Obtaining Hexoses from Chitosan through Depolymerization with Nitrous Acid.

BACKGROUND AND OBJECTIVE: Residues from shrimp farming have a great potential for sugar production and the production of derivatives for the low-carbon chemical industry. Obtainment of bioactives from chitosan has been extensively investigated using different methodologies. The purpose of this work was to study the chitosan depolymerization reaction aiming at the production of monomers without the use of additional enzymes or mineral acids. MATERIALS AND METHODS: In this work, we systematically study the effect of sodium nitrite concentration and reaction conditions (pH and temperature ranges) with acetic acid as the solvent on the chitosan depolymerization reaction aiming at the production of monomers, specifically 2,5- anhydromannose, without the use of additional enzymes or mineral acids. RESULTS: The results indicate that only a small range of reaction conditions and nitrite concentrations allow for obtaining the monomer, while in most combinations of these parameters, oligomers are obtained. We found that the temperature decisively affects the reaction yield, with the attainment of 2,5-anhydromannose favored at lower temperatures. CONCLUSION: The method proved to be simple and easy to perform allowing to obtain 2,5- anhydromannose with the use of low-cost reagents. This monomer can be converted into several derivatives for industrial application (5-Hydroxymethylfurfural, ethanol, etc.).

Preliminary Report on the Effect of Savanna Plants Leucaena leucocephala, Parkia platycephala and Senna alata against Eggs and Immature Stages of Trichostrongylid Nematodes In Vitro.

The current study evaluated the anthelmintic effect of different extracts of Leucaena leucocephala, Parkia platycephala, and Senna alata on trichostrongylid eggs and infective larvae and determined the potential active components of each plant. Dried and macerated plant material was concentrated using rotaevaporation to obtain the crude extract (CE), followed by solvent partitioning to obtain hexanic (HexE), acetatic (AcE), and butanolic (BuE) extracts used for phytochemical analysis and anthelmintic efficacy testing in vitro. All the crude and partitioned extracts tested showed inhibition activity in the hatching of trichostrongylid eggs. Larvicidal efficacy was observed at CE concentrations of 2.5, 5.0, and 7.5 mg/mL for P. platycephala and S. alata. However, L. leucocephala CE did not significantly reduce the number of living larvae in the tested concentrations. Chromatographic analysis revealed several active metabolites; gallic acid, ellagic acid, naringin, morin, and kaempferol on AcE of P. platycephala; gallic acid, rutin, and ellagic acid on BuE of P. platycephala; and gallic acid and naringin on BuE of L. leucocephala. The extracts of P. platycephala, L. leucocephala, and S. alata leaves showed egg hatching inhibition and larvicidal activity, probably produced by tannins and flavonoids, which may act alone or by synergism.

Cochlospermum regium (Mart. ex Schrank) Pilg.: Evaluation of chemical profile, gastroprotective activity and mechanism of action of hydroethanolic extract of its xylopodium in acute and chronic experimental models.

