Abstract Vigna unguiculata (L.) Walp (cowpea), Fabaceae family and also known as Leguminosae, is an important vegetable used as food in tropical regions, especially in Africa, South America and Asia countries. Phenolic compounds are associated with important biological properties and their occurrence in edible plants may result in a highly functional food. Chromatographic profiles of phenolic compounds were investigated in two cowpea cultivars, such as tracuateua (CT) and caldeirão (CC), and both were cultivated using High Performance Liquid Chromatography (HPLC) coupled to Mass Spectrometry (MS) (HPLC-DAD/MS/MS). The flavonols quercetin and kaempferol, the phenolic acids, p-coumaric and protocatechuic acid (PCA) were identified in cowpea (CC), while the phenolic acids, gallic and protocatechuic acids, were identified in the cowpea (CT). These phenolic compounds ratify cowpea as a functional and bioactive food, ensuring a healthy diet.
Resumo Vigna unguiculata (L.) Walp (feijão-caupi), pertencente à família Fabaceae, é um dos mais importantes vegetais utilizados como alimento em regiões de clima tropical, especialmente em países da África, América do Sul e Ásia. Compostos fenólicos estão associados a importantes propriedades biológicas, e sua ocorrência em plantas comestíveis pode implicar em um alimento altamente funcional. Foi investigada a presença de compostos fenólicos nos extratos brutos metanólicos de duas cultivares de feijão-caupi, cultivar tracuateua (CT) e cultivar caldeirão (CC), utilizando a técnica HPLC-DAD/MS/MS. Os flavonóis quercetina e canferol, e os ácidos fenólicos p-cumárico e protocatecuico foram identificados no feijão-caupi (CC), enquanto no feijão-caupi (CT) foram identificados ácidos fenólicos gálico e protocatecuico. Esses fenólicos ratificam o feijão-caupi como um alimento funcional e bioativo, garantindo uma dieta saudável.
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 1H and 13C (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.