Growth models of fractal interfaces in the description of microorganism colony growth: effect of photodynamic inactivation.

Candida albicans is responsible for most of the nosocomial infections that affect immunocompromised individuals. We investigated the application of eosin in photodynamic inactivation as a strategy in the inhibition of the growth of C. albicans and the morphological variation and growth dynamics in light of fractal theory. The damage caused to fungal structures alters the roughness of the colony, and these changes were described by parameters that were defined by mathematical models. Proliferation of the fungi should be inhibited in the center of the colonies and the analysis of the edges gives an indication about the dynamics of growth and cell reproduction.

Professional and informal help-seeking among low-income adolescents exposed to violence in the community and at school.

BACKGROUND: Adolescents may seek help for many reasons beyond health needs, such as personal stress due to violence exposure. OBJECTIVE: To investigate factors associated with receiving professional assistance and informal help due to violence exposure in the community and at school. PARTICIPANTS AND SETTING: This study was conducted in Itaboraí, a low-income medium-size city in the State of Rio de Janeiro, Southeast Brazil, characterized by poverty, inequality and violence. It analyses data reported by 669 in-school adolescents (11-15-years, 51.7% girls). METHODS: This is a cross-sectional study nested in a longitudinal study (Itaboraí Youth Study). The Itaboraí Youth Study involved a probabilistic community-based sample of 1409 6-to-15-year-olds based on a 3-stage probabilistic sampling plan that included a random selection of census units, eligible households and the target child. RESULTS: Professional assistance was mainly received from psychologists (the Brazilian population has free access to health services). Family members were the main source of informal help. Correlates of professional assistance were having clinical emotional problems and not counting on an adult (if needing help) for community violence victims, and absent father for community and school violence victims. Correlates of informal help were female sex, maternal anxiety/depression and absent father for community violence victims, and younger age and higher maternal education for school violence victims. CONCLUSIONS: The mental health needs of violence victims, and maternal difficulties to deal with the adolescent distress resulting from violence exposure (maternal increased burden due to father absence and/or having anxiety/depression) are important influences on the help-seeking process.

Latex membranes with methylene blue dye for antimicrobial photodynamic therapy.

The search for new materials that can be applied in the treatment of injured human tissues has led to the development of new dressings. Membranes have potential as dressing materials because they can be fitted to and interact with the tissue surface. In this study, we analyze the morphological properties and wettability of latex membranes, along with the incorporation of the photosensitizer methylene blue, in the context of the utility of the membranes in curative applications involving photodynamic therapy (PDT). It was observed that deposition of the photosensitizer into latex membranes increased both the surface roughness and wettability. Antifungal testing indicated that antimicrobial PDT assisted by the latex membranes incorporating methylene blue effectively inactivated Candida albicans.

Assessment of children in the autistic spectrum disorder that carry the Thr92Ala-DIO2 polymorphism.

INTRODUCTION: A polymorphism in the type 2 deiodinase (Thr92Ala-DIO2) gene has been associated with behavioral and cognitive dysfunction as well as neurodegeneration and oxidative stress in the central nervous system. OBJECTIVE: To test whether the minor allele (Ala92) frequency (MAF) is increased in children in the autism spectrum disorder (ASD), and whether carriers of the minor allele exhibit more severe symptoms and/or worse adaptive behavior. STUDY DESIGN: ASD children were evaluated at baseline and yearly throughout the study by psychologists using the following tools: autism behavior checklist, Vineland Adaptative Behaviour Scales II, non-verbal intelligence test SON-R 21/2-7, SON-R 6-40, Weschler scale for intelligence, and autism treatment evaluation checklist. SETTINGS: Academic outpatient mental health facility in Sao Paulo, Brazil. PARTICIPANTS: ASD boys and girls younger than 18 years of age. 132 consecutive ASD children, mostly boys (~ 80%); ~ 50% was classified as verbal. Exclusion criteria were coexistence of sensory and/or physical impairment, or any associated genetic syndromes. RESULTS: Median follow-up was for an uninterrupted period of 937 days (139-1375 days), which did not vary significantly among the genotypes. The MAF was 47% in ASD patients vs. 51% in a local reference population with similar ethnic background; the clinical severity and progression were not affected by the minor allele. Carriers of the minor allele exhibited higher adaptive behavior in the domains "daily living skills" and "communication", which correlated positively with the dose of the minor allele. CONCLUSION: The MAF is not different in ASD children, but carriers of the Thr92Ala-DIO2 polymorphism exhibited higher adaptive behavior.

