Biosynthesis of silver nanoparticles from Syzygium cumini leaves and their potential effects on odontogenic pathogens and biofilms.

This study analyzed the antimicrobial and antibiofilm action and cytotoxicity of extract (HEScL) and silver nanoparticles (AgNPs-HEScL) from Syzygium cumini leaves. GC-MS, UV-Vis, EDX, FEG/SEM, DLS and zeta potential assays were used to characterize the extract or nanoparticles. Antimicrobial, antibiofilm and cytotoxicity analyses were carried out by in vitro methods: agar diffusion, microdilution and normal oral keratinocytes spontaneously immortalized (NOK-SI) cell culture. MICs of planktonic cells ranged from 31.2-250 (AgNPs-HEScL) to 1,296.8-10,375 µg/ml (HEScL) for Actinomyces naeslundii, Fusobacterium nucleatum, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Streptococcus oralis, Veillonella dispar, and Candida albicans. AgNPs-HEScL showed antibiofilm effects (125-8,000 µg/ml) toward Candida albicans, Streptococcus mutans and Streptococcus oralis, and Staphylococcus aureus and Staphylococcus epidermidis. The NOK-SI exhibited no cytotoxicity when treated with 32.8 and 680.3 µg/ml of AgNPs-HEScL and HEScL, respectively, for 5 min. The data suggest potential antimicrobial and antibiofilm action of HEScL, and more specifically, AgNPs-HEScL, involving pathogens of medical and dental interest (dose-, time- and species-dependent). The cytotoxicity of HEScL and AgNPs-HEScL detected in NOK-SI was dose- and time-dependent. This study presents toxicological information about the lyophilized ethanolic extract of S. cumini leaves, including their metallic nanoparticles, and adds scientific values to incipient studies found in the literature.

Candida species biotypes and polyclonality of potentially virulent Candida albicans isolated from oral cavity of patients with orofacial clefts.

OBJECTIVES: This study evaluated the incidence of Candida species, and the genetic diversity and virulence of C. albicans of the oral cavity from patients with cleft lip and palate (CLP). MATERIALS AND METHODS: Oral samples were investigated by microbiological and species-specific PCR methods. The genetic diversity of C. albicans was established using isoenzyme markers, Nei's statistics, and clustering analysis. Hydrolytic enzymes (SAPs and PLs) were analyzed in vitro. RESULTS: Oral colonization by Candida species was observed in 29 patients with CLP (65.9%), and C. albicans was highly prevalent. SAP and PL activities were observed in 100% and 51.9% of isolates, respectively. High genetic diversity and patterns of monoclonal and polyclonal oral colonization by C. albicans were observed among patients with CLP. Two major polymorphic taxa (A and B) and other minor polymorphic taxa (C to J) were identified. Only one of the 16 clusters (taxon A) harbored strains from patients with and without CLP, whereas other clusters harbored strains exclusively from CLP patients. CONCLUSIONS: The anatomical conditions of the oral cavity of patients with CLP contribute to the high incidence of Candida species (C. albicans, C. krusei, C. tropicalis, and/or Candida spp.). Data suggest high genetic diversity of potentially virulent C. albicans strains in the oral cavity of CLP patients. CLINICAL RELEVANCE: Microbiological niches in orofacial clefts can contribute to the emergence of a relative clinical genotypic identity of C. albicans. However, orofacial rehabilitation centers can contribute to the direct and indirect sources of transmission and propagation of Candida species.

Antimicrobial effects of silver nanoparticles and extracts of Syzygium cumini flowers and seeds: Periodontal, cariogenic and opportunistic pathogens.

OBJECTIVE: This study aimed to analyze the antimicrobial effects of lyophilized hydroalcoholic extract (HEScSeed and HEScFlower) and silver nanoparticles (AgNPs-HEScSeed and AgNPs-HEScFlower) of S. cumini seed and flower, and to characterize some compounds of these extracts and their NPs. DESIGN: Phytochemical screening was performed by GC-MS. Nanoparticles were characterized by UV-vis spectroscopy, energy-dispersive X-ray (EDX) spectrophotometry, scanning electron microscopy (SEM) and field emission gun (FEG), dynamic light scattering (DLS) and zeta potential (ZP). Antimicrobial susceptibility tests were analyzed by broth microdilution and agar diffusion methods. RESULTS: HEScSeed and HEScFlower showed 7 and 17 phytochemical compounds, respectively. AgNPs-plant extracts were reported as stable and with variable shapes and sizes. All studied species (A. naeslundii, C. albicans, F. nucleatum, S. aureus, S. epidermidis, S. mutans, S. oralis and V. dispar) were susceptible to extracts and AgNPs-plant extracts, with varying degrees of antimicrobial activities (extract: 648.4-5,187.5 µg/mL; AgNPs-plant: 31.2-2,000 µg/mL). CONCLUSION: The extracts of S. cumini seed and flower have antimicrobial action against pathogens of medical and dental interest, whose MIC and MMC are species-dependent. The AgNPs-HEScSeed and AgNPs-HEScFlower have different shapes, sizes, organic compounds, stability and electronegativity (capping), characteristics that contribute to their bacteriostatic and fungistatic effects, but at significantly lower concentrations than plant extracts.

