Antimicrobial and toxicological activities of five medicinal plant species from Cameroon Traditional Medicine

<p>Abstract</p> <p>Background</p> <p>Infectious diseases caused by multiresistant microbial strains are on the increase. Fighting these diseases with natural products may be more efficacious. The aim of this study was to investigate the <it>in vitro </it>antimicrobial activity of methanolic, ethylacetate (EtOAc) and hexanic fractions of five Cameroonian medicinal plants (<it>Piptadeniastum africana</it>, <it>Cissus aralioides, Hileria latifolia, Phyllanthus muellerianus </it>and <it>Gladiolus gregasius) </it>against 10 pathogenic microorganisms of the urogenital and gastrointestinal tracts.</p> <p>Methods</p> <p>The fractions were screened for their chemical composition and <it>in vivo </it>acute toxicity was carried out on the most active extracts in order to assess their inhibitory selectivity.</p> <p>The agar well-diffusion and the micro dilution methods were used for the determination of the inhibition diameters (ID) and Minimum inhibitory concentrations (MIC) respectively on 8 bacterial species including two Gram positive species (<it>Staphylococcus aureus, Enterococcus faecalis)</it>, and six Gram negative <it>(Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Shigella flexneri, Salmonella typhi) </it>and two fungal isolates (<it>Candida albicans, Candida krusei)</it>. The chemical composition was done according to Harbone (1976), the acute toxicity evaluation according to WHO protocol and the hepatic as well as serum parameters measured to assess liver and kidney functions.</p> <p>Results</p> <p>The chemical components of each plant's extract varied according to the solvent used, and they were found to contain alkaloids, flavonoids, polyphenols, triterpens, sterols, tannins, coumarins, glycosides, cardiac glycosides and reducing sugars. The methanolic and ethylacetate extracts of <it>Phyllanthus muellerianus </it>and <it>Piptadeniastum africana </it>presented the highest antimicrobial activities against all tested microorganisms with ID varying from 8 to 26 mm and MIC from 2.5 to 0.31 mg/ml. The <it>in vivo </it>acute toxicity study carried out on the methanolic extracts of <it>Phyllanthus muellerianus </it>and <it>Piptadeniastrum africana </it>indicated that these two plants were not toxic. At the dose of 4 g/kg body weight, kidney and liver function tests indicated that these two medicinal plants induced no adverse effect on these organs.</p> <p>Conclusion</p> <p>These results showed that, all these plant's extracts can be used as antimicrobial phytomedicines which can be therapeutically used against infections caused by multiresistant agents.</p> <p>Phyllanthus muellerianus, Piptadeniastum africana, antimicrobial, acute toxicity, kidney and liver function tests, Cameroon Traditional Medicine</p

Paradigma da ciência, do saber e do conhecimento e a educação para a complexidade: pressupostos e possibilidades para a formação docente Paradigm of science, of wisdom and knowledge and education to the complexity: assumptions and possibilities for teacher training

Centrando leituras sobre as bases teóricas do paradigma científico dominante, em seus fundamentos racionalistas-cientificistas, determinantes na ciência, no saber e nos conhecimentos trabalhados na escola, apresentamos a proposição de uma educação voltada para a complexidade. Tal proposição surge do chamado paradigma emergente, o qual visa superar as inércias e a reatividade tradicionais nos procedimentos de escolarização e de formação docente e caminhar em situações pró-ativas e em prótopias mobilizadoras para a implementação de ações curriculares e educativas que possibilitem uma formação mais aberta, flexível e inter-transcultural, que culmine com uma educação mais humana e convivencial.<br>Focusing readings on the theoretical foundations of the dominant scientific paradigm, in their rationalist-cientificist pleas, determinants in science, in knowing and in the knowledge learned at school, we present the proposition of an education geared towards complexity. This proposition is the so-called emerging paradigm, which aims at overcoming the inertia and reactivity in the traditional procedures for education and teacher training and walk into proactive situations and mobilizing protopias for the implementation of curriculum and educational training actions to promote a more open, flexible and inter-cross learning, which will result in a more human and convivial education