Effect of Electrical Stimulation on PC12 Cells Cultured in Different Hydrogels: Basis for the Development of Biomaterials in Peripheral Nerve Tissue Engineering.

Extensive damage to peripheral nerves is a health problem with few therapeutic alternatives. In this context, the development of tissue engineering seeks to obtain materials that can help recreate environments conducive to cellular development and functional repair of peripheral nerves. Different hydrogels have been studied and presented as alternatives for future treatments to emulate the morphological characteristics of nerves. Along with this, other research proposes the need to incorporate electrical stimuli into treatments as agents that promote cell growth and differentiation; however, no precedent correlates the simultaneous effects of the types of hydrogel and electrical stimuli. This research evaluates the neural differentiation of PC12 cells, relating the effect of collagen, alginate, GelMA, and PEGDA hydrogels with electrical stimulation modulated in four different ways. Our results show significant correlations for different cultivation conditions. Electrical stimuli significantly increase neural differentiation for specific experimental conditions dependent on electrical frequency, not voltage. These backgrounds allow new material treatment schemes to be formulated through electrical stimulation in peripheral nerve tissue engineering.

Antimicrobial, Antioxidant, and Anti-Inflammatory Properties of Monofloral Honeys from Chile.

Honey is a mixture of compounds produced by bees that has been appreciated by humanity since the creation of the oldest civilizations. It has multiple uses and can be a highly nutritional and healing substance. It has been used in traditional medicine as a natural alternative for the treatment of diverse clinical conditions. This is due to its reported bioactive properties. The objective of this article is to exhibit and analyze the biological properties of different types of honey originating from Chile based on their antimicrobial, antioxidant, and anti-inflammatory activities, focusing primarily on recompiling experimental studies made on monofloral honey of plant species present in the Chilean territory. The result of this bibliographical review shows that Chilean honey possesses remarkable bioactive properties, mainly antimicrobial and antioxidant activities, with a few studies on its anti-inflammatory activity. Most of these results were attributed to monofloral honey belonging to ulmo (Eucryphia cordifolia) and quillay (Quillaja saponaria Molina) plant species. These properties are related to the presence of several bioactive components, such as phenolic components (mainly flavonoids), hydrogen peroxide (H2O2), enzymes, proteins, and carbohydrates. The biodiversity of the flora and the environmental conditions of the Chilean territory are responsible for the wide range of bioactive compounds and biological properties found in Chilean honey. Further studies must be made to uncover the medicinal potential of these native honeys.

Bioactive Lichen Secondary Metabolites and Their Presence in Species from Chile.

Lichens are symbiotic organisms composed of at least one fungal and one algal species. They are found in different environments around the world, even in the poles and deserts. Some species can withstand extreme abiotic conditions, including radiation and the vacuum of space. Their chemistry is mainly due to the fungal metabolism and the production of several secondary metabolites with biological activity, which have been isolated due to an increasing interest from the pharmaceutical community. However, beyond the experimental data, little is known about their mechanisms of action and the potential pharmaceutical use of these kinds of molecules, especially the ones isolated from lesser-known species and/or lesser-studied countries. The main objective of this review is to analyze the bibliographical data of the biological activity of secondary metabolites from lichens, identifying the possible mechanisms of action and lichen species from Chile. We carried out a bibliographic revision of different scientific articles in order to collect all necessary information on the biological activity of the metabolites of these lichen species. For this, validated databases were used. We found the most recent reports where in vitro and in vivo studies have demonstrated the biological properties of these metabolites. The biological activity, namely anticancer, antioxidant, and anti-inflammatory activity, of 26 secondary metabolites are described, as well as their reported molecular mechanisms. The most notable metabolites found in this review were usnic acid, atranorin, protolichesterinic acid, and lobaric acid. Usnic acid was the most investigated metabolite, in addition to undergoing toxicological and pharmacological studies, where a hepatotoxicity effect was reported due to uncoupling oxidative phosphorylation. Additionally, no major studies have been made to validate the pharmacological application of these metabolites, and few advancements have been made in their artificial growth in bioreactors. Despite the described biological activities, there is little support to consider these metabolites in pharmaceutical formulations or to evaluate them in clinical trials. Nevertheless, it is important to carry out further studies regarding their possible human health effects. These lichen secondary metabolites present a promising research opportunity to find new pharmaceutical molecules due to their bioactive properties.

Biological properties of exopolysaccharides produced by Bacillus spp.

There is currently a constant search for ecofriendly bioproducts, which could contribute to various biomedical applications. Among bioproducts, exopolysaccharides are prominent contemporary extracellular biopolymers that are produced by a great variety of bacterial species. These homo- or heteropolymers are composed of monomeric sugar units linked by glycosidic bonds, which are secreted to the external medium. Bacillus spp. are reported to be present in different ecosystems and produce exopolysaccharides with different biological properties such as antioxidant, antibacterial, antiviral anti-inflammatory, among others. Since a great diversity of bacterial strains are able to produce exopolysaccharides, a great variation in the molecular composition is observed, which is indeed present in some of the chemical structures predicted until date. These molecular characteristics and their relations with different biological functions are discussed in order to visualize future applications in biomedical section.

Antimicrobial Properties of Chilean Native Plants: Future Aspects in Their Application in the Food Industry.

Food contamination with microorganisms is responsible for food spoilage, deterioration and change of organoleptic properties of foods. Besides, the growth of pathogenic microorganisms can provoke serious health problems if food is consumed. Innovative packaging, such as active packaging, is increasing rapidly in the food industry, especially in applying antimicrobials into delivery systems, such as sachets. Chile is a relevant hotspot for biodiversity conservation and a source of unique bio-resources with antimicrobial potential. In this review, fifteen native plants with antimicrobial properties are described. Their antimicrobial effects include an effect against human pathogens. Considering the emergence of antimicrobial resistance, searching for new antimicrobials to design new strategies for food pathogen control is necessary. Chilean flora is a promising source of antimicrobials to be used in active packaging. However, further studies are required to advance from laboratory tests of their antimicrobial effects to their possible effects and uses in active films.

Phytochemical profile and antioxidant activity of extracts of the peruvian peppertree Schinus areira L. from Chile.

The Andean tree Schinus areira L. has multiple traditional uses, from the treatment of bronchitis and rheumatic diseases to menstrual cycle regulation and wound healing. With reported hypotensive, analgesic, antitumoral and anti-inflammatory properties, it acts predominantly against diseases related to oxidative stress. This study focuses on the antioxidant activity and phytochemical profile of the extracts of Schinus areira L. Serial extraction of the fruits was performed both by maceration and by Soxhlet. Total phenols and flavonoids were measured using the Folin-Ciocalteu method and AlCl3, respectively. In vitro antioxidant activity was determined by FRAP and DPPH. Results were similar for both extraction methods. Primary metabolites detected included carbohydrates, proteins and amino acids; secondary metabolites included tannins, flavonoids, saponins, steroids and triterpenes. Antioxidant activity was confirmed for ethyl acetate, methanolic and aqueous extracts. The methanolic extract had both the highest polyphenol content (>195 mg GAE/ g dry weight) and the highest antioxidant activity [EC50 > 476 µg/mL; >273 mg AA/g dry weight (DPPH); >301 mg AA/ g dry weight (FRAP)]. The extract does not produce macrophage cytotoxicity in RAW 264.7, which is indicated by an average cytotoxicity of 2% over 24 h. Our study serves as a starting point for future research on the pharmacological properties of Schinus areira L.