Antimicrobial potential, phytochemical profile, cytotoxic and genotoxic screening of Sedum praealtum A. DC. (balsam).

BACKGROUND: Sedum praealtum has been used for a long time in traditional medicine as an analgesic and anti-inflammatory agent. Its beneficial effects have been known since ancient times, when Latinos used it to treat sore and swollen eyes. This research evaluated the antimicrobial potential, the cytotoxic and genotoxic effects, and some chromatographic profiles of the hydroethanolic extract of leaves, stems and roots of S. praealtum. METHODS: The antimicrobial activities were carried out by broth microdilution and agar diffusion. In vitro cytotoxicity was evaluated by cell cultures of Aedes albopictus and the selectivity index (SI) was estimated: SI=CI50/MIC. Genotoxic and systemic toxic effects of S. praealtum leaves were analyzed by micronucleus assay in mice bone marrow. Chromatographic profiles and mass spectra were investigated by GC-MS. RESULTS: Gram-positive (B. subtilis, B. cereus, M. luteus, E. faecalis and S. aureus) and gram-negative (E. coli, E. aerogenes, S. marcescens, P. aeruginosa, P. mirabilis and S. typhimurium) bacteria exhibited MICs ranging from 12.5-50 and 0-50 mg/ml, respectively. Sedum praealtum showed no efficacy against M. tuberculosis and M. bovis. Cytotoxicity (CI50) of S. praealtum was 4.22 and 5.96 mg/ml for leaves and stems, respectively, while its roots showed no cytotoxicity. Micronucleated polychromatic erythrocytes (MNPCEs) analyzes showed no differences between treatment doses (0.5-2 g/kg) and negative control (NaCl), but the PCE/NCE ratio (polychromatic erythrocyte/normochromatic erythrocyte) showed significant differences. Phytochemical screening identified thirteen compounds in the leaves, stems and roots of S. praealtum potentially associated with their biological activities. CONCLUSIONS: This research comprises a first scientific study on genotoxicity, cytotoxicity and antimicrobial effects of S. praealtum (Balsam), and it provides an initial theoretical foundation for its comprehensive use. Results showed antibacterial action of S. praealtum against gram-positive bacteria and some gram-negative species (depending on the plant anatomical part), but ineffective antimycobacterial action. However, S. praealtum leaves and stems display potential cytotoxicity, contributing to the SI < 1 values. In addition, S. praealtum leaves exhibit no clastogenic and/or aneugenic effects, but it has systemic toxicity dose-independent.

Candida species biotypes in the oral cavity of infants and children with orofacial clefts under surgical rehabilitation.

Patients with orofacial clefts present various risk factors for oral infectious diseases, resulting from anatomical and physiological changes and those resulting from rehabilitating therapeutic interventions. The incidence of Candida species in groups of babies and children with orofacial clefts, during pre- and post-operative periods and until return to first consultation, and the profiles for antifungal sensitivity and virulence in vitro were investigated. Oral samples were collected at different times over the surgical procedures and post-surgical clinical consultation and seeded in chromogenic culture media CHROMagar Candida®. Candida biotypes were identified by accessing species-specific genomic DNA sequences by PCR techniques and electrophoretic procedures. Antifungal susceptibility testing was performed by the method of microdilution in broth using the antifungals amphotericin B (AP), nystatin (NYS) and fluconazole (FLC). SAP and PL exoenzyme activities were determined by classical microbiological methods. Some orofacial clefts occurred preferentially in male or female. Low incidence (39.1%) of oral colonization by Candida species (C. albicans, C. krusei, C. tropicalis and Candida spp.) was reported in patient admission to surgical ward, with no correlation to orofacial cleft types or surgical history. Significant reduction in frequencies of Candida and changes of species, over sampling periods, showed dynamic patterns of oral colonization: elimination, maintenance or neocolonization of the biotypes. These biotypes showed sensitivity to AP (100%), partial resistance to FLC (<10%) and variable MICs for NYS (0.125-4 µg/mL), in addition to strong exoenzyme activities, especially for SAP. Clinical and therapeutic conducts for surgical rehabilitation, anatomical and physiological characteristics of patients with orofacial clefts, and cultural behavior and regionalism of the patient population served could influence the frequencies and dynamics of oral colonization by Candida species. The data showed Candida biotypes resistant to FLC and sensitive (AP) or clinically compatible (NYS) to polyenes, especially C. albicans, in the oral cavity of patients predisposed to oral colonization and candidiases, contributing to clinical conducts in possible antifungal therapies. These biotypes were considered potentially virulent and able to partially modulate their virulence factors, especially SAP, under the conditions favored by host.

