MADUREIRA, Ana Margarida; DUARTE, Aida; CORREIA, Ana Isabel    TEIXEIRA, Generosa. Sanguisorba hybrida: pharmacognostic studies and antimicrobial activity evaluation of crude extracts. []. , 37, 4, pp.482-490. ISSN 0871-018X.

^len^aThe genus Sanguisorba L. (Rosaceae) includes perennials that are distributed throughout the northern hemisphere. Some species of this genus are known by their medicinal interest. In the present work the pharmacognostic characterization and the potential antimicrobial activity of several extracts of Sanguisorba hybrida, endemic in Portugal, were evaluated. The leaves of the plant have been observed under microscopy techniques, tector and secretor multicellular trichomes were seen on both leaf surfaces. With histochemical tests the in situ localization of compounds was recognized and the most relevant were mucilages, phenols and terpenoids. Powdered plant material was extracted with n-hexane, dichloromethane, ethyl acetate, methanol and water. Their phytochemical survey, through TLC on silica gel plates and the proper reagents, was performed and the previous results with histochemical tests were confirmed. All extracts were tested against reference and multiresistant bacterial strains: Gram-positive (Enteroccocus faecalis, Staphylococcus aureus, Staphylococcus epidermidis and Mycobacterium smegmatis); Gram-negative (Pseudomonas aeruginosa, Salmonella typhimurium, and Klebsiella pneumoniae) and the yeast Candida albicans. The minimum inhibitory concentrations (MIC) were determined by the serial broth micro dilution method. Appropriated antibiotics were used as controls. The methanol and water extracts showed better antimicrobial activity than n-hexane, dichloromethane, ethyl acetate extracts. Gram-positive bacteria were the most sensitive and the MIC values of 3.50-1.75 µg/mL were obtained using those polar extracts against Staphylococcus aureus, including strains resistant to meticillin (MRSA).^lpt^aO género Sanguisorba L. (Rosaceae) engloba plantas perenes distribuídas por todo o hemisfério norte, sendo algumas espécies conhecidas como medicinais. Neste trabalho realizou-se o estudo farmacognóstico e avaliou-se a atividade antimicrobiológica de vários extratos de uma espécie deste género, endémica de Portugal, Sanguisorba hybrida. Recorrendo a diferentes técnicas de microscopia observou-se, nas duas epidermes foliares, tricomas multicelulares de dois tipos, tectores e secretores. Com diferentes testes histoquímicos procedeu-se à localização in situ dos principais grupos de compostos. Os mais representativos foram mucilagens, fenóis e terpenóides. No estudo fitoquímico o material vegetal pulverizado foi extraído sequencialmente com solventes de polaridades crescentes: n-hexano (n-hex), diclorometano (CH2Cl2), acetato de etilo (AcOEt), metanol (MeOH) e água (H2O). Foi determinado o respetivo perfil fitoquímico através de cromatografia em placas de sílica. Todos os extratos foram posteriormente testados contra estirpes de bactérias sensíveis e multirresistentes Gram-positivas (Enteroccocus faecalis, Staphylococcus aureus, Staphylococcus epidermidis and Mycobacterium smegmatis), Gram-negativas (Pseudomonas aeruginosa, Salmonella typhimurium e Klebsiella pneumoniae) euma levedura, a Candida albicans. A concentração mínima inibitória (MCI) foi determinada pelo método de diluição em meio líquido. Foram usados antibióticos e antifúngicos como controlos. Os extratos polares, metanólico e aquoso, apresentaram atividade antimicrobiana superior à dos restantes extratos, menos polares. As bactérias Gram-positivas, Staphylococcus aureus, incluindo as estirpes resistentes à meticilina (MRSA) ensaiadas, foram as mais sensíveis aos referidos extratos (MCI 3,50-1,75 µg/mL).

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