Polyphenols represent a group of chemical substances common in plants, structurally characterized by the presence of one or more phenol units. Polyphenols are the most abundant antioxidants in human diets and the largest and best studied class of polyphenols is flavonoids, which include several thousand compounds. Numerous studies confirm that they exert a protective action on human health and are key components of a healthy and balanced diet. Epidemiological studies correlate flavonoid intake with a reduced incidence of chronic diseases, such as cardiovascular disease, diabetes and cancer. The involvement of reactive oxygen species (ROS) in the etiology of these degenerative conditions has suggested that phytochemicals showing antioxidant activity may contribute to the prevention of these pathologies. The present review deals with phenolic compounds in plants and reports on recent studies. Moreover, the present work includes information on the relationships between the consumption of these compounds, via feeding, and risk of disease occurrence, i.e. the effect on human health. Results obtained on herbs, essential oils, from plants grown in tropical, subtropical and temperate regions, were also reported

Currently, tissue cultures of species of agricultural importance have wide applicability in industrial production processes. Tissue culture is a name given to a set of techniques that allow the regeneration of cells, tissues and organs of plants, from segments of plant organs or tissues, using nutrient solutions in aseptic and controlled environment. This regeneration is based on the totipotency of plant cells. Totipotency is a capability indicating that plant cells, in different times, may express the potential to form a new multicellular individual. Tissue culture appears to be a good alternative to conventional propagation, requiring less physical space, with high multiplication rate, without incidence of pests and diseases during cultivation, and enabling higher control of the variables involved. Thus, in the in vitro environment, with the required stimuli and appropriate conditions, different cell types express different behaviors, possibly leading to cell multiplication and differentiation into a specific tissue, characterized by a form and a function, which may lead to the regeneration of a new individual

ResumoObjetivou-se avaliar o tipo de rizoma e o seccionamento do rizoma principal de taioba na produção de mudas. O experimento foi conduzido em Cáceres MT, no período de outubro de 2006 a março de 2007. Foi utilizado o delineamento em blocos casualizados, com sete tratamentos (tipo de rizoma-semente) e quatro repetições: brotação secundária pequena (BSP), brotação secundária média (BSM), rizoma principal seccionado em duas partes (RPA1/2), rizoma principal apical seccionado em quatro partes (RPA1/4) e oito partes (RPA1/8); e rizoma principal basal seccionado em quatro partes (RPB1/4) e oito partes (RPB1/8). Os propágulos foram plantados em leitos com areia sob telado com sombreamento de 50%, sendo as mudas posteriormente transplantadas a campo para mensurar o desenvolvimento vegetativo. Os melhores resultados, quanto à emissão de brotações, massas fresca e seca das folhas e raízes, e o comprimento do pecíolo, foram observados nos propágulos RPA1/2, RPA1/4 e RPA1/8. Os tecidos da porção apical favoreceram o desenvolvimento de estruturas adventícias nos propágulos, promovendo o incremento em área foliar e comprimento de pecíolo no desenvolvimento posterior da muda. Observou-se viabilidade da utilização do método de seccionamento de rizomas principais para a produção de taioba. A produção de mudas de taioba pode ser feita pelo método de seccionamento de rizoma principal, em duas, quatro, ou em até oito partes, com a utilização da porção apical do rizoma.Palavras-chave adicionais: clone; horticultura tropical; porção apical; propagação; Xanthosoma sagittifolium (L.) Schott. AbstractThe objective of this study was to evaluate the type of rhizome and the ways of the sectioning of the main rhizome on the production of seedlings. The experiment was carried out in Cáceres, state of Mato Grosso, Brazil, from October of 2006 to March of 2007. The experiment was set according to a randomized complete block design with seven treatments (only rhizome types ) and four repetitions : small secondary sprouting (BSP), medium secondary sprouting (BSM), main rhizome divided in two parts (RP1/2), apical main rhizome divided in four (RPA1/4) and eight parts (RPA1/8), and basal main rhizome divided in four (RPB1/4) and eight (RPB1/8) parts. The propagules were sown in a partially shaded (50%) sandy substratum and the resulting plantlets were later transplanted to the field so as to measure their vegetative growth. The best results as to sprouting, fresh and dry leaf and root weight, and petiole length were observed for treatments RPA1/2, RPA1/4, and RPA1/8. The apical portion tissues favored the development of adventitial structures in the propagules thus stimulating the increment of leaf area and petiole length. The sectioning of the main rhizome in two, four, or even eight parts was thus verified to be an economically viable technique for the production of tannia seedlings.

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O presente estudo teve como objetivo determinar os teores de clorofilas a e b, carotenoides totais, fenólicos totais, poder redutor e a inibição dos radicais ABTS e DPPH em frutos de jurubeba in natura e em conserva. O estudo foi dividido em duas etapas. Na primeira, frutos frescos foram avaliados segundo o estádio de maturação e o local de coleta. Na segunda etapa, conservas de jurubeba adquiridas no comércio local de Cáceres-MT foram avaliadas. O local de coleta não influenciou o conteúdo dos compostos bioativos avaliados, com exceção dos carotenoides totais. Da mesma forma, a atividade antioxidante foi pouco influenciada pelos locais de coleta. A maturação da jurubeba não teve influência sobre os antioxidantes avaliados. Entretanto, os frutos maduros apresentaram maior inibição do radical DPPH e maior poder redutor que os frutos imaturos. A conserva de jurubeba possui alto teor de compostos antioxidantes, comparável a alimentos de reconhecido potencial. Os resultados do presente estudo corroboram com as informações disponíveis na literatura, confirmando o potencial deste alimento como nutracêutico.