Antiulcer activity of Mauritia flexuosa L.f. (Arecaceae) pulp oil: An edible Amazonian species with functional properties.

Mauritia flexuosa, known as buriti in Brazil, is a widespread palm tree in Amazonia. It has many ethnobotanical uses, including food, oil, and medicine. The oil obtained from buriti's fruit pulp has high levels of monounsaturated fatty acids, carotenoids, and tocopherols, and is used in the food, cosmetic, and pharmaceutical industries for its antioxidant properties. Many biological activities have been reported for buriti oil, such as antioxidant, antimicrobial, chemopreventive, and immunomodulatory. Due to its high content of bioactive compounds, buriti oil is considered a functional ingredient with possible benefits in preventing oxidative stress and chronic diseases, particularly in the gastrointestinal tract. Peptic ulcer disease is a multifactorial disorder, involving lesions in the stomach and duodenum mucosa, which has a complex healing process. In this context, some nutrients and bioactive compounds help the maintenance of gastrointestinal mucosal integrity and function, such as carotenoids, tocopherols, and unsaturated fatty acids, which makes buriti oil an interesting candidate to be used in the prevention and management of gastrointestinal diseases. This study aimed to evaluate the gastroprotective and antiulcer effects of buriti oil and its possible mechanisms of action. Buriti oil reduced the ulcerative area and lipid peroxidation induced by ethanol. The gastroprotective activity of buriti oil partially depends on nitric oxide and sulfhydryl compounds. In acetic acid-induced gastric ulcers, buriti oil accelerated healing and stimulated the formation of new gastric glands. These results demonstrated the potential of buriti oil as a functional ingredient to promote health benefits in the gastrointestinal tract.

Association of solvents improves selected properties of experimental dental adhesives

Abstract: The aim of the study was to evaluate how the association of solvents (tetrahydrofuran [THF], dimethyl sulfoxide [DMSO], ethanol [ET] or acetone [ACT]) with experimental dental adhesives affects selected properties of experimental dental adhesives and dentin bond durability. Six adhesive combinations were prepared containing: 30 % ET, 30 % ACT, 30 % THF, 28 % ET + 2 % DMSO (ET+DMSO), 15 % ethanol + 15 % THF (ET+THF), or 28 % THF + 2 % DMSO (THF+DMSO). Thirty-six molars (n = 6) were cut to expose the coronary dentin, and were randomly divided according to the adhesives. They were restored, and then cut into resindentin sticks (1 mm²), and stored in distilled water for 24 h or 6 months, until conducting the microtensile bond strength and nanoleakage tests. Other experiments performed with adhesives included viscosity assessment using a rheometer, and degree of conversion using Fourier-transform infrared spectroscopy (FTIR). The data were analyzed statistically using two-way ANOVA and Tukey's test (p < 0.05). The adhesive formulated exclusively with THF showed the highest viscosity, followed by ET+THF, which obtained the highest degree of conversion compared to ET, and THF alone. ET+DMSO obtained the highest 24-h and aged bond strengths (p < 0.05). ET+THF increased the nanoleakage slightly after 6 months, but attained the only gap-free adhesive interface among all the groups. The combination of alternative solvents, particularly THF, with conventional ones (ET) has improved chemical properties, and the dentin bonding of experimental simplified adhesives.

Safety aspects of kraft lignin fractions: Discussions on the in chemico antioxidant activity and the induction of oxidative stress on a cell-based in vitro model.

Lignin is a complex phenolic biopolymer present in plant cell walls and a by-product of the cellulose pulping industry. Lignin has functional properties, such as antioxidant activity, that make it a potential natural active ingredient for health-care products. However, not all safety aspects of lignin fractions have been adequately investigated. Herein, we evaluated the antioxidant and genotoxic potential of two hardwood kraft lignins (F3 and F5). The chemical characterization of F3 and F5 demonstrated their thermal stability and the presence of different phenolic units, while the DPPH assay confirmed the antioxidant activity of these lignin fractions. Despite being antioxidants in the DPPH assay, F3 and F5 were capable of generating intracellular reactive oxygen species (ROS) and subsequently causing oxidative DNA damage (Comet assay) in HepG2 cells. The biological relevance of the DPPH assay might be uncertain in some cases; therefore, we suggest combining in chemico tests with biological system-based tests to determine efficacy and safety levels of lignins and define appropriate applications of lignins for consumer products. Moreover, kraft lignins obtained by acid precipitation may pose risks to human health; however, as genotoxicity is not the sole endpoint of toxicity required in hazard assessments, additional toxicological evaluations are needed.

Steam explosion pretreatment improves acetic acid organosolv delignification of oil palm mesocarp fibers and sugarcane bagasse.

Steam explosion can be used to pretreat lignocellulosic materials to decrease energy and chemical consumption during pulping to obtain environmentally friendly lignin and to improve lignin yield without changing its structure. The objective of this study was to evaluate the extraction of lignin from oil palm mesocarp fibers and sugarcane bagasse using steam explosion pretreatment followed by acetosolv. The biomasses were pretreated at 168 °C for a reaction time of 10 min. Steam explosion combined with acetosolv at lower severities was also carried out. Steam explosion followed by acetosolv increased the lignin yield by approximately 15% and 17% in oil palm mesocarp fibers and sugarcane bagasse, respectively. In addition, steam explosion decreased the reaction time of acetosolv four-fold while maintaining the lignin yield from sugarcane bagasse. Similar results were not obtained for oil palm mesocarp. High-purity and high-quality lignins were obtained using steam explosion pretreatment with structural characteristics similar to raw ones. Sugarcane bagasse lignin seems to be a better option for application in material science due its higher lignin yield and higher thermal stability. Our findings demonstrate that steam explosion is efficient for improving lignin yield and/or decreasing pulping severity.

Organic solvent fractionation of acetosolv palm oil lignin: The role of its structure on the antioxidant activity.

Pressed palm oil mesocarp fibers (PPOMF) are by-products from oil palm industry and represents a potential source of lignocellulosic biomass. In order to add value to this agro-waste, dewaxed palm oil acetosolv lignin (DPOAL) was extracted under eco-friendly pulping method. The chemical composition and structural characteristics of DPOAL were investigated. The results showed elevated yield (48.5%) and high purity (94.3%), besides a moderate average molecular weight (1394 g mol-1) and narrow polydispersity index (1.88). Structural characterization via FT-IR, 1H13C HSQC and 31P NMR indicated that DPOAL was a typical HGS-type lignin. In addition, to increase the phenolic hydroxyl contents and improve DPOAL's antioxidant properties through a simple method, a fractionation process with methanol, ethanol and acetone was carried out, obtaining the methanol (MeOH-F), ethanol (EtOH-F) and acetone (ACT-F) soluble fractions. These were characterized by FT-IR, DSC, 1H13C HSQC and 31P NMR, which showed higher values of phenolic and aliphatic hydroxyls groups compared to DPOAL. The antioxidant activity was evaluated by the free radical scavenging activity of 2,2­diphenyl­1­picrylhydrazyl radicals (DPPH·) and compared with commercial antioxidants, such as BHT and Irganox 1010. Interestingly, lignin samples had significantly lower IC50 values compared to commercial antioxidants, what suggests a great potential as novel natural antioxidant.