Leandro Wagner Figueira

This study aimed to determine the effects of low-temperature plasma jet produced in gas helium (LTP-helium) on cariogenic biofilms composedby Streptococcusmutans, Streptococcus sanguinis and Streptococcus gordonii, and also by the combination of Candida albicans, Lactobacillus acidophilus and S. mutans. Biofilms were treated for 1, 3, 5, and 7 minutes. A 0.12% chlorhexidine solution was used as the positive control and sterile physiologic solution was the negative control. Biofilm viability was analyzed by viable cell recovery, scanning electron microscopy, and confocal laser scanning microscopy. All assays were performed intriplicate in three independent experiments. Multispecies biofilms exposed to LTP-helium had a significant reduction in viability when compared to the negative control (p < 0.0001). For biofilm formedby S. mutans, S. sanguinis, and S. gordonii, LTP treatments for 5 and 7 minutes caused similar reduction of morethan 2 log₁₀. Also, a significant reduction in the viability of biofilms formedby C. albicans, L. acidophilus, and S. mutans was detected (p < 0.0001). In conclusion, LTP-helium reduced theviability of cariogenic biofilms with different microbial compositions, which indicates that LTP-helium is a potential tool for developing new protocols for dental caries prevention and treatment.

Objective: Evaluate the anti-biofilm activity of Gymnema sylvestre, Hamamelis virginiana, Juglans regia, Persea americana, Pfaffia paniculata, Rosmarinus officinalis, Stryphnodendron barbatiman and Thymus vulgaris extracts in 3 MDR strains and 1 ATCC (4352) of Klebsiella pneumoniae. Methods: First were made a screening with broth microdilution test, protocol M7-A9, according to CLSI. Extracts that presented values for Minimal Microbicidal Concentration (MMC) were selected for biofilms tests on 96 wells plates. Treatments used concentrations of 25 and 50 mg/mL, after biofilms were measured by biomass and MTT tests and statistically analyzed by ANOVA and Tukey test (p<0.05). Results: All extracts showed MIC for all K. pneumoniae strains studied, with values ranging from 12.5-100 mg/mL. Biomass of the strains ATCC and MDR strain (400381) of K. pneumoniae obtained reductions of 37.7 and 44.3% with P. paniculata and R. officinalis extracts. The isolate 386546 obtained a reduction of 29.7% (p<0.05) under R. officinalis action. Conclusion: Among the extracts studied, those that were most effective in the anti-biofilm action were J. regia, P. paniculata and R. officinalis. Therefore, these extracts could act as bactericidal agents against K. pneumoniae MDR.

Plasma is an electrically conducting medium that responds to electric and magnetic fields. It consists of large quantities of highly reactive species, such as ions, energetic electrons, exited atoms and molecules, ultraviolet photons, and metastable and active radicals. Non-thermal or cold plasmas are partially ionized gases whose electron temperatures usually exceed several tens of thousand degrees K, while the ions and neutrals have much lower temperatures. Due to the presence of reactive species at low temperature, the biological effects of non-thermal plasmas have been studied for application in the medical area with promising results. This review outlines the application of cold atmospheric pressure plasma (CAPP) in dentistry for the control of several pathogenic microorganisms, induction of anti-inflammatory, tissue repair effects and apoptosis of cancer cells, with low toxicity to healthy cells. Therefore, CAPP has potential to be applied in many areas of dentistry such as cariology, periodontology, endodontics and oral oncology.

Candida spp. are naturally opportunistic and can promote infections. These yeasts can form biofilm, after penetration and adhesion to the biotic or abiotic surfaces. Preexisting diseases, treatments with drugs and radiation therapy, medical procedures, and parafunctional habits favor the installation of a fungal infection. Increased resistance to the available antifungals has become a concern. Therefore, alternative methods to control them have been evaluated, including the use of plant substances. In this study, the antibiofilm effect of R. officinalis L. extract was analyzed on C. albicans, C. dubliniensis, C. glabrata, C. krusei, and C. tropicalis. A phytochemical analysis of the extract was performed. Biofilms were formed for 48 h and exposed to the different concentrations of the extract (50, 100, and 200 mg/mL) for 5 min or 24 h. The effect of the plant extract was compared to the antifungal nystatin. Rosmarinus officinalis L. extract was constituted of phenols and flavonoids, highlighting the presence of chlorogenic acid derivatives in its composition. Biofilm reductions were observed after exposure to the plant extract for both periods. The plant extract provided a reduction similar to the antifungal. Thus, R. officinalis L. extract showed antibiofilm effect on Candida spp. comparable to the nystatin.

