%0 Journal Article
%T Antimicrobial Activity of Cladonia verticillaris Lichen Preparations on Bacteria and Fungi of Medical Importance
%A Dalila de Brito Marques Ramos
%A Francis Soares Gomes
%A Thiago Henrique Napole£¿o
%A Patr¨ªcia Maria Guedes Paiva
%A Michele Dalvina Correia da Silva
%A Luana Cassandra Breitenbach Barroso Coelho
%J Chinese Journal of Biology
%D 2014
%R 10.1155/2014/219392
%X Cladonia verticillaris lichen lectin (ClaveLL) was purified using a previously established protocol and then evaluated for its potential antimicrobial activity. Initially, the autochthonous lichen was submitted to extraction with sodium phosphate buffer pH 7.0, followed by filtration and centrifugation to obtain crude extract. A salt fractionation was performed with 30% ammonium sulfate. After centrifugation, the protein fraction was loaded onto molecular exclusion chromatography using Sephadex G-100 matrix to purify active lectin. ClaveLL showed antibacterial activity against Gram-positive (Bacillus subtilis, Staphylococcus aureus, and Enterococcus faecalis) and Gram-negative (Escherichia coli and Klebsiella pneumoniae) assayed strains, with greater inhibitory effect on growth of E. coli (MIC of 7.18£¿¦Ìg£¿mL£¿1). The lowest minimum bactericidal concentration (MBC, 57.4£¿¦Ìg£¿mL£¿1) was detected against E. faecalis. The antifungal assay performed with Trichophyton mentagrophytes, Microsporum gypseum, Trichophyton rubrum, Trichosporon cutaneum, and Trichosporon asahi evaluated crude extract, fraction, and ClaveLL preparations. ClaveLL was the most active against T. rubrum with an inhibition percentage of 35% compared to negative control (phosphate buffer). Extract and fraction showed better activity on growth inhibition of T. mentagrophytes (35%). The results indicate the potential of ClaveLL and other C. verticillaris preparations as antimicrobial agents useful for applications focusing on human health. 1. Introduction The treatment of diseases caused by bacteria and fungi is becoming an issue of concern, due to the growing emergence of microorganism strains resistant to drugs and opportunistic fungi that cause serious infections in humans [1, 2]. Microbial resistance is a genetic phenomenon, in which the microorganisms have genes that encode biochemical mechanisms which prevent drug actions. It may be caused by mutations in the reproductive process of the microorganisms or by imported genes acquired through transduction, conjugation, and transformation mechanisms [3]. Microbial resistance is sometimes due to natural evolution of microorganisms; however, it gains importance through the excessive use of antimicrobial substances in medical, agricultural, and veterinary practices [4]. Therefore, the search for new antibiotics from natural sources has increased as an alternative to commercial drugs. Lichens are symbiotic associations between fungus and one or more algae and/or cyanobacteria [5]. Species of the genus Cladonia have been used in folk medicine to
%U http://www.hindawi.com/journals/cjb/2014/219392/