Jorge Kleber Chavasco

In vitro evaluation of the antimicrobial activity of endodontic sealers

The purpose of this study is to evaluate the antimicrobial activity of the endodontic sealers: N-Rickert, Sealapex, AH Plus, Mineral Trioxide Aggregate (MTA) and portland cement. The Agar diffusion method was used in plates previously inoculated with the following microorganisms: C. albicans, S. aureus, E. faecalis, E. coli. The diameters of microbial inhibition zones were measured after 24 hours of incubation in kiln at 37 degrees C. According to the methodology used, it was possible to conclude that only the sealers AH Plus and N-Rickert presented antimicrobial activity against C. albicans, S. aureus, and E. coli; no antimicrobial activity in MTA, Sealapex and portland cement was observed. N-Rickert presented the largest inhibition zones varying from 8 to 18 mm, and the microorganism E. faecalis was resistant against all sealers tested.

Antimicrobial activity of benzophenones and extracts from the fruits of Garcinia brasiliensis.

The pericarp and seeds from fruits of Garcinia brasiliensis were subjected to extraction with hexane and ethanol. The pericarp hexane extract (PHE) and seed ethanol extract (SEE) were purified by silica gel column chromatography, which permitted isolation of the prenylated benzophenones 7-epiclusianone (1) and guttiferone-A (2), respectively. The antimicrobial activity of PHE, SEE, and compounds 1 and 2 were evaluated against Candida albicans, Staphylococcus aureus, Escherichia coli, and Bacillus cereus cultures. The minimum inhibitory concentration and minimum bactericidal concentration were established. The substances presented activity against S. aureus and B. cereus as follows: PHE, 4.0 microg/mL and 2.4 microg/mL; SEE, 10.0 microg/mL and 12.6 microg/mL; 7-epiclusianone, 1.2 microg/mL and 0.6 microg/mL; and guttiferone-A, 2.4 microg/mL and 2.4 microg/mL, respectively. The direct relationship between the lipophilic character of the structure and activity in Gram-positive bacteria was specifically observed. Therefore these extracts and prenylated benzophenones represent an interesting topic for further studies and open possibilities for an alternative control of diseases associated with Gram-positive bacteria.

Molecular identification of Candida dubliniensis isolated from oral lesions of HIV-positive and HIV-negative patients in São Paulo, Brazil

Candida dubliniensis is a new, recently described species of yeast. This emerging oral pathogen shares many phenotypic and biochemical characteristics with C. albicans, making it hard to differentiate between them, although they are genotypically distinct. In this study, PCR (Polymerase Chain Reaction) was used to investigate the presence of C. dubliniensis in samples in a culture collection, which had been isolated from HIV-positive and HIV-negative patients with oral erythematous candidiasis. From a total of 37 samples previously identified as C. albicans by the classical method, two samples of C. dubliniensis (5.4%) were found through the use of PCR. This study underscores the presence of C. dubliniensis, whose geographical and epidemiological distribution should be more fully investigated.

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.

Antimycobacterial activity evaluation and MIC determination of liophilizated hydroalcoholic extracts of Bixa orellana L., Bixaceae

Bixa orellana is used in popular medicine against several diseases. Extracts of its fruit, root and leaf presented antimicrobial activity, while seed extract showed negative results. This study aimed at verifying the antimycobacterial activity of B. orellanalyophilized hydroalcoholic extracts over Mycobacterium tuberculosis, and determine the Minimum Inhibitory Concentration against five bacteria. Antimycobacterial activity was determined by diffusion technique, while MIC was assessed by diffusion and colorimetric analysis. MICs were 0.3, 0.5 and 0.2 mg/mL respectively, for leaf, root and stem extracts, against M. tuberculosis. Stems extract showed 1.2 mg/mL for B. cereus, 1.53 mg/mL for S. aureusand S. typhimurium, 4.50 mg/mL for P. aeruginosaand 8.01 mg/mL for P. mirabillis.Leaf extracts showed 0.66 mg/mL for P. aeruginosa, 0.94 mg/mL for P. mirabillis, 1.88 mg/mL for S. aureus, 3.95 mg/mL for B. cereusand 8.37 mg/mL for S. typhimurium. Roots extracts showed 0.25 mg/mL for P. aeruginosa,0.31 mg/mL for S. aureus, 0.62 mg/mL for S. typhimuriumand 3.00 mg/mL for B. cereusand P. mirabillis. Leaf and stem extracts showed antimycobacterial activity. MICs were lower in colorimetric analysis than in agar diffusion. Extracts revealed bacteriostatic activity against the five bacterial.

