Antonio Marcos Saraiva

Antimicrobial activity and phytochemical profile from the roots of Lippia alba (Mill.) N.E. Brown

Lippia alba (Mill.) N.E. Brown (Verbenaceae) e geralmente usada na medicina popular brasileira para o tratamento de doencas gastricas, febre, asma e como tranquilizante. Este trabalho avaliou a atividade antimicrobiana dos extratos acetato de etila, metanol e aquoso das raizes de L. alba usando metodos de difusao em pocos e o perfil fitoquimico. Os resultados obtidos mostraram que os extratos acetato de etila e metanol apresentaram atividade antimicrobiana contra Staphylococcus aureus (ATCC 6538P), Staphylococcus aureus (ATCC 6538) e Klebsiella pneumonia (ATCC 10031). Terpenoides, fenilpropanoides e acucares foram detectados na analise fitoquimica.

Determinação de atividade antimicrobiana de extratos de plantas de uso popular como antiflamatório

Antimicrobial activities of “babacu” (Orbignya martiana), “cardo santo” (Argemone mexicana), “mentrasto” (Ageratum conyzoides), “cavalinha” (Equisetum yeamalis) and “terramicina” (Alternanthera brasiliana), used by Brazilian population as antiinflamatory medicine, were studied on Staphylococcus aureus. The freezer dried hydroalcoholic extracts solutions were tested for 7 strains of Staphylococcus aureus, which two of those are methicillin resistant (MRSA). The diffusion method on agar-agar, using holes technique, with tetracycline chlorydrate as standard. “Babacu”, “cardo santo” and “terramicina” showed antimicrobial activity, within of those “terramicina” inhibited 6 strains, presenting zone inhibition of 22 mm compared to standard antibiotic (34 mm), except the seventh strain which was also tetracycline resistant.

Which Approach Is More Effective in the Selection of Plants with Antimicrobial Activity

The development of the present study was based on selections using random, direct ethnopharmacological, and indirect ethnopharmacological approaches, aiming to evaluate which method is the best for bioprospecting new antimicrobial plant drugs. A crude extract of 53 species of herbaceous plants collected in the semiarid region of Northeast Brazil was tested against 11 microorganisms. Well-agar diffusion and minimum inhibitory concentration (MIC) techniques were used. Ten extracts from direct, six from random, and three from indirect ethnopharmacological selections exhibited activities that ranged from weak to very active against the organisms tested. The strain most susceptible to the evaluated extracts was Staphylococcus aureus. The MIC analysis revealed the best result for the direct ethnopharmacological approach, considering that some species yielded extracts classified as active or moderately active (MICs between 250 and 1000 µg/mL). Furthermore, one species from this approach inhibited the growth of the three Candida strains. Thus, it was concluded that the direct ethnopharmacological approach is the most effective when selecting species for bioprospecting new plant drugs with antimicrobial activities.

Antimicrobial activity and bioautographic study of antistaphylococcal components from Caesalpinia pyramidalis Tull.

A determinacao da atividade antimicrobiana dos extratos metanolicos e em acetato de etila da folha, casca do caule, casca da raiz, flor, fruto e semente de Caesalpinia pyramidalis Tull. foi realizada frente a dezessete isolados de Staphylococcus aureus MRSA multirresistentes, dois isolados de S. aureus MSSA e duas cepas padrao, pelas tecnicas de poco/difusao em agar e determinacao das CMI pelo metodo de diluicao em agar/multiinoculador de Stears. O extrato metanolico de casca da raiz indicou uma boa atividade, com CMI inferior a 0.5 mg.mL-1. Os extratos secos por extracao em acetato de etila apresentaram menor atividade que se poderia explicar por problemas de solubilidade e menor difusao no meio de cultura em agar. Resultados das bioautografias confirmaram zonas de inibicao correspondente as substâncias ativas presente na folha, como tambem na flor da C. pyramidalis. No estudo fitoquimico das folhas, casca da caule, casca da raiz, flor e fruto dos extratos de C. pyramidalis evidenciou-se a presenca de varios constituintes com reconhecida atividade antimicrobiana, entre estes o acido ursolico, quercetina, catequina, acido elagico, sitosterol, flavonoides, proantocianidinas e acido galico. Entre todos os metabolitos citados, somente o ultimo nao observamos, por CCD, na casca da raiz de C. pyramidalis.