Nisin

Antimicrobial peptides (AMPs) are small cationic peptides which protect their hosts against bacteria, protozoa, viruses, and fungi. Bacterial AMPs are called bacteriocins, and are produced by both Gram-positive and Gram-negative bacteria. Because of their high potency and specificity, bacteriocins are considered as promising antimicrobial agents for different applications, including food preservation and infection treatment; specially the ones produced by acid lactic bacteria species (Gram-positive). Nisin is the most intensively studied and used bacteriocin, it is found commercially available and its use is regulated in over 50 countries. Therefore, special attention is given to this bacteriocin

The influence of pH, polyethylene glycol and polyacrylic acid on the stability of stem bromelain

Enzyme stability is critical in biotechnology, pharmaceutical and cosmetic industries. Investigations on this subject have drawn attention because of its practical application. Bromelain is a thiol-endopeptidase, obtained from pineapple (Ananas comosus), known for its clinical and therapeutic applications, particularly to selective burn debridement and improvement of antibiotic action and anti-inflammatory activities. To date, the use of bromelain in pharmacological or industrial applications is limited, due to commercial availability, costs, and sensitivity to pH and temperature. Therefore, a better understanding of enzyme stability would be of great interest. The aim of this study was to evaluate bromelain activity and stability in several pH (2.0 to 8.0) and in polyethylene glycol and polyacrylic acid solutions. We observed that bromelain was able to maintain its stability at pH 5.0 for the temperatures studied. PEG solutions increased bromelain stability, but PAA solutions had the opposite effect.Estabilidade de enzimas é uma questão fundamental em indústrias biotecnológicas, farmacêuticas e cosméticas. As investigações sobre o assunto têm chamado a atenção por sua aplicação prática. A bromelina é uma tiol-endopeptidase, obtida a partir do abacaxi (Ananas comosus). É conhecida por suas aplicações clínicas e terapêuticas, especialmente para desbridamento seletivo de queimaduras, melhoria de ações antibiótica e de atividades anti-inflamatórias. Até o momento, a utilização da bromelina em aplicações farmacológicas industriais é limitada, devido à disponibilidade comercial, os custos, a sensibilidade ao pH e temperatura. Portanto, a maior compreensão da estabilidade desta enzima seria de grande interesse. O objetivo deste estudo foi avaliar a estabilidade da atividade da bromelina em vários pH (2,0 a 8,0) e em soluções de polietilenoglicol e de ácido poliacrílico. Observamos que a bromelina foi capaz de manter a sua estabilidade em pH 5.0, em todas as temperaturas estudadas. Soluções de PEG aumentaram a estabilidade da bromelina, enquanto que soluções de PAA obtiveram efeito oposto

Bem-estar animal em laboratório: enriquecimento ambiental apresenta efeito positivo na experimentação animal

Reproductive and developmental toxicology has focused on the need to approach the effects of organism exposure to various drugs during pregnancy after the mid-50’s, when the thalidomide tragedy stroke humanity. In recent decades, this area of study has developed a lot due to animal testing, raising awareness on the need to improve the quality of life of such animals. Therefore, this paper aims to investigate how the science of animal welfare can improve scientific research as a whole, including the reproductive and developmental toxicology fields, by emphasizing environmental enrichment in animal facilities. To do so, we conducted an integrative literature review on several quantitative and qualitative methodological approaches that are applicable to toxicology studies. Here, we present evidence that environmental enrichment improves animal welfare and prevents or reduces the negative effects of captive housing, which must be a principle of toxicological research for ethical, legal and scientific reasons.Na toxicologia da reprodução e do desenvolvimento, a atenção necessária foi dada aos efeitos da exposição do organismo às inúmeras drogas durante o período gestacional somente após a metade dos anos 50, quando a tragédia da talidomida atingiu a humanidade. Assim, esta área alcançou desenvolvimento científico com a contribuição da experimentação animal nas últimas décadas. O uso de animais de laboratórios para a pesquisa científica expôs a necessidade de melhorar a qualidade de vida destas espécies. Portanto, este trabalho tem como objetivo investigar como a ciência do bem-estar animal pode melhorar a pesquisa científica como um todo, incluindo na área de toxicologia da reprodução e de desenvolvimento, enfatizando o enriquecimento ambiental em biotérios. Uma revisão integrativa de literatura foi realizada, incluindo abordagens quantitativas e qualitativas, quais podem ser aplicadas para estudos de toxicologia. Aqui, são mostradas evidências de que o enriquecimento ambiental melhora o bem-estar animal e previne ou reduz os efeitos negativos do cativeiro, qual deve um princípio da pesquisa toxicológica por razões éticas, argumentos legais e garantias científicas

