Estudo fitoquímico das folhas de capim annoni-2 (Eragrostis plana Nees) coletadas no inverno e verão

Abstract

The Annoni-2 grass (Eragrostis plana Nees) is a poaceae that presents allelophatic potential as observed in other research. In this study, the extracts were obtained from leaves collected during summer and winter. The extraction process was performed using solvents in a increasing order of polarity (petroleum ether, etyl acetate and methanol) and the extracts were analyzed and compared regarding the composition and/or concentration of metabolites produced. The techniques utilized were high performance liquid chromatography and infrared spectroscopy, and, the data obtained from the infrared analisys was compared using PCA, then the fractionation of summer and winter ethyl acetate extracts was carried out and the isolated compounds were identified by spectrometric and spectroscopic methods: NMR 1H and 13C, experiments of HSQC and HMBC and GC-MS. The results show the extracts are rich when it comes to probable variety of chemical compounds. It is also observed that, statistically, the solvents used in the extraction process influence the diversity of chemical compounds more than the season in which the leaves were collected. Triacylglycerol and rotenoid were identified from the fractionation summer ethyl acetate extract, and the presence of a rotenoid in the leaves of Annoni-2 grass, can justify the allelopathic action observed in this species in other works.