A randomised clinical pilot trial to test the effectiveness of parent training with video modelling to improve functioning and symptoms in children with autism spectrum disorders and intellectual disability.

BACKGROUND: Poor eye contact and joint attention are early signs of autism spectrum disorder (ASD) and important prerequisites for developing other socio-communicative skills. Teaching parents evidence-based techniques to improve these skills can impact the overall functioning of children with ASD. We aimed to analyse the impact of conducting a group parent-training intervention with video modelling to improve the intelligent quotient (IQ), social and communication functioning and to minimise symptoms in children with ASD and intellectual disability (ID). METHODS: Study design: A multicentre, single-blinded, randomised clinical pilot trial of parent training using video modelling was conducted. SAMPLE: Sixty-seven parents of children with ASD, aged between 3 and 6 years and with IQs between 50 and 70, were randomised: 34 to the intervention group and 33 to the control group. Intervention program: The intervention group received parent training over 22 sessions, and the control group received the standard community treatment. INSTRUMENTS: Pre-evaluation and post-evaluation (week 28), the following were used: Autism Diagnostic Interview, Vineland Adaptive Behaviour Scale I, Snijders-Oomen Nonverbal Intelligence Test, Autism Behaviour Checklist and Hamilton Depression Rating Scale. DATA ANALYSIS: Intention to treat and complier-average causal effect (CACE) were used to estimate the effects of the intervention. RESULTS: There was a statistically significant improvement in the Vineland standardized communication scores in CACE (Cohen's d = 0.260). There was a non-statistically significant decrease in autism symptomatology (Autism Behaviour Checklist total scores) and a significant increase in the non-verbal IQ in the intervention group. After the false discovery rate correction was applied, IQ remained statistically significant under both paradigms. The effect size for this adjusted outcome under the intention-to-treat paradigm was close to 0.4, and when considering adherence (CACE), the effect sizes were more robust (IQ's Cohen's d = 0.433). CONCLUSIONS: Parent training delivered by video modelling can be a useful technique for improving the care given to children with ASD and ID, particularly in countries that lack specialists.

The role of xenobiotic-metabolizing enzymes in the placenta: a growing research field.

Introduction: The placenta is a temporary and unique organ that allows for the physical connection between a mother and fetus; this organ regulates the transport of gases and nutrients mediating the elimination of waste products contained in the fetal circulation. The placenta performs metabolic and excretion functions, on the basis of multiple enzymatic systems responsible for the oxidation, reduction, hydrolysis, and conjugation of xenobiotics. These mechanisms give the placenta a protective role that limits the fetal exposure to harmful compounds. During pregnancy, some diseases require uninterrupted treatment even if it is detrimental to the fetus. Drugs and other xenobiotics alter gene expression in the placenta with repercussions for the fetus and mother's well-being.Areas covered: This review provides a brief description of the human placental structure and function, the main drug and xenobiotic transporters and metabolizing enzymes, placenta-metabolized substrates, and alterations in gene expression that the exposure to xenobiotics may cause.Expert opinion: Research should be focused on the identification and validation of biological markers for the assessment of the harmful effects of some drugs in pregnancy, including the evaluation of polymorphisms and methylation patterns in chorionic villous samples and/or amniotic fluid.

In silico evaluation of the stress fields on the cortical bone surrounding dental implants: Comparing root-analogue and screwed implants.

