Triterpenoides, fenólicos e efeito fitotóxico das folhas de Eugenia flavescens DC (Myrtaceae)

This research deals with the chemical study and evaluation of the phytotoxic effects of the methanol extract of E. flavescens leaves. The compounds were isolated using classic chromatographic techniques and the identification of the phenolic profile was proposed from the HPLC/DAD/MS-MS data. Structure elucidation of the compounds was performed by H-1 and C-13 (1D e 2D) NMR techniques and HRMS. The chemical study led to the isolation of betulinic acid (1) and lupeol (2), identified in mixture quercitrin (3) and catechin (4) beyond myricetrin (5) in mixture with (3). In addition, several phenolic compounds were identified, among them, flavonoids and phenolic acids. For bioassays phytotoxic effect were used as test plants two invasive species, M. pudica and S. obtusifolia. The methanol extract showed significant seed germination inhibition. The triterpenoid 1 showed low inhibition effects on seed germination and moderate effects on radicle and hypocotyl growth. The mixture of flavonoids 3/4 showed effective phytotoxic effects, inhibiting 92.1% of the seed germination of M. pudica and 63.0% of S. obtusifolia. Inhibitions of 72.5% and 76.1% of M. pudica radicle and hypocotyl growths were observed, respectively, and 74.5% and 78.0% of S. obtusifolia for the same bioassays, respectively.