Polysaccharides from exudate gums of plants and interactions with the intestinal microbiota: A review of vegetal biopolymers and prediction of their prebiotic potential.

Polysaccharides in plant-exuded gums are complex biopolymers consisting of a wide range of structural variability (linkages, monosaccharide composition, substituents, conformation, chain length and branching). The structural features of polysaccharides confer the ability to be exploited in different industrial sectors and applications involving biological systems. Moreover, these characteristics are attributed to a direct relationship in the process of polysaccharide enzymatic degradation by the fermentative action in the gut microbiota, through intrinsic interactions connecting bacterial metabolism and the production of various metabolites that are associated with regulatory effects on the host homeostasis system. Molecular docking analysis between bacterial target proteins and arabinogalactan-type polysaccharide obtained from gum arabic allowed the identification of intermolecular interactions provided bacterial enzymatic mechanism for the degradation of several arabinogalactan monosaccharide chains, as a model for the study and prediction of potential fermentable polysaccharide. This review discusses the main structural characteristics of polysaccharides from exudate gums of plants and their interactions with the intestinal microbiota.

Performance of collagen-based matrices from Nile tilapia skin: A pilot proteomic study in a murine model of wound healing.

Full-thickness cutaneous trauma, due to the lack of dermis, leads to difficulty in epithelialization by keratinocytes, developing a fibrotic scar, with less elasticity than the original skin, which may have disorders in predisposed individuals, resulting in hypertrophic scar and keloids. Biomedical materials have excellent characteristics, such as good biocompatibility and low immunogenicity, which can temporarily replace traditional materials used as primary dressings. In this work, we developed two dermal matrices based on Nile tilapia collagen, with (M_GAG) and without (M) glycosaminoglycans, using a sugarcane polymer membrane as a matrix support. To assess the molecular mechanisms driving wound healing, we performed qualitative proteomic analysis on the wound bed in an in vivo study involving immunocompetent murine models at 14 and 21 days post-full-thickness skin injury. Gene Ontology and Pathway analysis revealed that both skins were markedly represented by modulation of the immune system, emphasizing controlling the acute inflammation response at 14 and 21 days post-injury. Furthermore, both groups showed significant enrichment of pathways related to RNA and protein metabolism, suggesting an increase in protein synthesis required for tissue repair and proper wound closure. Other pathways, such as keratinization and vitamin D3 metabolism, were also enriched in the groups treated with M matrix. Finally, both matrices improved wound healing in a full post-thick skin lesion. However, our preliminary molecular data reveals that the collagen-mediated healing matrix lacking glycosaminoglycan (M) exhibited a phenotype more favorable to tissue repair, making it more suitable for use before skin grafts.

Biocompatibility and immunostimulatory properties of fish collagen and shrimp chitosan towards peripheral blood mononuclear cells (PBMCs).

Several naturally occurring biopolymers are commercially produced from livestock and farmed animals processing wastes, including aquatic organisms. These wastes are considered valuable coproducts of fishery processing industry, from which biopolymers may be recovered and exploited for their bioactive potential. The aim of this work was to prepare polymeric films from collagen and chitosan solutions, extracted from fishery discards, and investigate the cytotoxicity and immunomodulatory activity towards human peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from healthy donors and treated with Chitosan, Collagen, Chitosan+Collagen solutions and Chitosan+Collagen film in order to measure the changes in cell viability, cytosolic calcium concentration ([Ca2+]cyt), mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS) levels, differentiation and activation of T CD8+ and CD4+ lymphocytes, and cytokine production. Results showed that collagen and chitosan preparations did not show cytotoxic effect, while cellular IL-6, IL-10, and TNF-α release was observed. Chitosan and collagen were able to promote non-cytotoxic PBMCs activation through cytosolic and mitochondrial ROS production. There was a noteworthy phenotyping of lymphocytes T CD8+ and CD4+ counting and an increase of [Ca2+] cyt and ΔΨm levels. These results suggest that chitosan/collagen-based biomaterials produce immunostimulatory effects on PBMC with potential to biomedical approaches.

Acetylcholinesterase from the charru mussel Mytella charruana: kinetic characterization, physicochemical properties and potential as in vitro biomarker in environmental monitoring of mollusk extraction areas.