Aquecimento ôhmico: novos desafios no tratamento térmico de materiais

[Excerto] Introdução: O tratamento térmico de materiais encontra-se dentre os processos mais utilizados industrialmente. Na indústria de alimentos, por exemplo, o tratamento térmico (por possuir ação letal sobre microorganismos) é o principal procedimento físico de que a tecnologia de alimentos dispõe para aumentar a vida útil dos alimentos (Ordóñez et al., 2005). Desta forma, novos métodos de aquecimento que acarretem em baixo gasto energético ou em maior eficiência energética continuam a atrair interesse Palaniappan e Sastry, 1992). Dentre as tecnologias de aquecimento emergentes, o aquecimento ôhmico apresenta-se bastante promissor. [...]info:eu-repo/semantics/publishedVersio

Antimicrobial effectiveness of silver nanoparticles co-stabilized by the bioactive copolymer pluronic F68

Abstract\ud \ud \ud \ud Background\ud \ud Silver nanoparticles (AgNps) have attracted much interest in biomedical engineering, since they have excellent antimicrobial properties. Therefore, AgNps have often been considered for incorporation into medical products for skin pathologies to reduce the risk of contamination. This study aims at evaluating the antimicrobial effectiveness of AgNps stabilized by pluronic™ F68 associated with other polymers such as polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP).\ud \ud \ud \ud Methods\ud \ud AgNps antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method. The action spectrum was evaluated for different polymers associated with pluronic™ F68 against the gram negative bacteria P. aeuroginosa and E. coli and the gram positive bacteria S. Aureus.\ud \ud \ud \ud Results\ud \ud AgNps stabilized with PVP or PVA and co-stabilized with pluronic™ F68 are effective against E. coli and P. aeruginosa microorganisms, with MIC values as low as 0.78% of the concentration of the original AgNps dispersion. The antimicrobial action against S. aureus is poor, with MIC values not lower than 25%.\ud \ud \ud \ud Conclusions\ud \ud AgNps stabilized by different polymeric systems have shown improved antimicrobial activity against gram-negative microorganisms in comparison to unstabilized AgNps. Co-stabilization with the bioactive copolymer pluronic™ F68 has further enhanced the antimicrobial effectiveness against both microorganisms. A poor effectiveness has been found against the gram-positive S. aureus microorganism. Future assays are being delineated targeting possible therapeutic applications.This research was supported by grants from FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil), CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil) and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil)

Production of bacterial cellulose nanocrystals via enzymatic hydrolysis and evaluation of their coating on alginate particles formed by ionotropic gelation

This study aimed to obtain the bacterial cellulose nanocrystals (CNC) by enzymatic hydrolysis and verify the CNC application as coating material in alginate particles. Therefore, the production of CNC was carried out through two enzymatic hydrolysis methods involving a time period of 48 and 72 h. 0.35 mg of dry mass of cellulose was produced approximately 1.6 × 1011 CNC/mL. The CNC obtained by enzymatic hydrolysis at 72 h (Method II) was applied to cover the alginate particles, obtained by ionotropic gelation. The CNC Zeta potential value was about +15 mV and for alginate particles -26.46 ± 1.48 mV. These results confirmed the application of CNC as coating material for alginate particles. It brings an incremental contribution to the knowledge advancement in the pharmaceutical and food area, allowing the engineering of systems to use a mixed composition of nanobiomaterials to modify the release pattern of drugs, macromolecule, nutrients, stabilizers and target specific drug release.The authors acknowledge financial support from Coordination for Higher Level Graduate Improvements (CAPES/Brazil, Grant Numbers 001), National Council for Scientific and Technological Development (CNPq/Brazil), and the State of São Paulo Research Foundation (FAPESP/Brazil, grant numbers 2019/22,626–5 and 2018/10,508–5).info:eu-repo/semantics/publishedVersio

Libidibia ferrea loaded in bacterial nanocellulose: evaluation of antimicrobial activity and wound care / Libidibia ferrea loaded in bacterial nanocellulose: evaluation of antimicrobial activity and wound care

The effects of Bacterial Nanocellulose (BNC) loaded with Libidibia ferrea (Lf) hydroalcoholic extract were investigated on the healing process of burn in diabetic and non-diabetic animals. In vivo assay was performed with 36 male rats, with streptozotocin-induced diabetes and burns induced by contact. Animals were divided into Nd-BNC (Non-diabetic + Bacterial nanocellulose membranes); Nd-BNC-Lf (Non-diabetic + Bacterial nanocellulose membranes + Libidibia ferrea); D-BNC (Diabetic + Bacterial nanocellulose membranes); D-BNC-Lf (Diabetic + Bacterial nanocellulose membranes + Libidibia ferrea). Wounds were evaluated for 28 days histologically. Lf extract and BNC-Lf extract showed antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The severe degree of infection, granulation and inflammation observed after 14 days in diabetic rats (exposed or not to Lf extract), disappeared after 21 days. On the 28th day, there was no histological difference among the groups. BNC-Lf extract demonstrated to have antimicrobial activity, however as an wound dressing, both BNC or BNC-Lf extract were effective in the healing of second-degree burn wounds

Effect of polysaccharide sources on the physicochemical properties of bromelainchitosan nanoparticles

