Produção in vivo e in vitro de alcalóides esteroidais e compostos fenólicos em espécies nativas do gênero Solanum, com ênfase em Solanum pseudocapsicum L.

Abstract

The objectives of this work were to evaluate the content of esteroid alkaloids and phenolic compounds in native and exotic plants of the genus Solanum, as well as the in vitro culture and transformation of S. pseudocapsicum and their influence on the production of alkaloids and phenolics. The results showed high variability in esteroid alkaloids and phenolics among Solanum species currently found in south Brazil. The highest alkaloid content was determined in the aereal parts, particularly young leaves, of S. pseudocapsicum, with solanocapsine identified as the main alkaloid. High in vitro multiplication rates of S. pseudocapsicum were obtained on MS medium supplemented with 4.4 μM benzyladenine, and abundant rooting was observed on MS medium with 2.46 μM indolebutyric acid or 5.71 μM indoleacetic acid. Plant biomass and esteroid alkaloid content was stimulated by benzyladenine concentration up to 4.4 μM, attaining alkaloid concentrations significantly highers than those evidenced in young leaves of in vivo plants. S. pseudocapsicum genetic transformation with A. rhizogenes was efficient, with spontaneous regeneration of tranformed plants that exhibited typical phenotypic traits. The mean alkaloid content of transformed and non-transformed plants was similar. However, one transformant exhibited a 56% increase in alkaloid content, indicating that the selection of transformants can contribute to enhance the production of these compounds. The analysis of the extracts allowed identifying modifications on the substitution patherns on the esteroidal ring in transformed plantas, indicating that metabolic modification produced by transformation affect the cyclization process. [resumo fornecido pelo autor]