ETHNOPHARMACOLOGICAL RELEVANCE: Cochlospermum regium (Bixaceae) is a native shrub of Brazil and its xylopodium (infusion/decoction) is being used for the treatment of gastritis, ulcers, arthritis, intestinal infections, gynaecological infections, skin diseases, among others. The aim of the present study was to evaluate the gastroprotective/antiulcer activity and the mechanism of action of hydroethanolic extract of C. regium xylopodium (HECr), using in vitro and in vivo models. Additionally, phytochemical constituents were identified by high-performance liquid chromatography (HPLC). MATERIALS AND METHODS: C. regium xylopodium was macerated with ethanol/water to obtain the HECr. The phytochemical characterisation was carried out by HPLC. The antiulcer efficacy of HECr (25, 100 and 400 mg/kg, p.o.) was evaluated using acute acidified ethanol (HCl/EtOH), piroxicam and water immersion-induced experimental ulcer models. Chronic gastric ulcer healing activity of HECr was evaluated through acetic acid (99.8%) - induced model. Histological analysis and myeloperoxidase (MPO), glutathione (GSH), catalase (CAT) activities were also evaluated in chronic ulcer induced gastric tissues. The plausible mode of action of the HECr was assessed by estimation of gastric wall mucus production and the role of gastric secretion in pylorus ligature. The animals were also pre-treated with various inhibitors which includes indomethacin (10 mg/kg, p.o.) a selective inhibitor of cyclooxygenase, L-NAME (10 mg/kg, i.p.), an inhibitor of nitric oxide synthase, glibenclamide, a ATP-sensitive potassium channels (K+ATP) blocker (5 mg/kg, p.o.) or yohimbine (2 mg/kg, i.p.), an α2-adrenergic receptor antagonist. In vitro, Helicobacter pylori action was done by broth microdilution method. RESULTS: The HPLC analysis data revealed the presence of gallic acid, rutin, myricetin, morin and kaempferol. HECr promoted protective effect against acute ulcers induced by HCl/EtOH with inhibitions of 47.52% (p < 0.01) and 62.69% (p < 0.001) at 100 and 400 mg/kg, and in piroxicam by 34.11% (p < 0.05), 49.14% (p < 0.01) and 61.34% (p < 0.001), at 25, 100 or 400 mg/kg, respectively, and in water restraint stress by 78.26% inhibition, p < 0.001, at the dose of 400 mg/kg when compared to the vehicle control group respectively. In the chronic gastric ulcer model, HECr (25, 100 and 400 mg/kg p.o.) significantly (p < 0.001) decreased the injured area by 58.80%, 77.87% and 71.10% respectively. Histological examination indicated that oral treatment of HECr promoted healing of gastric lesions by regenerating gastric mucosa layer with less inflammatory cells. HECr augmented the GSH, CAT activities and reduced MPO level. The pre-treatment with HECr increased the gastric wall mucus production. It also significantly altered the gastric secretion parameters by causing the reduction in the gastric juice volume, elevated the pH level and reduced the total acidity at all doses tested when compared with the vehicle group. HECr at the most active dose (100 mg/kg) reversed completely the reduction of PGs, NO production, closure of K+ATP- channels and α2-adrenoreceptor blockage - induced damages. In microdilution assay, the HECr showed good anti-Helicobacter pylori effect with MIC = 100 µg/mL. CONCLUSION: The HECr presented preventive and curative effects in the experimental gastric ulcer models, besides good anti-Helicobacter pylori activity, which supports the traditional medicinal use of the xylopodium of this plant for gastrointestinal diseases. The underlying mechanisms of this antiulcerogenic/antiulcer action involve, at least, augmentation of mucus production, inhibition of gastric secretion, stimulation of PGs and NO synthesis. And that it involves activation of K+ATP channels and α-2-adrenergic receptors, in addition to an antioxidant activity, probably due to the presence of gallic acid and flavonoids in HECr.

Hydroethanolic extract from Echinodorus scaber Rataj leaves inhibits inflammation in ovalbumin-induced allergic asthma.

ETHNOPHARMACOLOGICAL RELEVANCE: Echinodorus scaber, Alismataceae, is popularly known in Brazil as "chapéu-de-couro". The plant leaves are used by the population as decoction, infusion, or maceration in bottled spirits, to treat inflammatory respiratory diseases. AIM OF THE STUDY: To investigate the anti-inflammatory mechanism of the hydroethanolic extract of leaves of Echinodorus scaber (HEEs) in allergic asthma. A phytochemical analysis of the extract was performed as well. MATERIALS AND METHODS: The leaves of Echinodorus scaber were prepared by maceration in 75% ethanol. Preliminary phytochemical analysis was carried out using basic classical methods, and the secondary metabolites detected in HEEs were analyzed and confirmed by high-performance liquid chromatography (HPLC). The in vivo anti-inflammatory activity of HEEs was evaluated in Swiss male albino mice sensitized and challenged by OVA. The HEEs (1, 5 and 30mg/kg, p.o.) was administered to mice twice a day, 1h before the challenge, from days 19 through 24. The mechanism of action of HEEs was studied by evaluating the levels of TH2 cytokines (IL-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) and IgE production in blood plasma. Histopathological changes triggered by OVA-sensitization/challenge in the lung tissue were also investigated. RESULTS: HEEs reduced total leukocyte, eosinophil, neutrophil, and mononuclear cell counts at all doses tested, with maximum effect at 30mg/kg (73.9%, 75.9%, 75.5%, and 65.2% reduction, p<0.001, respectively). Increases in TH2 cytokine secretion (IL-4, IL-5 and IL-13) and in IgE levels were also attenuated by HEEs. Preliminary phytochemical screening seems to indicated the presence of phenolic compounds, flavonoids and alkaloids. HPLC analyses evidenced the presence of phenolic compounds, such as gallic acid, rutin and vitexin. CONCLUSION: Our findings provided pharmacological preclinical evidence for the popular use of the leaves of Echinodorus scaber in allergic inflammation. Its anti-inflammatory effect was dependent on the decrease in migratory inflammatory cells, and both TH2 cytokines and IgE levels. It is suggested that vitexin, gallic acid and rutin, known anti-inflammatory compounds, may participate in the anti-asthamtic effect of the HEEs, by acting jointly along with other components present in the extract.