Acetylcholinesterase (AChE; EC 3.1.1.7) from aquatic organisms have been used to evaluate the exposure of specimens to pesticides and heavy metals at sublethal levels in environmental samples. AChE of Mytella charruana was extracted to characterize its physicochemical and kinetic properties as well as the effect of organophosphate (dichlorvos, diazinon, chlorpyrifos, methyl-parathion and temephos), carbamates (carbaryl, carbofuran and aldicarb), benzoylureas (diflubenzuron and novaluron), pyrethroid (cypermethrin) and juvenile hormone analog - JHA (pyriproxyfen) and the effect of metal ions: Hg2+, Cd2+, Pb2+, As3+, Cu2+ and Zn2+, in order to evaluate the potential of the enzyme as biomarker. The optimum pH of M. charruana AChE was 8.5 and the maximum activity peak occurred at 48 °C, being highly thermostable maintaining 97.8% of its activity after incubation at 60 °C. The Michaelis-Menten constants (km) for the substrates acetylthiocholine and propionylthiocholine were 2.8 ± 1.26 and 4.94 ± 6.9 mmol·L-1, respectively. The Vmax values for the same substrates were 22.6 ± 0.90 and 10.2 ± 4.94 mU·mg-1, respectively. Specific inhibition results suggest an AChE presenting active site with dimensions between those of AChE and butyrylcholinesterase (BChE). The IC20 values related to the effect of the pesticides on the enzyme showed higher inhibitory power of temephos (0.17 µmol·L-1), followed by aldicarb (0.19 µmol·L-1) and diflubenzuron (0.23 µmol·L-1). Metal ions inhibited M. charruana enzyme in the following order: Hg2+ > Pb2+ > Cd2+ > As3+ > Cu2+ > Zn2+. These data suggest that the enzyme showed potential as in vitro biomarker of the exposure to temephos, mercury, zinc and copper.

Non-clinical repeated dose 28-day oral toxicity, reproductive toxicity and cytotoxicity studies of the polar fraction of Parkinsonia aculeata aerial parts extract.

This study was aimed to evaluate toxicity in repeated doses for 28 days, reproductive toxicity and cytotoxicity of a polar fraction obtained from the hydroethanolic extract of Parkinsonia aculeata (PfrHEPA) in experimental models. To perform the toxicity test in repeated doses for 28 days, male and female Wistar rats were treated via orogastric for 28 days with PfrHEPA (35, 70 or 140 mg/kg) according to the guidelines established by the Organisation for Economic Co-operation and Development (OECD) number 407 (1995). For assessment, the impact of PfrHEPA on the reproductive output various parameters were measured, including maternal weight, no. of pregnant females, female fertility index (%), gestation lengthtime, implantation sites, litter size and placental index of test animals. The cytotoxicity of PfrHEPA was performed on the tumor lines NCI-H292 (human lung carcinoma), HL-60 (human promyelocytic leukemia) and HCT-116 (colorectal cancer). In the repeated dose toxicity test for 28 days, no mortality was observed in the male and female rats treated with PfrHEPA as well as morphological changes and biochemical and hematological parameters. In the reproductive toxicity test, no abnormalities were observed related to the toxicological parameters in both mothers and offspring. Regarding the cytotoxicity assay, the PfrHEPA fraction did not demonstrate significant cytotoxic effect on the cell lines analyzed. The present results suggest the use of PfrHEPA is safe and well tolerated in rats. Further studies are planned to identify and purify the active compounds for subsequent in vivo evaluation.

Dose-dependent effects of astaxanthin on cortical spreading depression in chronically ethanol-treated adult rats.

BACKGROUND: The consumption of alcoholic drinks is a frequent drug-abuse situation, which is associated to a wide variety of pathological disturbances affecting several organs, including the brain. We have previously shown in the developing rat brain that ethanol intake facilitates the propagation of cortical spreading depression (CSD), an excitability-related neural phenomenon present in several animal species. This electrophysiological effect was attenuated by a shrimp (Litopenaeus vannamei) carotenoids extract. Here we investigated the effects of pure astaxanthin, the main carotenoid found in shrimp, on CSD. METHODS: Adult Wistar rats were treated per gavage, during 18 days, with 2.5, 10 or 90 microg/kg/d astaxanthin dissolved in ethanol (3 g/kg) and CSD was recorded on the cortical surface 1 to 3 days thereafter. Four groups, treated respectively with ethanol, distilled water and soybean oil with- and without astaxanthin were also studied for comparison with the ethanol + astaxanthin groups. RESULTS: Ethanol-treated rats displayed higher CSD-velocities (mean values, in mm/min, per hour of recording ranging from 4.08 +/- 0.09 to 4.12 +/- 0.16), compared to the distilled water-group (from 3.19 +/- 0.13 to 3.27 +/- 0.06). Addition of astaxanthin to ethanol lead to lower CSD-velocities in a dose-dependent manner, ranging from 3.68 +/- 0.09 to 3.97 +/- 0.22 for the 2.5 microg/kg/d-dose, from 3.29 +/- 0.09 to 3.32 +/- 0.07 for the 10 microg/kg/d-dose, and from 2.89 +/- 0.13 to 2.92 +/- 0.11 for the 90 microg/kg/d-dose. The velocities of the soybean oil groups (with and without astaxanthin) were not statistically different from the 10 microg/kg/d astaxanthin + ethanol and distilled water groups. CONCLUSION: The results demonstrate the antagonistic effect of astaxanthin against the ethanol-induced facilitation of CSD propagation. Probably carotenoid antioxidant properties are involved in such effects.