Tooth loss is a problem that affects both old and young people. It may be caused by several conditions, such as poor oral hygiene, lifestyle choices or even diseases like periodontal disease, tooth grinding or diabetes. Nowadays, replacing a missing tooth by an implant is a very common process. However, many limitations regarding the actual strategies can be enumerated. Conventional screwed implants tend to induce high levels of stress in the peri-implant bone area, leading to bone loss, bacterial bio-film formation, and subsequent implant failure. In this sense, root-analogue dental implants are becoming promising solutions for immediate implantation due to their minimally invasive nature, improved bone stress distribution and because they do not require bone drilling, sinus lift, bone augmentation nor other traumatic procedures. The aim of this study was to analyse and compare, by means of FEA, the stress fields of peri-implant bone around root-analogue and screwed conventional zirconia implants. For that purpose, one root-analogue implant, one root-analogue implant with flaps, two conventional implants (with different threads) and a replica of a natural tooth were modelled. COMSOL was used to perform the analysis and implants were subjected to two simultaneous loads: 100 N axially and 100 N oblique (45°). RESULTS: revealed that root-analogue implants, namely with flaps, should be considered as promising alternatives for dental implant solutions since they promote a better stress distribution in the cortical bone when compared with conventional implants.

Color stability of repairs on bis-acryl resin submitted to thermal aging and immersion in beverages.

OBJECTIVE: Defects/bubbles can occur during the manufacture of bis-acryl resin provisional restorations, requiring repair or new prosthesis. This study evaluated the color stability of bis-acryl resin specimens repaired, aging, and immersioned in beverages. MATERIAL AND METHODS: Eighty disks were made of bis-acryl resin. Twenty disks were not repaired (BCR), 20 disks were repaired with the same bis-acryl resin (BCR-BCR), 20 disks were repaired with flowable resin (BCR-FR), and 20 disks received an adhesive layer prior to flowable resin repair (BCR-AFR). Coordinates L*a*b* were obtained. Ten disks from each group were thermocycled (5000 cycles) and the others were immersed in coffee with sugar (n = 5) and cola-based soft drinks (n = 5) for 7 days. Color, lightness, chroma, and hue differences were calculated by the CIEDE2000 formula, analyzed by two-way analysis of variance. Multiple comparisons were made with the Tukey's HSD test (α = .05). RESULTS: BCR-FR group presented the highest color differences (5.6) between groups repaired (P < .001). BCR-BCR group showed the smallest color differences (0.9) after aging (P = .003), but the greatest variation between T0 and T1 (about 1 ΔE). BCR-ARF immersed in coffee showed the greatest color differences (20.6) (P < .001). CONCLUSIONS: Aging and immersion altered the colorimetric behavior of repairs, especially after the use of coffee. CLINICAL IMPLICATIONS: Repairs are indicated when defects and bubbles are present in the surface of the bis-acryl resin provisional restorations after its manufacture. However, they may present noticeable color changes, especially when the use of coffee is frequent.

Fractal analysis and mathematical models for the investigation of photothermal inactivation of Candida albicans using carbon nanotubes.

Candida albicans is responsible for the majority of nosocomial infections affecting immunocompromised patients. Systemic antifungals may promote microbial resistance, which has led to the search for alternative treatments, such as photothermal therapy (PTT). PTT assumes that the interaction of electromagnetic radiation with a photothermal agent generates heat that can lead to the destruction of tumor cells and the death of microorganisms. Carbon nanotubes (CNTs) have the potential for applications in biomedical systems, including acting as controlled deliverers of drugs, biosensors and scaffolds for tissue engineering and regenerative medicine. Furthermore, the absorption of radiation by CNTs in the infrared region induces an increase in temperature, which makes CNTs candidates for photothermal agents. In this work, the photothermal inactivation of C. albicans was evaluated by multiple wall CNTs associated with laser radiation in the near-infrared region. The mechanisms that are involved in inactivation were evaluated through cell susceptibility studies and an analysis of microscopic images that are associated with mathematical models and fractal concepts. The results indicate that direct contact between the cells and CNTs without irradiation does not lead to cell death, whereas the laser-mediated process is effective in inactivation. The application of the laws of scale and fractal concepts indicate that in the control groups, there are two distinct regimes that are delimited by the mean diameter of the microorganisms, as described by the Eden model and by the quasi-Euclidean surface. For the irradiated groups, the surfaces present only one regime described by Kardar-Parisi-Zhang, KPZ. The analysis of the fractality of the system by mathematical models can help in the identification of new strategies for the inactivation of microorganisms.