Physicochemical properties and antioxidant capacity of propolis of stingless bees (Meliponinae) and Apisfrom two regions of Tocantins, Brazil / Propriedades físico-químicas e capacidade antioxidante de própolis de abelhas sem ferrão (Meliponinae) e Apis de duas regiões do Tocantins, Brasil

The composition of propolis depends on time, vegetation and the location of the collection area. The objective of this study was to determine the physicochemical characteristics, the concentration of phenol compounds and the antioxidant capacity of propolis of native stingless bees (Meliponinae) and Apis from the State of Tocantins. Extraction with 80% ethanol (v/v) was performed in order to obtain the extracts. Parameters examined were: propolis mass loss by desiccation at 105 ºC, ashes, wax concentration and pH. Furthermore, the propolis antioxidant activity was measured, as well as the total concentration of phenol compounds. The extracts were also analyzed by high performance liquid chromatography. The total concentration of phenol compounds varied between 121.78 and 631.29 (mg GAE g-1). The antioxidant activity expressed by the value of CE50 varied between 29.81 and 845.38 µg mL-1. High performance liquid chromatography analysis allowed us to infer the existence of phenol compounds. The results indicated that the studied propolis samples constitute good sources of natural antioxidants. The variety of phenol compounds identified in this study, and the diverse biological functions reported in literature for these compounds indicated that this stingless bee propolis (Meliponinae) and Apis has a high pharmacological potential.

A composição da própolis depende do tempo, da vegetação e a localização da área de coleta. Este estudo teve como objetivo determinar as características físicas e químicas, o teor de compostos fenólicos e capacidade antioxidante da própolis de abelhas nativas sem ferrão (Meliponinae) e Apis do Estado do Tocantins. Para a obtenção dos extratos empregou-se extração com etanol 80% (v/v). Os parâmetros analisados foram: perda de peso por dessecação a 105 °C, cinzas, Teor de cera e pH. Além dessas foi mensurada a atividade antioxidante e o teor de compostos fenólicos totais. Adicionalmente os extratos de própolis foram também analisados por cromatografia líquida de alta eficiência. O teor de compostos fenólicos totais variou entre 121,78 e 631,29 (mg GAE g-1). A atividade antioxidante expressa pelo valor de CE50 variou entre 29,81 e 845,38 µg mL-1. As análises por cromatografia líquida de alta eficiência permitiram inferir a existência de compostos fenólicos. Os resultados indicaram que as amostras de própolis estudadas constituem boas fontes de antioxidantes naturais. A variedade de compostos fenólicos identificada neste estudo, e as diversas funções biológicas relatadas na literatura para estes compostos, indicaram que a própolis de abelhas sem ferrão (Meliponinae) e Apis tem um grande potencial farmacológico.

Efeito da adição de soro de queijo no processo de obtenção de etanol a partir de batata-doce / Addition effect of cheese whey in the process of obtaining ethanol from sweet potato

Estudou-se o incremento na produção convencional de etanol de batata-doce [Ipomoea batatas (L.) Lam.] incorporando soro de queijo ao processo e a variação nos teores de proteína bruta dos resíduos sólidos úmidos gerados por esses processos utilizando-se dois cultivares selecionados no estado do Tocantins. O incremento na produção convencional de álcool de batata-doce alcançou um porcentual de 16,6 por cento quando o soro de queijo hidrolisado foi incorporado ao processo, resumidos em até 28,9 litros a mais de etanol por tonelada de raiz. Houve uma variação no teor de proteína bruta nos resíduos sólidos úmidos gerados nos processos substituídos pelo soro de queijo em comparação ao gerado pelo processo testemunha de até 32,1 por cento a mais de proteína. Os resultados obtidos mostram a viabilidade da incorporação do soro de queijo no processo convencional de produção de etanol de batata-doce, possibilitando o reaproveitamento deste coproduto da indústria de laticínio.

This work studied the increase in conventional ethanol production from sweet potato after adding cheese whey to the process, as well as variation in the amount of crude protein in solid waste generated by these processes, using two cultivars developed in Tocantins. Ethanol production increased by 16.6 percent when hydrolysed cheese whey was added to the process, resulting in up to 28.9 extra liters of alcohol per ton of rooted potato. Adding cheese whey to the process generated 32.1 percent more crude protein content in the solid waste compared with the control process. The obtained results show the viability of incorporating cheese whey in the production of ethanol from sweet potato, enabling the reuse of this by-product of the dairy industry.