Dynamics of the seasonal airborne propagation of Staphylococcus aureus in academic dental clinics.

OBJECTIVE: Staphylococcus aureus strains can be disseminated during dental treatments and occasionally lead to the contamination and infection of patients and dentists, which is an important public health problem. The dynamics of the airborne propagation and the genetic diversity of S. aureus isolated in an academic dental clinic environment were investigated using isoenzyme typing. Materials and MethodsThe isoenzymes of 44 previously reported isolates were obtained from fresh cultures and extracted using glass beads. Nine isoenzymes were investigated using multilocus enzyme electrophoresis (MLEE). The genetic diversity and relationship among the strains (electrophoretic type - ET) were determined using statistics previously described by Nei25 (1972) and the SAHN grouping method (UPGMA algorithm). RESULTS: Clonal pattern analyses indicated a high level of genetic polymorphism occurring among the 33 ETs, which were grouped into five taxa. Each taxon presented one or more clusters that were moderately related and that contained two or more identical/highly related isolates, revealing seasonal airborne propagation in these dental clinic environments. CONCLUSIONS: These data suggest the occurrence of active microevolutionary processes in S. aureus as well as the possibility of environmental propagation during a 14-month time span. Such findings are important to show that multiuser academic dental clinics can retain certain strains that are spreadable to different niches.

Dynamics of the seasonal airborne propagation of Staphylococcus aureus in academic dental clinics

Abstract Objective Staphylococcus aureus strains can be disseminated during dental treatments and occasionally lead to the contamination and infection of patients and dentists, which is an important public health problem. The dynamics of the airborne propagation and the genetic diversity of S. aureus isolated in an academic dental clinic environment were investigated using isoenzyme typing. Material and Methods The isoenzymes of 44 previously reported isolates were obtained from fresh cultures and extracted using glass beads. Nine isoenzymes were investigated using multilocus enzyme electrophoresis (MLEE). The genetic diversity and relationship among the strains (electrophoretic type - ET) were determined using statistics previously described by Nei25 (1972) and the SAHN grouping method (UPGMA algorithm). Results Clonal pattern analyses indicated a high level of genetic polymorphism occurring among the 33 ETs, which were grouped into five taxa. Each taxon presented one or more clusters that were moderately related and that contained two or more identical/highly related isolates, revealing seasonal airborne propagation in these dental clinic environments. Conclusions These data suggest the occurrence of active microevolutionary processes in S. aureus as well as the possibility of environmental propagation during a 14-month time span. Such findings are important to show that multiuser academic dental clinics can retain certain strains that are spreadable to different niches.

Isoenzyme genotyping and phylogenetic analysis of oxacillin-resistance Staphylococcus aureus isolates

Aim: The propagation of S. aureus in hospital and dental environments is considered an important public health problem since resistant strains can cause serious infections in humans. The genetic variability of 99 oxacillin-resistant S. aureus isolates (ORSA) from the dental patients (oral cavity) and environments (air) was studied by isoenzyme genotyping. Methods: S. aureus isolates were studied using isoenzyme markers (alcohol dehydrogenase, sorbitol dehydrogenase, mannitol-1-phosphate dehydrogenase, malate dehydrogenase, glucose dehydrogenase, D-galactose dehydrogenase, glucose-6-phosphate dehydrogenase, catalase and α/ß-esterase) and genetic (Nei's statistics) and cluster analysis (UPGMA algorithm). Results: A highly frequent polyclonal pattern was observed in this population of ORSA isolates, suggesting various sources of contamination or microbial dispersion. Genetic relationship analysis showed a high degree of polymorphism between the strains, and it revealed three taxa (A, B and C) distantly genetically related (0.653≤dij≤1.432) and fifteen clusters (I to XV) moderately related (0.282≤dij<0.653). These clusters harbored two or more highly related strains (0≤dij<0.282), and the existence of microevolutionary processes in the population of ORSA. Conclusion: This research reinforces the hypothesis of the existence of several sources of contamination and/or dispersal of ORSA of clinical and epidemiologically importance, which could be associated with carriers (patients) and dental environmental (air) (AU)

