Chemical composition, antioxidant and antibacterial activities of essential oils from leaves and flowers of Eugenia klotzschiana Berg (Myrtaceae)

ABSTRACT Many essential oils (EOs) of different plant species possess interesting antimicrobial effects on buccal bacteria and antioxidant properties. Eugenia klotzschiana Berg (pêra-do-cerrado, in Portuguese) is a species of Myrtaceae with restricted distribution in the Cerrado. The essential oils were extracted through the hydrodistillation technique using a modified Clevenger apparatus (2 hours) and chemically characterized by GC-MS. The major compounds were α-copaene (10.6 %) found in oil from leaves in natura, β-bisabolene (17.4 %) in the essential oil from dry leaves and α-(E)-bergamotene (29.9 %) in oil from flowers. The antioxidant activity of essential oils showed similarities in both methods under analysis (DPPH and ABTS˙+) and the results suggested moderate to high antioxidant activity. The antibacterial activity was evaluated by determining minimum inhibitory concentrations (MICs), using the microdilution method. MIC values below 400 µg/mL were obtained against Streptococcus salivarius (200 µg/mL), S. mutans (50 µg/mL), S. mitis (200 µg/mL) and Prevotella nigrescens (50 µg/mL). This is the first report of the chemical composition and antibacterial and antioxidant activities of the essential oils of E. klotzschiana. These results suggest that E. klotzschiana, a Brazilian plant, provide initial evidence of a new and alternative source of substances with medicinal interest.

Comparative study of the antimicrobial efficacy of chlorhexidine gel, chlorhexidine solution and sodium hypochlorite as endodontic irrigants

The purpose of this study was to assess the in vitro the antimicrobial efficacy of chlorhexidine gluconate gel as an endodontic auxiliary chemical substance compared to sodium hypochlorite (NaOCl) and chlorhexidine gluconate solution. The antimicrobial efficacy of the tested substances was evaluated using the agar diffusion test. The growth inhibition zones produced by 0.2 percent, 1 percent and 2 percent chlorhexidine gel were evaluated against 5 facultative anaerobic bacteria and 4 pigmented Gram-negative anaerobes, and compared to the results obtained by NaOCl and chlorhexidine solution. The largest growth inhibition zones were produced when the test bacteria were in contact with 2 percent chlorhexidine gluconate gel (11.79 mm), being significantly different (p<0.05) from the growth inhibition zones produced by all NaOClconcentrations, including 5.25 percent (9.54 mm). However, there was no statistically significant difference (p>0.05) between the growth inhibition zones obtained with equal concentrations of chlorhexidine solution and gel. The results of this study indicate that, as far as its antimicrobial properties are concerned, chlorhexidine gel has a great potential to be used as an endodontic auxiliary chemical substance.

O objetivo deste estudo foi avaliar in vitro a atividade antimicrobiana do gluconato de clorexidina gel, como irrigante endodôntico, comparando-o ao hipoclorito de sódio (NaOCl) e ao gluconato de clorexidina líquido. A atividade antimicrobiana das substâncias testadas foi avaliada pelo teste de difusão em ágar. As zonas de inibição de crescimento bacteriano produzidas pela clorexidina gel a 0,2 por cento; 1 por cento e 2 por cento foram observados frente a 5 espécies de bactérias anaeróbias facultativas e 4 espécies de anaeróbios estritos, Gram-negativos e produtores de pigmento negro; e comparados com os resultados obtidos pelo NaOCl e pela clorexidina líquida. As maiores zonas de inibição foram produzidas quando as bactérias testadas ficaram em contato com a clorexidina a 2 por cento em gel (11,79 mm), apresentando diferença estatisticamente significante (p<0,05) quando comparados às zonas de inibição de crescimento bacteriano produzidas por todas as concentrações avaliadas de NaOCl, incluindo 5,25 por cento (9,54 mm). No entanto, não houve diferença estatisticamente significante (p>0,05) comparando as zonas produzidas por concentrações equivalentes de clorexidina líquida ou gel. Os resultados indicaram que a clorexidina em gel tem grande potencial para ser usada como substância química auxiliar quanto às suas propriedades antimicrobianas.

Susceptibilidad in vitro de bacterias anaeróbicas en infecciones pleuropulmonares / In vitro antimicrobial susceptibility of anaerobic bacteria isolated from pleuropulmonary infections

Background: Aspirative pleuropulmonary infections are usually caused by anaerobic flora of the mouth, mainly Prevotella, Fusobacterium and Peptostreptococcus spp. Penicillin in high doses is the traditional treatment for this type of infections but the rising resistance developed in recent years has induced the empiric use of clindamycin, increasing treatment costs. Aim: To study antimicrobial susceptibility of anaerobic bacteria isolated from pleuropulmonary infections. Material and methods: Thirty two strains obtained from bronchoalveolar lavage and 15 strains isolated from pleural effusions between 2000 and 2002, were studied. The phenotype of strains was identified using the semiautomated API 20 A method and their susceptibility to penicillin (PNC), clindamycin (CM) and chloramphenicol (CAF) was tested using the E test methods. Results: All the strains were susceptible to CAF, 95% to CM and 74.4% to PNC. The predominant genus was Prevotella, which also exhibited the higher resistance. Conclusions: As CM and CAF are active "in vitro", high rates of clinical response should be expected. In contrast, PNC is less effective, especially against pigmented Prevotella.

Evaluation of antibacterial activity of Mangifera indica on anaerobic dental microglora based on in vivo studies.

The present study was carried out to compare the subgingival plaque microflora in mango leaf users. Fifty subjects of both sexes, 25 of them used tooth brush and 25 used mango leaf as their home care hygiene device were included in the study. The microbiological evaluation for specific bacterial counts of Actinobacillus actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Fusobacterium nucleatum and Peptostreptococcus micros were carried out for all subject. Specific microbial evaluation revealed significant decrease in the proportion of P. intermedia and P. gingivalis in mango leaf users compared to tooth brush users. It shows that mangiferin possesses antibacterial activity in vivo against specific periodontal pathogens such as P. intermedia and P. gingivalis. Use of mango leaf in conjunction with a tooth brush will be a good home care device for maintenance of oral hygiene.