Caracterización fitoquímica y actividad antibacteriana del extracto orgánico de Lonchocarpus parviflorus frente a Escherichia coli y Staphylococcus aureus, patógenos de importancia clínica

Abstract

The objective of the present investigation was to analyze the antibacterial potential of the aqueous fraction of the organic extract methanol/dichloromethane (1:1) of Lonchocarpus parviflorus, an unexplored plant species of the Fabaceae family. Its effect on reference pathogenic bacterial strains Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 8739 was evaluated. The collection of this species was carried out in the Cerro Blanco tropical dry forest located in the city of Guayaquil-Ecuador. The process for obtaining the aqueous fraction of the organic extract was carried out in the chemical synthesis and characterization laboratories of ESPOL, where the leaves were dried in an oven, pulverized in an electric mill, and subjected to a non-conventional extraction method, followed by freeze-drying. The fraction underwent phytochemical screening, which included 13 qualitative tests for secondary metabolites. The results revealed the minimal presence of compounds such as alkaloids and coumarins. Antibacterial activity was evaluated in vitro at a concentration of 47,800 µg/mL, using the microdilution assay to determine the Minimum Inhibitory Concentration (MIC). However, the aqueous fraction of the leaves did not show significant antibacterial activity against strains of clinical interest used in the study at the concentration evaluated. This study represents the first evaluation of the antibacterial potential of the aqueous fraction of the organic extract of L. parviflorus leaves at this concentration.