Actividad antimicobacteriana in vitro de Gaillardia cabrerae y G. megapotamica var. scabiosioides (Asteraceae)

Abstract

Se ensayó la actividad antimicobacteriana in vitro de los extractos diclorometánico (DCM) y metanólico (MeOH) de G. cabrerae y G. megapotamica var. scabiosoides frente a dos cepas de Mycobacterium tuberculosis (H37Rv y MDR), por medio del test colorimétrico TEMA, determinándose la concentración inhibitoria minima (MIC) en ug extracto/ml. Los extractos DCM de ambas especies de Gaillardia y el extracto MeOH de G. cabrerae exhibieron actividad antimicobacteriana frente a ambas cepas con MICs de 50-100 ug/ml. Dos de las fracciones obtenidas a partir del extracto metanólico de G. cabrerae presentaron actividad antimicobacteriana. El screening fitoquímico de las fracciones activas reveló la presencia de sesquiterpenlactonas, flavonoides glicosilados y sus aglicones como componentes mayoritarios.

Dichloromethane and methanol extracts from two argentine species of Gaillardia (Asteraceae): G. cabrerae Covas and G. megapotamica (Spreng.) Baker var. scabiosoides (Arn. ex DC.) Baker were assayed for their in vitro activity against two strains of Mycobacterium tuberculosis (H37Rv y MDR) by means of the TEMA colorimetric test. The minimum inhibitory concentration (MIC) in ug/ml was determinate. Dichloromethane extracts of both Gaillardia spp. and methanol extract of Gaillardia cabrerae exhibited antimycobacterial activity against both strains with a MIC range 50-100 ug/ml. The methanol extract of G. cabrerae was fractionated and two fractions were active. Phytochemical screening of the active fractions showed the presence of sesquiterpene lactones, aglycones and glycosilated flavonoids as main compounds.