Green Synthesis of Antileishmanial and Antifungal Silver Nanoparticles Using Corn Cob Xylan as a Reducing and Stabilizing Agent.

Corn cob is an agricultural byproduct that produces an estimated waste burden in the thousands of tons annually, but it is also a good source of xylan, an important bioactive polysaccharide. Silver nanoparticles containing xylan (nanoxylan) were produced using an environmentally friendly synthesis method. To do this, we extracted xylan from corn cobs using an ultrasound technique, which was confirmed by both chemical and NMR analyses. This xylan contained xylose, glucose, arabinose, galactose, mannose, and glucuronic acid in a molar ratio of 50:21:14:9:2.5:2.5, respectively. Nanoxylan synthesis was analyzed using UV-vis spectroscopy at kmax = 469 nm and Fourier transform infrared spectroscopy (FT-IR), which confirmed the presence of both silver and xylan in the nanoxylan product. Dynamic light scattering (DLS) and atomic force microscopy (AFM) revealed that the nanoxylan particles were ~102.0 nm in size and spherical in shape, respectively. DLS also demonstrated that nanoxylan was stable for 12 months and coupled plasma optical emission spectrometry (ICP-OES) showed that the nanoxylan particles were 19% silver. Nanoxylan reduced Leishmania amazonensis promastigote viability with a half maximal inhibitory concentration (IC50) value of 25 µg/mL, while xylan alone showed no effective. Additionally, nanoxylan exhibited antifungal activity against Candida albicans (MIC = 7.5 µg/mL), C. parapsilosis (MIC = 7.5 µg/mL), and Cryptococcus neoformans (MIC = 7.5 µg/mL). Taken together, these data suggest that it is possible to synthesize silver nanoparticles using xylan and that these nanoxylan exert improved antileishmanial and antifungal activities when compared to the untreated polysaccharide or silver nitrate used for their synthesis. Thus, nanoxylan may represent a promising new class of antiparasitic agents for use in the treatment of these microorganisms.

Preparation and properties of cellulose nanocomposite films with in situ generated copper nanoparticles using Terminalia catappa leaf extract.

In the present work, copper nanoparticles (CuNPs) were in situ generated inside cellulose matrix using Terminalia catappa leaf extract as a reducing agent. During this process, some CuNPs were also formed outside the matrix. The CuNPs formed outside the matrix were observed with transmission electron microscope (TEM) and scanning electron microscope (SEM). Majority of the CuNPs formed outside the matrix were in the size range of 21-30nm. The cellulose/CuNP composite films were characterized by Fourier transform infrared spectroscopic, X-Ray diffraction and thermogravimetric techniques. The crystallinity of the cellulose/CuNP composite films was found to be lower than that of the matrix indicating rearrangement of cellulose molecules by in situ generated CuNPs. Further, the expanded diffractogram of the composite films indicated the presence of a mixture of Cu, CuO and Cu2O nanoparticles. The thermal stability of the composites was found to be lower than that of the composites upto 350°C beyond which a reverse trend was observed. This was attributed to the catalytic behaviour of CuNPs for early degradation of the composites. The composite films possessed sufficient tensile strength which can replace polymer packaging films like polyethylene. Further, the cellulose/CuNP composite films exhibited good antibacterial activity against E.coli bacteria.

Antioxidant Activity of Different Fractions of Methanolic Extract of the Golden Chanterelle Mushroom Cantharellus cibarius (Higher Basidiomycetes) from Iran.

Natural compounds with antioxidant activity can be useful for treatment of reactive oxygen species-related diseases, comprising atherosclerosis, inflammatory injury, cardiovascular disease, cancer, diabetes, Alzheimer's disease, cataracts, autism, and aging. The current study was perform to assay the antioxidant activity different fractions of methanolic extract of golden chanterelle mushroom Cantharellus cibarius, a mushroom found in the north of Iran. Different fractions of methanolic extract of this mushroom, including n-hexane, chloroform, ethyl acetate, n-butanol, and water, were evaluated for antioxidant activity using six in vitro assay systems. Mushroom fruit was obtained from the local market, Sari (northern Iran). The n-hexane fraction had higher amounts of flavonoids contents (40.01 ± 1.30 mg quercetin equivalent g-1 of extract) and the highest exhibition of nitric oxide scavenging activity (77.21 ± 1.48%). The highest content of phenol was observed in the n-butanol fraction, which was 40.97 ± 0.99 mg gallic acid equivalent g-1 of extract. Among all the fractions, the ethyl acetate fraction was found to show higher DPPH scavenging activity (33.43 ± 1.30%) and the aqueous fraction to display the most reducing power. The highest Fe2+ chelating activity was observed in the chloroform fraction and then in the n-hexane fraction (86.13 ± 1.61 and 80.68 ± 2.07, respectively). The results all together signify C. cibarius as a valuable source of natural bioactive compounds with antioxidant activity.

Isolation and characterization of biologically active melanin from Actinoalloteichus sp. MA-32.

