) state has the character of electron transfer from the tertiary amine group of the vitamin E moiety to the duroquinone moiety, the decay from S(4) to S(2) corresponds to the dynamic process following the photoexcitation of the duroquinone moiety of the model system, i.e., the initial stage of antioxidant reaction of vitamin E. Calculations of the kinetic parameters for the electron transfer have been carried out in the framework of the Marcus-Jortner-Levich formalism. Our calculations confirm that the electron transfer from S(4) to S(2) possesses the character of the inverted regime and the barrier is negligibly small.     

4-(7-甲氧基-2,2-二甲基-2,3-二氢苯并呋喃-5-基)-2-苄亚氨基噻唑的合成与生物活性

呋喃酚经醚化、傅克酰化、α-溴代、噻唑环化和亚胺化等反应合成了16种4-(7-甲氧基-2,2-二甲基-2,3-二氢苯并呋喃-5-基)-2-苄亚氨基噻唑新化合物.化合物的结构经1H NMR、质谱和元素分析等确证.杀虫活性实验结果表明,化合物2a和2i在500 mg/L对棉红蜘蛛死亡率分别为53.10%和67.71%,杀菌活性实验结果表明,化合物2a和2k在25 mg/L对油菜菌核病菌抑制率分别为57.9%和59.8%,除草活性实验结果表明,2l在2250 g.ai/ha浓度下对苘麻、刺苋、藜具有一定的除草活性.     

Effect of X-radiation on lipid peroxidation and antioxidant systems in rats treated with saponin-containing compounds

The aim of this study was to investigate the effect of three saponin-containing plant species extracts (Aesculuc hippocastanum L. seed extract [AHE], Medicago sativa L. extract [MSE] and Spinacia oleracea L. extract [SOE]) on lipid peroxidation and on antioxidant systems in rats exposed to X-rays (XR). The rats were divided into three categories. The first category served as controls and received only a standard diet. The second category served as the radiation group and received 5 and 10 Gy XR dose. The third category (XR+extract-treated) received plant extracts (25.0 or 50.0 mg kg(-1) live weight) and 5 or 10 Gy XR dose. Blood samples were analyzed for their content of malondialdehyde (MDA), reduced glutathione (GSH), plasma vitamin C, beta-carotene and retinol. In animals receiving XR, the plasma MDA (P < 0.001) value significantly increased but the level of GSH (P < 0.01), vitamin C (P < 0.001), retinol and beta-carotene (P < 0.001) decreased significantly with increasing XR doses. In the XR+extract-treated groups, the concentrations of MDA increased significantly with increasing radiation but their concentrations decreased significantly with increasing extract concentrations. Plasma concentrations of GSH, beta-carotene, retinol and vitamin C in XR+extract-treated groups decreased significantly with increasing XR dose but their concentrations increased with increasing extract doses. Further, comparison of blood samples of XR+extract-treated groups with those from the control group showed that GSH, beta-carotene, retinol and vitamin C values increased significantly but that MDA values decreased significantly. The results showed that all extracts have enhanced the antioxidant status and decreased the incidence of free radical-induced lipid peroxidation in blood samples of rats exposed to XR. However, the antioxidant effect of AHE-administered animals was more effective than that of MSE- and SOE-administered whole-body XR rats. We conclude that the supplementation with saponin-containing extracts may serve to reinforce the antioxidant systems, thus having protective effect against cell damage by XR.     

Antioxidant activity and total phenols in different extracts of four Staphylea L. Species

Staphylea L. is a deciduous ornamental shrub that possesses significant cytotoxic and antibacterial activity, although the chemical composition of its extracts and the identity of the structures responsible for these biological activities are not yet known. In this study we have determined the total phenolic content in chloroform and ethyl acetate extracts of four Staphylea species: Staphylea colchica Stev., S. elegans Zab., S. holocarpa Hemsl. and S. pinnata L.. The antioxidant potential (DPPH radical and peroxynitrite scavenging activity) of these extracts was also determined and a correlation between the phenolic content and antioxidant activities of the ethyl acetate extracts has been found. Ethyl acetate extracts were more active and one of them, obtained from S. colchica Stev., possessed the highest activity.     

Simultaneous determination of carotenoids, tocopherols, and gamma-oryzanol in crude rice bran oil by liquid chromatography coupled to diode array and mass spectrometric detection employing silica C30 stationary phases

Crude rice bran oil contains tocopherols (vitamin E), carotenoids (vitamin A), and phytosterols, which possess antioxidant activities and show promising effects as preventive and therapeutic agents. The aim of this work was to establish methods and to compare C18 and C30 silica stationary phases in order to separate and detect tocopherols, carotenoids, and gamma-oryzanol in one single run. Comparing RP-LC on silica C18 and C30, higher resolution between all target compounds was obtained using the C30 stationary phase. Methanol was used as eluent and the elution strength was increased by the addition of tert-butyl methyl ether for highly hydrophobic analytes such as gamma-oryzanol. Detection was accomplished by diode array detection from 200 to 500 nm. Absorbance maxima were found at 295 nm for tocopherols, 324 nm for gammaoryzanol, and 450 nm for carotenoids. Furthermore, compounds were characterized and identified on the basis of their UV-spectra. Both RP systems were coupled to MS (LC-MS) by using an atmospheric pressure chemical ionization interface.     

天然维生素E分析的样品前处理方法研究新进展

维生素E是一种天然抗氧化剂,有重要的生理功能,其含量的分析检测至关重要。样品前处理在维生素E的分析检测过程中耗时最长,作用也最重要,并在一定程度上决定了样品中天然维生素E分析过程的效率和分析结果的信度。近年来,该领域的研究人员在样品前处理方面做了大量工作,开发出众多简捷、高效、可靠的维生素E提取方法。该文综述了皂化法、溶剂提取法、加压溶剂提取法、超临界流体萃取法和固相萃取法等近年发展起来的天然维生素E提取方法,介绍和评述了其应用及优缺点,并提出了发展方向。     

Transformations of chromanol and tocopherol and synthesis of ascorbate conjugates

α-Tocopherol and as a model compound pentamethylchromanol could be transferred into simple and more complex 5a-ether derivatives including galactopyranose as well as ascorbic acid conjugates. Following elaboration of a glucopyranoside spacer element this could be used for tethering the vitamin E and the vitamin C components to give novel conjugates for subsequent biostudies concerning their proposed synergism of antioxidant properties in tissues.