Tamizaje fitoquímico y actividad antibacteriana in vitro de extractos y fracciones de tres especies colombianas del género Hypericum / Phytochemical screening and in vitro antibacterial activity of extracts and fractions from three Colombian species of the genus Hypericum

RESUMEN

Introducción: el género Hypericum se caracteriza por poseer gran importancia etnobotánica en diferentes culturas a nivel mundial lo cual ha impulsado los estudios para el aislamiento e identificación de metabolitos bioactivos. Objetivo: realizar la caracterización fitoquímica preliminar y el estudio de actividad antibacteriana in vitro de extractos y fracciones de tres especies colombianas del género Hypericum. Métodos: a partir de las hojas secas de Hypericum myricariifolium Hieron, Hypericum mexicanum L. e Hypericum juniperinum Kunth se obtuvieron los extractos etanólicos, se realizó el tamizaje fitoquímico preliminar y se obtuvieron fracciones de polaridad creciente (hexano, cloroformo, acetato de etilo y metanol). Se evaluó la actividad antibacteriana in vitro de extractos y fracciones por el ensayo de difusión en agar frente a Staphylococcus aureus (ATCC 29213), Staphylococcus epidermidis (ATCC 1228) y Escherichia coli (ATCC 8739). A las fracciones y extractos que presentaron mayor inhibición del crecimiento bacteriano se les determinó la CMI por el método de dilución en micropozos (SPOTi). Resultados: el análisis fitoquímico preliminar mostró la posible presencia de esteroides, terpenos, fenoles, flavonoides y quinonas. Los extractos y fracciones de H. mexicanum y H. myricariifolium resultaron activos frente...(AU)

ABSTRACT

Introduction: The genus Hypericum has been awarded great ethnobotanical importance by various cultures worldwide, which has given an impulse to the conduct of studies aimed at isolating and identifying its bioactive metabolites. Objective: Perform a preliminary phytochemical characterization and study the antibacterial activity in vitro of extracts and fractions from three Colombian species of the genus Hypericum. Methods: Ethanolic extracts were obtained from dry leaves of Hypericum myricariifolium Hieron, Hypericum mexicanum L. and Hypericum juniperinum Kunth. Preliminary phytochemical screening was performed and increasing polarity fractions were obtained (hexane, chloroform, ethyl acetate and methanol). In vitro antibacterial activity of the extracts and fractions was evaluated with the agar diffusion test against Staphylococcus aureus (ATCC 29213), Staphylococcus epidermidis (ATCC 1228) and Escherichia coli (ATCC 8739). The MIC was determined for fractions and extracts displaying greater bacterial growth inhibition, using the microwell dilution method (SPOTi). Results: Preliminary phytochemical analysis showed the possible presence of steroids, terpenes, phenols, flavonoids and quinones. Extracts and fractions of H. mexicanum and H. myricariifolium were active against all strains with inhibition haloes above 15 mm. The extract of H. juniperinum was active against gram-positive strains. The total extract and the hexane fraction of H. mexicanum displayed the best activity against S. epidermidis with an MIC of 0.05 mg/mL and 0.001 mg/mL, respectively. Conclusions: Preliminary phytochemical characterization revealed the prevailing presence of phenolic metabolites in extracts of the three study species. Ethanolic extracts and low polarity fractions of these species exhibit high inhibitory activity against gram-positive bacteria (S. aureus and S. epidermidis) responsible for a large number of skin infections(AU)