Essential oil content of pepper-rosmarin as a function of harvest time/Teor de oleo essencial de alecrim-pimenta em funcao do horario de colheita

The pepper-rosmarin is an important medicinal plant, native of Northeast of Brazil, that, because of its essential oil, presents great antifungal and antibacterial potential. One of the factors that affect the secondary metabolites content of plants is the harvest time, thus, the knowledge of this factor subsidizes the decisions agronomic species, favoring the increase of essential oil content at the harvest moment. Thus, the aim of this research was to evaluate the effect of harvest time on the essential oil production of pepper-rosmarin (Lippia sidoides Cham.). The experiment was carried out in the Instituto of Ciencias Agrarias of Universidade Federal of Minas Gerais (ICA/UFMG), Montes Claros, Minas Gerais, Brazil. It was installed in a randomized block design, with five treatments consisted by harvest times (6:00, 9:00, 12:00, 15:00 and 18:00) with six replications (number of collections in each treatment). The leaves were obtained from stock plants of medicinal vegetable garden of ICA/UFMG. The essential oil was obtained by hydrodistillation in a Clevenger apparatus. The regression analysis presented a cubic effect to the essential oil content, being that the highest value, 5,78% in relation to dry matter, was obtained at 9h59min. Therefore, it was recommended the harvest time of pepper-rosmarin leaves next to 10h. Key words: Lippia sidoides Cham., medicinal plants, thymol, carvacrol, monoterpenes. O alecrim-pimenta e uma importante planta medicinal, nativa do nordeste brasileiro, que, devido ao seu oleo essencial, apresenta grande potencial antifungico e antibacteriano. Um dos fatores que afetam o teor de metabolitos secundarios das plantas e o horario de colheita, assim, o conhecimento desse fator subsidia as decisoes agronomicas da especie, favorecendo o aumento do teor de oleo essencial no momento da colheita. Dessa forma, o objetivo do presente trabalho foi avaliar o efeito do horario de colheita na producao de oleo essencial de alecrim-pimenta (Lippia sidoides Cham.). O experimento foi desenvolvido no Instituto de Ciencias Agrarias da Universidade Federal de Minas Gerais (ICA/UFMG), Montes Claros, Minas Gerais, Brasil. Utilizou-se o delineamento experimental em blocos casualizados com cinco tratamentos, definidos pelos horarios de coleta das folhas (6:00, 9:00, 12:00, 15:00 e 18:00) e seis repeticoes, sendo esse o numero de coletas em cada tratamento. As folhas foram obtidas de plantas matrizes do Horto Medicinal do ICA/UFMG. O oleo essencial fo