Growth, development and content of flavonoids in calendula (Calendula officinalis L.)

Flavonoids, the pharmaco-active compounds studied in this work, in general, are located in the shoots as natural pigments that protect the plants from damage by oxidizing agents. The experiment was conducted in the greenhouse of the Fitotecnia Department, Federal University of Vicosa, Minas Gerais Staty. The experimental design was completely randomized with five treatments and five replications. The treatments were the time of harvest: zero, three, six, nine, and twelve days after anthesis (DAA). The height of the plant (mm), stem diameter (mm), number of leaves and total flavonoid content (%, w [w.sup.-1]) were determined. We developed growth curves for calendula with growth behavior assessed through time for height, stem diameter and number of leaves. The time of the harvest season positively influenced the total flavonoid contents and the average productivity of flowers, and the highest content of flavonoids was found three DAA. The average productivity of the flowers and the accumulation of flavonoids were heterogeneous among harvest times (0, 3, 6, 9 and 12 days after anthesis). The highest yield of flavonoids was obtained three days after anthesis; therefore, a harvest of the inflorescences is recommended every three days. Keywords: secondary metabolism, phenolic compounds, harvest season, plant performance. Os compostos farmaco-ativos estudado no trabalho, os flavonoides, de maneira geral, estao localizados na parte aerea das plantas. Sao pigmentos naturais presentes nos vegetais e protegem o organismo do dano por agentes oxidantes. O experimento foi conduzido na casa de vegetacao do Departamento de Fitotecnia da Universidade Federal de Vicosa, MG. O delineamento utilizado foi o inteiramente casualizado, com cinco tratamentos e cinco repeticoes. Os tratamentos foram as epocas de colheita: zero, tres, seis, nove e doze dias apos a antese (DAA). Foram avaliadas a altura da planta (mm), o diametro do caule (mm), o numero de folhas e o teor total de flavonoides (%, p [p.sup.-1]). Foi realizada a curva de crescimento da calendula e seu desempenho quanto a altura, diametro e numero de folhas ao longo do tempo de avaliacao. A epoca de colheita influenciou positivamente no teor total de flavonoides e na produtividade media dos capitulos florais, sendo que aos tres DAA foi encontrado maior teor de flavonoides. A resposta foi heterogenea entre as epocas de colheita (0, 3, 6, 9 e 12 dias apos a antese) quanto a produtividade media das flores e o acumulo de fl