Medicinal plants with antimicrobial action have been investigated for uses against biofilms, among which, Cymbopogon nardus, citronella, stands out as a promising species. The present study aims to evaluate the antimicrobial and antibiofilm action of the essential oil of C. nardus (EOCN) and geraniol on Gram-negative and positive bacteria from the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration and inhibition of biofilms. In the results, the EOCN produced a 41 mm halo on S. aureus, which was susceptible with MIC values of 0.5 and 0.25 mg/mL for the EOCN and geraniol respectively, both with bactericidal effect. The antibiofilm action was confirmed, the EOCN and geraniol reduced the biofilm biomass of S. aureus up to 100% between 0.5 and 4 mg/mL concentrations. The reduction of cell viability was 0.25 and 1 mg/mL, of EOCN and geraniol, respectively. EOCN and geraniol were shown to be promising antibiotic against S. aureus.

The main objective of this study was to conduct a review of bioactive substances derived from plants which show antimicrobial/antibiofilm properties. Vegetable species were widely employed as ingredients in medicine based on traditional knowledge. Various secondary metabolites have been proven to inhibit bacterial growth. Bacterial resistance mechanisms have increased over the years. Biofilms are types of bacterial association which gives the communities a higher resistance to drugs. The formation process of biofilms, the problems caused by them and the natural substances, as well as their main chemical components and action mechanisms, have been described according to existing literature.

Resumo É apresentado o levantamento florístico da família Turneraceae no estado do Ceará, Brasil. Foram reconhecidos dois gêneros e 22 espécies: Piriqueta com sete espécies e Turnera com 15, das quais Turnera reginae é uma nova ocorrência. De modo geral, as espécies apresentam ampla distribuição, sendo frequentemente encontradas na vegetação da caatinga, carrasco, cerrado, floresta ombrófila e tabuleiros litorâneos, associando-se principalmente a áreas abertas e antropizadas. São apresentadas fotografias, chaves, descrições, comentários gerais e mapas de distribuição das espécies no Ceará.