CHEMICAL CHARACTERIZATION AND EVALUATION OF ANTIBACTERIAL, ANTIFUNGAL, ANTIMYCOBACTERIAL, AND CYTOTOXIC ACTIVITIES OF Talinum paniculatum

SUMMARY In this study, the bioactivity of Talinum paniculatum was evaluated, a plant widely used in folk medicine. The extract from the T. paniculatum leaves (LE) was obtained by percolation with ethanol-water and then subjecting it to liquid-liquid partitions, yielding hexane (HX), ethyl acetate (EtOAc), butanol (BuOH), and aqueous (Aq) fractions. Screening for antimicrobial activity of the LE and its fractions was evaluated in vitro through broth microdilution method, against thirteen pathogenic and non-pathogenic microorganisms, and the antimycobacterial activity was performed through agar diffusion assay. The cytotoxic concentrations (CC90) for LE, HX, and EtOAc were obtained on BHK-21 cells by using MTT reduction assay. The LE showed activity against Serratia marcescens and Staphylococcus aureus, with Minimum Inhibitory Concentration (MIC) values of 250 and 500 µg/mL, respectively. Furthermore, HX demonstrated outstanding activity against Micrococcus luteusand Candida albicans with a MIC of 31.2 µg/mL in both cases. The MIC for EtOAc also was 31.2 µg/mL against Escherichia coli. Conversely, BuOH and Aq were inactive against all tested microorganisms and LE proved inactive against Mycobacterium tuberculosis and Mycobacterium bovis as well. Campesterol, stigmasterol, and sitosterol were the proposed structures as main compounds present in the EF and HX/EtOAc fractions, evidenced by mass spectrometry. Therefore, LE, HX, and EtOAc from T. paniculatum showed potential as possible sources of antimicrobial compounds, mainly HX, for presenting low toxicity on BHK-21 cells with excellent Selectivity Index (SI = CC90/MIC) of 17.72 against C. albicans.

Phytochemical profile, antibacterial, antioxidant and cytotoxicity activities of Euphorbia cotinifolia

The aim of this study was to determine the content of phenolic compounds and flavonoids, the antibacterial, antioxidant and cytotoxicity activities of hydroethanolic extracts of root, stem, leaf and fruit of Euphorbia cotinifolia. Phytochemical screening was performed using spectrophotometric methods (phenolic and flavonoid content) and liquid cromatography. The antibacterial activity was determined by agar diffusion and broth microdilution technique. Additionally, antioxidant activity was determined by diphenylpicrylhydrazyl (DPPH) radical scavenging method and cytotoxicity by the MTT method using BHK-21 (newborn hamster’s kidney) cells. All extracts presented notable content of phenolic compounds, flavonoids and tannins. The high-performance liquid chromatography with photodiode array detection (HPLC-DAD) analysis showed higher concentration of phenolic compounds in dried leaves than in fresh leaves and it indicated the presence of caffeic acid. The extracts of leaf, stem, root and fruit showed activity against five gram-positive bacteria, six gram-negative bacteria and two yeasts, but not for mycobacterial. The highest antioxidant activity was exhibited in the extract of dried leaf (EC50 = 7.32 μg/ml). Extracts showed no cytotoxicity at the concentrations tested. All extracts showed antibacterial, antifungal and antioxidant activities, phenolic compounds, tannins and flavonoids. The results provided evidence that the studied plant might indeed be potential sources of natural antioxidant and antimicrobial agents. Key words: Euphorbia cotinifolia, antimibacterial, antioxidant, phenolic compounds, flavonoids.