Simple ultrasound method to obtain starch micro- and nanoparticles from cassava, corn and yam starches.

Starch nanoparticles (SNP) were produced employing a simple ultrasound method without chemical additives from cassava, corn, and yam starches, which contain 18%, 25% and 30% amylose, respectively. Simultaneously, starch microparticles (SMP) were also obtained, which were significantly smaller than the native starch granules. The yield of the process for all starch sources was 12 ±â€¯1% SNP and 88 ±â€¯5% SMP, starting with aqueous starch suspensions at 10% and 30 min of sonication. Yam starch (higher amylose content) resulted in smaller SMP (1-3 µm) and SNP (8-32 nm) than did those obtained from corn (SMP = 3-6 µm; SNP = 36-68 nm) and cassava (SMP = 3-7 µm; SNP = 35-65 nm) starches. Nanoparticles from all starch sources had lower crystallinity and lower thermal stability than did the native starches or SMP. Ultrasonication was efficient to yield SNP and SMP without the addition of any chemical reagent or employing a purification step.

Color stability of a bis-acryl composite resin subjected to polishing, thermocycling, intercalated baths, and immersion in different beverages.

OBJECTIVE: To evaluate the color of a bis-acryl resin after polishing, aging, and colorants. MATERIALS AND METHODS: From the 140 disks obtained, 35 were not polished (NP), 35 were polished with 3-µm (3P), 35 with 3- and 1-µm (1P), and 35 with 3-, 1-, and 0.5-µm sized particles (05P). Five disks of each group were thermocycled for 20, 100, and 200 cycles. Sixty disks were thermocycled and kept in beverages (tea, wine, and coffee) after four cycles. Sixty disks were immersed in the beverages for 24 hours, a week, and a month. The coordinates L*a*b* were measured and the color differences were analyzed by ANOVA. The lightness, chroma, and hue differences were evaluated by repeated measures ANOVA. Comparisons were made with Tukey's test (α = 0.05). RESULTS: Similar behaviors were observed between 3P and 05P groups (1.53 and 1.95ΔE00 ) (P < .05). The NP group submitted to 200 cycles showed the biggest color differences (3.02) (P = .003). The greatest color differences were observed in the NP group submitted to immersion in coffee (8.30) and wine (7.93) (P < .05). CONCLUSIONS: The polished surfaces were the least stained. Coffee and wine provided the greatest color changes, both for baths and immersions. CLINICAL SIGNIFICANCE: Polishing of provisional surfaces restorations made of bis-acrylic resin is essential to minimize staining caused by aging and use of colorants, regardless of the particle size present in the polishing paste. The contact with coffee and red wine should be avoided, especially for clinical times greater than 1 week.

Immobilization of triclosan and erythrosine in layer-by-layer films applied to inactivation of microorganisms.

The use of layer-by-layer (LbL) deposition technique allows materials, such as drugs, to be self-assembled in multilayers with other electrolytes by combining their properties in a nanostructured system. Triclosan (TCS) is commonly used as a drug because of its bactericidal action, while erythrosine (ERY) has been used as a photosensitizer in photodynamic therapies because of its high light absorptivity in the visible region of the electromagnetic spectrum. The major advantage of investigating systems immobilized in LbL films is the benefit of characterizing the interaction through available substances in solid state techniques. It was possible to immobilize in LbL films, ERY, and ERY + TCS. The results show that the growth of the films was linear, indicating the deposition of the same amount of material from the first bilayer without substrate interference. The release analysis showed slow kinetics, which occurred more rapidly for ERY LbL films, probably due to apparent activation energy, which were higher for films with TCS. The combination of TCS, ERY, and laser light (532 nm) for photodynamic inactivation of the fungus Candida albicans was analyzed, and the results were promising for future studies in applications, such as coating surfaces of dental implants.

