Análise da cadeia produtiva do capim limão: estudo de caso / Proposals and recommendations for qualification of the production chain of lemon grass (Cymbopogon citratus ) (DC. ) Stapf (Poaceae)

RESUMO: Apresentam-se 26 propostas e recomendações aos agentes econômicos da cadeia produtiva do capim-limão, considerando resultados de diferentes estudos sobre o cultivo e a comercialização desta espécie no Estado do Paraná, Brasil. As propostas e recomendações estão categorizadas de acordo aos distintos problemas identificados, com ênfase no cultivo e processamento, posto que estas atividades foram evidenciadas como as mais problemáticas e limitadoras da oferta de produto adequado ao comércio e ao consumo. Objetivou-se contribuir para a melhor qualificação desta cadeia produtiva gerando benefícios, tanto aos distintos atores nela envolvidos, como também promovendo as bases para garantir a segurança alimentar do consumidor.

Twenty-six proposals and recommendations for the economic agents of the production chain of lemon grass are presented, considering the results of different studies related to the cultivation and commercialization of this specbies in the Paraná State, Brazil. These proposals and recommendations were categorized according to the different problems identified, with an emphasis on the cultivation and processing, since these were evidenced as the most problematic and limiting factors in relation to the offer of an adequate product for both trade and consumption. We aim to contribute to the improvement of the production chain of lemon grass, generating benefits to the different players involved in this chain as well as promoting bases to ensure food safety to consumers.

Autopolyploidy differentially influences body size in plants, but facilitates enhanced accumulation of secondary metabolites, causing increased cytosine methylation.

Whole genome duplication leads to autopolyploidy and brings about an increase in cell size, concentration of secondary metabolites and enhanced cytosine methylation. The increased cell size offers a positive advantage to polyploids for cell-surface-related activities, but there is a differential response to change in body size across species and taxonomic groups. Although polyploidy has been very extensively studied, having genetic, ecological and evolutionary implications, there is no report that underscores the significance of native secondary metabolites vis-à-vis body size with ploidy change. To address this problem we targeted unique diploid-autotetraploid paired sets of eight diverse clones of six species of Cymbopogon- a species complex of aromatic grasses that accumulate qualitatively different monoterpene essential oils (secondary metabolite) in their vegetative biomass. Based on the qualitative composition of essential oils and the plant body size relationship between the diploid versus autotetraploid paired sets, we show that polyploidy brings about enhanced accumulation of secondary metabolites in all cases, but exerts differential effects on body size in various species. It is observed that the accumulation of alcohol-type metabolites (e.g. geraniol) does not inhibit increase in body size with ploidy change from 2× to 4× (r = 0.854, P < 0.01), but aldehyde-type metabolites (e.g. citral) appear to drastically impede body development (r = -0.895). Such a differential response may be correlated to the metabolic steps involved in the synthesis of essential oil components. When changed to tetraploidy, the progenitor diploids requiring longer metabolic steps in production of their secondary metabolites are stressed, and those having shorter metabolite routes better utilize their resources for growth and vigour. In situ immunodetection of 5-methylcytosine sites reveals enhanced DNA methylation in autopolyploids. It is underpinned that the qualitative composition of secondary metabolites found in the vegetative biomass of the progenitor diploid has a decisive bearing on the body size of the derived autotetraploids and brings about an enhancement in genome-wide cytosine methylation.

Activity of essential oils from Brazilian medicinal plants on Escherichia coli.

Essential oils obtained from leaves of 29 medicinal plants commonly used in Brazil were screened against 13 different Escherichia coli serotypes. The oils were obtained by water-distillation using a Clevenger-type system and their minimal inhibitory concentration (MIC) were determined by microdilution method. Essential oil from Cymbopogon martinii exhibited a broad inhibition spectrum, presenting strong activity (MIC between 100 and 500 microg/mL) against 10 out of 13 Escherichia coli serotypes: three enterotoxigenic, two enteropathogenic, three enteroinvasive and two shiga-toxin producers. C. winterianus inhibited strongly two enterotoxigenic, one enteropathogenic, one enteroinvasive and one shiga-toxin producer serotypes. Aloysia triphylla also shows good potential to kill Escherichia coli with moderate to strong inhibition. Other essential oils showed antimicrobial properties, however with a more restricted action against the serotypes studied. Chemical analysis of Cymbopogon martinii essential oil performed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS) showed the presence of compounds with known antimicrobial activity, including geraniol, geranyl acetate and trans-cariophyllene, which tested separately, indicated geraniol as antimicrobial active compound. The significant antibacterial activity of Cymbopogon martinii oil suggests that they could serve as a source for compounds with therapeutic potential.