Melanins are enigmatic pigments and biological macromolecules that are produced by a wide variety of microorganisms including several species of bacteria and fungi. The present study was carried out on isolation and characterization of melanin from marine actinobacteria, Actinoalloteichus sp. MA-32. Medium composition and culture conditions for the melanin production by Actinoalloteichus sp. MA-32 were optimized using two statistical methods: Plackett-Burman design applied to find the key ingredients and conditions for the best yield of melanin production and central composite design used to optimize the concentration of the four significant variables: glycerol, L-tyrosine, NaCl and trace salt solution. The melanin was optimally active at pH 7-9 and temperature 45-60°C and it was most stable up to pH 11 and 4% of NaCl concentration. Melanin was examined by UV-vis absorption spectroscopy and infrared spectrometry. Melanin has potential antibacterial activity as it showed greater antagonistic and it has a strong antioxidant potential observed in the in vitro evaluation of its DPPH radical-scavenging activity, superoxide radical-scavenging activity, nitric oxide-scavenging activity, reducing power and metal chelating activity. The observed activities indicate that melanin might be a novel potential antioxidant. This study suggested that the melanin could potentially be used as a natural antioxidant in the food, cosmetic and pharmaceutical industries.

The neuroprotective activities and antioxidant activities of the polysaccharides from Saccharina japonica.

The crude polysaccharide (W) was extracted by water from Saccharina japonica and five fractions were separated by anion-exchange chromatography. And their chemical constituents, neuroprotective activities and antioxidant activities were studied. It showed that W had the neuroprotective activity while its fractions did not. In addition, the fractions displayed higher activities on hydroxyl-radical scavenging effects and reducing power than these of W. Moreover, it was speculated that the neuroprotective activities of samples were related to the hydroxyl-radical scavenging effect and reducing power while did not relate to superoxide-radical scavenging effect. Finally, it was concluded that some fractions could be good candidate antioxidants in food chemistry owing to the high antioxidant activities and their non-toxic characteristics.

Differences in the phenolic composition and antioxidant properties between Vitis coignetiae and Vitis vinifera seeds extracts.

Phenolic compounds were extracted from European and Japanese grapevine species (Vitis vinifera and V. coignetiae) seeds using 80% methanol or 80% acetone. The total content of phenolic compounds was determined utilizing Folin-Ciocalteu's phenol reagent, while the content of tannins was assayed by the vanillin and BSA precipitation methods. Additionally, the DPPH free radical and ABTS cation radical scavenging activities and the reduction power of the extracts were measured. The HPLC method was applied to determine the phenolic compounds, such as phenolic acids and catechins. The seeds contained large amounts of tannins and gallic acid and observable quantities of catechins, p-coumaric, ferulic and caffeic acids. The dominant form of phenolic acids in the extracts was the ester-bound form. The content of total phenolics was higher in the European grape V. vinifera seeds, which also contained more tannins, catechins and phenolic acids, except for caffeic acid. Extracts from V. vinifera seeds showed better radical scavenger properties and stronger reducing power. The total contents of phenolic compounds and tannins in acetone extracts were higher than in methanolic extracts. Acetone extracts also exhibited stronger antiradical properties as well as stronger reducing power.

Antioxidant activity of polyphenol and ultrasonic extracts from fruits of Crataegus pentagyna subsp. elburensis.

The effects of two extracting methods on the total phenolic and total flavonoid contents of Crataegus pentagyna subsp. elburensis Waldst. & Kit. ex Willd fruit extracts were investigated. Antioxidant activities of polyphenol (PP) fraction and ultrasonic (US) extraction were evaluated with four different in vitro antioxidant tests. IC(50) for DPPH radical-scavenging activity was 32.2 ± 1.6 for PP fraction and 36.7 ± 1.5 µg mL(-1) for US extract. Reducing powers of extracts increased with the increase of their concentrations. PP fraction exhibited high reducing power at 2-32 µg mL(-1). Extracts exhibited good H(2)O(2) radical scavenging and Fe(2+) chelating ability. Their high phenolic and flavonoid contents could be responsible for their antioxidant activity and pharmacologic actions.

Variation in antioxidant attributes at three ripening stages of guava (Psidium guajava L.) fruit from different geographical regions of Pakistan.

The present investigation was carried out to appraise the levels of total phenols and vitamin C as well as antioxidant potential at three different ripening stages (un-ripe, semi-ripe and fully-ripe) of guava (Psidium guajava L.) fruit collected from three different geographical regions of Pakistan (Islamabad, Faisalabad and Bhakkar). The antioxidant potential of guava fruit extracts was assessed by means of different in-vitro antioxidant assays, namely inhibition of peroxidation in linoleic acid system, reducing power and radical scavenging capability. Overall, fruit at the un-ripe stage (G1) exhibited the highest levels of TPC, TFC, reducing power and DPPH radical scavenging activity, followed by the semi-ripe (G2) and fully-ripe (G3) stages. On the other hand, vitamin C content increased as the fruit maturity progressed, with highest value seen at the fully-ripe stage (G3) followed by the semi-ripe (G2) and un-ripe stage (G1). The concentration of vitamin C in fruits varied as: Faisalabad (136.4-247.9 mg 100 g⁻¹), Islamabad (89.7-149.7 mg 100 g⁻¹) and Bhakkar (73.1-129.5 mg 100 g⁻¹). The results showed that different stages of maturation and geographical locations had profound effects on the antioxidant activity and vitamin C contents of guava fruit.

