Síntese de chalconas e avaliação como agentes inibidores e/ou promotores do desenvolvimento vegetal

Abstract

The work proposes the synthesis of a collection of chalcones and the study of their effects on weed control and the improvement of forest species. The herbicidal activity of the synthesized compounds was evaluated in three different experiments: in vitro, on weeds and in molecular docking. Eleven chalcones (25a-k) were synthesized and characterized. The results of the in vitro chlorophyll a fluorescence reading showed that, compared to the control, the fluorinated chalcones 25g and 25k showed the most significant results in altering photosynthetic parameters. Molecular modeling showed that the chalcones interact with the structure of the D1 protein, in which the carbonyl group and fluorine form hydrogen bonds with residues Phe265 and His215, respectively. In tests with weeds, chalcone 25k reduced the germination and growth of species of the Amaranthus genus. Compounds 25i and 25k had a greater influence as pre-emergent agents on Leucaena seeds and chalcones 25b and 25i, at a concentration of 50 µM, interfered with the functioning of the photosynthetic apparatus of Leucaena seedlings. The experiments and data analysis of the dose response relationship of chalcones 25a, 25f, 25g and AIB in the species Schizolobium parahyba var. amazonicum showed that 25f has a hormetic effect, and the best concentration for seedling development is 5 µM. In addition, 25f (5 µM) associated with AIB (10 µM) promotes the induction of roots in in vitro multiplication.