Surgical management of long bone fractures in cats using cortical bone allografts preserved in honey.

This report describes comminuted fractures in 2 cats repaired by stabilization with cortical bone allografts that had been preserved in honey. Both cats exhibited appropriate post-operative weight-bearing. Preservation of bone in honey is a simple and widely available alternative for bone banking. This is the first report of a bone defect in cats repaired with bone preserved in honey.

Gestion chirurgicale de fractures osseuses longues chez les chats à l'aide d'une allogreffe de la corticale préservée dans du miel. Ce rapport décrit deux fractures comminutives réparées par la stabilisation à l'aide de l'allogreffe de la corticale qui avait été préservée dans du miel. Les deux chats ont manifesté une mise en charge postopératoire appropriée. La préservation de l'os dans du miel est une méthode de remplacement simple et facilement disponible comme ostéothèque. Il s'agit du premier rapport d'un défaut osseux chez des chats qui a été réparé à l'aide d'un os préservé dans du miel.(Traduit par Isabelle Vallières).

Violence and child mental health in Brazil: The Itaboraí Youth Study methods and findings.

OBJECTIVES: To demonstrate a study design that could be useful in low-resource and violent urban settings and to estimate the prevalence of child violence exposure (at home, community, and school) and child mental health problems in a low-income medium-size city. METHODS: The Itaboraí Youth Study is a Norway-Brazil collaborative longitudinal study conducted in Itaboraí city (n = 1409, 6-15 year olds). A 3-stage probabilistic sampling plan (random selection of census units, eligible households, and target child) generated sampling weights that were used to obtain estimates of population prevalence rates. RESULTS: Study strengths include previous pilot study and focus groups (testing procedures and comprehension of questionnaire items), longitudinal design (2 assessment periods with a mean interval of 12.9 months), high response rate (>80%), use of standardized instruments, different informants (mother and adolescent), face-to-face interviews to avoid errors due to the high frequency of low-educated respondents, and information gathered on a variety of potential predictors and protective factors. Children and adolescents presented relevant levels of violence exposure and clinical mental health problems. CONCLUSIONS: Prevalence estimates are probably valid to other Brazilian low-income medium-size cities due to similarities in terms of precarious living conditions. Described study methods could be useful in other poor and violent world regions.

Incorporation of triclosan and acridine orange into liposomes for evaluating the susceptibility of Candida albicans.

Candida albicans is responsible for many of the infections affecting immunocompromised individuals. Although most C. albicans are susceptible to antifungal drugs, uncontrolled use of these drugs has promoted the development of resistance to current antifungals. The clinical implication of resistant strains has led to the search for safer and more effective drugs as well as alternative approaches, such as controlled drug release using liposomes and photodynamic inactivation (PDI), to eliminate pathogens by combining light and photosensitizers. In this study, we used layer-by-layer (LBL) assembly to immobilize triclosan and acridine orange encapsulated in liposomes and investigated the possibility of controlled release using light. Experiments were carried out to examine the susceptibility of C. albicans to PDI. The effects of laser irradiation were investigated by fluorescence microscopy, atomic force microscopy, and release kinetics. Liposomes were successfully prepared and immobilized using the self-assembly LBL technique. Triclosan was released more quickly when the LBL film was irradiated. The release rate was approximately 40% higher in irradiated films (fluence of 15J/cm2) than in non-irradiated films. The results of the susceptibility experiments and surface morphological analysis indicated that C. albicans cell death is caused by photodynamic inactivation. Liposomes containing triclosan and acridine orange may be useful for inactivating C. albicans using light. Our results lay the foundation for the development of new clinical strategies to control resistant strains.

Immobilization of chlorophyll by using layer-by-layer technique for controlled release systems and photodynamic inactivation.

