The secretions of the mandibular and metapleural glands of leaf cutting ants contain antimicrobial substances that protect the mutualistic fungal colony within the nest from attack by parasitic micro-organisms. The major constituents of these secretions (citral, 4-methyl-3-heptanol, 2-heptanone, 3-octanone, 4-methyl-2-heptanone, beta-citronellol, geraniol, phenylacetic, indolacetic, hexanoic and octanoic acids were tested against resistant strains of the human pathogens, Escherichia coli, Staphylococcus aureus and Candida albicans. Assays were carried out using filter paper discs impregnated with either hexane or water solutions of the analytes in the concentration range 250-6,000 ng/microl. Although most of the tested compounds presented strong antibacterial and antifungal activities, citral, geraniol, 4-methyl-3-heptanol, hexanoic and octanoic acids were the most effective, particularly against C. albicans. The results suggest that these compounds may be of potential value as antibiotics in the treatment of human candidiasis.

Gênero Candida é encontrado vivendo de forma simbionte na microbiota da mucosa reprodutiva e gastrointestinal de 50-70% dos indivíduos saudáveis, em determinadas condições esses micro-organismos podem se tornar patogênicos, a ponto de se tornar a terceira causa das septicemias ao redor do mundo. Podem causar infecções superficiais, atingindo mucosas e pele, bem como infecções invasivas, em órgãos e tecidos profundos como intestino, pulmão e sangue. A espécie mais isolada em infecções causadas pelo gênero é a Candida albicans, porém é cada vez mais recorrente o isolamento de espécies de Candida não-albicans, como: C. glabrata, C. krusei, C. tropicalis e C. parapsilosis. Além disso, C. albicans e espécies de C. não-albicans vêm sendo cada vez mais relatadas pelo aparecimento de resistência aos antifúngicos de uso clínico, dificultando o tratamento de infecções causadas por estas cepas. Este trabalho teve como objetivo reunir informações atualizadas sobre o gênero Candida sobre fatores de virulência, epidemiologia, candidíase, tratamentos e mecanismos de resistência.

The present study consisted in optimizing the extractive method of polyphenols and total tannins of leaves of Syzygium cumini (L) Skeels assisted by microwaves to potentiate the antimicrobial activity of the dried extract of S. cumini against sensitive and resistant strains. A Box-Behnken design that consisted of 27 experimental runs coupled with a desirability function for multiple response optimization was employed to optimize the total polyphenols content and total tannins content. Antimicrobial sensitivity tests were evaluated by obtaining the minimum inhibitory concentration, minimum fungicidal concentration and minimum bactericidal concentration in 96-well petri dishes. The optimal extraction conditions were found to be 8 min of extraction, under 300 w of microwave power, using a 1:34 g/mL solid/solvent ratio and 38% of ethanol concentration as extraction solvent. The parameter with the greatest infl uence in the extraction was primarily the time, followed by the potency and proportion solid/ solvent. This yielded a total polyphenol content of 87.37 ± 1.85 mg TAE g -1 ext and a total tannin content of 79.68 ± 1.64 mg TAE g -1 ext. All tested microorganisms were sensitive to the extract, evidencing the effectiveness of the extraction method optimization.

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