Biosynthesis of silver nanoparticles using citrus sinensis peel extract and its antibacterial activity.

Biosynthesis of silver nanoparticles (AgNPs) was achieved by a novel, simple green chemistry procedure using citrus sinensis peel extract as a reducing and a capping agent. The effect of temperature on the synthesis of silver nanoparticles was carried out at room temperature (25°C) and 60°C. The successful formation of silver nanoparticles has been confirmed by UV-vis, FTIR, XRD, EDAX, FESEM and TEM analysis and their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa (gram-negative), and Staphylococcus aureus (gram-positive) has been studied. The results suggest that the synthesized AgNPs act as an effective antibacterial agent.

Biological synthesis of silver and gold nanoparticles using apiin as reducing agent.

We report a novel strategy for the biological synthesis of anisotropic gold and quasi-spherical silver nanoparticles by using apiin as the reducing and stabilizing agent. The size and shape of the nanoparticles can be controlled by varying the ratio of metal salts to apiin compound in the reaction medium. The resultant nanoparticles were characterized by UV-vis-NIR, transmission electron microscopy (TEM), FT-IR spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The interaction between nanoparticles with carbonyl group of apiin compound was confirmed by using FT-IR analysis. TEM photograph confirming the average size of the gold and silver nanoparticles were found to be at 21 and 39 nm. The NIR absorption of the gold nanotriangles is expected to be of application in hyperthermia of cancer cells and in IR-absorbing optical coatings.

Enhanced antioxidant bioactivity of Salvia miltiorrhiza (Danshen) products prepared using nanotechnology.

The traditional Chinese medicine, Salvia miltiorrhiza (Danshen), promotes blood circulation and relieves blood stasis, also demonstrating good antioxidant activity. In the present study, therefore, the antioxidant activities of medicinal plant materials prepared using nanotechnology or traditional grinding methods were compared using three biological assays. It was found that the nanotechnology preparation had stronger antioxidant bioactivities. Complementary quantitative analysis of four active constituents, salvianolic acid B, cryptotanshinone, tanshinone I and tanshinone IIA, by HPLC revealed only marked differences for salvianolic acid B. The results indicate that the polar active constituent in the nanotechnology samples was released faster compared to the traditionally powdered samples.

Mutagenicity of cooked hamburger is controlled delicately by reducing sugar content in ground beef.

Effect of sugars added to ground beef on the generation of mutagenicity of cooked hamburger was investigated. Mutagenicity of hamburger was assayed by the Ames test using Salmonella typhimurium TA98 strain with metabolic activation after the mutagens were purified by use of blue rayon. Intrinsic reducing sugar content in ground beef was estimated to be 0.07% (w/w). Mutagenicity of hamburger was sharply or delicately controlled by the amount of a reducing sugar added to ground beef. Mutagenicity was increased more than 2-folds by addition of 0.08% (w/w) glucose, fructose or lactose but decreased to about a half by addition of more than 0.67% (w/w) each of the reducing sugars. Mutagenicity of cooked hamburger was not influenced by addition of sucrose at the ranges between 0.08 and 0.67% (w/w). When red wine with 0.10% (w/w) equivalent amount of reducing sugars or white wine with 0.13% (w/w) equivalent amount of reducing sugars were added to the ground beef, mutagenicity of cooked hamburger was similarly increased 1.6-1.8-fold. Controlling the reducing sugar content in ground beef would be a simple way to regulate the mutagenicity of cooked hamburgers.

Zeta-crystallin catalyzes the reductive activation of 2,4,6-trinitrotoluene to generate reactive oxygen species: a proposed mechanism for the induction of cataracts.

Exposure to 2,4,6-trinitrotoluene (TNT) has been shown to cause induction of cataract in which oxidative stress plays a critical role. From bovine lens we purified to homogeneity and identified an enzyme that catalyzes the reduction of TNT, resulting in the production of reactive oxygen species. The final preparation of TNT reductase showed a single band with a subunit molecular weight of 38 kDa on SDS-PAGE. Sequence data from peptides obtained by digestion with lysylendopeptidase Achromobacter protease I (API) revealed that TNT reductase is identical to zeta-crystallin. Superoxide anions were formed during reduction of TNT by zeta-crystallin, though negligible enzyme activity or protein content for superoxide dismutase, a superoxide scavenging enzyme, was found in the lens. Thus, the present results suggest that the induction of cataracts by TNT may be associated with increased oxidative stress, as a result of reductive activation of TNT generating superoxide anions, there being minimal antioxidant enzyme activity for defense against reactive oxygen species exogenously produced in the lens.