Objective: The use of medicinal plants may be an alternative method for the control of Candida spp. responsible for human infections. This study evaluated the antifungal effect of Schinus terebinthifolius extract (Brazilian Peppertree) on C. albicans, C. dubliniensis, C. glabrata, and C. krusei planktonic cultures and biofilms. Material and Methods: Minimum inhibitory concentration (MIC) and minimum fungal concentration (MFC) of the plant extract were determined by the broth microdilution method. Biofilms formed in microplate wells were exposed to the extract for 5 min (50, 100 and 200 mg/mL) or 24 h (25, 50 and 100 mg/mL). After determination of colony-forming units per milliliter (CFU/mL), the data were analyzed by one-way ANOVA and Tukey’s Test (P ? 0.05). Results: Different MIC (mg/mL) were found, such as 0.39 (C. dubliniensis), 1.56 (C. albicans), and 3.13 (C. glabrata and C. krusei). Besides, MFC (mg/mL) of 0.78 (C. dubliniensis) and 3.13 (C. albicans, C. glabrata and C. krusei) were also observed. Regarding the biofilms, significant reductions (log10) were found after 5 min and 24 h exposure to the plant extract, compared to the control group. However, C. dubliniensis was significantly affected only in 24 h treatment. Conclusion: S. terebinthifolius extract presented a significant antifungal effect on C. albicans, C. dubliniensis, C. glabrata, and C. Krusei both in planktonic cultures and biofilms.

Aim: Plant products have been evaluated to control opportunistic micro-organisms, as well as fortify immune system cells. Thus, Curcuma longa L. (turmeric) extract was evaluated in interactions of ...

Finding an effective alternative way to aid defense cells to fight Streptococcus mutans was the main goal of this study. The effect of plant extracts from Curcuma longa L. (turmeric), Rosmarinus officinalis L. (rosemary), and Thymus vulgaris L. (thyme) was evaluated on murine macrophages (RAW 264.7) infected by S. mutans. Minimum inhibitory concentration (MIC) of the extracts was determined. Macrophages were infected by S. mutans and treated with each extract. From the supernatants, it was measured nitric oxide (NO) level. Posteriorly, RAW 264.7 were lysed to expose living and phagocytosed bacteria. Cytotoxicity was checked by lysosomal activity analysis, using neutral red assay. Each extract helped RAW 264.7 to eliminate S. mutans during infection, as observed by a significant bacterial reduction. Significant cell viability was also found. Besides, an increased production of NO was verified using R. officinalis L. and T. vulgaris L. extracts. The evaluated extracts demonstrated an effective action to assist RAW 264.7 to fight S. mutans during infection.

As folhas de tomilho são utilizadas como condimento, conservante alimentício e para fins medicinais. O objetivo desse estudo foi avaliar a ação antimicrobiana do extrato de tomilho sobre biofilme composto por C. albicans e S. mutans. Para tanto, suspensões de cada micro-organismo foram ajustadas a 10⁷ UFC/mL e adicionadas (100 µL/poço de cada) em placa de microtitulação. Após 90 min de incubação, o sobrenadante foi substituído por 200 µL/poço de BHI+YNB (1:1). O biofilme de 48 h foi exposto por 5 min ao extrato de tomilho ou à solução salina. Após lavagens com salina, 100 µL/poço de solução de MTT foi adicionada e incubada por 1 h, esta solução foi substituída por dimetilsulfóxido (100 µL/poço) e a placa foi incubada por mais 10 min e agitada por outros 10 min. Os valores de densidade óptica (DO) foram obtidos em λ = 570nm e convertidos em percentual de viabilidade, analisados estatisticamente por T-Test (p ≤ 0,05). O extrato de tomilho reduziu significativamente a viabilidade do biofilme polimicrobiano (64 ± 11%). Com isso, foi constatado o efeito antimicrobiano do extrato de tomilho sobre o biofilme composto por C. albicans e S. mutans.

Alcachofra é um vegetal utilizado na culinária e algumas de suas ações biológicas foram descritas, como ação antioxidante e anti-inflamatória, porém foi pouco relatada sua atividade sobre micro-organismos. Com isso, o objetivo do presente estudo foi verificar o efeito antimicrobiano do extrato de alcachofra sobre P. aeruginosa. Primeiramente, foi verificada a ação deste extrato sobre cultura planctônica, pelo método de microdiluição em caldo (50 a 0,09 mg/mL), em seguida, sobre biofilme formado por 48 h em poços de placas de microtitulação, com exposição de 5 min ao extrato de alcachofra (200 mg/mL). Solução salina 0,9% e clorexidina 0,12% foram utilizadas como controles. As reduções do biofilme foram verificadas pelo teste de MTT e analisadas estatisticamente por ANOVA e Tukey Test (p ≤ 0,05). Em culturas planctônicas foi verificado que as concentrações avaliadas não foram efetivas (CIM > 50 mg/mL), contudo, sobre o biofilme foi verificada redução significativa de 42 ± 16%. Desta forma, pode-se concluir que o extrato de alcachofra apresentou efeito antimicrobiano sobre biofilme de P. aeruginosa.