Seaweed is a rich source of bioactive sulfated polysaccharides. We obtained six sulfated polysaccharide-rich fractions (UF-0.3, UF-0.5, UF-0.6, UF-0.7, UF-1.0, and UF-2.0) from the green seaweed Udotea flabellum (UF) by proteolytic digestion followed by sequential acetone precipitation. Biochemical analysis of these fractions showed that they were enriched with sulfated galactans. The viability and proliferative capacity of 3T3 fibroblasts exposed to FeSO4 (2 µM), CuSO4 (1 µM) or ascorbate (2 mM) was not affected. However, these cells were exposed to oxidative stress in the presence of FeSO4 or CuSO4 and ascorbate, which caused the activation of caspase-3 and caspase-9, resulting in apoptosis of the cells. We also observed increased lipid peroxidation, evaluated by the detection of malondialdehyde and decreased glutathione and superoxide dismutase levels. Treating the cells with the ultrafiltrate fractions (UF) fractions protected the cells from the oxidative damage caused by the two salts and ascorbate. The most effective protection against the oxidative damage caused by iron was provided by UF-0.7 (1.0 mg/mL); on treatment with UF-0.7, cell viability was 55%. In the case of copper, cell viability on treatment with UF-0.7 was ~80%, but the most effective fraction in this model was UF-2.0, with cell viability of more than 90%. The fractions, mainly UF-0.7 and UF-2.0, showed low iron chelating activity, but high copper chelating activity and total antioxidant capacity (TAC). These results suggested that some of their protective mechanisms stem from these properties.

Background: Chagas disease, also known as American Trypanosomiasis, is caused by the protozoan Trypanosoma cruzi. It is occurring in Americas, including USA and Canada, and Europe and its current treatment involves the use of two drugs as follows: benznidazole (BNZ) and nifurtimox, which present high toxicity and low efficacy during the chronic phase of the disease, thus promoting the search for more effective therapeutic alternatives. Amongst them xylan, a bioactive polysaccharide, extracted from corn cob. Methods: Ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy (FITR), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy, atomic force microscopy, plasma optical emission spectroscopy (ICP-OES), dynamic light scattering (DLS) have been used to characterize the silver-xylan nanoparticles (NX). Their cytotoxicity was evaluated with 3-bromo(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) test. MTT and flow cytometry were used to ascertain the anti-Trypanosoma cruzi activity. Results: UV-Vis spectroscopy gave plasmon resonance ranging between 400 and 450 nm while FITC and Raman spectroscopy proved nano interface functionalized with xylan. ICP-OES data showed NX with xylan (81%) and silver (19%). EDS showed NX consisting of carbon (59.4%), oxygen (26.2%) and silver (4.8%) main elements. Spherical NX of 55 nm average size has been depicted with SEM and AFM, while DLS showed 102 ± 1.7 nm NX. The NX displayed negligible cytotoxicity (2000 µg/mL). NX (100 µg/mL) was more effective, regardless of experiment time, in affecting the ability of parasites to reduce MTT than BZN (100 µg/mL). In addition, NX (100 µg/mL) induced death of 95% of parasites by necrosis. Conclusion: This is the first time silver nanoparticles are presented as an anti-Trypanosoma cruzi agent and the data point to the potential application of NX to new preclinical studies in vitro and in vivo.

Neglected agricultural products (NAPs) are defined as discarded material in agricultural production. Corn cobs are a major waste of agriculture maize. Here, a methanolic extract from corn cobs (MEC) was obtained. MEC contains phenolic compounds, protein, carbohydrates (1.4:0.001:0.001). We evaluated the in vitro and in vivo antioxidant potential of MEC. Furthermore, its antiproliferative property against tumor cells was assessed through MTT assays and proteins related to apoptosis in tumor cells were examined by western blot. MEC showed no hydroxyl radical scavenger capacity, but it showed antioxidant activity in Total Antioxidant Capacity and DPPH scavenger ability assays. MEC showed higher Reducing Power than ascorbic acid and exhibited high Superoxide Scavenging activity. In tumor cell culture, MEC increased catalase, OPEN ACCESSMolecules 2014, 19 5361 metallothionein and superoxide dismutase expression in accordance with the antioxidant tests. In vivo antioxidant test, MEC restored SOD and CAT, decreased malondialdehyde activities and showed high Trolox Equivalent Antioxidant Capacity in animals treated with CCl 4 . Furthermore, MEC decreased HeLa cells viability by apoptosis due an increase of Bax/Bcl-2 ratio, caspase 3 active. Protein kinase C expression increased was also detected in treated tumor cells. Thus, our findings pointed out the biotechnological potential of corn cobs as a source of molecules with pharmacological activity.

