ABSTRACT The antimicrobial potential of extracts of bark and leaves of Cassia bakeriana Craib, Fabaceae, against aerobic and anaerobic oral bacteria was evaluated by the microdilution broth method. For crude ethanol extracts and organic fractions tested, the bark dichloromethane phase showed a significant antibacterial effect, with MIC values ranging from 12.5 to 100 µg/ml for most of the microorganisms tested. Thus, a bioassay-guided fractionation of this fraction was performed. This fractionation led to isolation of the 1,8-dihydroxy-anthraquinone-3-carboxylic acid, also known as cassic acid or rhein. It is the first time that this bioactive anthraquinone has been isolated from this plant. Rhein exhibited good selectivity and high activity against anaerobic microorganisms, with MIC values ranging between 3.12 µg/ml (11.0 µM) and 25 µg/ml (88.0 µM). These results were considered very promising since the most active samples and rhein showed greater selectivity against oral microorganisms than toxicity to Vero cells.

Um total de 479 casos de diarréia aguda e de 337 crianças sem diarréia (controles) foi investigado em um estudo longitudinal de 2 anos na cidade de São Luís (MA) em crianças menores de 5 anos de idade, a fim de estabelecer a incidência e a distribuição etária e sazonal de rotavírus, bem como determinar a severidade da doença nesta região do Brasil. A incidência de Rotavírus apresentou os maiores índices durante o primeiro ano de vida das crianças, com média anual de 25% entre os pacientes atendidos nos principais hospitais pediátricos da cidade e em Unidades de Saúde da periferia. O estudo mostrou que a relevância dos rotavírus como agentes etiológicos da diarréia aguda na infância já acaba aos 18 meses de idade das crianças desta região, quando os valores de positividade caem a apenas 4%, como no grupo controle. A distribuição bimensal de rotavírus não apresentou perfil tipicamente sazonal, ocorrendo 1 pico de incidência no ano de 1986, durante a estação chuvosa, e 2 picos no ano de 1987, dos quais um na estação chuvosa e outro, durante a época seca do ano. O estudo também mostrou que a doença diarreica é mais severa entre os casos positivos para rotavírus do que entre negativos, apresentando maior freqüência de evacuações diárias, de vômitos e febre, levando ao índice acima de 2 vezes maior de casos de desidratação moderada ou severa. Finalmente, é feita uma análise em relação ao efeito que a imunoprofilaxia poderá ter sobre os elevados índices de mortalidade infantil registrados nesta região do país.

A total of 479 diarrhoeic children and 337 children without diarrhoea (controls) less than 5 years old were investigated in a two-year study in the city of S. Luís (MA), with the purpose to determine the incidence, the age distribution and the seasonality of rotaviruses, as well as to establish the severity of the disease in this region between the North and the Northeast of Brazil. rotavirus incidence was highest in children of the 1st. year of life, showing an average of 25% per year among the diarrhoeic patients attending the two main hospitals and three health units at the periphery of the city. It was shown that rotaviruses are significant enteropathogens in children less than 18 months old. Frequency of rotaviruses droped in diarrhoeic patients 18 to 23 months old to only 4%, the same percentage observed in children of the control group. A typical seasonal distribution of rotaviruses was not seen during the two years of study. There was a peak in the incidence of rotaviruses in 1986, during the rainy season, and two peaks in 1987, one in the rainy season and one in the dry season. It was also shown that severity of diarrhoea in rotavirus positive cases was higher than in the negative cases. Rotavirus diarrhoeic patients had more loose stools per day, and higher frequencies of vomiting and fever, resulting more often (> 2 times) in moderate or severe dehydration. Finally, it is concluded that the introduction of immunoprophylaxis may reduce significantly the high mortality rates in early childhood observed in S. Luís.