The development of systems for the controlled release of drugs is important because they allow the control of drug absorption and tissue distribution and also can reduce local toxicity. This study aimed to assemble and characterize two types of release systems, consisting of layer-by-layer films obtained from poly(allylamine) hydrochloride with chlorophyll (PAH/CHL films) or chlorophyll incorporated into dipalmitoylphosphatidylcholine liposomes (PAH/Lip+CHL films). For these systems, the molecular aggregation, growth process, thermally stimulated desorption, wettability, and controlling release of CHL was studied by using UV-vis spectroscopy and wetting contact angle analysis. In addition, experiments of photodynamic inactivation using PAH/CHL or PAH/Lip+CHL films with a 633-nm laser light were performed and the susceptibility of Candida albicans (C. albicans) to this approach was examined. Fluorescence and atomic force microscopies were used to investigate the surface morphology after the application of the photoinactivation procedure. A redshift of the UV-vis spectrum associated to films when compared with the spectrum of the CHL solution indicated a molecular aggregation of CHL molecules in the films. The film growth process was determined by a nucleation and a growth of spheroids or rods for either PAH/Lip+CHL or PAH/CHL films, respectively. Thermally activated desorption experiments indicated that interactions between CHL and PAH (126kJ/mol) in PAH/CHL or between Lip+CHL and PAH (140kJ/mol) in PAH/Lip+CHL films may be governed by electrostatic interactions. The wettability of PAH/Lip+CHL films was larger than that for PAH/CHL films, which can be attributed to hydrophilic groups on the surface of the DPPC liposomes. Release experiments revealed that free CHL in PAH/CHL films was released more slowly than its partner incorporated into liposomes. After the photodynamic inactivation, results of survival fraction and fluorescence microscopy revealed that C. albicans presented similar susceptibility for the two kinds of films. AFM supported the fluorescence one suggesting that cell death of C. albicans may occur due to damages to its cell wall by C. albicans.

Spray layer-by-layer films for photodynamic inactivation.

BACKGROUND: A novel approach for photodynamic inactivation of Candida albicans is proposed. This method consists of realizing inactivation using ultraviolet light (254nm) combined with spraying layer-by-layer films of acridine orange. METHODS: To evaluate the effectiveness of the approach, the C. albicans were immobilized on quartz slices and covered with the spray layer-by-layer films. The fungi were analyzed using experiments to determine cell viability, as well as by fluorescence and atomic force microscopy. RESULTS: Viability analysis of C. albicans after photodynamic inactivation assisted by the films indicates cell death. The extent of cell death increases as the number of film layers increases. Fluorescence and atomic force microscopy analyses corroborated the cell death of C. albicans, which is posited to be due to damages to the fungi cell wall. CONCLUSIONS: Our approach has the potential to be used as an alternative for photodynamic inactivation of C. albicans. In addition, this method could be used in clinical procedures, such as for the decontamination of medical devices.

Preparation of succinylated cellulose membranes for functionalization purposes.

The anhydroglucose chains of cellulose possess hydroxyls that facilitate different chemical modification strategies to expand on, or provide new applications for membranes produced by the bacteria Gluconacetobacter xylinus. Conjugation with biomolecules such as proteins, especially by the amine groups, is of great value and interest for the production of biomaterial derivatives from bacterial cellulose. To assist in these modifications, cellulose was succinylated in order to prevent steric hindrance and to create an attachment point for conjugation. Bacterial cellulose membranes were first treated in dichloromethane and reacted with succinic anhydride through a series of conditions. The membrane structure remained intact after these first processes and the product was confirmed by Infra-Red spectroscopy and solid state nuclear magnetic resonance and characterized by X-ray diffraction, thermogravimetry and atomic force microscopy. Hydrolyzed collagen was used as a model protein of interest to be conjugated to these membranes, which furnished a biomaterial functionalized over its surface.

ISOLATION AND GENOTYPING OF CLOSTRIDIUM PERFRINGENS FROM FREE-LIVING SOUTH AMERICAN COATI (NASUA NASUA).