Genotoxicidade de Helianthus annuus Linné, 1753 (Asteraceae): novas perspectivas e tendências

A presente revisao reune informacoes acerca dos aspectos genotoxicos de Helianthus annuus Linne (girassol), ate o presente momento na literatura. O girassol e uma importante fonte de oleo natural e sua ampla aplicabilidade e atribuivel ao variavel repertorio fitoquimico. A acao preventiva da diurese, diarreia e doencas inflamatorias, alem dos efeitos de alivio dos sintomas asmaticos, protecao gastrica, cicatrizacao, acao anti-inflamatoria e antimicrobiana foram reconhecidas quanto as propriedades farmacologicas do girassol. Com um grande potencial fitoquimico, e importante tambem analisarmos seu potencial toxico e genotoxico. Varios resultados inconclusivos a respeito da correlacao entre a carcinogenese e o oleo de girassol foram observados na literatura. Por outro lado, um numero limitado de informacoes sobre a mutagenese ou antimutagenese do extrato hidroalcoolico e distintas fontes do oleo de sementes de girassol, submetido ou nao ao estresse termico, foi relatado. Esta revisao apresentara os atuais trabalhos envolvendo a acao genotoxica ou anti genotoxica de H. annuus L., colaborando com a implantacao de limites ao consumo, potenciais riscos a saude ou medidas estrategicas quimiopreventivas.

ANÁLISE MICROBIOLÓGICA DE FORMIGAS CAPTURADAS EM AMBIENTE HOSPITALAR DA CIDADE DE ALFENAS/MG DOI: http://dx.doi.org/10.5892/ruvrd.v13i1.2082

One of the problems associated with urbanization is the increase in diseases caused or transmitted by arthropods. These animals constitute a potential danger to public hea lth when the infestation occurs in hospitals, becau se they have the ability to carry pathogens, acting as mechanical ve ctors. The objective was verify the contamination of ants found in a city hospital Alfenas, MG. The specimens of ants we re collected manually with the aid of sterile force ps and immediately placed in test tubes containing 5 mL of sterile saline. The samples in saline were inocula ted in BHI broth. Then the specimens were placed in test tubes contai ning absolute alcohol for preservation and identifi cation. Microorganisms in the integument of ants has been i dentified with the turbidity of the BHI broth - inc ubated at 37 ° C for 48 hours. After cultivation, the material was s ubmitted to the techniques of isolation and identif ication of microorganisms. The main genera of ants were found Monomorium and Paratrechina. The main identified microorganisms, Staphylococcus aureus , Enterobacter aerogenes, Klebsiella pneumonie, Pseud omonas aeruginosa and Escherichia coli . The presence of potentially pathogenic bacteria i n the integument of ants found in the hospital aler t to

Brief review on the effect of low-power laser irradiation on neutrophils with emphasis on emerging fungal infections

Polymorphonuclear neutrophils (PMN) participate in an active way in the innate immunity developed after the fungal infection paracoccidioidomycosis (PCM). Nevertheless, the sole participation of neutrophils is not sufficient to eradicate PCM`s pathogenic fungus: Paracoccidioides brasiliensis (Pb). In that way, we aimed to develop a treatment capable of stimulating PMN to the site of injury through low-level laser therapy (LLLT). (LLLT) is safe to use and has not been linked to microorganism resistance so far; in addition, based on previous studies we understand that LLLT may be useful to treat several medical conditions through the stimulation and activation of certain types of cells. This brief review is based on the novel attempt of activating PMN against a fungal infection.