Chemical Screening of <i>Urochloa humidicola</i>: Methods for Characterizing Secondary Metabolites and Allelopathic Activity on Forage Legumes

Abstract

The aim of this study was to identify the main classes of secondary metabolites present in the root and shoot crude extracts and fractions from the forage grass Urochloa humidicola (Rendle) Morrone & Zuloaga and to evaluate the allelopathic effect of these metabolites on forage legumes for intercropping. Phytochemical prospecting analyses, 1 H NMR and capillary electrophoresis were performed on extracts of U. humidicola. Allelopathic activity was evaluated in germination of Stylosanthes, Macrotyloma axillare and Lactuca sativa L. (standard) in the presence of crude extracts, isolated saponins, flavonoids and trans-cinnamic acid. The metabolite classes present in the extracts could be determined by the combined use of the tested analytical techniques, but their use alone was usually not sufficient to chemically characterize the species. Capillary electrophoresis was effective in detecting phenolic compounds. Macrotyloma axillare was tolerant to crude extracts of U. humidicola.Saponins and trans-cinnamic acid, but not the flavonoids, reduced germination of the target plants.

Phytotoxic Potential and Phenolic Profile of Extracts from Scrophularia striata

“…Its potential has been investigated in a wide range of biological contexts. Allelopathic effects of hesperidin have been mentioned in previous reports [ 51 , 52 ].…”

Flow Cytometry-Based Determination of Ploidy from Dried Leaf Specimens in Genomically Complex Collections of the Tropical Forage Grass Urochloa s. l.

“…Seasonal and regional differences in accumulation of secondary products may cause differences in staining for flow cytometry. Secondary metabolites and their phytotoxicity on forage legumes have been recognized in Urochloa tropical forage grasses [ 21 , 22 , 23 , 24 ], which has been suggested to make it difficult to analyze these plants by flow cytometry [ 25 ].…”

Allelopathic properties of Calliandra haematocephala Hassk. extracts and fractions as an alternative for weed management in quinoa and rice crops

“…Five fractions were generated, using the remaining extract amount, divided in three parts of equal volume, as explained below. The different fractions were obtained via various methods described in Seidel (2005), Otsuka (2005), Evans and Evans (2019) and Ribeiro et al (2018).…”

“…Furthermore, the aqueous fractionation to get F3 was extracted from 1 3 of the crude flower extract (F0), using first petroleum ether and adding a 50:50 methanol/water mixture. These processes allowed separating the residual liquid and to ease the determination of flavonoids, hydrosoluble tannins and reducing sugars in a more efficient (Sherma 2000;Seidel 2005;Otsuka 2005;Ivanova-Petropulos et al 2010;Evans and Evans 2019;Ribeiro et al 2018). See also Figure A9 † Sesquiterpenes were identified after TLC in both extract methods ‡ All results for F4 were negative way.…”