Genotoxicidade de Helianthus annuus Linné, 1753 (Asteraceae): novas perspectivas e tendências / Genotoxicity of Helianthus annuus Linné, 1753 (Asteraceae): new perspectives and trends

A presente revisão reúne informações acerca dos aspectos genotóxicos de Helianthus annuus Linné (girassol), até o presente momento na literatura. O girassol é uma importante fonte de óleo natural e sua ampla aplicabilidade é atribuível ao variável repertório fitoquímico. A ação preventiva da diurese, diarreia e doenças inflamatórias, além dos efeitos de alívio dos sintomas asmáticos, proteção gástrica, cicatrização, ação anti-inflamatória e antimicrobiana foram reconhecidas quanto às propriedades farmacológicas do girassol. Com um grande potencial fitoquímico, é importante também analisarmos seu potencial tóxico e genotóxico. Vários resultados inconclusivos a respeito da correlação entre a carcinogênese e o óleo de girassol foram observados na literatura. Por outro lado, um número limitado de informações sobre a mutagênese ou antimutagênese do extrato hidroalcoólico e distintas fontes do óleo de sementes de girassol, submetido ou não ao estresse térmico, foi relatado. Esta revisão apresentará os atuais trabalhos envolvendo a ação genotóxica ou anti genotóxica de H. annuus L., colaborando com a implantação de limites ao consumo, potenciais riscos à saúde ou medidas estratégicas quimiopreventivas.(AU)

The present review gathers information about the genotoxic aspects of Helianthus annuus Linné (sunflower), until the present moment in the literature. Sunflower is an important source of natural oil and its wide applicability is attributable to the variable phytochemical repertoire. The preventive action of diuresis, diarrhea and inflammatory diseases, besides the effects of relief of asthmatic symptoms, gastric protection, healing, anti-inflammatory and antimicrobial action were recognized regarding the pharmacological properties of the sunflower. With great phytochemical potential, it is also important to analyze its toxic and genotoxic potential. Several inconclusive results regarding the correlation between carcinogenesis and sunflower oil were observed in the literature. On the other hand, a limited number of information on the mutagenesis or anti-mutagenesis of the hydroalcoholic extract and different sources of sunflower seed oil, whether or not subjected to thermal stress, was reported. This review will present the current works involving the genotoxic or anti genotoxic action of H. annuus L., collaborating with the implementation of consumption limits, potential health risks or strategic chemopreventive measures.(AU)

In vitro screening antibacterial activity of Bidens pilosa Linné and Annona crassiflora Mart. against oxacillin resistant Staphylococcus aureus (ORSA) from the aerial environment at the dental clinic.

Currently multiresistant Staphylococcus aureus is one common cause of infections with high rates of morbidity and mortality worldwide, which directs scientific endeavors in search for novel antimicrobials. In this study, nine extracts from Bidens pilosa (root, stem, flower and leaves) and Annona crassiflora (rind fruit, stem, leaves, seed and pulp) were obtained with ethanol: water (7:3, v/v) and their in vitro antibacterial activity evaluated through both the agar diffusion and broth microdilution methods against 60 Oxacillin Resistant S. aureus (ORSA) strains and against S. aureus ATCC6538. The extracts from B. pilosa and A. crassiflora inhibited the growth of the ORSA isolates in both methods. Leaves of B. pilosa presented mean of the inhibition zone diameters significantly higher than chlorexidine 0.12% against ORSA, and the extracts were more active against S. aureus ATCC (p < 0.05). Parallel, toxicity testing by using MTT method and phytochemical screening were assessed, and three extracts (B. pilosa, root and leaf, and A. crassiflora, seed) did not evidence toxicity. On the other hand, the cytotoxic concentrations (CC50 and CC90) for other extracts ranged from 2.06 to 10.77 mg/mL. The presence of variable alkaloids, flavonoids, tannins and saponins was observed, even though there was a total absence of anthraquinones. Thus, the extracts from the leaves of B. pilosa revealed good anti-ORSA activity and did not exhibit toxicity.

Evaluation of antimicrobial and cytotoxic activities of plant extracts from southern Minas Gerais cerrado.

