Allelopathic Potential of Rapanea umbellata Leaf Extracts

Abstract

The stressful conditions associated with the Brazilian savanna (Cerrado) environment were supposed to favor higher levels of allelochemicals in Rapanea umbellata from this ecosystem. The allelopathic potential of R. umbellata leaf extracts was studied using the etiolated wheat coleoptile and standard phytotoxicity bioassays. The most active extract was selected to perform a bioassay-guided isolation, which allowed identifying lutein (1) and (-)-catechin (2) as potential allelochemicals. Finally, the general bioactivity of the two compounds was studied, which indicated that the presence of 1 might be part of the defense mechanisms of this plant.

Herbicidal activity of kidney leaf mud plantain leaves extracts on the germination of four species

“…In this research, the root length of lettuce Grand Rapids cultivar was affected by all concentrations tested, unlike the Grandes Lagos cultivar, which was affected only by the highest concentration, highlighting the importance of using different concentrations of extracts, cultivars and species. In a study conducted by Novaes et al (2013), the variables of lettuce aerial part and root length were more affected by the ethyl acetate extract of Rapanea umbelata leaves than the germination variable, regardless of the concentration used. In another research, lettuce did not prove as sensitive to the application of the extracts of wolf apple's leaves (Solanum lycocarpum) as the tomato and cress species, but the root was the most affected organ (Oliveira et al, 2012).…”

Phytotoxic study of glycosylated flavonols from Annona coriacea (Annonaceae) on cultivated species and an invasive grass.

“…The following 4 mm of the coleoptiles were cut and selected for bioassays. The groups and the isolated compounds were diluted in phosphatecitrate buffer solution containing 2% sucrose and 0.5% DMSO (Nitsch and Nitsch 1956), at pH 5.6, to the nal bioassay concentrations of 0.8, 0.4 and 0.2 mg mL − 1 for the groups and 1 mM, 0.3 mM, 0.1 mM and 0.03 mM for isolated compounds, usual in this bioassay (Novaes et al 2013b;Rial et al 2014). Five coleoptiles and 2 mL of each sample dilution were placed into a test tube (three tubes per dilution).…”

PHYTOTOXIC CONSTITUENTS FROM ENDOPHYTIC FUNGUS Xylaria cubensis ASSOCIATED WITH Eugenia brasiliensis

“…Data were evaluated by the percentage of inhibition or stimulation compared to the negative control, where 0 % denotes the control length, while positive values imply growth stimulation and negative values imply inhibition. 19 Statistical analyses: All the results were tested for normality and homogeneity using the Shapiro-Wilk and Levene tests, respectively. Normal homogeneous data were analyzed by ANOVA, followed by Tukey test (p < 0.05) using PAST version 2.5.…”