The importance of Clostridium perfringens for most wild animal species remains unclear. This study aimed to isolate and genotype C. perfringens in stool samples from free-living South American coati (Nasua nasua) in Brazil. Forty-six free-living N. nasua were trapped and stool samples were collected. Two different protocols for C. perfringens isolation were tested: direct plating onto selective agar and pre-enrichment in broth followed by plating in selective agar. Clostridium perfringens type A was isolated from 15 (32.6%) animals by direct plating and 36 (78.3%) animals by broth PE, and the rate of isolation was significantly different between these two methods (P < 0.01). Twelve of the 36 (33.3%) isolated strains by the PE protocol were positive for the ß-2 toxin-encoding gene (cpb2) whereas the enterotoxin-encoding gene (cpe) and necrotic enteritis like-B toxin gene (netb) were not found. These results suggest that C. perfringens is commonly part of the microbiota of free-living coatis. Additionally, the use of a PE protocol appears to be essential for studies on C. perfringens in this species.

Efeito de diferentes técnicas extrativas no rendimento, atividade antioxidante, doseamentos totais e no perfil por clae-dad de dicksonia sellowiana (presl. ). Hook, dicksoniaceae / Effect of different extraction techniques on the yield, antioxidant activity, total dosages, and profile by hplc-dad of Dicksonia sellowiana (Presl. ). Hook, dicksoniaceae.

RESUMO A espécie Dicksonia sellowiana, conhecida popularmente como xaxim, é uma samambaia natural do continente americano e encontrada no Brasil na Mata Atlântica. Em 2001 sua utilização para confecção de vasos para jardinagem foi proibida, e a mesma foi inserida na lista do IBAMA como espécie ameaçada de extinção. O presente trabalho descreve o efeito de diferentes técnicas de extração, incluindo ultra-som, turbólise, maceração, infusão, decocto e soxhlet utilizando etanol e solvente hidroalcoólico 70%, sob aspectos físicos e químicos. Foi avaliado o rendimento de cada extração, o perfil por CLAE-DAD, o conteúdo de polifenóis, flavonoides, proantocianidinas e esteroides além das atividades antioxidantes pelos métodos DPPH e redução do complexo fosfomolibdênio. Os dados foram avaliados estatisticamente através de desvio padrão, Tuckey e PCA. Os resultados demonstraram que a extração por Soxhlet utilizando ambos os solventes é a que possui maior rendimento final, porém o rendimento não está diretamente relacionado com o aumento nos teores de bioativos totais e atividades antioxidantes. As extrações por decocção e turbólise utilizando solvente hidroalcoólico foram as que apresentaram melhores resultados nos teores totais e na atividade antioxidante, resultados que ficam evidentes quando avaliados por PCA, demonstrando que este solvente e estas extrações são mais seletivas no estudo proposto.

ABSTRACT The species Dicksonia sellowiana, popularly known as xaxim, is a fern native to the Americas and found in Brazil in the Atlantic Forest. In 2001, its use for making gardening pots was banned, and it was added to the IBAMA [Brazilian Institute of the Environment and Renewable Natural Resources] list as an endangered species. This paper describes the effect of different extraction techniques – including ultrasound, turbolysis, maceration, infusion, decoction, and soxhlet using ethanol and 70% hydroalcoholic solvent on its physical and chemical aspects. The yield of each extraction was evaluated, as well as the profile by HPLC-DAD, the polyphenol content, flavonoids, proanthocyanidins, and steroids, in addition to the antioxidant activities through the DPPH and phosphomolybdenum complex reduction methods. The data were statistically analyzed through standard deviation, Tukey, and PCA. The results showed that the soxhlet extraction using both solvents had the highest overall yield; however, the yield is not directly related to the increase in total bioactive content and antioxidant activities. Extractions by decoction and turbolysis using a hydroalcoholic solvent exhibited the best results in total content and antioxidant activity – results that are evident when evaluated through PCA, demonstrating that this solvent and these extractions are the most selective in the proposed study.