Polysaccharides containing sulfated L-fucose are often called fucans. The seaweed Spatoglossum schröederi synthesizes three fucans, among which fucan A is the most abundant. This polymer is not cytotoxic against various normal cell lines and is non-toxic to rats when administered at high doses. In addition, it exhibits low toxicity against tumor cells. With the aim of increasing the toxicity of fucan A, silver nanoparticles containing this polysaccharide were synthesized using a green chemistry method. The mean size of these nanoparticles was 210nm. They exhibited a spherical shape and negative surface charge and were stable for 14 months. When incubated with cells, these nanoparticles did not show any toxic effects against various normal cell lines; however, they decreased the viability of various tumor cells, especially renal adenocarcinoma cells 786-0. Flow cytometry analyses showed that the nanoparticles induced cell death responses of 786-0 cells through necrosis. Assays performed with several renal cell lines (HEK, VERO, MDCK) showed that these nanoparticles only induce death of 786-0 cells. The data obtained herein leads to the conclusion that fucan A nanoparticles are promising agents against renal adenocarcinoma.

A 12.4 kDa laminarin (LM) composed of β(1→3)-glucan with β(1→6)-branches was extracted from brown seaweed Lobophora variegata and modified via carboxylation using dielectric barrier discharge (LMC), conjugation with gallic acid (LMG), and sulfation (LMS). Analyses of the chemical composition of LMC, LMG, and LMS yielded 11.7% carboxyl groups, 1.5% gallic acid, and 1.4% sulfate content, respectively. Antioxidant activities of native and modified laminarins were assessed using six different in vitro methods. Sulfation stopped the antioxidant activities of LM. On the other hand, carboxylation improved cooper chelation (1.2 times). LMG was found to be a more efficient antioxidant agent than LM in terms of copper chelation (1.3 times), reducing power (1.3 times), and total antioxidant capacity (80 times). Gallic acid conjugation was further confirmed using Fourier transform infrared spectroscopy (FT-IR) and one- and two-dimensional NMR spectroscopy analyses. LMG also did not induce cell death or affect the cell cycle of Madin–Darby canine kidney (MDCK) cells. On the contrary, LMG protected MDCK cells from H2O2-induced oxidative damage. Taken together, these results show that LMG has the potent antioxidant capacity, and, therefore, potential applications in pharmacological and functional food products.

No abstract

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.

Fucus vesiculosus is a brown seaweed used in the treatment of obesity. This seaweed synthesizes various bioactive molecules, one of them being a sulfated polysaccharide known as fucoidan (FF). This polymer can easily be found commercially, and has antiadipogenic and lipolytic activity. Using differential precipitation with acetone, we obtained four fucoidan-rich fractions (F0.5/F0.9/F1.1/F2.0) from FF. These fractions contain different proportions of fucose:glucuronic acid:galactose:xylose:sulfate, and also showed different electrophoretic mobility and antioxidant activity. Using 3T3-L1 adipocytes, we found that all samples had lipolytic action, especially F2.0, which tripled the amount of glycerol in the cellular medium. Moreover, we observed that FF, F1.0, and F2.0 have antiadipogenic activity, as they inhibited the oil red staining by cells at 40%, 40%, and 50%, respectively. In addition, they decreased the expression of key proteins of adipogenic differentiation (C/EBPα, C/EBPβ, and PPARγ). However, F0.5 and F0.9 stimulated the oil red staining at 80% and increased the expression of these proteins. Therefore, these fucoidan fractions have an adipogenic effect. Overall, the data show that F2.0 has great potential to be used as an agent against obesity as it displays better antioxidant, lipolytic and antiadipogenic activities than the other fucoidan fractions that we tested.