Bromelain, a set of proteolytic enzymes potential pharmaceutical applications, was encapsulated in chitosan nanoparticles to enhance enzyme stability, and the effect of different chitosan sources was evaluated. Chitosan types (i.e., low molecular weight chitosan, chitosan oligosaccharide lactate, and chitosan from shrimp shells) produced nanoparticles with different physicochemical properties, however in all cases, particle size and zeta potential decreased, and polydispersity index increased after bromelain addition. Bromelain encapsulation was higher than 84% and 79% for protein content and enzymatic activity, respectively, with low molecular weight chitosan presenting the highest encapsulation efficiency. Nanoparticle suspension was also tested for accelerated stability and rheological behavior. For the chitosan–bromelain nanoparticles, an instability index below 0.3 was recorded and, in general, the loading of bromelain in chitosan nanoparticles decreased the cohesiveness of the final suspension.This research was granted by FAPESP (2016/03444-5,2017/05275-9,and2017/05333-9), CNPq and FAEPEX, and by the Portuguese Science and Technology Foundation, Ministry of Science and Education (FCT/MEC) through national funds, and co-financed by FEDER, under the project reference M-ERA-NET/0004/2015 (PAIRED) Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio

Curcumin encapsulation in nanostructures for cancer therapy: a 10-year overview

Journal pre-proofsCurcumin (CUR) is a phenolic compound present in some herbs, including Curcuma longa Linn. (turmeric rhizome), with a high bioactive capacity and characteristic yellow color. It is mainly used as a spice, although it has been found that CUR has interesting pharmaceutical properties, acting as a natural antioxidant, anti-inflammatory, antimicrobial, and antitumoral agent. Nonetheless, CUR is a hydrophobic compound with low water solubility, poor chemical stability, and fast metabolism, limiting its use as a pharmacological compound. Smart drug delivery systems (DDS) have been used to overcome its low bioavailability and improve its stability. The current work overviews the literature from the past 10 years on the encapsulation of CUR in nanostructured systems, such as micelles, liposomes, niosomes, nanoemulsions, hydrogels, and nanocomplexes, emphasizing its use and ability in cancer therapy. The studies highlighted in this review have shown that these nanoformulations achieved higher solubility, improved tumor cytotoxicity, prolonged CUR release, and reduced side effects, among other interesting advantages.This study was funded by the Coordination for Higher Level Graduate Improvements (CAPES/Brazil, finance code 001), National Council for Scientific and Technological Development (CNPq/Brazil, PIBIC process #123483/2020-4), State of São Paulo Research Foundation (FAPESP/Brazil, processes #2017/10789-1, #2018/10799-0, #2018/06475-4, #2018/07707-6, #2019/08549-8, and #2020/03727-2). This work was also supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and the project AgriFood XXI (NORTE-01-0145-FEDER-000041) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Our Figures were created with BioRenderinfo:eu-repo/semantics/publishedVersio

Flavonoid-enriched plant-extract-loaded emulsion: a novel phytocosmetic sunscreen formulation with antioxidant properties

The aim of this study was to develop a phytocosmetic sunscreen emulsion with antioxidant effect, containing a blend of flavonoid-enriched plant extracts. In vitro sun protection factor, antioxidant activity, skin irritation, photostability, cutaneous permeation, and retention of flavonoids were evaluated. Thermodynamically stable emulsions were obtained and tested for sensorial analysis after loading the blend of extracts. The selected emulsion was stable when stored at low temperatures (5 C), for which after 120 days the concentration of quercetin and rutin were above their limit of quantification, i.e., 2.8 ± 0.39 µg/mL and 30.39 ± 0.39 µg/mL, respectively. Spreadability, low rupture strength and adhesiveness were shown to be similar to a conventional topical product. Higher brittleness, pseudo-plastic, and viscoelastic behaviors were also recorded for the developed phytocosmetic sunscreen. The product presented a critical wavelength of 387.0 nm and ultraviolet rays A and B (UVA/UVB) rate of 0.78, confirming that the developed formulation shows capacity for UVA/UVB protection, protecting skin against damages caused by Ultraviolet (UV) radiation. Rutin was shown to permeate the skin barrier and was also quantified in the stratum corneum (3.27 ± 1.92 µg/mL) by tape stripping and retention test (114.68 ± 8.70 µg/mL). The developed flavonoid-enriched phytocosmetic was shown to be non-irritant to skin by an in vitro assay. Our results confirm the antioxidant activity, sun protection, and physical properties of the developed phytocosmetic for topical application.This research was funded by FAPESP (grant number 2015/25533‐7 and 2017/14757‐7), CAPES and CNPq. The authors also received support from the Portuguese Science and Technology Foundation (FCT/MCT) and from European Funds (PRODER/COMPETE) under the project reference M‐ERA‐NET/0004/2015‐PAIRED, co‐financed by FEDER, under the Partnership Agreement PT2020, and PhD scholarship (SFRH/BD/130555/2017).info:eu-repo/semantics/publishedVersio