The antimicrobial activity of plant hidroethanolic extracts on bacteria Gram positive, Gram negative, yeasts, Mycobacterium tuberculosis H37 and Mycobacterium bovis was evaluated by using the technique of Agar diffusion and microdilution in broth. Among the extracts evaluated by Agar diffusion, the extract of Bidens pilosa leaf presented the most expressive average of haloes of growth inhibition to the microorganisms, followed by the extract of B. pilosa flower, of Eugenia pyriformis' leaf and seed, of Plinia cauliflora leaf which statistically presented the same average of haloes inhibitory formation on bacteria Gram positive, Gram negative and yeasts. The extracts of Heliconia rostrata did not present activity. Mycobacterium tuberculosis H37 and Mycobacterium bovis (BCG) appeared resistant to all the extracts. The susceptibility profile of Candida albicans and Saccharomyces cerevisiae fungi were compared to one another and to the Gram positive Bacillus subtilis, Enterococcus faecalis and the Gram negative Salmonella typhimurium bacteria (p > 0.05). The evaluation of cytotoxicity was carried out on C6-36 larvae cells of the Aedes albopictus mosquito. The extracts of stem and flower of Heliconia rostrata, leaf and stem of Plinia cauliflora, seed of Anonna crassiflora and stem, flower and root of B. pilosa did not present toxicity in the analyzed concentrations. The highest rates of selectivity appeared in the extracts of stem of A. crassiflora and flower of B. pilosa to Staphylococcus aureus, presenting potential for future studies about a new drug development.

Evaluation of attimicrobial and cytotoxic activties of plant extracts from souuthern minas gerais cerrado / Avaliacao das atividades antimicrobiana e citotoxica de extratos de plantas do Cerrado do Sul de Minas Gerais

The antimicrobial activity of plant hidroethanolic extracts on bacteria Gram positive, Gram negative, yeasts, Mycobacterium tuberculosis H37 and Mycobacterium bovis was evaluated by using the technique of Agar diffusion and microdilution in broth. Among the extracts evaluated by Agar diffusion, the extract of Bidens pilosa leaf presented the most expressive average of haloes of growth inhibition to the microorganisms, followed by the extract of B. pilosa flower, of Eugenia pyriformis' leaf and seed, of Plinia cauliflora leaf which statistically presented the same average of haloes inhibitory formation on bacteria Gram positive, Gram negative and yeasts. The extracts of Heliconia rostrata did not present activity. Mycobacterium tuberculosis H37 and Mycobacterium bovis (BCG) appeared resistant to all the extracts. The susceptibility profile of Candida albicans and Saccharomyces cerevisiae fungi were compared to one another and to the Gram positive Bacillus subtilis, Enterococcus faecalis and the Gram negative Salmonella typhimurium bacteria (p > 0.05). The evaluation of cytotoxicity was carried out on C6-36 larvae cells of the Aedes albopictus mosquito. The extracts of stem and flower of Heliconia rostrata, leaf and stem of Plinia cauliflora, seed of Anonna crassiflora and stem, flower and root of B. pilosa did not present toxicity in the analyzed concentrations. The highest rates of selectivity appeared in the extracts of stem of A. crassiflora and flower of B. pilosa to Staphylococcus aureus, presenting potential for future studies about a new drug development.

Foi avaliada a atividade antimicrobiana de extratos hidroetanólicos de plantas sobre bactérias Gram positiva, Gram negativa, leveduras, Mycobacterium tuberculosis H37 e Mycobacterium bovis pela técnica de difusão em Agar e microdiluição em caldo. Dentre os extratos avaliados pelo método de difusão em Agar, o extrato da folha de Bidens pilosa apresentou a mais expressiva média de halos de inibição de crescimento frente aos microrganismos, seguido pelo extrato da flor de B. pilosa, da folha e semente de Eugenia pyriformis, da folha de Plinia cauliflora que apresentaram estatisticamente a mesma média de formação de halos inibitórios sobre bactérias Gram positivas, Gram negativas e leveduras. Os extratos de Heliconia rostrata não apresentaram atividade. Mycobacterium tuberculosis H37 e Mycobacterium bovis (BCG) mostraram-se resistentes a todos os extratos. O perfil de sensibilidade dos fungos Candida albicans e Saccharomyces cerevisiae foram comparáveis entre si e entre as bactérias Gram positivas Bacillus subtilis, Enterococcus faecalis e Gram negativa Salmonella typhimurium (p > 0.05). A avaliação da citotoxicidade foi realizada sobre células C6-36 de larvas de mosquito Aedes albopictus. Os extratos de caule e flor de H. rostrata, folha e caule de P. cauliflora, semente de Anonna crassiflora e caule, flor e raiz de B. pilosa não apresentaram toxicidade nas concentrações avaliadas. Os maiores índices de seletividade foram apresentados pelos extratos de caule de A. crassiflora e flor de B. pilosa para Staphylococcus aureus, apresentando potencial para estudos como futuros candidatos a fármacos.